EP1890535A1

EP1890535A1 - Wax emulsions to increase biocidal properties in paints

Info

Publication number: EP1890535A1
Application number: EP05766763A
Authority: EP
Inventors: Amaro Izquierdo Ramis; Joan Seguer Bonaventura
Original assignee: Laboratorios Miret SA
Current assignee: Laboratorios Miret SA
Priority date: 2005-06-07
Filing date: 2005-06-07
Publication date: 2008-02-27
Also published as: BRPI0520315A2; WO2006131147A1

Abstract

A composition comprising an effective amount of a wax and/or a paraffin in combination with a biocide is disclosed. The composition comprising wax/and or paraffin is added to waterborne paints thereby increasing the efficacy of the biocides. The paint displays an improved blocidal property. Leaching of the biocides from the layer of paint is reduced.

Description

Wax emulsions to increase biocidal properties in paints

Field of the invention.

This invention relates to a composition comprising a biocidal compound to be used in water-borne paints.

More particularly the invention relates to compositions comprising a biocidal compound containing an effective amount of wax or paraffin to improve the efficacy of the water-borne paint compositions,

The prior art

The paints used on jobsites today are a blend of pigments, resins, solvents, and additives. The pigments provide colour and hiding ability and the resins determine the physical properties such as adhesion, abrasion resistance, and exterior durability. Common types of resins found in paint include <?alkyd, acrylic, vinyl, and poly-urethane. Solvents- keep paints in liquid form so they can be applied easily. The solvent may constitute up to 90% of the paint by weight or volume. Solvent-borne (oil- based) paints use hydrocarbons produced from oil as the solvent. Water- borne (latex) paints use water as the main solvent, but usually in combination with one or more other solvents made from hydrocarbons.

Most solvent-borne paints contain hydro-carbon solvents such as stoddard solvent, mineral spirits, and varsol. High performance coatings such as epoxy paints may contain other solvents such as ketones, xylene, or toluene.

Water-borne paints use mostly water as the solvent. Glycols or other solvents are also commonly present in water-borne paints but they typically constitute at most 10% of the total weight. The chemistry of water-borne paints is more diverse and complex than that of solvent-based paints. Generally, a water-borne paint composition is composed of four basic components: binder, aqueous carrier, pigments and additives. The components of the conventional water-borne paint 5 compositions are easily decomposed and the shelf-life of the compositions is usually not very long. Hence, as one of the additives a preservative agent needs to added.

For example, water-borne paints contain many additives such as preservatives and fungicides, surfactants, and solvents.

10 Additives in paints are used to adjust the acidity (pH) of the paint, or add special properties, such as resistance to microorganisms. In water-borne paints there may be small amounts (typically less than 1%) of ammonia, alcohol, glycol ether, and formaldehyde. Most manufacturers have stopped using ammonia and formaldehyde because of the unpleasant odours and

15 potential health effects. The preservatives and fungicides such as methylisothiazolinone currently contained in water-borne paints do not evaporate readily and are only present in very small amounts. if"

Paint components usually enter the body through inhalation of vapour and skin contact with liquid paint. The hydrocarbon solvents used in 20 conventional alkyd paints can produce high vapour concentrations during painting and for several hours afterward. Painters and other workers have complained about eye irritation, the unpleasant odour, and even dizziness and nausea from the use of solvent-borne paints. In areas with poor ventilation, deaths have occurred.

25 Long-term exposure to organic solvents from paint has been shown to cause brain damage in painters. This occupational disease, called Painter's Syndrome, is characterized by mood disturbances and a decrease in learning, motor, and visual abilities. There is also some evidence of increased rates of cancer thought to be related to the hydrocarbon solvent.

Skin contact with solvent-borne paints and the solvents needed to remove paint from the skin can dry out the skin and in some cases lead to long- term skin problems (dermatitis). Contact with water-borne paints can also lead to skin problems because some preservatives are known to cause allergic reactions.

Water-borne paints generally pose less of a hazard than solvent-based paints. The use of a half-mask respirator with dust/mist cartridges is recommended for spraying water-borne paint. In bathrooms and other enclosed areas, a half-mask respirator with organic vapour cartridges and a dust/mist prefilter is recommended.

Water-borne paints are far less harmful to the environment. Conventional paints use solvents which contribute to the formation of smog and ozone in the atmosphere.

Antifouling paints containing biocides are used on ship hulls to prevent organisms from growing on the bottom of boats. Fouling organisms include both animals (e.g. barnacles, molluscs, polychaete worms, encrusting hydroids, bryozoa and sea squirts) and plants (e.g. green, red and brown algae and diatoms). By settling or clinging onto a ship's hull, these fouling organisms can cause higher fuel consumption due to increased drag, and interfere with the performance and durability of the craft. Tributyltin (TBT), known for its highly toxic and endocrine-disrupting properties, has been the biocide most frequently used in antifouling paints over the past three decades. Because of the detrimental impacts of TBT, its use has been restricted - for example, as long ago as 1989 the EU banned its use on sea-going vessels under 25m (mainly recreational craft). Although the input of organotins was reduced in the coastal waters of some countries that implemented the ban, the continued use of these paints elsewhere has resulted in large releases of toxic chemicals into the environment. TBT can be found in seabirds, marine mammals and fish all over the world.

