WO2021120142A1

WO2021120142A1 - A method for extending the open time of paints and a paint composition

Info

Publication number: WO2021120142A1
Application number: PCT/CN2019/126858
Authority: WO
Inventors: Bing HONG; Stephane Streiff; Congyu BAO; Peng Xu; Jean-Christoph Castaing
Original assignee: Rhodia Operations
Priority date: 2019-12-20
Filing date: 2019-12-20
Publication date: 2021-06-24

Abstract

An improved method to extend the open time, in particular with respect to cheap and environmentally-friendly extender with less or even no additional VOCs. A paint composition comprising a polyoxometalate and a base water-borne paint composition, wherein the polyoxometalate extends at least 20% of the open time of the base water-borne paint composition.

Description

A method for extending the open time of paints and a paint composition

TECHNICAL FIELD

The present invention relates to a method for extending the open time of paints and a paint composition.

BACKGROUND

Low volatile organic compound (VOC) aqueous paints have been developed as an alternative to environmentally unfriendly VOC solvent-based paints in response to environmental regulations limiting the level of VOCs in paint compositions. One of the challenges of formulating water-based paint formulations is achieving an acceptable balance of properties both during application and in the final film compared to the traditional solvent based paints. In particular, the low VOC aqueous paints dry faster, have shorter open time, and poorer flow and leveling. Open time reflects the amount of time within which paint can be reworked on a surface post application, and for water-based formulations is up to 10 minutes. Open time problems include, but are not limited to, skinning of left-open paints, not being able to cut back or blend in during brushing and rolling, and non-uniformity of sprayed surfaces. These problems are further exacerbated under fast dry conditions such as low humidity and high temperature.

Some attempts to extend the open time have included adding crosslinkable oligomers or emulsion polymers to the paint formulation. However, it is difficult to overcome the inherent problems, such as poor compatibility, gloss decrease.

Some small organic glycol molecules like glycol, ethylene glycol and propylene glycol are also used to improve open time and wet edge and are universally considered to be VOCs. Nevertheless, large amount (up to 20wt. %) of such glycol compounds is always required to achieve desired performance, which results in high VOC.

CN Patent Applications No. 104130688 A, 104177942 A, 104293175 A, 104693954 A, 106318050 A, 106349789 A and 107964313 A disclose coating or paint composition comprising heteropoly acid. However, none of them teaches the composition can extend the open time.

Hence, there is still a need to develop an improved method to extend the open time, in particular with respect to cheap and environmentally–friendly extender with less or even no additional VOCs.

SUMMARY OF THE INVENTION

The present invention therefore relates to a method for extending the open time of paints in need thereof, wherein the method comprising adding a polyoxometalate to a base water-borne paint composition in an amount effective to extend the open time.

Applicant surprisingly discovered that the polyoxometalate can extends at least 20%of the open time of the base water-borne paint composition.

The present invention also concerns a paint composition comprising a polyoxometalate and a base water-borne paint composition, wherein the polyoxometalate extends at least 20%of the open time of the base water-borne paint composition.

DEFINITIONS

Throughout the description, including the claims, the term "comprising one" should be understood as being synonymous with the term "comprising at least one" , unless otherwise specified, and "between" should be understood as being inclusive of the limits.

As used herein, the terminology " (C _n-C _m) " in reference to an organic group, wherein n and m are both integers, indicates that the group may contain from n carbon atoms to m carbon atoms per group.

The articles “a” , “an” and “the” are used to refer to one or to more than one (i.e., to at least one) of the grammatical object of the article.

The term “and/or” includes the meanings “and” , “or” and also all the other possible combinations of the elements connected to this term.

It is specified that, in the continuation of the description, unless otherwise indicated, the values at the limits are included in the ranges of values which are given.

Ratios, concentrations, amounts, and other numerical data may be presented herein in a range format. It is to be understood that such a range format is used merely for convenience and brevity and should be interpreted flexibly to include not only the numerical values explicitly recited as the limits of the range, but also all the individual numerical values or sub-ranges encompassed within that range as if each numerical value or sub-range is explicitly recited.

