WO2006127335A1

WO2006127335A1 - Carbonate esters as coalescing agents in coatings

Info

Publication number: WO2006127335A1
Application number: PCT/US2006/018964
Authority: WO
Inventors: Rodney W. Parr; Katty F. Darragas; Martin M. Michiels
Original assignee: Huntsman Petrochemical Corporation
Priority date: 2005-05-24
Filing date: 2006-05-17
Publication date: 2006-11-30
Also published as: TW200700513A

Abstract

The present invention provides a waterborne coating composition that includes a synthetic resin and one or more carbonate esters as a coalescing agent. The waterborne coatings containing the carbonate esters according to the invention exhibit enhanced film forming characteristics and improved physical properties.

Description

ITED STATES PATENT AND TRADEMARK OFFICE

CARBONATE ESTERS AS COALESCING

AGENTS IN COATINGS

CARBONATE ESTERS AS COALESCING AGENTS IN COATINGS

CROSS-REFERENCE TO RELATED APPLICATION This application claims priority to United States provisional application U.S.

Pat. App. No. 60/683,977 filed on May 24, 2005.

STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT Not Applicable.

FIELD OF THE INVENTION

The present invention is directed to waterbome coatings containing one or more carbonate esters useful as coalescing agents to aid in the formation of continuous films.

BACKGROUND OF THE INVENTION Federal clean air guidelines and volatile organic compound (VOC) reduction levels have required paint manufacturers to develop a range of highly effective, compliant waterbome coatings. These waterborne coatings, for almost all applications, must be capable of forming a strong, adherent and continuous film at a reasonably low temperature when applied to a surface and dried. In order to achieve this, it is common to add a coalescing agent to the coating composition. The function of a coalescing agent is to soften the polymer particles and promote their coalescence into a homogeneous continuous film.

U.S. Pat. Nos. 3,399,158, 3,790,520, 4,111,881, 4,435,534, 4,489,188, 4,525,512, 4,894,406, 5,186,744, 5,236,987. 5,238,987, 5,756,569. 6,110,998 and 6,187,385 describe several different coalescing agents used in coating applications. Disadvantages associated with the above-mentioned coalescing agents are: they either evaporate too slowly; are inefficient at reducing minimum film forming temperatures; emit an objectionable odor; exhibit poor hydrolytic stability; are costly; or produce coatings having diminished physical properties such as poor water resistance, gloss, storage stability and opacity.

SUMMARY OF THE INVENTION

The present invention provides coalescing agents for use in waterborne coating compositions. The waterborne coating compositions include a synthetic resin, a coalescing agent comprising one or more carbonate esters and optionally conventional additives. The waterborne coating compositions containing the coalescing agent of the present invention have good film-forming and hardness development characteristics. In addition, the waterborne coating compositions made with the coalescing agents of the present invention meet VOC requirements and have greatly reduced odor.

DETAILED DESCRIPTION OF THE INVENTION

The present invention generally relates to waterborne coating compositions containing a synthetic resin, a coalescing agent according to the present invention and optional conventional additives.

Coalescing agents reduce polymer-polymer chain interactions, thereby increasing the segmental motion within the polymer chains. The action of the coalescing agent is determined by the presence (both in the polymer and coalescing agent) of groups capable of interaction, by the shape of the molecule, and other geometrical factors. It has been surprisingly found that the carbonate esters of the present invention have a good profile^alance of these interactive, shape and geometrical properties, and in addition are EHS friendly and do not detract from other paint properties. Thus, the carbonate esters of the present invention provide as good or better coalescence performance than conventional coalescing agents used in waterborne coatings while at the same time having a much lower odor and environmental impact.

The term "waterborne coating" refers to coatings that primarily use water to disperse the synthetic resin and which are spread over a surface to form a solid protective, decorative or functional adherent film. Waterborne coatings are classified based on how the synthetic resin is fluidized and include water-soluble/water-reducible solutions, water- dispersible/colloidal dispersions and emulsions paints.