All waterborne paint needs to be preserved against the growth of bacteria and mold in the wet state. For many years, formaldehyde-releasing

^"compounds have been used in latex paint because of their low cost and high efficacy. Formaldehyde releasers are compounds that are synthesized by the condensation of formaldehyde, an amine and eventually a glycol.

For latex paint, these are azoni-adamantane chlorides, oxazolidines and triazines. This reaction is readily reversible as the pH drops. Formaldehyde release of these types of compounds will be low at high pH. In a typical latex paint of pH 9, formaldehyde release would normally be quite low. But since the metabolites of bacteria are acidic, the release of the formaldehyde increases with the degree of bacterial contamination of the paint. This makes predicting free-formaldehyde concentration in a paint difficult. Although these biocides have worked well for many years, the trend has been to move away from preservatives that may release n .formaldehyde. <irι

Another possible manner of preservation is the use of sodium pyrithione. Sodium pyrithione is a water-soluble fungicide used primarily in metalworking fluids. Bacteria can also be controlled with sodium pyrithione, though at a high cost. This cost can be offset if it is also desirable to have a dry film fungicide in the paint, since sodium pyrithione and zinc oxide together provide protection of the paint film against the growth of mildew and algae. Soluble zinc from the zinc oxide will react with sodium pyrithione in a water-based system to produce zinc pyrithione. The rate is influenced by the pH. The higher the pH, the more soluble the zinc oxide becomes, allowing the reaction with sodium pyrithione to proceed faster. This reaction also occurs in latex paint. Since there are many materials in latex paint, the rate of reaction will vary and will be influenced by additional factors other than pH. Adsorption of pyrithione onto the zinc oxide particle can occur and will be influenced by pH as well. Other metals can also react to produce additional salts of pyrithione, but this reaction can be used to an advantage.

Any sodium pyrithione that is not converted to zinc pyrithione will provide good short-term protection of the dry film against mildew. Due to the water solubility of the sodium pyrithione, this protection will not last as long as might be desired. However, the high water solubility will help to kill any mildew that might already be established on the surface before being painted, therefore preventing mildew from growing through the paint film. The pyrithione is the active part of both the sodium and zinc pyrithione molecules. The higher water solubility of sodium pyrithione provides a much higher concentration of pyrithione to kill microorganisms but will wash out of a paint film in a relatively short time. The zinc pyrithione, formed from zinc oxide and sodium pyrithione, will only be soluble at about 8 ppm with a pH of 7.

The solubility is higher above and below pH 7, but is still quite low. This property makes zinc pyrithione₍ a good fungicide for long-term protection of a paint film, but sometimes the short-term efficacy is not always as good as other available fungicides when compared at low concentrations. This is because some of these fungicides have a higher water solubility (160 ppm for iodo propynyl butyl carbamate (IPBC) and 460 ppm for n- octyl-isothiazolone(OIT)). This higher water solubility provides a higher concentration of available fungicide on the paint surface.

This is also the reason why these relatively soluble fungicides perform well the first year of exposure and generally lose significant efficacy after one year with moderate rainfall. Since these fungicides display the higher water solubility, they will wash out of the paint film faster than zinc pyrithione, which provides long-term dry-film preservation. The porosity of the paint film will affect the rate of fungicide leaching from the film. The molds and bacteria that form on dried paint surfaces indoors can contribute to sick-building syndrome, related to an environment where indoor air quality is further compromised by cleaning chemicals, volatile organic chemicals (VOCs) emitted by furnishings, and ozone emitted from facsimile and copying machines. For the truly health-conscious, coatings are now available to treat metal surfaces in houses to prevent the spreading of bacteria, fungi, and mold.

Although biocides are generally used at a level of 1% or less by weight, U.S. paint makers add some 32 million Ib, or $110 million worth, of them annually to the paints they ship to users. Most of the opportunity for biocide suppliers is in preserving dry paint films. About 56% of biocides by volume are soid to keep paint films wholesome looking. Another 27% preserve liquid latex paints, solvent-based paints generally do not require in-can preservation. Antifoulants to preserve marine paints make up the remaining 17% of biocides sold.

The water-borne paint compositions contain perishable materials and must therefore be preserved. These emulsions are mainly preserved with 0,5 - 2% of a formulation which contains between 10-30% of biocides.