DETAILS OF THE INVENTION

In general, by “open time” is meant the time interval during which freshly applied paint can be blended with subsequently applied paint without the appearance of lack of uniformity. Specifically, open time is the time in which irregularities in a freshly applied coating can be repaired, while the period in which a coating can be applied over an existing paint film without leaving lap marks is the wet edge time. There are numerous methods to characterize open time and wet edge time. One of the most common techniques requires a paint film to be drawn down on a sealed chart with a series of ‘X’ marks in the center of the drawdown. After fixed periods of time, paint is brushed back and forth across the film. The point at which the edge of the drawdown can no longer be worked into the body of the paint is referred to as the wet edge time, while the time at which the ‘X’ begins to show through the paint is the open time. These techniques are further described in Example 1.

As used herein, polyoxometalate is a polyatomic ion, usually an anion, that consists of three or more transition metal, lanthanide metal or actinide metal oxyanions linked together by shared oxygen atoms to form closed 3-dimensional frameworks.

Polyoxometalate (hereinafter “POM” ) used in the method according to the present invention may be a compound having general formula (I) :

[X ¹ _iX ² _jH _k] {M ¹ _m [Y _n (M ² _aM ³ _bM ⁴ _cO _d) (H ₂O) _e] }

(I)

wherein:

- X ¹ or X ² is selected from the group consisting of alkali metal cation, alkaline rare metal cation, lanthanide cation and (R ₁R ₂R ₃R ₄) N ⁺, wherein R ₁, R _2, R ₃ and R ₄, independently from each other, represent H or hydrocarbon radical,

- M ¹ is selected from the group consisting of lanthanide, Ti, V, Cr, Mn, Fe, Co, Ni, Cu or Zn,

- Y is selected from the group consisting of P, As, Sb, Si, Ge, Sn, B or Co,

- M ², M ³ or M ⁴ is selected from the group consisting of lanthanide, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Mo or W, and at least one of M ², M ³ and M ⁴ is V, Mo or W,

- i, j and k are integers ranging from 0 to 28 and i + j + k = 3 to 28,

- m is an integer ranging from 0 to 4,

- n is an integer ranging from 0 to 10,

- a, b and c are integers ranging from 0 to 30, and a + b + c = 2 to 30,

- d is an integer ranging from 7 to 120, and

- e is an integer ranging from 0 to 50.

Preferably, X ¹ or X ² can be selected from the group consisting of alkali metal cation, alkaline rare metal cation and (R ₁R ₂R ₃R ₄) N ⁺, more preferably selected from the group consisting of alkali metal cation and (R ₁R ₂R ₃R ₄) N+ and most preferably selected from the group consisting of K ⁺, Na ⁺, Li ⁺ and NH ₄ ⁺.

Preferably, M ¹ can be Cu, Zn, Ce or Eu.

Preferably, Y can be B, P, Si, Ge or Sb and more preferably P or Si.

Preferably, at least one of M ², M ³ and M ⁴ can be Mo or W and more preferably W.

Preferably, i, j and k are integers ranging from 0 to 20 and i + j + k = 3 to 20.In a preferred embodiment, i + j ≥1.

In some embodiments, m is 0.

Preferably, n is an integer ranging from 0 to 5.

Preferably, a, b and c are integers ranging from 0 to 20 and a + b + c = 2 to 20.

Preferably, d is an integer ranging from 30 to 80.

The structure of POM is not particularly limited. Preferred structure can be Keggin, Lacunary Keggin or Wells-Dawson. More preferably, POMs having Lacunary or Wells-Dawson structure are chosen.

Non limiting examples of POM are: H ₃ [PW ₁₂O ₄₀] , H ₄ [SiW ₁₂O ₄₀] , Na ₄ [SiW ₁₂O ₄₀] , Na ₃ [PW ₁₂O ₄₀] , Na ₃ [PMo ₁₂O ₄₀] , K ₅ [BW ₁₂O ₄₀] , Na ₆ [CoW ₁₂O ₄₀] , K ₅ [PVW ₁₁O ₄₀] , K ₅ [SiVW ₁₁O ₄₀] , Na ₇ [PW ₁₁O ₃₉] , Na ₉ [PW ₉O ₃₄] , Na ₈ [α-SiW ₁₁O ₃₉] , Na ₁₀ [SiW ₉O ₃₄] , Na ₉ [SbW ₉O ₃₃] , K ₆ [α-P ₂W ₁₈O ₆₂] , Na ₉ [P ₂Nb ₃W ₁₅O ₆₂] , (NH ₄) ₆ [β-P ₂W ₁₈O ₆₂] , K ₂Eu ₃H ₃ [Ge ₂Ti ₆W ₁₈O ₇₇] , (Me ₃NH) ₈ [Si ₂Nb ₆W ₁₈O ₇₇] , Na ₇ [Ti ₂W ₁₀PO ₄₀] , K ₇ [Ti ₂W ₁₀PO ₄₀] , K ₉H ₅ [Ge ₂Ti ₆W ₁₈O ₇₇] , K ₁₃ [Eu (SiW ₁₁O ₃₉) ₂] , K ₁₀ [Zn ₄ (H ₂O) ₂ (PW ₉O ₃₄) ₂] , K ₁₂ [Cu ₃ (PW ₉O ₃₄) ₂] and K ₁₃ [Ce ^III (SiW ₁₁O ₃₉) ₂] ·26H ₂O.

