WO2015034357A1

WO2015034357A1 - Paint composition comprising a polyelectrolyte complex

Info

Publication number: WO2015034357A1
Application number: PCT/NL2014/050605
Authority: WO
Inventors: Wilhelmus Maria Van Der Krieken; Wilhelmus Johannes Antonius MEULEMEESTERS; Christiaan Gerardus Johannes Maria Jans
Original assignee: Ceradis B.V.
Priority date: 2013-09-04
Filing date: 2014-09-04
Publication date: 2015-03-12

Abstract

The invention relates to a paint composition comprising a pigment and a polyelectrolyte complex of a polyanion and a polycation. The invention further relates to methods for producing the paint composition, to methods for producing a painted object by application of the paint composition, to the use of the paint composition, and to a painted object comprising a pigment and a polyelectrolyte complex.

Description

TITLE: Paint composition comprising a polyelectrolyte complex FIELD

The present invention relates to a paint composition comprising a pigment and a polyelectrolyte complex of a polyanion and a polycation, preferably further incorporating an antimicrobial agent.

INTRODUCTION

A paint composition typically contains four essential ingredients: carrier liquid, binder, pigment, and additives.

Pigments provide the paint with both decorative and protective features. Pigments are solid particles used to provide the paint with various qualities, including but not limited to color, opacity, and durability. The paint may also contain other solid particles such as polyurethane beads. Pigments and other solids add bulk to the paint and their levels are related to the gloss or flatness of the paint.

Additives are typically used at relatively low levels in the paint formulation, but contribute to various properties of paints, including rheology, stability, paint performance, and application quality.

Antimicrobial agents are additives which work to eliminate microorganisms such as bacteria, algea and fungi. A variety of antimicrobial agents are known and are used for various purposes, Such antimicrobial agents include inorganic agents, for example, those containing metal ions, such as silver, zinc, and copper. There are also organic biocides including organic acids, phenols, alcohols, polyene macrolides, and quaternary ammonium compounds.

Attack of microorganisms such as fungi and algae, either in a wet paint composition or after the application of the paint composition, can destroy the protective and/or decorative funtions of a paint. In addition, development of especially moulds in buildings such as homes increases the risk of health problems such as asthma, respiratory symptoms and airway infections. Paint films can be made fungi- algae- and bacteria-free by incorporating a suitable antimicrobial agent in the paint formulation. Reduction in antimicrobial activity of a paint film is mostly attributed to factors such as degradation of of the antimicrobial agent and dissipation of the antimicrobial agent from paint film due to washing out and/or volatilization from the paint film. The life of a paint film will be enhanced if the antimicrobial agent is retained in the film and on the film surface for a longer period of time.

This extended duration of biocidal activity can be achieved by incorporating the antimicrobial agent in a polyelectrolyte complex of a polyanion and a polycation.

SUMMARY OF THE INVENTION

The invention provides a paint composition comprising a pigment and a

polyelectrolyte complex of a polyanion and a polycation. The polyanion and the polycation are present in a relative amount of between 1:2 and 60: 1 (w/w). The polyelectrolyte complex has preferably further incorporated at least one

antimicrobial agent.

A polyelectrolyte complex of a polyanion and a polycation is an irreversible and insoluble complex. The polyelectrolyte complex has sticky properties and contains polar parts (charged) and apolar parts. The aromatic moieties in the complex may have affinity for pigments and/or for antimicrobial agents. In combination with the sticky character of the polyelectrolyte complex, the pigment and/or antimicrobial agent will be optimally deposited and adhered to a product.

It was surprisingly found that said complex, having incorporated at least one antimicrobial agent, dramatically improved the protective effect of antimicrobial agents such as chlorothalonil against fungi, in comparison with an antimicrobial agent without said polyelectrolyte complex. Without being bound by theory, said polyelectrolyte complex may provide improved, longer lasting, adherence of the antimicrobial agent to the painted object and/or the adherence to the microbe. The polyanion is preferably selected from the group consisting of a natural polyanion such as xanthan gum, alginate, a lignin compound such as hgnosulfonate, pectin, carrageenan, humate, fulvate, angico gum, gum Kondagogu, sodium alkyl naphtalene sulfonate (Morwet), poly-y-glutamic acid, maleic starch half-ester, carboxymethyl cellulose, chondroitin sulphate, dextran sulphate, hyaluronic acid and a synthetic polyanion such as poly(acrylic acid), polyphosphoric acid, and poly(L-lactide). A most preferred polyanion is a lignin compound such as

Hgnosulfonate. The polycation is preferably selected from the group consisting of poly-L-lysine, epsilon-poly-L-lysine, poly-L-arginine, poly-allylamine, chitosan oligosaccharide, and chitosan. A most preferred polycation is chitosan.