The manner of preservation had practical disadvantages, one of these disadvantages that the biocide which has been added to achieve the wanted biocidal effect is leaching from the paint layer, so that the biocidal effect is disappearing with time.

It is the object of the present invention to provide a biocidal composition which is stable and which is capable of providing a biocidal effect to water- borne paint compositions of long duration. Disclosure of the invention.

In accordance with the present invention, there is provided a composition comprising an effective amount of a wax or a paraffin in combination with a biocide.

The addition of such a composition based on wax or paraffin to the water- borne paint increases surprisingly the effectiveness of the biocides. having improved biocidal properties.

According to a preferred embodiment the composition has the following general composition:

water 25 - 80% by weight, paraffin and/or wax 1 - 50% by weight, thickener 1 - 10% by weight, surfactants 0.1 - 5% by weight and biocide 1 - 20% by weight.

According to a more preferred embodiment the composition has the following general composition :

water 25 - 80% by weight, paraffin 10 - 40% by weight, wax 1 - 5 % by weight, thickener 1 - 10% by weight, surfactants 0.1 - 5% by weight, fungicide 1 - 10 % by weight , algaecide 1 - 10 % by weight, preservatives "in can" 0-1 % by weight and antioxidants 0 - 1 % by weight. The composition of the invention contains a wax or a paraffin.

The term wax has traditionally referred to a substance that is secreted by bees (beeswax) and used by them in constructing their honeycombs.

Wax is a generic name for a large range of products consisting of long- chain fatty acids esterified with long-chain fatty alcohols, triterpene alcohols or steroid alcohols. Chemically, a wax may also be an ester of ethylene glycol (ethane 1,2-diol) and two fatty acids, as opposed to a fat which is an ester of glycerin (propane 1,2,3-triol) and three fatty acids. It is a type of lipid.

Waxes generally include the following subgroups:

natural waxes, synthetic waxes, mineral hydrocarbon waxes and petroleum waxes, or paraffin waxes.

Each type of wax is defined according to its properties such as hardness, melting point, viscosity, colors etc. All these properties define the potential applications. In modern terms, wax is an imprecisely defined term generally understood to be a substance with properties similar to beeswax, namely

• plastic (malleable) at normal ambient temperatures,

• a melting point above approximately 45 ⁰C (which differentiates waxes from fats and oils), • a relatively low viscosity when melted (unlike many plastics),

• insoluble in water and

• hydrophobic. Paraffin is a common name for a group of high molecular weight alkane hydrocarbons with the general formula C_nH_2n+2, where n is greater than about 20.

In the United Kingdom and South Africa the fuel known elsewhere as kerosene is called paraffin oil (or just paraffin), and the solid forms of paraffin are called paraffin wax.

For example, straight-chain hydrocarbons with 18 or higher carbons in the molecule are called petroleum wax or paraffin wax, because they are solid at room temperature but become liquid quickly upon heating. On the other hand, straight-chain hydrocarbons with 13 carbons in the molecule is called Liquid Petroleum Wax or Liquid Paraffin Wax because it is also straight-chain hydrocarbon as paraffin wax, although it is liquid at the room temperature.

Paraffin is also a technical name for an alkane in general, but in most cases it refers specifically to a linear, or normal alkane, while branched, or isoalkanes are also called isoparaffins (Latin para+affinis with the meaning here of "lacking affinity", or "lacking reactivity").

Paraffins are mostly found as a white, odorless, tasteless, waxy solid, with a typical melting point between about 47°C and 65°C. They are insoluble in water, but soluble in ether, benzene and certain esters. Paraffins are unaffected by most common chemical reagents, but burn readily.

Food-grade paraffin wax is used in some candies to make them look shiny. Although edible, it is nondigestible; it passes right through the body without being broken down. Non-food grade paraffin wax can contain oils and other impurities which may be toxic or harmful.

Paraffin wax is not used much to make original models for casting, as it is relatively brittle at room temperature and usually cannot be cold-carved without excessive chipping and breaking. Soft, pliable waxes such as beeswax are preferred for modelling.

The property which makes the waxes and paraffins suitable to achieve the favorable property according to the invention is probably their hydrophobicity. It appears to be the consequence of this specific property that biocides are more efficiently bound to the paint layer.

As will be discussed hereafter, the composition of the invention is provided as an emulsion. It is an advantage of the paraffins that they are emulsified easily and this makes them particularly suitable to be used in the compositions of the invention.

Any kind of wax is in principle suitable to be used in the composition according to the invention. It is preferred to use paraffin waxes in the compositions of the invention. The most suitable waxes and paraffins are such waxes or paraffins which display a melting point at a temperature between 50 and 60 ⁰C.

The most suitable paraffin is the type of product which is sold under the commercial names Redezon 100 or Cera 100 (manufacturer Repsol). The types of paraffin which may be used vary from the types 50/52 to 68/70, the most preferred type is the one 55/60.