The base water-borne paint composition is not particularly limited and preferably comprises a solvent and a binder.

The base water-borne paint composition herein is defined as a composition where the solvent is water. In some embodiments, the solvent is a mixed solvent of water and at least one water-miscible solvent, such as short chain water-soluble alcohol and/or glycol, such as ethylene glycol, diethylene glycol, propylene glycol, and glycerin. The short chain water-soluble alcohol and/or glycol may be present in the amount of about 1 to about 30 volume %, or about 10 to about 30 volume %, or about 10 to about 20 volume %, or about 1 to about 10 volume %based on the volume of the solvent.

Particular embodiments of the base water-borne paint compositions of the disclosure is wherein the binder comprises homopolymers and copolymers of acrylic and methacrylic acids and esters thereof, copolymers of acrylic and methacrylic acids and esters thereof with styrene, vinyl monomers, and ethylene; vinyl acetate-ethylene copolymers, polyvinyl alcohol, polyurethanes, epoxide polymers, epoxy-modified acrylic polymers, and mixtures of two or more of the aforementioned polymers. In one embodiment, the binder is acrylic polymer, vinyl/acrylic copolymers, styrenated acrylic polymer, and vinyl acetate/ethylene copolymers. The binder of the disclosure is present in the paint composition in an effective amount to bind the pigment particles together into a cohesive paint film upon drying.

Particular embodiments of the base water-borne paint compositions of the disclosure further comprise, but are not limited to, one or more of thickeners, pigments, light stabilizers, surfactants, defoamers, humectants, and biocides provided that they do not adversely affect the open time extender's synergistic effect on paints’ open time or dry film properties.

Thickeners included in the paint composition of the present disclosure typically comprise the aqueous emulsion reaction product of an unsaturated carboxylic acid monomer, e.g., methacrylic acid; a monoethylenically unsaturated monomer different from the carboxylic acid monomer, e.g. ethyl acrylate; a macromonomer comprising a hydrophobic portion and an alkoxylated portion which is polymerizable with the other monomers; and a monomer having latent crosslinking functionality. Suitable thickeners include UCAR 146 and UCAR Polyphobe TR115, Acrysol RM 500, Acrysol DR-1, Acrysol DR-73, Acrysol ASE 60 HEC, and HEUR/HIRESOL (grades 80, 85, 500, 370, 180, 200, 1800, and 2000) .

The thickeners may be varied depending on the desired uniform viscosity. The selection of suitable thickener and the quantity to be used for the paint composition of the present disclosure is within the skill of the person skilled in the art using routine trial and experimentation.

One or more pigments may be included in the paint composition. Pigmentation provides color and opacity and may contribute to other properties of the paint composition. For example, the pigment particle size and shape, ease of wettability or properties relating to specific density contribute to the viscosity and application characteristics of the wet paint composition and ultimately properties of the dried paint coatings. The choice of pigment may have an effect on the choice of other ingredients such as thickeners, and a skilled artisan will determine the appropriate selection of pigment and the quantity to be used using routine trial and experimentation.