The at least one antimicrobial agent preferably is or comprises a copper salt, zinc pyrithione, a formaldehyde, 3-iodopropargyl-n-butylcarbamate (IPBC), 2-n-octyl-4- isothiazohn-3-one (OIT), 4,5-dichloro-2-(n-octyl)-4-isothiazohn-3-one (DCOIT), carbendazim (CBZ), chlorothalonil (CTL; CAS: 1897-45-6), and/or n-butyl-1,2- benzisothiazolin-3-one, and/or a polyene fungicide such as natamcyin. A most preferred antimicrobial agent is chlorothalonil (CTL; CAS: 1897-45-6).

A preferred paint composition according to the invention further comprises a carrier liquid and a binder.

The invention additionally provides a method for producing a paint composition comprising a pigment and a polyelectrolyte complex of a polyanion and a polycation, the method comprising a) providing an aqueous solution of a polyanion, wherein the concentration of said polyanion is from 0.1-60 w/v%, b) providing a polycation, c) mixing the polycation with the polyanion solution, thereby forming a precipitate, d) crushing the formed precipitate to form a suspension, and e) adding the suspension to a pigment. It is preferred that at least one antimicrobial agent is added prior to the addition of the suspension to a pigment.

The invention further provides a method for producing a painted object, comprising a) applying a composition comprising a pigment and a poly electrolyte complex of a polyanion and a polycation whereby the polyanion and the polycation are present in a relative amount of between 1:2 and 60: 1 (w/w) to a object; and b) drying the applied comprosition, thereby producing a painted object.

The invention further provides a use of a paint composition comprising a pigment and a polyelectrolyte complex of a polyanion and a polycation, whereby the polyanion and the polycation are present in a relative amount of between 1:2 and 60: 1 (w/w), for painting of a object. Said paint composition preferably comprises at least one antimicrobial agent. Said use preferably is for preventing, reducing and/or eliminating the presence of pathogenic moulds such as Stachybotrys chartarum.

The invention further provides a painted object comprising a pigment and a polyelectrolyte complex of a polyanion and a polycation, whereby the polyanion and the polycation are present in a relative amount of between 1:2 and 60: 1 (w/w).

DETAILED DESCRIPTION

The present invention provides a paint composition comprising a pigment and a poly electrolyte complex of a polyanion and a polycation, whereby the polyanion and the polycation are present in a relative amount of between 1:2 and 60: 1 (w/w). Said composition preferably further comprises a carrier liquid, binder, and additives. Each of these ingredients may comprise a single component or several different components that are mixed into the composition. At least one antimicrobial agent is preferably incorporated into the polyelectrolyte complex.

The term "polyelectrolyte" refers to a molecule consisting of a plurality of charged groups that are linked to a common backbone. In the context of this application, the term "polycation" is interchangeable with the term "positively charged

polyelectrolyte" and the term "polyanion" is interchangeable with the term

"negatively charged polyelectrolyte".

The term "polyelectrolyte complex" refers to a complex of oppositely charged polyelectrolytes (a polyanion and a polycation) which form strong electrostatic links, thus avoiding the use of covalent cross-linkers. The complex is not soluble. In a watery solution at a pH of about 4.5, polycations such as chitosan polymers are positively charged and the cationic amino groups on the glucosamine subunits can interact electrostatically with anionic groups (usually sulfonic acid groups) of poly anions such as lignosulfonate to form polyelectrolyte complexes.

Said polyanion is preferably one or more polymers selected from the group

consisting of a natural polyanion such as xanthan gum, alginate, a lignin compound such as lignosulfonate, pectin, carrageenan, humate, fulvate, angico gum, gum Kondagogu, sodium alkyl naphtalene sulfonate (Morwet), poly-y-glutamic acid, maleic starch half-ester, carboxymethyl cellulose, chondroitin sulphate, dextran sulphate, hyaluronic acid and a synthetic polyanion such as poly(acrylic acid), polyphosphoric acid, and poly(L-lactide).

Preferably, said polyanion is selected from the group consisting of xanthan gum, alginate, humate and lignosulfonate. A most preferred polyanion is or comprises a lignin compound such as lignosulfonate. Said polyanion may comprise two or more distinct polyanions such as, for example, xanthan gum and a lignin compound such as lignosulfonate or pectin and a lignin compound such as lignosulfonate. The term "lignin compound" refers to a compound that is derived from naturally occurring lignin or lignen by a process that includes sulphonation. The resulting sulfonic acids are strong acids and lignin compounds are therefore negatively charged at pH values below 7. A preferred lignin compound is selected from Kraft lignin, organosolv lignin and/or lignosulfonate.

A Kraft lignin is a polyphenolic product from the Kraft pulping process for the conversion of wood into wood pulp. Included are derivatives from Kraft lignin obtained by oxidation or other chemical modification as is known to the skilled person.