The most suitable type of wax is Cera LP (Licowax LP flakes; manufactured by Clariant). This type of wax comprises a fatty acid of 24 to 34 carbon atoms with CAS number 68476-03-9.

The amount of wax or paraffin in the composition of the invention is 1 to 50 % by weight. According to a preferred embodiment the amount of wax or paraffin is 5 to 45 % by weight, according to an even more preferred embodiment the amount of wax or paraffin is 15 to 40 % by weight, according to yet a further preferred embodiment the amount of wax or paraffin is 25 to 35 % by weight.

It is a further preferred embodiment that the compositions according to the invention contain both a wax and a paraffin.

A composition on the basis of paraffin alone displays the wanted improvement of the biocidal efficacy and the presence of paraffin leads to highly stable compositions. Addition of a minor amount of wax leads to a further improvement of the properties.

On the other hand, a composition on the basis of wax alone may display a viscosity value which is too high for easy handling. This phenomenon makes the combined presence of wax and paraffin the more preferable embodiment.

In the combined application of wax and paraffin in the composition of the invention the same types of wax and paraffin are preferred as in the use of wax or paraffin alone.

In the combined application the preferred amount of paraffin is 10 to 40 % by weight, the amount of wax 1 to 5 % by weight, a more preferred amount in the combined application is 15 to 30 % by weight for the paraffin and 2 to 4,5 % by weight for the wax.

A further component of the present invention is a thickener. Different thickeners can be used. Historically, cellulose based materials (such as hydroxyethyl cellulose and sodium carboxymethyl cellulose), and to a lesser extent certain polyacrylates, have dominated the emulsion paint thickener market. While such cellulose based materials and polyacrylates are still commonly used for this application, a new class of thickeners, associative thickeners, has become available to the paint manufacturer. These are low molecular weight synthetic polymers or modified cellulose based materials which have several advantages over the conventional cellulose based materials. They impart a more Newtonian rheology, are stable to enzymatic degradation and can impart good gloss, flow, and anti-spatter properties to emulsion paints.

The most preferred thickener according to the invention is casein. Casein is a natural phosphoprotein obtained from milk through extraction at the isolectric point. Commercial names of the casein products which can be used in the composition of the invention are Caseina® (manufactured by Brenntag), Industrial acid casein (manufactured by Unilait, France) and Caseina Acide industrial (manufactured by Becamo).

The amount of the thickener in the composition of the invention is 1 to 10 % by weight, more preferred 3 to 8 % by weight.

Another component of the composition of the invention is a surfactant. The presence of the surfactant shall allow the emulsification of wax and paraffin and shall provide the required stability to the emulsion, so that an acceptable shelf-life can be achieved.

Any conventional surfactant which is known in the art can be used, such as in particular the general groups of the non-ionic surfactants and the anionic surfactants.

The definition of a surfactant is a linear molecule with a hydrophilic (attracted to water) head and a hydrophobic (repelled by water) end. Surfactants tend to clump together when in solution, forming a surface between the fluid and air with the hydrophobic tails in the air and the hydrophilic heads in the fluid. Often surfactants will form "bubbles" within the fluid, leading to a small sphere of heads surrounding a pocket of air containing the tails. They can also form bubbles in air, leading to two nested spheres of surfactant, between them a thin layer of water, surrounding a pocket of air - and antibubbles in fluid - a layer of air surrounding a pocket of water.

Suitable surfactants for the purpose of the invention are such surfactants which are capable to provide the composition of the invention its character of a stable emulsion which can be shelved for a substantial time without showing signs of instability such as clouding, separation of layers or deposit.

Non-ionic surfactants comprise the following options:

• Natural alcohol ethoxylates (C12-C16 alkylethoxylate containing n mols of ethoxy, n can be between 1 and 80, most suitably 20); a commercial product is Genapol C 200 (manufactured by Clariant);

• Oleylethoxylates with n mols of ethoxy, n can be between 1 and 80, most suitably 20; a commercial product is Genapol O 200 (manufactured by Clariant);

• Tallow fatty alkyl ethoxylate with n mols of ethoxy, n can be between 1 and 80, most suitably 20; a commercial product is

Genapol T 200 (manufactured by Clariant);

• Oxoalkylethoxylates (C12-C15 oxoalkylethoxylate with n mols of ethoxy, n can be between 1 and 80, most suitably 20); a commercial product is Genapol OX 100 (manufactured by -Glariant); • Oxo-alcohol ethoxylates (C14-C15 oxoalkylethoxylate with n mols of ethoxy, n can be between 1 and 80, most suitably 20); a commercial product is Genapol OA 080 (manufactured by Clariant);

• Isotridecyl ethoxylate with n mols of ethoxy_f n can be between 1 and 80_/ most suitably 20; a commercial product is Genapol X150 (manufactured by Clariant) and Imbentin T/150 (manufactured by

Dr. KoIb); • Alkylphenol ethoxylates, the most suitable one being nonylphenol with 14 to 15 mols of ethoxy; commercial products are Arkopal N 150 (Clariant) and Imbentin N/98 (Dr KoIb);

• Ethylene/propylene oxide block copolymer, a commercial product is Pluronic PE9400 (BASF): ;

• Ethoxylated Castor oil; commercial products are Hedipin-R/300 (Dr. KoIb), Emulsogen EL (Clariant) and Eumulgin PRT36 (Cognis).