Color pigments may be organic or inorganic compounds, natural or synthetic and these may be used separately or in combination. Titanium dioxide is a common white pigment with a high refractive index and excellent hiding power (the ability to render paint opaque) . It is frequently used with both colored organic and inorganic pigments. Suitable titanium dioxides are available under the

(DuPont Company, Wilmington, Del. ) ,

(Millennium Chemicals, Maryland) ,

(Tronox Incorporated, Oklahoma) ,

TR-90 and

CR-826. Iron oxides range in color from yellow and red to brown and black. Azo pigments are a common class of organic color pigments. Pigments called “extender” pigments may be used in conjunction with other pigments. The use of extender pigments reduces shrinkage stresses within the paint film and increases the pigment volume content at relatively low cost. Extender pigments include those based on carbonates, silicates, sulfates, barytes and mica. The use of extender pigments aids in viscosity and flow control and reinforces the dry film strength.

The surfactant useful in the base water-borne paint compositions may be nonionic or anionic surfactant. Examples of suitable surfactants include, but are not limited to, sodium lauryl sulfate, sodium dodecyl benzene sulfonate, dioctylsulfosuccinate, sodium polyoxyethylene lauryl ether sulfate, sodium dodecyl diphenyloxide disulfonate and other diphenylsulfonate derivatives, and sodium salt of tert-octylphenoxyethoxypoly ethoxyethyl sulfate, sorbitan monolaurate, polyoxyethylene 80 sorbitan laurate, polyoxyethylene 40 sorbitol septaoleate, polyoxyethylene alkyl phenol surfactants, and N, N-bis-carboxyethyl lauramine. Suitable surfactants also include, but are not limited to, commercially available Orotan 1124, Orotan 1288, Orotan 731 DP, Orotan 850, Aerosol TR-70S, Lecithin, EFKA 6220, Igepal CO 430, Igepal CO 530, linear alcohol ethoxylates (L-12-3 and L-24-4) , Lutensol XP40, Lutensol XP50, Pluronic L64, Tergitol 15-S-3, Tergitol 15-S-5, Tetronic 901, Tetronic 90R4, Triton X-207, Dextrol OC-50, Disperbyk, Nekal 25L, Pluronic 17R4, Pluronic L44, Pluronic L64, Pluronic F68, Pluronic 25R4, APE dodoxynol-6 (RC-520) , Tamol 1124, Tamol 731, Tamol 681, Tamol 165, Triton CF-10, Surfactol 365, Surfynol CT-121,

TMN-6,

15-S-5,

15-S-20, and

15- S-30, and DOWFAX ^TM.

Examples of suitable defoamers include, but are not limited to, polysiloxane-polyether copolymers such as those sold by Tego under the tradename Foamex ^TM, those sold under the tradename BYK ^TM, those sold under the tradename Drewplus ^TM, those sold under the tradename Surfynol ^TM, those sold under the tradename

and the like, and combinations thereof.

The base water-borne paint composition can notably those commercially available, for example, the Nippon Paint Odour-less All-in-1.

The amount of POM effective to extend the open time depends on the specific base water-borne paint composition. Preferably, the weight ratio of POM is from 0.01wt. %to 5wt. %based on the total weight of the paint composition and more preferably 0.01wt. to 1wt. %.

It shall be understood by the skilled person that the POM can be mixed with the base water-borne paint composition to obtain a homogeneous composition by well-known ways.

Preferably, the polyoxometalate can extend at least 50%of the open time of the base water-borne paint composition. More preferably, the polyoxometalate can extend at least 75%of the open time of the base water-borne paint composition. Most the polyoxometalate can extend at least 100%of the open time of the base water-borne paint composition.

In some embodiments, the polyoxometalate can extend at most 300%of the open time of the base water-borne paint composition. More preferably, the polyoxometalate can extend at most 200%of the open time of the base water-borne paint composition.

In an exemplified embodiment, when the base water-borne paint composition has an open time being 4 mins, the polyoxometalate can extend the open time to 5 to 8 mins.

The polyoxometalate may be a compound having general formula (I) and exemplary preferred POMs as above mentioned.