Water-soluble coatings are coatings in which individual molecules of water-soluble resins are dissolved completely in water. Water-soluble resins are generally produced via polycondensation or polymerization reactions in an organic medium. As a result, they generally contain organic co-solvents like alcohols, glycol ethers or other oxygen-containing solvents that are soluble or miscible with water (organic content less than 10 to 15%).

Because of viscosity anomalies, waterborne coatings made with water-soluble binders have only about 30 to 40% solids content by weight.

Water-dispersible coatings, or colloidal coatings, are coatings that have small clusters of insoluble resin particles suspended in water. Mechanical agitation is sufficient to suspend the clusters. Emulsions are similar to water-dispersibles. However, resin clusters in emulsions tend to be larger, and an emulsifier is required to keep the clusters in suspension. Synthetic Resin

As a first essential component, the waterborne coating compositions of the present invention include a synthetic resin selected from acrylic latex polymers, vinyl latex polymers, waterborne alkyds and mixtures thereof. The "term "latex" as used herein refers to stable solutions, dispersions or emulsions of resin particles in an aqueous system. The term "polymer" is used to denote a homopolymer or copolymer.

Almost all types of resins are available in a waterborne version, including vinyls, two- component acrylics, epoxies, epoxy esters, polyesters, styrene-butadiene, amine-solubilized, carboxyl-terminated alkyd and urethanes.

In one embodiment, the synthetic resin is an acrylic latex polymer or vinyl latex polymer formed by the polymerization of known monoethylenically unsaturated monomers, such as, but not limited to, a monoethylenically unsaturated monomer having the formula (I):

CH₂=C(R³)COOR⁴ (I) where R³ is hydrogen or a C₁-C₃ alkyl group, and R⁴ is a C₁-C_2O alkyl group, phenyl, benzyl, hydroxy-(C₁-C₄)-alkyl, alkoxy-(C₁-C₄)-alkyl, cyclopentyl, cyclohexyl, C₁-C₄-alkylfuryl, tetrahydrofuryl, C₁-C₄-alkyltetrahydrofuryl and combinations of these monomers thereof.

Examples of comonomers, include, but are not limited to, methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, isopropyl (meth)acrylate, butyl (meth)acrylate, isobutyl (meth)acrylate, hexyl (meth)acrylate, isocetyl (meth)acrylate, isodecyl (meth)acrylate, lauryl (meth)acrylate, stearyl (meth)acrylate, phenoxyethyl (meth)acrylate, methoxyethyl (meth)acrylate, benzyl (meth)acrylate, ethoxyethyl (meth)acrylate, 2- ethylhexyl (meth)-acrylate, cyclopentyl (meth)acrylate, and isobornyl (meth)acrylate, as well as combinations of those monomers thereof.

Other suitable polymerizable monoethylenically unsaturated monomers include sytrenic monomers, vinyl ester monomers or olefin monomers. Styrenic monomers include styrene or substituted styrene, such as p-methyl styrene, o-methyl styrene and combinations thereof. Vinyl ester monomers include compounds such as vinyl acetate and di-n- butylmaleate and compounds having the general formula (II):

CH₂=CH-OC(=O)-(C-(R⁵)₂)_n (II) where R⁵ is a hydrogen or a C_1-12 alkyl group and n is an integer of 1-20. Olefin monomers include ethylene, propylene and diolefin monomers such as butadiene.

In another embodiment, the synthetic resin is a waterborne alkyd. Waterborne alkyds are synthetic resins produced from the reaction of an oil or fatty acid, polyol(s) and polyacids.

The oil or fatty acid used in the preparation of the waterborne alkyd include, but are not limited to, fatty acids such as tall oil fatty acid, linseed oil, soybean oil, coconut oil, castor oil, sunflower oil, and safflower oil.