Anionic surfactants comprise the following options: • Aryl sulphonates sodium salt,

• Olein sulphonates sodium salt,

• Alkyl sulphates sodium salt,

• Alkylic ether sulphates,

• Tributylphenolether sulphates, • Nonylphenolethersulphates,

• Sulphosuccinates,

• Sulphosuccinamates,

• Phosphoric acid monoesters,

• Alkyl phosphoric acid mono/diesters, • Copolymerizable anionic emulsifiers.

Preferred surfactants are the surfactants belonging to the class of the non-ionic surfactants.

When the biocidal composition in the form of an emulsion according to the invention does not contain the surfactant or contains an amount of surfactant which is relatively low, the amount of the thickener to be added in the composition of the invention, in particular the amount of casein according to the preferred embodiment should be at least 3 % by weight.

The active ingredient of the composition of the invention is the biocide. The biocide shall protect the paint against any kind of attack of fungi or algae, accordingly it is appropriate to add a biocide with a fungicidal or algaecidal effect. In principle, as such biocides any product known in the art with an effect on the growth of bacteria, algae or fungi may be used.

The most preferred biocides to be used in the composition of the invention are IPBC, terbutryn, cybutryne, OIT, thiabendazole, and zinc-2-pyridine thiol 1-oxide. IPBC, OIT, thiabendazole and zinc-2-pyridine thiol 1-oxide are fungicidal compounds. Terbutryn and cybutrin are algaecidal compounds.

Combinations of the biocidal compounds are possible as well. Two fungicidal compounds may be combined in a product, such as IPBC and zinc-2-pyridine thiol 1-oxide, just as well as two algaecidal compounds such as terbutryn and cybutrin. However, for the intended practical use of the composition of the invention it is more suitable to combine a fungicidal compound with an algaecidal compound.

The concentration of the biocide in the composition of the invention has to be selected td provide the wanted biocidal, algaecidal or fungicidal effect. The usual concentration of the biocide in the composition of the invention is 1 to 20 % by weight. A preferred concentration of the biocide in the composition of the invention is 2 to 15 % by weight, an even more preferred amount is 5 to 10 % by weight. If the composition of the invention comprises a combination of a fungicidal compound with an algaecidal compound it is preferred that in this embodiment the concentration of the fungicidal compound in the composition is 1 to 10 % by weight and the concentration of the algaecidal compound 1 to 10 % by weight, more preferred the concentration of the fungicidal compound 2 to 7,5 % by weight and the concentration of the algaecidal compound 2 to 7,5 % by weight. The liquid basis for the composition of the invention is water. Water in the context of the invention means any kind of aqueous liquid, such as tap water, purified water, desalted water, distilled water, demineralised water, buffers, etcetera. For the purpose of the invention the selection of the type of aqueous liquid is not essential, but demineralised water is preferred. Certain amounts of an organic solvent may be present, but this amount should be not more than 10 % by volume based on the total volume of the aqueous liquid and the organic solvent.

It is a further option in the present invention that the biocidal composition comprises additional components such as preservatives and antioxidants which may support the stability of the composition.

The preparation of the composition of the invention is based on processes which are known in the art. It is for instance possible to combine all components in a container and finally add water. In order to obtain the emulsion, treatment with an ultrasonic device may be required.

The composition of the invention is added to a water-borne paint to provide the required biocidal activity. It is preferred to combine the paint basis and the composition of the invention immediately before use. The combination can be achieved while using conventional mixing techniques, intensive manual agitation is usually sufficient.

The amount of the composition of the invention which is added to the water-borne paint depends on the intended use and on the properties of the water-borne paint and the biocidal composition of the invention. The usual amount of the composition to be added to the water-borne paint is 0.5 to 5 % by weight based on the total weight of the water-borne paint. In order to illustrate the effects of the compositions of the invention a number of experiments have been performed. The assays were performed with three kinds of water-borne paints, based on acrylic, acrylic styrene and vinyl veove resins.