In some preferred embodiments, i + j ≥1. Non limiting examples of such POM are: Na ₄ [SiW ₁₂O ₄₀] , Na ₃ [PW ₁₂O ₄₀] , Na ₃ [PMo ₁₂O ₄₀] , K ₅ [BW ₁₂O ₄₀] , Na ₆ [CoW ₁₂O ₄₀] , K ₅ [PVW ₁₁O ₄₀] , K ₅ [SiVW ₁₁O ₄₀] , Na ₇ [PW ₁₁O ₃₉] , Na ₉ [PW ₉O ₃₄] , Na ₈ [α-SiW ₁₁O ₃₉] , Na ₁₀ [SiW ₉O ₃₄] , Na ₉ [SbW ₉O ₃₃] , K ₆ [α-P ₂W ₁₈O ₆₂] , Na ₉ [P ₂Nb ₃W ₁₅O ₆₂] (NH ₄) ₆ [β-P ₂W ₁₈O ₆₂] , K ₂Eu ₃H ₃ [Ge ₂Ti ₆W ₁₈O ₇₇] , (Me ₃NH) ₈ [Si ₂Nb ₆W ₁₈O ₇₇] , Na ₇ [Ti ₂W ₁₀PO ₄₀] , K ₇ [Ti ₂W ₁₀PO ₄₀] , K ₉H ₅ [Ge ₂Ti ₆W ₁₈O ₇₇] , K ₁₃ [Eu (SiW ₁₁O ₃₉) ₂] , K ₁₀ [Zn ₄ (H ₂O) ₂ (PW ₉O ₃₄) ₂] , K ₁₂ [Cu ₃ (PW ₉O ₃₄) ₂] and K ₁₃ [Ce ^III (SiW ₁₁O ₃₉) ₂] ·26H ₂O.

The base water-borne paint composition is not particularly limited and preferably comprises a solvent and a binder. The solvent and the binder can be those defined above.

The weight ratio of the polyoxometalate to the binder may be in the range of 0.0001 to 5 and preferably 0.01 to 0.5.

The paint compositions of the disclosure further comprise, but are not limited to, one or more of above defined thickeners, pigments, light stabilizers, surfactants, defoamers, humectants, and biocides provided that they do not adversely affect the open time extender's synergistic effect on paints’ open time or dry film properties.

The weight ratio of the polyoxometalate to the thickener may be in the range of 0.01 to 5 and preferably 0.5 to 1.

The weight ratio of the polyoxometalate to the pigment may be in the range of 0.0001 to 5 and preferably 0.01 to 0.5.

The weight ratio of the polyoxometalate to the surfactant may be in the range of 0.01 to 5 and preferably 0.5 to 1.

Applicant also surprisingly discovered the POM can lower the minimum film formation temperature of the binder in a paint composition.

The following examples are included to illustrate embodiments of the invention. Needless to say, the invention is not limited to described examples.

EXPERIMENTAL PART

Materials

- Nippon paint, Odour-less All-in-1, purchased from Alibaba.

- H ₃ [PW ₁₂O ₄₀] , CAS No. 12501-23-4, 99%, Sigma-Adrich.

- H ₄ [SiW ₁₂O ₄₀] , CAS No. 12027-43-9, 99%, Sigma-Adrich.

- Propylene glycol, CAS No. 57-55-6, >99.5%, Sigma-Aldrich.

- Rhodoline 2809, CAS No. 61827-42-7, >90%, Solvay.

- Rhodoline DF681F, defoamer, Solvay.

- Rhodoline 111, dispersant, Solvay.

- Acrylate latex AC261, polyacrylate, SolvayHBR250, CAS No. 9004-62-0, Ashland.

- AMP95, CAS No. 124-68-5, >95%, Angus Chemical Company.

- TiO ₂, CAS No. 13463-67-7, Dupont.

- Kaolin Clay. CAS 1332-58-7, BASF.

- CC700, Calcium carbonate 700 mesh, CAS No. 471-34-1 , 98%, J&K Chemical.

- RHODIASOLV DIB, Mixture, Coalescing agent, Solvay.

- Acrysol TT-935, Rheology modifier agent, Dow chemical.

- Kathon CG, Preservative, Dow chemical.

Preparation of POMs

The POMs were prepared according to the corresponding literature description as shown in the Table 1.

Table 1

Preparation of home-made paint composition

Table 2

In the container, water was added under stirring (200 rpm) , then Propylene glycol, Rhodoline 2809, Rhodoline DF681F and Rhodoline 111 were added. HBR 250 and AMP-95 were added and the stirring was increased to 2000 rpm for 20 mins. Then TiO ₂, Kaolin Clay and CC700 were added gradually under stirring for 30mins. Then the stirring was slowed down to 200 rpm, the AC261, was added and 5 mins later, the Rhodiasolve DIB and Rhodoline DF681F were added. Arysol TT-935 and Kathon CG were added with the rest water under stirring. The mixture was stirred for 30mins to afford the homogeneous paints.