An organosolv lignin is a polyphenolic product from delignification processes using organic solvents. Included are derivatives from organosolv lignin obtained by oxidation or other chemical modification as is known to the skilled person.

Lignosulfonate (also termed lignosulphonate, lignosulfate, lignin sulfonate, ligninsulfonate, ligninsulfonic acid, lignosulfonic acid, lignosulfuric acid, or LST 7) is a water-soluble anionic polymer which is, for example, formed as a by-product in the sulphite pulping process. Lignosulfonates generally have a wide molecular weight distribution, typically in the range of about 500 to about 150,000.

Lignosulfonates may comprise different metal or ammonium ions as counter cations of the sulfonate groups such as, for example, copper, zinc, calcium, sodium, potassium, magnesium and aluminium. Suitable examples of lignosulfonates comprise sodium lignosulfonate (e.g. sold as BORRESPERSE NA®, Borregaard LignoTech Ltd, Germany), calcium lignosulfonate (e.g. sold as BORRESPERSE CA®, Borregaard LignoTech Ltd, Germany), ammonium lignosulfonate, potassium lignosulfonate, modified lignosulfonate, derivatives of lignosulfonate, or mixtures thereof. Modified lignosulfonates, and derivatives of lignosulfonates are described in U.S. Patent Nos.: 3639263, 3923532, 4006779, 4017475, 4019995, 4069217,

4088640, 4133385, 4181652, 4186242, 4196777, 4219471, 4236579, 4249606, 4250088, 4267886, 4269270, 4293342 4336189, 4344487, 4594168, 4666522,

4786438, 5032164, 5075402, 5286412, 5401718, 5446133, 5981433, 6420602, and 7238645, which are incorporated herein by reference.

A preferred lignin compound is lignosulfonate. A preferred lignosulfonate is copper, zinc, calcium, sodium, potassium, ammonium, magnesium and/or aluminium lignosulfonate, preferably calcium, sodium, potassium or ammonium lignosulfonate, most preferred calcium lignosulfonate.

A most preferred polyanion is a lignin compound such as lignosulfonate, most preferred calcium lignosulfonate.

Said polycation is preferably one or more polymers selected from the group consisting of poly-L-lysine, epsilon-poly-L-lysine, poly-L-arginine, poly-allylamine, chitosan oligosaccharide, and chitosan. Most preferably, said polycation comprises or is chitosan.

As used herein, the term "chitosan" refers to a linear polysaccharide composed of randomly distributed 6-(l-4)-linked D-glucosamine (deacetylated unit) and N-acetyl- D-glucosamine (acetylated unit). Chitosan is produced by deacetylation of chitin. The term "chitosan" relates to chitosan, chitosan derivatives and mixtures of chitosan and chitosan derivatives.

The term chitosan relates to linear p-(l→4)-linked glucosamin and N- acetylglucosamin. It may be produced from chitin or its sodium salt (e.g. originating from shrimp) by treatment with aqueous sodium hydroxide at elevated

temperatures, or by enzymatic treatment with, for example, a chitin deacetylase (EC 3.5.1.41). Further sources of chitin are fungi, including Basidiomycetes, Ascomycetes, and Phycomycetes, where it is a component of cell walls and structural membranes of mycelia, stalks, and spores. A most preferred chitosan is from fungi or derived from fungi. Typically, deacetylation as determined by colloidal titration is from 50 to 99.9 %, preferably from 70 to 99.8 % and most preferably from 90 to 99.7 %, as compared to chitin. Chitosan derivatives can be prepared by reactions at the amino group (e.g. by N-acylation, formation of N-alkylidene and N-arylidene derivatives, N-alkylation and N-arylation) or at hydroxy groups, as is known to the skilled person.

It was found that a polyanion, for example a lignin compound such as

lignosulfonate, forms a stable, insoluble polyelectrolyte complex with a polycation such as chitosan. Pigments are solid particles used to provide the paint composition with various qualities, including but not limited to color, opacity, and durability. The paint composition may also contain other solid particles such as polyurethane beads or other solids. The term pigment, as used herein, refers to both pigments and dyes. Preferred pigments comprise one or more of a nitroso compound, a nitro compound, a monoazo compound, a diazo compound, a stilbene compound, a diarylmethane compound, a triarylmethane compound, a xanthene compound, an acridine compound, a quinoline compound, a methine compound, a thiazole compound, an indamine compound, an indophenol compound, an azine compound, an oxazine compound, a thiazine compound, an aminoketone, an anthraquinone, an indigoid compound, a phthalocyanine, a natural dye, and/or an inorganic pigment, such as titanium dioxide, aluminum silicate, chromium oxide, zirconium oxide and/or manganese oxide.