Vinyl veove resins are copolymers of vinyl acetate and a VeoVa monomer. VeoVa products are monomers that can offer a variety of unique properties to polymers prepared from it and other co-monomers. VeoVa is a vinyl ester of Versatic acid, a synthetic saturated monocarboxylic acid of highly branched structure containing nine or ten carbon atoms. Inclusion of such a monomer in polymer systems introduces very good alkali resistance, UV resistance and hydrophobicity to the polymer. The inclusion of VeoVa monomers can provide hydrocarbon solubility or a low-energy coating surface and also adds steric bulk to the polymer providing protection to less stable monomers like vinyl acetate. VeoVa monomers essentially differ in the glass transition temperature of their homopolymers. VeoVa 10 provides a balance of flexibility and hardness whereas VeoVa 9, containing shorter and more heavily branched carbon chains, provides rigidity to the polymer. VeoVa monomers are used as modifying co-monomers in the preparation of vinyl acetate based polymer latices, which are used for the manufacture of speciality emulsion paints. VeoVa monomers are also used as co-monomers with acrylates for the production of emulsion-, solution- and bulk polymers such as acrylic automotive and powder coatings.

VeoVa monomers react readily with vinyl acetate to prepare binders for interior and exterior paint. The ease of preparation and the superior performance of these latex systems have enabled VeoVa-based systems to capture a large portion of the latex paint market in Western Europe, Latices can also be made from VeoVa and various acrylates that can be used as coatings for wood and plastics. VeoVa/ vinyl acetate system can also be used to prepare cement additives or adhesives.

u 1 % of each new formulate has been added to each paint.

The addition of 1% of this formulate increases surprisingly the effectiveness of the biocides in the dry film paints.

The following biocides have been assayed in the composition according to the invention, these biocides are particularly preferred:

2-tert-butylamino-4-ethyl-propylamino-6-methyl~thio-l,3,5~triazine (terbutryn), (CAS Number: 886-50-0)

3-iodo-2-propynyl butyl carbamate (IPBC) ((CAS Number: 55406-53-6) 2-n-octyl-2H-isothiazol-3-one (OIT) (CAS Number: 26530-20-1) Thiabendazole (CAS Number 148-79-8)

Zinc-2-pyridine thiol 1-oxide (CAS Number: 13463-41-7) 2-tert-butylamino-4-cyclopropylamino-6-methyl-thio-l,3,5-triazine (cybutryne) (CAS Number: 28159-98-0)

The invention is now explained by a number of examples.

Examples

In the following examples the term pbw. refers to parts by weight.

Paint 1: pure acrylic based paint

Water 6.4 pbw. Hydroxyethylcellulose (1) 9.7 pbw.

Hexametaphosphate (2) 1.2 pbw.

Titanium oxide 16 pbw. Barium sulfate 2.2 pbw.

Acrylic resin 63 pbw.

Butyl glycol acetate 1.5 pbw.

(l) as a 2% solution in water (2) as a 10 % solution in water

Hydroxyethylcelluiose was supplied by the company Dow Chemicals under the tradename Cellosize®, hexametaphosphate was provided as the sodium salt by the company Brenntag, the acrylic resin used in the example was the product sold under the tradename Craymul 2167 XP® by the company Cray Valley, titanium oxide was purchased from American elements, barium sulfate from Alkemi and butyl glycol acetate from BASF.

The biocidal effect of a number of different formulations 1 to 9 upon addition to the paint 1 was investigated.

Formula 1

Water 58.77 pbw.

Refinated paraffin 33.95 pbw.

Cera LP 2 pbw.

BHT 0.02 pbw.

Casein 4 pbw. Ammonium hydroxide 25% 0.76 pbw.

BIT (1) 0.5 pbw.

Formula 2

Water 71.48 pbw.

Casein 5 pbw.

IPBC 10 pbw. Terbutryn 3 pbw. OIT 5 pbw.

C13 oxo alcohol ethoxylate 5 pbw. BIT (1) 0.5 pbw. BHT 0.02 pbw.

Formula 3

Water 35.53 pbw.

Refinated paraffin 33.95 pbw.

Cera LP 2 pbw.

Casein 5 pbw.

IPBC 10 pbw. Terbutryn 3 pbw.

OIT 5 pbw.

C13 oxo alcohol ethoxylate 5 pbw.

BIT (1) 0.5 pbw.

BHT 0.02 pbw.

Formula 4

Water 71.48 pbw.

Casein 5 pbw. Zinc-2-pyridine thiol 1-oxide 10 pbw.

Terbutryn 3 pbw.

OIT 5 pbw.

C13 oxo alcohol ethoxylate 5pbw.

BIT (I) 0.5 pbw. BHT 0.02 pbw. Formula 5

Water 35.53 pbw.

Refinated paraffin 33.95 pbw. Cera LP 2 pbw.

Casein 5 pbw.

Zinc-2-pyridine thiol 1-oxide 10 pbw.

Terbutryn 3 pbw.

OIT 5 pbw. C13 oxo alcohol ethoxylate 5pbw.

BIT (1) 0.5 pbw.

BHT 0.02 pbw.

Formula 6

Water 71.48 pbw.

Casein 5 pbw.