Example 1:

The Commercial available Nippon Paint was used as base paint and 0.5wt. %commercial and home-made POMs was added and mixed homogeneously. Then the open time was evaluated according to one of the most common method:

One strip (150 μm thickness) was painted by a roller on black scrub test panel (Leneta P121-10N 165 x 432 mm) at 22 ℃ at 50%relative humidity.

Then a serious of ‘X’ marks were made in the center of drawdown.

At fixed time interval (2 mins) , the ‘X’ mark was brushed back&forth for 15 times with a brush.

The open-time was recorded when a ‘X’ mark was still observable after brush and dried.

It is show in Table 3 that paint compositions comprising a POM can significantly extend the open time of commercial paint composition.

Table 3

Example 2:

A home-made composition was used as base paint and 0.1wt. %commercial and home-made POMs was added and mixed homogeneously. 1.2wt. %propylene glycol was used as benchmark. Then the open time was evaluated by the same method of Example 1:

Table 4

It is show in Table 4 that paint compositions comprising a small amount of POM can significantly extend the open time of home-made paint composition, which have same or better performance than benchmark.

Example 3:

The POMs can also decrease the MFFT (minimum film formation temperature) of the latex. AC-261 Acrylic Emulsion (Dow chemicals) was used as example. 0.2wt. %of POMs based on the solid content of emulsion was added and stirred. The MFFT with/without the POMs were shown in Table 5.

Table 5 The MFFT of latexes with/without 0.2wt. %of POMs as additive.

In the Table 5, all the POMs prepared decreased the MFFT of the latex by 1-2.3 ℃ for AC-261, which is comparable to the conventional coalescence like

DIB.

In conclusion, the addition of POMs in the water-borne paints not only extend the open time but also decrease the MFFT of the binder, which can further reduce the organic additives usage in the formulation without sacrifice of the performance.

Claims

A method for extending the open time of paints in need thereof, wherein the method comprising adding a polyoxometalate to a base water-borne paint composition in an amount effective to extend the open time.
The method according to claim 1, wherein the polyoxometalate is a compound having general formula (I) :

[X ¹ _iX ² _jH _k] {M ¹ _m [Y _n (M ² _aM ³ _bM ⁴ _cO _d) (H ₂O) _e] }

(I)

wherein:

- X ¹ or X ² is selected from the group consisting of alkali metal cation, alkaline rare metal cation, lanthanide cation and (R ₁R ₂R ₃R ₄) N ⁺, wherein R ₁, R _2, R ₃ and R ₄, independently from each other, represent H or hydrocarbon radical,

- M ¹ is selected from the group consisting of lanthanide, Ti, V, Cr, Mn, Fe, Co, Ni, Cu or Zn,

- Y is selected from the group consisting of P, As, Sb, Si, Ge, Sn, B or Co,

- M ², M ³ or M ⁴ is selected from the group consisting of lanthanide, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Mo or W, and at least one of M ², M ³ and M ⁴ is V, Mo or W,