Said paint composition preferably comprises between about 0.1 - 60 % (w/w) of one or more pigments, preferably between about 0.5 -50 % (w/w), preferably between about 1 - 40 % (w/w), preferably between about 5 - 30 % (w/w), preferably between about 10-25 % (w/w), preferably between about 20 - 25 % (w/w) of one or more pigments. A preferred composition according to the invention further comprises at least one antimicrobial agent.

The term "antimicrobial agent", as is used herein, refers to a natural or chemical substance capable of inhibiting and/or eliminating the growth of microorganisms or their spores. Said antimicrobial agent is preferably an antifungal, antibacterial or antialgea compound, or a compound having a broad spectrum of activity against fungi and/or bacteria and/or algeae. A most preferred antimicrobial agent inhibits the growth of algae and fungi such as Stachybotrys chartarum, Cladosporium sphaerospermum, Aspergillus versicolor, Aspergillus glaucus, Penicillium

chrysogenum, Penicillium aurantiogriseum, Penicillium spinulosum, Penicillium brevicompactum, Chaetomium globosum, Stachybotrys chartarum, Acremonium strictum, Alternaria alternate, Aureobasidium pullulans, Phoma sp and Fusarium species on the surface of the paint after it has been applied.

An antimicrobial agent of the present invention preferably is one or more of an inorganic, organometallic and metal-organic or organic antimicrobial agents.

Examples of inorganic antimicrobial agents include copper salts such as copper oxide, copper thiocyanate, copper bronze, copper carbonate, copper chloride, copper hydroxide (Cu(OH)2 ), copper oxychloride (CuC12 · 3Cu(OH)2), Bordeaux mixture (CuS04.3Cu(OH)2.3CaS04), copper nickel alloys, and silver salts such as silver chloride or nitrate.

Examples of organometallic and metal-organic antimicrobial agents include zinc pyrithione (the zinc salt of 2-pyridinethiol-l -oxide), copper pyrithione, bis (N- cyclohexyl-diazenium dioxy) copper, zinc ethylene-bis(dithiocarbamate) (i.e. zineb), zinc dimethyl dithiocarbamate (ziram), and manganese ethylene- bis(dithiocarbamate) complexed with zinc salt (i.e. mancozeb). Examples of organic antimicrobial agents include formaldehyde, , 3-iodopropargyl- n-butylcarbamate (IPBC), 2-n-octyl-4-isothiazolin-3-one (OIT), 4,5-dichloro-2-(n- octyl)-4-isothiazohn-3-one (DCOIT), carbendazim (CBZ), chlorothalonil (CTL; CAS: 1897-45-6), n-butyl-l,2-benzisothiazolin-3-one, dodecylguanidine

monohydrochloride, thiabendazole, N-trihalomethyl thiophthalimides,

trihalomethyl thiosulphamides, N-aryl maleimides such as N-(2,4,6-trichlorophenyl) maleimide, 3-(3,4-dichlorophenyl)-l , 1 -dimethylurea (diuron), 2,3,5,6-tetrachloro-4- (methylsulphonyl) pyridine, 2-methylthio-4-butylamino-6-cyclopopylamino-s- triazine, 3-benzo[b]thien-yl-5,6-dihydro-l ,4,2-oxathiazine 4-oxide, 4,5-dichloro-2-(n- octyl)-3(2H)-isothiazolone, 2,4,5,6-tetrachloroisophthalonitrile, tolylfluanid, dichlofluanid, diiodomethyl-p-tosylsulphone, capsciacin, N-cyclopropyl-N'-(l , 1 - dimethylethyl)-6-(methylthio)- 1 ,3,5-triazine-2,4-diannine, 3-iodo-2-propynylbutyl carbamate, medetomidine, 1 ,4-dithiaanthraquinone-2,3-dicarbonitrile (dithianon), boranes such as pyridine triphenylborane, a phthalimide fungicide such as

3aR,7aS)-2-[(trichloromethyl)sulfanyl]-3a,4,7,7a-tetrahydro-lH-isoindole-l,3(2H)- dione, orange oil, limonene, 3-chloor-N-[3-chloor-2,6-dinitro-4-(trifluormethyl)fenyl]- 5-(trifluormethyl)-2-pyridinamine, a conazole fungicide such as, for example, (RS)-l- (6-allyloxy-2,4-dichlorophenethyl)imidazole (imazalil; Janssen Pharmaceutica NV, Belgium) and N-propyl-N-[2-(2,4,6-trichlorophenoxy)ethyl] imidazole- 1-carboxamide (prochloraz), a polyene fungicide such as natamycin and quaternary ammonium salts such as didecyldimethylammonium chloride and an

alkyldim ethylb enzylamm onium chloride .