Thiabendazole 10 pbw. Terbutryn 3 pbw.

OIT 5 pbw.

C13 oxo alcohol ethoxylate 5 pbw.

BIT (1) 0.5 pbw.

BHT 0.02 pbw.

Formula 7

Water 35.53 pbw.

Refinated paraffin 33.95 pbw. Cera LP 2 pbw.

Casein 5 pbw.

Thiabendazole 10 pbw. Terbutryn 3 pbw. OIT 5 pbw.

C13 oxo alcohol ethoxylate 5pbw. BIT (1) 0.5 pbw. BHT 0.02 pbw

Two further examples 8 and 9 are provided in which the biocide terbutryn has been replaced for the biocide cybutrin.

Formula 8

Water 71.48 pbw.

Casein 5 pbw. IPBC 10 pbw.

Cybutryne 3 pbw.

OIT 5 pbw.

C13 oxo alcohol ethoxylate 5 pbw.

BIT (1) 0.5 pbw. BHT 0.02 pbw.

Formula 9

Water 35.53 pbw. Refinated paraffin 33.95 pbw.

Cera LP 2 pbw.

Casein 5 pbw.

IPBC 10 pbw.

Cybutryne 3 pbw. OIT 5 pbw.

C13 oxo alcohol ethoxylate 5 pbw.

BIT (I) 0.5 pbw. BHT 0.02 pbw.

In the above formulations the Refinated paraffin is bought as the product Redezon 100 from the company Repsol, Cera LP is bought as the product Licowax LP FL from the company Clariant, thiabendazole was purchased under the trademark Metasol TK 100® from the company Bayer, BHT (antioxidant) is 2,6-di-tert-butyl-4-methylphenol and was purchased under the trademark Ionol CP from the company Quimidroga, Casein was bought as the product Casein ind. from the company Brenntag, BIT (preservative) was bought under the trademark Proxel Press Paste from the company Arch Chemicals B. V., IPBC was bought under the trademark Preventol MP 100 from the company Bayer, Terbutryn was bought as the product Terbutryn Tech from the company Ciba, OIT was bought under the trademark Kathon 893 F from the company Rohm & Haas, C13 oxo alcohol ethoxylate was bought under the trademark Emulan TO 4070 from the company BASF, zinc-2-pyridine thiol 1-oxide was bougt as Zinc Omadine Powder from the company Arch Chemicals B. V. and cybutryne was bought as the product Cybutryn Tech from the company Ciba.

Preparation of the examples and the formulations.

Paint 1 was prepared by providing 640 g of water into a beaker. Under stirring under high speed (1000 rpm) 970 g of hydroxyethylcellulose was added as a 2% solution in water, together with 120 g of hexametaphosphate as a 10 % solution in water. Then 1600 g of titanium oxide and 220 of barium sulfate were added. Finally, 150 g of butyl glycol acetate were added, thereafter, the stirring speed was reduced to 400 rpm and 6300 g acrylic resin were added.

The formulations 1 to 9 were prepared as follows:

In a carefully cleaned and purged installation deionised water was loaded and stirred under 80 rpm. So far as required the refinated paraffin PS 55/60 was added and the preparation was heated to 80-85 ⁰C. The temperature was maintained until melting and incorporation of the paraffin was observed. The stirring at the increased temperature was maintained. So far as required the wax product Cera LP was added. Stirring was continued until visual confirmation that melting and incorporation had occurred.

Stirring was continued at 110 rpm.

Casein and the non-ionic surfactant were added. The addition of casein had to be monitored in order to be sure of the absence of lumps. The temperature was maintained at 80-85⁰C and stirring was continued at 80 rpm. Stirring was continued until homogeneity of the composition was observed.

In order to prepare the composition to be tested, 10 g of the above formulates 1, 2, 3, 4, 5, 6, 7, 8 or 9 were added to the acrylic paint. The viscosity of the product was adjusted with water to a viscosity value of 1500 cPs.

In order to demonstrate the fungicidal properties of the novel emulsion of the present invention, pieces of paper about 2 cm diameter were treated with the paint, then allowed to lixiviation (or not), later drying the papers, and placing them in Petri dishes containing agar which has been inoculated with different microorganisms. After inoculation at 25⁰C for 5 days, sterile areas of 30 mm diameter were observed. Outside these areas, black/green mold growth was observed. This demonstrates that the fungicide protects the paint and a limited area around the paint. This demonstrates that the wax emulsion dispersed phase reduces the leaching of the fungicide in the paint. Moreover, lixiviation has been carried out during 48 hours with the pieces of the painted papers in water. These paints have been described with the letter w behind the formula and number.

Table I shows the inhibition halos (in mm) against fungi and algae in an acrylic paint:

Table I. Inhibition halos (in mm) against fungi and algae in an acrylic paint

w (*) : lixiviation during 48 hours of the pieces of the painted papers in water.