- i, j and k are integers ranging from 0 to 28 and i + j + k = 3 to 28,

- m is an integer ranging from 0 to 4,

- n is an integer ranging from 0 to 10,

- a, b and c are integers ranging from 0 to 30, and a + b + c = 2 to 30,

- d is an integer ranging from 7 to 120, and

- e is an integer ranging from 0 to 50.
The method according to claim 2, wherein Y is B, P, Si, Ge or Sb and more preferably P or Si.
The method according to claim 2, wherein n is an integer ranging from 0 to 5.
The method according to claim to any one of claims 1 to 4, wherein the polyoxometalate is selected from the group consisting of: H ₃ [PW ₁₂O ₄₀] , H ₄ [SiW ₁₂O ₄₀] , Na ₄ [SiW ₁₂O ₄₀] , Na ₃ [PW ₁₂O ₄₀] , Na ₃ [PMo ₁₂O ₄₀] , K ₅ [BW ₁₂O ₄₀] , Na ₆ [CoW ₁₂O ₄₀] , K ₅ [PVW ₁₁O ₄₀] , K ₅ [SiVW ₁₁O ₄₀] , Na ₇ [PW ₁₁O ₃₉] , Na ₉ [PW ₉O ₃₄] , Na ₈ [α-SiW ₁₁O ₃₉] , Na ₁₀ [SiW ₉O ₃₄] , Na ₉ [SbW ₉O ₃₃] , K ₆ [α-P ₂W ₁₈O ₆₂] , Na ₉ [P ₂Nb ₃W ₁₅O ₆₂] , (NH ₄) ₆ [β-P ₂W ₁₈O ₆₂] , K ₂Eu ₃H ₃ [Ge ₂Ti ₆W ₁₈O ₇₇] , (Me ₃NH) ₈ [Si ₂Nb ₆W ₁₈O ₇₇] , Na ₇ [Ti ₂W ₁₀PO ₄₀] _, K ₇ [Ti ₂W ₁₀PO ₄₀] , K ₉H ₅ [Ge ₂Ti ₆W ₁₈O ₇₇] , K ₁₃ [Eu (SiW ₁₁O ₃₉) ₂] , K ₁₀ [Zn ₄ (H ₂O) ₂ (PW ₉O ₃₄) ₂] , K ₁₂ [Cu ₃ (PW ₉O ₃₄) ₂] and K ₁₃ [Ce ^III (SiW ₁₁O ₃₉) ₂] ·26H ₂O.
The method according to any one of claims 1 to 5, wherein the base water-borne paint composition comprises a mixed solvent of water and at least one water-miscible solvent, which is present in the amount of 1 to 30 volume %, or 10 to 30 volume %, or 10 to 20 volume %, or 1 to 10 volume %based on the volume of the solvent.
The method according to any one of claims 1 to 6, wherein the weight ratio of the POM is from 0.01wt. %to 5wt. %based on the total weight of the paint composition and preferably from 0.01wt. to 1wt. %based on the total weight of the paint composition.
A paint composition comprising a polyoxometalate and a base water-borne paint composition, wherein the polyoxometalate extends at least 20%of the open time of the base water-borne paint composition.
The composition according to claim 8, wherein the polyoxometalate is a compound having general formula (I) :

[X ¹ _iX ² _jH _k] {M ¹ _m [Y _n (M ² _aM ³ _bM ⁴ _cO _d) (H ₂O) _e] }

(I)

wherein:

- X ¹ or X ² is selected from the group consisting of alkali metal cation, alkaline rare metal cation, lanthanide cation and (R ₁R ₂R ₃R ₄) N ⁺, wherein R ₁, R _2, R ₃ and R ₄, independently from each other, represent H or hydrocarbon radical,

- M ¹ is selected from the group consisting of lanthanide, Ti, V, Cr, Mn, Fe, Co, Ni, Cu or Zn,

- Y is selected from the group consisting of P, As, Sb, Si, Ge, Sn, B or Co,

- M ², M ³ or M ⁴ is selected from the group consisting of lanthanide, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Mo or W, and at least one of M ², M ³ and M ⁴ is V, Mo or W,

- i, j and k are integers ranging from 0 to 28 and i + j + k = 3 to 28,

- m is an integer ranging from 0 to 4,

- n is an integer ranging from 0 to 10,

- a, b and c are integers ranging from 0 to 30, and a + b + c = 2 to 30,

- d is an integer ranging from 7 to 120, and

- e is an integer ranging from 0 to 50.
The composition according to claim 9, wherein i + j ≥1.
The composition according to any one of claims 8 to 10, wherein the polyoxometalate extends the open time to 5 to 8 mins when the base water-borne paint composition has an open time being 4 mins.
The composition according to any one of claims 8 to 11, wherein the base water-borne paint composition comprising a solvent and a binder and the weight ratio of the polyoxometalate to the binder is in the range of 0.0001 to 5 and preferably 0.01 to 0.5.
The composition according to any one of claims 8 to 12, wherein the composition further comprises a thickener and the weight ratio of the polyoxometalate to the thickener is in the range of 0.01 to 5 and preferably 0.5 to 1.
The composition according to any one of claims 8 to 13, wherein the composition further comprises a pigment and the weight ratio of the polyoxometalate to the pigment is in the range of 0.0001 to 5 and preferably 0.01 to 0.5.
The composition according to any one of claims 8 to 14, wherein the composition further comprises a surfactant the weight ratio of the polyoxometalate to the surfactant is in the range of 0.01 to 5 and preferably 0.5 to 1.