The term "polyene fungicide", as used herein, refers to polyene macrolide

antimicrobial agent that possess antifungal activity, including natamycin, lucensomycin, filipin, nystatin or amphotericin B, most preferred natamycin.

Derivatives of a polyene fungicide, such as derivatives of natamycin, are also included. A preferred derivative is a salt or a solvate of a polyene fungicide and/or a modified form of a polyene fungicide such as e.g. differently shaped crystal forms such as the needle-shaped crystal of natamycin described in US7727966. The effective amount of an antimicrobial agent depends on the type of antimicrobial agent and the object to which the antimicrobial agent is added. Thus, the required concentration may differ depending on the efficacy of the individual antimicrobial agent, as is well known to the person skilled in the art. Preferred concentrations are between 1 and 20.000 ppm, more preferred between 50 and 10.000 ppm, most preferred between 500 and 2000 ppm.

The at least one antimicrobial agent preferably is or comprises a fungicide, preferably a copper salt, zinc pyrithione, a formaldehyde, 3-iodopropargyl-n- butylcarbamate (IPBC), 2-n-octyl-4-isothiazolin-3-one (OIT), 4,5-dichloro-2-(n-octyl)- 4-isothiazolin-3-one (DCOIT), carbendazim (CBZ), chlorothalonil (CTL; CAS: 1897- 45-6), and/or n-butyl-l,2-benzisothiazolin-3-one.

A paint composition according to the invention preferably further comprises a carrier liquid and a binder. Each of such ingredients may comprise a single component or several different components that are mixed into the paint

composition.

Said carrier liquid is a fluid component of the paint and serves to carry all of the other paint components. The carrier liquid provides the means of "carrying" the pigment and binder in a consistency such that it can be conveniently stored and applied to the surface that is painted. The carrier liquid is part of the wet paint and usually evaporates as the paint forms a film and dries on a surface. Said carrier liquid is usually water in latex paints such as acrylic paints, vinylic paints and polyvinyl acetate paints. The carrier liquid is usually an organic solvent such as linseed oil, petroleum distillate, alcohols, ketones, esters, and/or glycol ethers in oil- based paints such as alkyd paints. The amount and type of liquid is usually determined by features of the other paint components.

A binder of a paint composition causes the paint to form a film on and adhere to a surface. In a latex paint, the binder comprises a latex resin, usually selected from acrylics, vinyl acrylics, or styrene acrylics. The latex resin particles usually are dispersed in water as the carrier liquid. A binder in an oil-based paint is either natural, synthetic or a combination thereof. A natural binder in an oil-based paint is preferably made from a vegetable oil such as linseed oil, tung oil and soya oil, which oxidizes and hardens upon drying. A synthetic binder in an oil-based paint is preferably based on modified oils called alkyds.

Further additives in a paint composition according to the invention comprise defoamers, which break bubbles that are formed in paint during handling, thickeners and rheology modifiers which provide consistency and viscosity and improve the leveling and resistance to spattering, fillers such as calcium carbonate and hydrated magnesium silicate (talc), setting salts such as cobalt octoate, UV stabilizers, and surfactants, which stabilize the paint composition so that the components will not separate.

The invention further provides a method for producing a paint composition comprising a pigment and a polyelectrolyte complex of a polyanion and a polycation, the method comprising a) providing an aqueous solution of a polyanion, wherein the concentration of said polyanion is from 0.1-60 w/v%, preferably 1-50%, preferably about 25%, b) providing a polycation, c) mixing the polycation with the polyanion solution such that the polyanion and the polycation are present in a relative amount of between 1:2 and 60: 1 (w/w), thereby forming a precipitate, d) crushing the formed precipitate to form an suspension, and e) adding the suspension to a pigment.

The method preferably comprises a) providing an aqueous solution of a polyanion, wherein the concentration of said polyanion is from 0.1-60 w/v%, preferably 1-50%, preferably about 25%, b) providing an aqueous acidic solution of a polycation, wherein the concentration of said polycation is from 0.1-30 w/v%, preferably 1-10%, preferably about 5%, and the pH is below pH=5,5, c) adding the polyanion solution to the polycation solution, or vice versa, thereby forming a precipitate, d) crushing the formed precipitate to form an suspension, and e) adding the suspension to a pigment. The terms "polyanion", "polycation", "poly electrolyte complex", and "pigment" are used in a method of the invention as defined herein before.

An aqueous solution of a polyanion, such as a lignin compound, is preferably prepared by dissolving the polyanion, such as a lignin compound, preferably lignosulfonate, in an aqueous solution, preferably water.