The polyol(s) used in the preparation of waterborne alkyds include, but are not limited to, glyercol, neopentyl glycol, cyclohexanedimethanol, ethylene glycol, propylene glycol, pentaerythritol, neononyl glycol, diethylene glycol, dipropylene glycol, trimethyl pentanediol, triethylene glycol, trimethylolpropane, dipentaerythritol, and tripentaerythritol.

The polyacids used in the preparation of waterborne alkyds include, but are not limited to, cyclohexanedicarboxylic acid, isophthalic acid, terephthalic acid, phthalic anhydride, adipic acid, oxalic acid, malonic acid, dimethylrnalonic acid, succinic acid, glutaric acid, trimethyladipic acid, pimelic acid, 2,2-dimethylglutaric acid, azelaic acid, sebacic acid, fumaric acid, maleic acid, itaconic acid, 2,5-norbomane dicarboxylic acid, 1,4- naphthalic acid, diphenic acid, 4,4'-oxydibenzoic acid, diglycolic acid, thiodipropionic acid, 4,4'-oxydibenzoic acid, diglycolic acid, thiodipropionic acid, 4,4'-sulfonyldibenzoic acid,

4,4'-diphenyidicarboxylic acid, and 2,6-naphthalene dicarboxylic acid. Suitable dicarboxylic acids used in waterborne alkyds include aliphatic dicarboxylic acids, aromatic dicarboxylic acids, alicyclic dicarboxylic acids or mixtures of two or more of these acids.

The synthetic resins of the present invention may be prepared by conventional methods known in the art. The polymerizations may be conducted in batch reactions or continuously over a wide range of temperatures up to about 95°C. Although heat and UV light may be used to initiate the polymerization, one may include a free radical generating catalyst to aid in the polymerization. These free radical generating catalysts include both organic and inorganic peroxides, inorganic persulfates, organic hydroperoxides, azo compounds, redox catalysts and reduced metal catalysts. Other additives that may also be used during polymerization include an acid or base to adjust the pH of the aqueous dispersion, buffers, and inorganic salts.

Coalescing Agent

The carbonate esters employed as coalescing agents in the present invention are represented by the general formula (III):

l ^"-^r. '

wherein R₁, R₂, R₄ and R₅ are independently selected from hydrogen, an alkyl, an aryl, a cycloalkyl, a heteroaryl, an alkenyl and a heteroatom and R₃ and R₆ are independently selected from null, hydrogen, an alkyl, an aryl, a cycloalkyl, a heteroaryl, an alkenyl and a heteroatom with the proviso that when R₃ and R₆ are both null, the carbonate ester is a 5- membered ring represented by the general formula (IV):

(IV)

R .R

R R

and when either R₃ or R₆ is null the other is an alkyl and the carbonate ester is a 6-membered ring represented by the general formula (V):

O

(V)

R C C R

2 / \ ^R 5

^R 7 %

wherein R₇ and R₈ are independently selected from hydrogen, an alkyl, an aryl, a cycloalkyl, a heteroaryl, an alkenyl and a heteroatom.

As used herein, the term "alkyl" denotes branched or unbranched hydrocarbon chains containing 1 to 20 carbons, preferably 3 to 18 carbons, and more preferably 4 to 12 carbons, in the normal chain, such as, methyl, ethyl, propyl, isopropyl, butyl, sec-butyl, iso-butyl, tert- butyl, pentyl, hexyl, isohexyl, heptyl, 2-methylpentyl, 2-ethylhexyl, 4,4-dimethylpentyl, octyl, 2,2,4-trimethylpentyl and the like. The term "branched" used here and throughout the text means one or more lower alkyl groups, such as methyl, ethyl, propyl or butyl, are attached to a linear chain. Further, alkyl groups, as defined herein, may optionally be substituted on any available carbon atom with one or more functional groups commonly attached to such chains, such as, but not limited to hydroxy, to form 4-butoxymethyl and the like.