(**) : Ch/ore/fa vulgaris and Stichococcus bacillaris. Paint 2: acrylic styrene based paint

Water 7.5 pbw.

Hydroxyethylcellulose (l) 9.4 pbw. Hexametaphosphate (2) 1.2 pbw.

Titanium oxide 15.2 pbw.

Barium sulfate 24.6 pbw.

Acrylic styrene resin 40.9 pbw.

Butyl glycol acetate 1.2 pbw.

(1) as a 2% solution in water

(2) as a 10 % solution in water

Hydroxyethylcellulose was supplied by the company Dow Chemicals under the tradename Cellosize®, hexametaphosphate was provided as the sodium salt by the company Brenntag, the acrylic styrene resin used in the example was the product sold under the tradename Craymul 2110® by the company Cray Valley, titanium oxide was purchased from American elements, barium sulfate from Al'kemi and butyl glycol acetate from BASF.

Preparation of paint 2 was performed in similar manner as has been described for paint 1.

An amount of 1% formulate 1, 2, 3, 4, 5, 6, I₁ 8 or 9 was added to the acrylic styrene based paint in a manner similar as described in connection with the combinations with paint 1.

The biocidal effects of the compositions was determined in the same manner as described for the paint preparation 1.

Table II shows the inhibition halos (in mm) against fungi and algae in an acrylic styrene based paint: Table II. Inhibition halos (in mm) against fungi and algae in an acrylic styrene paint

(**) : Ch/orella vulgaris and Stichococcus bacillaήs. Paint 3: vinyl veove based paint

Water 19 pbw.

Hydroxyethylcellulose (l) 6.3 pbw.

Hexametaphosphate (2) 1.5 pbw. Titanium oxide 16.5 pbw.

Calcium carbonate 28.5 pbw.

Vinyl veove 27 pbw.

Butyl glycol acetate 1.2 pbw.

(l) as a 2% (w/v) solution in water (2) as a 10 % (w/v) solution in water

Hydroxyethylcellulose was supplied by the company Dow Chemicals under the tradename Cellosize®, hexametaphosphate was provided as the sodium salt by the company Brenntag, the vinyl veove used in the example was the vinyl versate product sold under the tradename Craymul 2326® by the company Cray Valley, titanium oxide was purchased from American elements, calcium carbonate from SA Reverte and butyl glycol acetate from BASF.

Preparation of paint 3 was performed in similar manner as has been described for paint 1.

An amount of 1% formulate 1, 2, 3, 4, 5, 6, 7, 8 or 9 was added to the vinyl veove based paint in a manner similar as described in connection with the combinations with paint 1. The biocidal effects of the compositions was determined in the same manner as described for the paint preparation 1.

In the table III is shown the inhibition halos (in mm) against fungi and algae in a vinyl veove paint:

Table III. Inhibition halos (in mm) against fungi and algae in a vinyl veove paint

(**) : Chlorella vulgaris and Stichococcus bacillaris.

Claims

WHAT WE CLAIM IS:

1. A biocidal composition in the form of an emulsion, comprising:

(a) paraffin and/or wax (b) a biocide and / or mixtures of biocides dispersed in said emulsion.

2. A biocidal composition according to claim 1 comprising the following components: water 25 - 80% by weight, paraffin and/or wax 1 - 50% by weight, thickener 1 - 10% by weight, surfactants 1 - 5% by weight and biocide 1 - 20% by weight.

3. A biocidal composition according to claim 1 comprising the following components: water 25 - 80% by weight, paraffin 10 - 40% by weight, wax 1 - 5 % by weight, thickener 1 - 10% by weight, surfactants 1 - 5% by weight, fungicide 1 - 10 % by weight , algaecide 1 - 10 % by weight, preservatives "in can" 0 - 1 % by weight and antioxidants 0 - 1 % by weight.

4. The water-borne composition according to claim 2, wherein the biocide is selected from the group consisting of IPBC, terbutryn, cybutryne, OIT, thiabendazole, and zinc-2-pyridine thiol 1-oxide.

5. A composition as described in claim 1 wherein said biocide is IPBC.

6. A composition as described in claim 1 wherein said biocide is terbutryn.

7. A composition as described in claim 1 wherein said biocide is cybutrin.

8. A composition as described in claim 1 wherein said biocide is OIT.

9. A composition as described in claim 1 wherein said biocide is thiabendazole.

10. A composition as described in claim 1 wherein said biocide is Zinc-2- pyridine thiol 1-oxide.

11. A composition as described in any of claims 1 to 9 wherein said wax comprises a mixture of paraffin and wax.

12. The composition of any of the previous claims wherein the binder is casein.

12. Use of the biocidal composition of any of the previous claims as an additive to water-borne paint compositions.

13. Water-borne paint composition comprising the composition according to any of claims 1 to 11.