An aqueous solution of a polycation, preferably chitosan, is preferably prepared by solubilizing the polycation in an aqueous acidic solution comprising an acid such as, for example, lactate, hydrochloric acid, phosphorous acid and/or ascorbic acid. The amount of acid that is required to solubilize the polycation, preferably chitosan, depends on the polycation, as is known to the skilled person. For example, for solubilizing chitosan, in general, about 6 ml 37% HC1 is required to obtain a solution of 10 gram chitosan in 1 liter in water. As an alternative, a polycation, preferably chitosan, is dissolved in an aqueous solution, preferably water, for example by gently shaking at 20-23 °C overnight, whereby a salt, preferably NaCl, is preferably added to the aqueous solution at a concentration between 1 mM and 1 M, preferably about 100 mM. A polyanion solution, preferably a lignosulfonate, xanthan gum, humate, or alginate solution, is preferably added drop wise to the solution comprising a polycation, preferably a chitosan compound. If required, the pH is kept between pH 1 and pH 5.5 by the addition of an acid, preferably hydrochloric acid, lactic acid, ascorbic acid, phosphorous acid, nonanoic acid or acetic acid. The pH is more preferably kept between pH 2.0 and pH 5.0, more preferably between pH 3.0 and pH 4.5 during the formation of a poly electrolyte complex. The temperature is preferably between 0 °C and 100 °C, more preferred between 10 °C and 60 °C, more preferred ambient temperature (15-25 °C). The resulting mixture is preferably stirred during formation of the poly electrolyte complex and the poly electrolyte complex is preferably allowed to settle overnight. Following settlement of the poly-electrolyte complex, a dispersing agent and/or a wetting agent is preferably added and the precipitate is crushed, preferably by milling for example in a bead mill, to provide a suspension comprising the polyelectrolyte complex of a polyanion and a polycation.

Said suspension is either generated in an aequeous solution, preferably water, for latex paints such as acrylic paints, vinylic paints and polyvinyl acetate paints, or in an organic solvent such as linseed oil, petroleum distillate, alcohols, ketones, esters, and/or glycol ethers for oil-based paints such as alkyd paints.

Said dispersing agent, when present, is preferably one or more compounds selected from lignin sulphonate, a carboxyl-containing polymer such as polyacrylate and/or carboxyl-containing polyurethanes, a styrene acrylic polymer, an acrylic co-polymer, polyurethane, an alkylpolysaccharide, salts of aliphatic rosin and naphthenic acid, condensation products of formaldehyde of low molecular weight and naphthene sulfonic acid, higher alkyl sulfate such as sodium lauryl sulfate, alkyl aryl sulfonate such as dodecylbenzene sulfonate, sodium salt or potassium salt of isopropyl benzenesulfonic acid or isopropyl naphthalenesulfonic acid, sulfosuccinates such as sodium dioctyl sulfosuccinate, alkaline metal salt of higher alkyl sulfosuccinic acid such as sodium octyl sulfosuccinate, sodium N-methyl-N-palmitoyltaurate, sodium oleylisethionate (SIC), alkaline metal salts of alkyl aryl polyethoxyethanol sulfuric acid or sulfonic acid such as sodium t-octylphenoxy polyethoxyethanol sulfate having 1 - 5 oxyethylene units, and ethoxylated tristyrenephenol phosphate, for example poly ethoxylated fosforic acid. Typical dispersing agents are l-(2- aminoethyl)piperazine, 2-amino-6-methoxybenzothiazole, 4-(2-aminoethyl)pyridine, 4-(aminomethyl)pyridine, 3-amino-l,2,4-triazole, l-(3-aminopropyl)imidazole, 4-(2- hydroxyethyl)pyridine and l-(2-hydroxyethyl)imidazole. A disperging agent is preferably present in an amount of between 0 to up to 10% (w/v), more preferred between 0.01 to up to 5 % (w/v), more preferred between 0.02 to up to 1 % (w/v), more preferred about 0.05 % (w/v). Said wetting agent, when present, is preferably one or more compounds selected from di-octylsuccinate, polyoxyethylene/polypropylene and tri-stearyl

sulphonate/phosphate. A typical wetting agent is ethoxylated alkanol (e.g. the product with CAS RN=68439-45-2). A wetting agent is preferably present in an amount of between 0 to up to 10% (w/v), more preferred between 0.01 to up to 5 % (w/v), more preferred between 0.02 to up to 1 % (w/v), more preferred about 0.05 % (w/v).

The relative amount of a polyanion and a polycation that are combined in step c) of a method according to the invention is between 1:2 and 60: 1 (w/w), preferably between 2:1 and 30: 1 (w/w), more preferred between about 5: 1 and about 15: 1 (w/w), even more preferred about 5: 1. If required, an acid is added to the polycation- polyanion mixture to keep the pH of the mixture below pH=7, preferably below pH=5.5 in step c) of a method according to the invention. The final pH value of the resulting suspension comprising at least one antimicrobial agent may be adjusted to a pH value of between 3-12, more preferred between 4-9, most preferred between pH 5-8.