The term "alkenyl" as used herein by itself or as part of another group refers to straight or branched chain radicals of 2 to 20 carbons, preferably 3 to 18 carbons, and more preferably 4 to 12 carbons with one or more double bonds in the normal chain, such as vinyl, 2-propenyl, 3-butenyl, 2-butenyl, 4-pentenyl, 3-pentenyl, 2-hexenyl, 3-hexenyl, 2-heptenyl, 3-heptenyl, 4-heptenyl, 3-octenyl, 3-nonenyl, 4-decenyl, 3-undecenyl, 4-dodecenyl, 4,8,12- tetradecatrienyl, and the like. Unless otherwise indicated, the term "cycloalkyl" as employed herein alone or as part of another group includes saturated cyclic hydrocarbon groups containing 1 to 3 rings, appended or fused, including monocyclicalkyl, bicyclicalkyl and tricyclicalkyl, containing a total of 3 to 20 carbons forming the ring and which include cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl, cyclooctyl, and cyclodecyl. The cycloalkyl groups selected for use in the present invention are cyclic groups exhibiting good stability in the waterborne coatings, including, but not limited to, cyclohexyl.

Unless otherwise indicated, the term "aryl" as employed herein alone or as part of another group refers to monocyclic and bicyclic aromatic groups containing 6 to 10 carbons in the ring portion (such as phenyl, 1-naphthyl and 2-naphthyl). Further, "aryl", as defined herein, may optionally be substituted with one or more functional groups, such as alkyl, alkenyl, cycloalkyl, aryl, arylalkyl, arylalkenyl, or hydroxy.

The terms "arylalkyl" and "arylalkenyl" as used alone or as part of another group refer to alkyl and alkenyl groups, respectively, as defined above having an aryl substituent as defined above. Representative examples of arylalkyl include, but are not limited to, benzyl, 2- phenylethyl, 3-phenylpropyl, benzhydryl and naphthylmethyl and the like.

The term "heteroatom" refers to oxygen, nitrogen, phosphorus or sulfur and the term heteroaryl refers to an aryl in which one or more atoms in the closed ring structure is a heteroatom. Any combination of R₁, R₂, R₃, R₄, Rs, R₆, R7, and R₈, groups may be used, thus for example; the R_1-8 groups may be selected to form a symmetrical carbonate ester such as di- (2-ethylhexyl) carbonate. Furthermore, two or more carbonate esters may be combined to form the coalescing agent to provide optimum film forming characteristics and broaden the range of effective application temperatures for the coating composition while meeting the VOC requirements.

The carbonate ester selected for use in the present invention will depend, to some extent, on the composition of the synthetic resin used in the waterborne coating. For example, an alkyd resin will require a different carbonate ester or mixture of carbonate esters than an acrylic resin. One method which may be used to predict the optimum carbonate ester for use in a particular synthetic resin includes the Hildebrand solubility parameters as described in CRC Handbook of Solubility Parameters, A. Barton (CRC Press, 1983) which is incorporated herein by reference.

The carbonates esters described above may be prepared by any method known in the art. For example, the carbonate esters may be prepared by reacting phosgene with one or more alcohols in the presence of a base. In addition, the carbonate esters may be prepared by transesterification of dimethyl carbonate with alcohols in the presence of a catalyst such as titanate ester. Furthermore, the carbonate esters of the present invention may be produced as described in Synthesis and Characterization of Dialkyl Carbonates Prepared from Mid-, Long-Chain, and Guerbet Alcohols, James A. Kenar et al. (JAOCS 81, 285-291 March 2004) incorporated herein by reference, in which a series of carbonate esters were synthesized through a carbonate interchange reaction by heating alcohols with diethyl carbonate in the presence of a catalyst such as n-butylin oxide. Of particular interest are carbonate esters derived from ethoxylated or propoxylated alcohols. Conventional Additives

The waterborne coatings of the present invention may include conventional additives known in the art. Conventional additives include, but are not limited to, thickeners, defoaming and antifoaming agents, flow-control agents, fillers, adhesion promoters, corrosion inhibitors, catalysts, surfactants, pigment wetting and dispersing agents, UV absorbers and stabilizers, flatting agents, and antimicrobial agents.

The waterborne coating compositions as set forth above, may also include one or more pigments. The pigments used are generally organic or inorganic pigments well-known in the surface coatings industry such as, titanium dioxide, zinc oxide, red, brown, yellow and orange iron oxide, chromium oxide, carbon black, and copper phthalocyanine. The pigments are typically added at a concentration of about 1 to about 70 wt. % based on the total weight of the synthetic resin and coalescing agent in the waterborne coating composition. The waterborne coatings of the present invention may also include amines or alkanolamines as needed to adjust the pH of the compositions. Typically, the pH of most coating compositions falls within the range of about 7-10. Neutralization of water-borne coating systems is often desirable because charged polymer particles tend to have better water dispersibility, and thus neutralization with an amine or alkanolamine can help to stabilize a coating formulation. Examples of suitable amines and alkanolamines include, but are not limited to, aqueous ammonium hydroxide, triethylamine, triethanolamine, ethanolamine, N,N-dimethylethanolamine and the like, and mixtures thereof. Formulation and Application of the Waterborne Coating Compositions

To make the waterborne coating compositions of the present invention, the components above are combined together using means well known in the art such as stirrers, pumps, homogenizers, etc. The relative levels of the components are selected to give the required performance of the composition in a coating application, with an eye toward making sure on the one hand that a component is present at a sufficient level to be effective, but on the other hand that excessive cost is avoided by limiting the upper range of the component.

Generally, the waterborne coating composition will contain from about 10 to about 80 weight percent of synthetic resin; about 10 to about 80 weight percent of water; from about 0 to about 50 percent of conventional additives; and, a coalescing amount of the coalescing agent. Coalescing amount means an amount that will facilitate the formation of a continuous film upon drying a coating of the resin under the drying conditions to be employed, such as ambient conditions or elevated temperatures. The coalescing amount will vary depending on the type of synthetic resin, formulation, and the carbonate ester or blend of carbonate esters used. However, in most waterborne coating compositions, a coalescing amount is within the range of about 0.25 to about 25 weight percent of the waterborne coating composition. In one embodiment, the coalescing agent is added at an amount from about 0.5 to about 15 weight percent of the waterborne coating composition. In another embodiment, the coalescing agent is added at an amount ranging from about 1 to about 4 weight percent of the waterborne coating composition. As noted above, the coalescing agent may comprise one or a mixture of carbonate esters according to the present invention.

The compositions may be easily prepared in any suitable vessel or container. The order of mixing the components is not particularly important and generally the various components can be added sequentially or all at once in the form of aqueous solutions. Thus, the waterborne coatings can be prepared by combining, in any order, a synthetic resin and the coalescing agent, together with any desired conventional additives, and blended until a homogeneous coating composition is obtained. Once formulated, the waterborne coating compositions of the present invention can be packaged in a variety of containers such as steel, tin, or aluminum cans, plastic or glass bottles.

The waterborne coating compositions may be applied to a substrate by any known methods, such as brushing, rolling, spraying, dipping, flow coating, electrodeposition and electrostatic airless spraying and allowed to dry at ambient conditions or elevated temperatures. Elevated temperatures may be achieved using drying methods, such as oven- drying or forced air drying techniques, for accelerating the rate of drying. The substrate may include, but is not limited to, an article comprising wood, steel, aluminum, plastic, fiber cement siding, for example, HARDIPLANK®, and galvanized sheeting. The waterborne coating compositions of the present invention may also be used as a sealant to fill an opening or space.