It is further preferred that least one antimicrobial agent is added prior to the addition of the suspension comprising a polyelectrolyte complex to a pigment. Said least one antimicrobial agent is as defined herein above. Without being bound by theory, said polyelectrolyte complex provides improved, longer lasting, adherence of the antimicrobial agent to a painted object and/or adherence to a microbe.

A composition comprising a pigment and a polyelectrolyte complex can be provided as a ready-for-use product or as a concentrate. The ready-for-use product may be in the form of an aqueous solution, suspension, aqueous dispersion, oil solution, oil dispersion, or an aerosol preparation. The concentrate can be used, for example, as an additive for coating, or can be diluted prior to use with additional solvents or suspending agents.

The invention further provides a method for producing a painted object, comprising a) applying a composition comprising a pigment and a polyelectrolyte complex of a polyanion and a polycation whereby the polyanion and the polycation are present in a relative amount of between 1:2 and 60: 1 (w/w) to a object; and b) drying the applied comprosition, thereby producing a painted object.

The composition comprising a pigment and a polyelectrolyte complex can be added directly to a object according to any method known in the art, such as spraying the composition on a object, dipping or immersing a object in the composition, or brushing or rolling the composition onto a object.

Said object may be any object composed of any material.

Most preferred materials are materials applied in building constructions such as houses and include but are not limited to wall materials / materials applied in building constructions such as e.g. gypsum, plaster, stones, cement, concrete, wood, resins, wallpaper and materials applied in kits.

Other materials include glass, plastic, metal, porcelain and other ceramics and/or wood. It is preferred that the surface of the material is cleaned to remove dirt and grease, prior to application of a paint composition according to the invention. In addition, the surface may be roughened, if required, as is known to a person skilled in the art, prior to application of a paint composition according to the invention. Furthermore, a primer might be applied to ensure better adhesion of paint to the surface.

Preferred glass objects include, but are not limited to, mirrors, tabletops, vases and windowpanes. Preferred metal objects include, but are not limited to, appliances, barbecue grills, bicycles, fences, file cabinets, fireplace screens, hardware, light fixtures, radiators, buckets and cans.

Preferred plastic objects include, but are not limited to, acrylic, automotive parts, fiberglass, garbage cans, laminates, mini-blinds, outdoor furniture and shutters. Preferred porcelain and ceramic objects include, but are not limited to, brick, bathtubs, flowerpots, lamp bases, servingware, sinks and tiles.

Preferred wooden objects include, but are not limited to, cork, finished and unfinished wooden pieces, MDF, wicker, wood composite.

The invention further provides the use of a paint composition comprising a pigment and a polyelectrolyte complex of a polyanion and a polycation, whereby the poly anion and the polycation are present in a relative amount of between 1:2 and 60: 1 (w/w) for painting of an object.

The invention further provides a painted object comprising a pigment and a polyelectrolyte complex of a polyanion and a polycation, whereby the polyanion and the polycation are present in a relative amount of between 1:2 and 60: 1 (w/w). The paint composition comprising a pigment and a polyelectrolyte complex will form a film on the object that is painted.

A dried paint film comprising an antimicrobial agent, a pigment and a

polyelectrolyte complex is capable of reducing gram positive bacteria, gram negative bacteria, and viruses by greater than 3 logs within 2 hours of application. The bacterial and viral reduction is measured in a test based on the JiS Z 2801 modified for paints as described herein and compared to a control paint that does not contain an antimicrobial agent such as a quaternary ammonium compound.

Examples

Example 1:

10 gram of Chitosan was suspended in 885 mL water, 5 gram 37% HC1 was added to completely dissolve the chitosan. Then 100 gram Calcium-Lignosulfonate was added portion wise to the solution. A milky solution appeared immediately and solids precipitated from the solution. When 40-50 grams of the Ca-LS was added a rise in viscosity was observed and the aqueous solution thickened and the poly electrolyte clearly separated as a solid from the aqueous phase. By addition of the remaining 50 gr Ca-LS the aqueous phase became less viscous. The solid was settled overnight.

The formed precipitate is crushed by milling in the presence of Tamol (SIC), a dispersing agent from Rohm and Haas Company, and Triton, a wetting agent from Union Carbide Corporation (UCC), and in the presence or absence of chlorothalonil (CTL). Titanium oxide is added as a pigment.

The following compositions are generated:

3 wooden plywood boards (9.5cm x 9.5cm) are painted with approximately 2 gram of paint for each of the compositions. The paint is allowed to dry for 4 hours at RT.

The hardness of the paint is evaluated by touching with a finger on the basis of the following criteria.

O: The paint film did not feel tacky.

Δ: The paint film felt slightly tacky.

X: The paint film felt distinctly tacky.