EXAMPLES 1-9 Minimum Film Formation Temperature (MFFT)

In this example, di-(2-ethylhexyl) carbonate, 4~isopropyl-5,5-dimethyl-2,3-dioxal-2- one, 4-(Ci₂-C₁₄)-l,3-dioxal-2-one and 4-butoxymethyl-l,3-dioxal-2-one were evaluated as a coalescing agent. A commercially available acrylate latex (Primal® AC 507, Rohm and Haas) containing either: (i) no coalescing agent; (ii) a carbonate; (iii) a prior art coalescing agent generally used commercially in latex emulsions; or one of (iv) di-(2-ethylhexyl) carbonate, 4-isopropyl-5₅5-dimethyl-2₅3-dioxal-2-one, 4-(C₁₂-C₁₄)-l,3-dioxal-2-one or A- butoxymethyl-l,3-dioxal-2-one were tested for the ability of the coalescing agent to aid film formation as indicated by the determination of the minimum film formation temperature (MFFT) of the acrylate latex. The test was carried out by visual observation of cracking or whitening of the film dried over a plastic substrate having a controlled temperature gradient.

In measuring the MFFT, the coalescing agent was added to the latex, mixed well, and allowed to stand in a sealed container at 5O⁰C for 1.5 weeks. Just prior to testing, the temperature gradient was established across the thin plastic sheet and allowed to equilibrate until the temperature gradient was constant. The latex was spread uniformly over the plastic sheet, allowed to dry, and the point on the plastic sheet at which the film became discontinuous (corresponding to a measured temperature) was identified and recorded as the MFFT. The results are shown in Table 1.

Table 1

Minimum film formation temperature is a direct indication of the coalescing effect of coalescing agents in waterborne coating compositions. As can be seen in Table 1, di-(2- ethylhexyl) carbonate is a very effective coalescing agent in that it reduces substantially the

MFFT of the latex tested, as compared to the latex having either no coalescing agent added or carbonate added. Furthermore, the MFFT obtained with di-(2-ethylhexyl) carbonate was at least comparable to that obtained with the conventional and widely used coalescing agent,

Texanol®. In addition, the latex containing di-(2-ethylhexyl) carbonate as a coalescing agent exhibited excellent hydrolytic stability and had significantly less odor than the latex containing Texanol®. EXAMPLE 10 (Prophetic)

High Gloss Paint

The following waterborne coating composition may be prepared by mixing the following listed components: Component Wt. %

Water 10

Dispersant 1

Surfactant . 7

■ Defoamer 0.2 Ammonia 0.2

■ Antimicrobial Agent 0.1 • Pigment 24

■ Synthetic resin 56

■ Carbonate ester 1.5

EXAMPLE 11 (Prophetic)

Semi-Gloss Paint

The following waterborne coating composition may be prepared in accord with the invention: Component Wt. %

- Water 15

- Thickener 0.2

- Surfactant 0.2

- Defoamer 0.5

- Catalyst 1.5

- Antimicrobial Agent 0.1

- Pigment 28

- Synthetic resin 52

- Carbonate ester 2.5

EXAMPLE 12 f Prophetic)

Gloss Enamel

The following waterborne coating composition may be prepared in accord with the invention:

Component Wt. %

Water 15

Thickener 0.5

Surfactant 0.5

Dispersant 1

Antimicrobial Agent 1

Ammonium Hydroxide 3

• Pigment 18

■ Synthetic resin 55

■ Carbonate ester 6

EXAMPLE 13 (Prophetic)

Interior Flat Paint

- Water 35

- Thickener 1

- Surfactant 0.48

- Defoamer 0.01

- Catalyst 0.01

- Filler 19

- Pigment 21

- Synthetic resin 21

- Carbonate ester 2.5

EXAMPLE 14 CProϋheticϊ

Sealant

Component Wt. %

Water 30

Filler 30

Synthetic resin 20

Pigment 8

Catalyst ^' 9

■ Carbonate Ester 3

EXAMPLES 15-16 fProphetic)

Matte Furniture Coating

The following waterborne coating compositions may be prepared in accord with the invention:

Component Wt. %

Water 10

Surfactant 5

■ Thickener 2

■ Synthetic resin 70

■ Wax Emulsion 4.5

■ Matting Agent 1

■ Ammonia 2.5

■ Carbonate Ester 5 Component Wt. %

Water 23

Pigment 13

Thickener 17

Synthetic resin 15

Dispersant 1.5

Filler 12

Ammonia 0.5

Carbonate Ester 18

Although making and using various embodiments of the present invention have been described in detail above, it should be appreciated that the present invention provides many applicable inventive concepts that can be embodied in a wide variety of specific contexts.

The specific embodiments discussed herein are merely illustrative of specific ways to make and use the invention, and do not delimit the scope of the invention.

Claims

What is claimed is: L A waterborne coating composition comprising a synthetic resin, a coalescing agent and optional conventional additives wherein the coalescing agent comprises one or more carbonate esters having the formula (III):

wherein R₁, R₂, R₄ and R₅ are independently selected from hydrogen, an alkyl, an aryl, a cycloalkyl, a heteroaryl, an alkenyl and a heteroatom and R₃ and R₆ are independently selected from null, hydrogen, an alkyl, an aryl, a cycloalkyl, a heteroaryl, an alkenyl and a heteroatom with the proviso that when R₃ and R₆ are both null, the carbonate ester is a 5-membered ring represented by the general formula (IV):

and when either R₃ or R₆ is null the other is an alkyl and the carbonate ester is represented by the general formula (V):

O

(V)

R C C R

¹ / \_c / \

^R ₂ / \ ^R 5

R R

7 8

2. The waterbome coating composition of claim 1, wherein the synthetic resin is an acrylic latex polymer.

3. The waterborne coating composition of claim 1, wherein the synthetic resin is a vinyl latex polymer.

4. The waterborne coating composition of claim 1, wherein the coalescing agent is present in the coating composition in a coalescing amount.

5. The waterborne coating composition of claim 4, wherein the coalescing amount is within the range of from about 0.5 to about 25 weight percent of the waterborne coating composition.

6. The waterborne coating composition of claim 1 , wherein the carbonate ester is di (2- ethylhexyl) carbonate.

7. The waterborne coating composition of claim 1 , wherein the carbonate ester is A- isopropyl-5 , 5 -dimethyl- 1 ,3 -dioxal-2-one .

8. The waterborne coating composition of claim 1, wherein the carbonate ester is A- butoxymethyl- 1 ,3 -dioxal-2-one.

9. A method for formulating a waterborne coating composition comprising combining (i) a coalescing amount of a coalescing agent comprising one or more carbonate esters having the formula (III)

wherein R₁, R₂, R₄ and R₅ are independently selected from hydrogen, an alkyl, an aryl, a cycloalkyl, a heteroaryl, an alkenyl and a heteroatom and R₃ and R₆ are independently selected from null, hydrogen, an alkyl, an aryl, a cycloalkyl, a heteroaryl, an alkenyl and a heteroatom with the proviso that when R₃ and R₆ are both null, the carbonate ester is a 5-membered ring represented by the general formula (IV)

O

and when either R₃ or R₆ is null the other is an alkyl and the carbonate ester is represented by the general formula (V)

O

(V)

R

wherein R₇ and R₈ are independently selected from hydrogen, an alkyl, an aryl, a cycloalkyl, a heteroaryl, an alkenyl and a heteroatom with (ii) a synthetic resin and (iii) optional conventional additives.

10. A method for coating a substrate comprising forming a waterborne coating composition by combining (i) a synthetic resin with (ii) a coalescing agent comprising one or more carbonate esters having the formula (III)

O

O

(V)

R C C R

/ \_c / \

R _{/ v} R

2 / \ 5

R R

7 8

wherein R₇ and R₈ are independently selected from hydrogen, an alkyl, an aryl, a cycloalkyl, a heteroaryl, an alkenyl and a heteroatom and optional conventional additives and (iii) optional conventional additives and applying the waterborne coating composition to the surface of the substrate.

11. The method of claim 10, wherein the substrate is selected from the group consisting of wood, steel, aluminum, plastic, fiber cement siding and galvanized sheeting.