The acid resistance is tested by placing a 40% sulfuric acid aqueous solution (0.2 ml) as a spot on the test sheet, followed by heating to 60°C for 15 minutes, rinsing with water, and visually scoring the extent to which a mark has been produced.

O: Virtually no change to be seen in the paint film.

Δ: A slight water mark was seen.

X: A pronounced water mark was seen.

The weatherability of the paint film is assessed visually after being exposed using standard procedures, scuh as ASTM D1006 / D1006M - 13 for conducting exterior exposure tests of paints on wood. The results show that a combination of Chitosan - Calcium-lignosulfonate complex and cblorothalonil (composition A) improves the acid resistance and weatherability of the paint on the paint surface, compared to the controls.

Example 3

The anti-fungal activity is determined by adding 100 spores of Stachybotrys chartarum produced using well known methods per gram of paint to compositions A-D:

3 wooden plywood boards (9.5cm x 9.5cm) are painted with approximately 2 gram of paint for each of the compositions. The paint is allowed to dry overnight at RT. The painted boards are stored at 25 °C at a humidity of at least 90%. The growth on the painted boards is detected visually by eye, and the number of colonies is counted. The results show that a combination of Chitosan - Calcium-lignosulfonate complex and chlorothalonil (composition A) significantly inhibits the growth of fungi on the paint surface, compared to the controls.

Claims

1. A paint composition comprising a pigment and a poly electrolyte complex of a polyanion and a polycation, whereby the polyanion and the polycation are present in a relative amount of between 1:2 and 60:1 (w/w).

2. The composition according to claim 1, whereby at least one antimicrobial agent is incorporated into the poly electrolyte complex.

3. The composition according to claim 1 or claim2, whereby the polyanion is selected from the group consisting of a polyanion such as xanthan gum, alginate, a lignin compound such as lignosulfonate, pectin, carrageenan, humate, fulvate, angico gum, gum Kondagogu, sodium alkyl naphtalene sulfonate (Morwet), poly-γ- glutamic acid, maleic starch half-ester, carboxymethyl cellulose, chondroitin sulphate, dextran sulphate, hyaluronic acid and a synthetic polyanion such as poly(acrylic acid), polyphosphoric acid, and poly(L-lactide).

4. The composition according to any one of the previous claims, whereby the polyanion is a lignin compound such as lignosulfonate.

5. The composition according to any one of the previous claims, whereby the polycation is selected from the group consisting of poly-L-lysine, epsilon-poly-L- lysine, poly-L-arginine, poly-allylamine, chitosan oligosaccharide, and chitosan.

6. The composition according to any one of the previous claims, whereby the polycation is chitosan.

7. The composition according to any one of claims 2-6, wherein the at least one antimicrobial agent is or comprises a copper salt, zinc pyrithione, formaldehyde, 3- iodopropargyl-n-butylcarbamate (IPBC), 2-n-octyl-4-isothiazolin-3-one (OIT), 4,5- dichloro-2-(n-octyl)-4-isothiazohn-3-one (DCOIT), carbendazim (CBZ), chlorothalonil (CTL; CAS: 1897-45-6), and/or n-butyl-l,2-benzisothiazolin-3-one.

8. The composition according to any one of claims 2-7, wherein the antimicrobial agent is chlorothalonil (CTL; CAS: 1897-45-6).

9. The composition according to any one of the previous claims, further comprising a carrier liquid and a binder.

10. A method for producing a paint composition comprising a pigment and a poly electrolyte complex of a polyanion and a polycation, the method comprising a) providing an aqueous solution of a polyanion, wherein the concentration of said polyanion is from 0.1-60 w/v%,

b) providing a polycation,

c) mixing the polycation with the polyanion solution, thereby forming a precipitate,

d) crushing the formed precipitate to form an suspension, and

e) adding the suspension to a pigment.

11. The method according to claim 10, whereby at least one antimicrobial agent is added prior to the addition of the suspension to a pigment.

12. A method for producing a painted object, comprising

a) applying a composition comprising a pigment and a polyelectrolyte complex of a polyanion and a polycation whereby the polyanion and the polycation are present in a relative amount of between 1:2 and 60: 1 (w/w) to an object; and

b) drying the applied comprosition, thereby producing a painted object.

13. Use of a paint composition comprising a pigment and a polyelectrolyte complex of a polyanion and a polycation, whereby the polyanion and the polycation are present in a relative amount of between 1:2 and 60: 1 (w/w), for painting of a object.

14. Use according to claim 13, whereby the composition further comprises at least one antimicrobial agent, for preventing, reducing and/or ehminating the presence of pathogenic moulds such as Stachybotrys chartarum.

15. A painted object comprising a pigment and a poly electrolyte complex of a polyanion and a polycation, whereby the polyanion and the polycation are present in a relative amount of between 1:2 and 60:1 (w/w).