Rheology modifiers for improving viscosity loss upon coloring in paint formulations containing organophosphorus functionalized latexes

Abstract

The present invention relates to a composition comprising (i) polymer particles comprising structural units of an organophosphorus monomer and (ii) a hydrophobically modified alkylene oxide-urethane polymer having a hydrophobic fragment represented by Structure I: wherein Ar1, Ar2, R1, m and n are defined herein. The composition of the present invention provides viscosity stability when colored for paints containing hydrophobically modified oxyalkylene-urethane rheology modifiers, more particularly HEUR rheology modifiers. # imgabs0 #

Description

BACKGROUND OF THE INVENTION

[0001] The present invention relates to rheological modifiers having an improved viscosity retention of pigmented coating formulations.

[0002] Hydrophobically modified alkylene oxide urethane polymers, and more particularly hydrophobically modified ethylene oxide urethane polymers (HEUR), are preferred rheological modifiers for paints due to the combination of good flow and leveling and reduced water sensitivity. HEUR builds viscosity in aqueous dispersions through associative thickening, and this viscosity is sensitive to the addition of solvents and surfactants that may disrupt the HEUR associative network. When pigmented with pigment dispersions and concentrates, HEUR-thickened formulations typically lose a significant amount of viscosity because these pigments consist of organic and inorganic pigments, solvents, and surfactants that act to disperse and stabilize the pigment particles. When added to a coating formulation, the pigment dilutes the paint, contributes solvents and surfactants, and redistributes the pre-existing surfactants throughout the formulation - all of which tend to reduce the viscosity established by the HEUR thickener. SUMMARY OF THE INVENTION

[0003] The present invention addresses the need in the art by providing a composition comprising: (i) polymer particles comprising structural units of an organophosphorus monomer and (ii) a hydrophobically modified alkylene oxide-urethane polymer having a hydrophobic moiety represented by Structure I:

[0004]

[0005] wherein the dashed line represents the point of attachment of the moiety to the hydrophobically modified alkylene oxide-urethane polymer; Ar 1 is unsubstituted phenyl, naphthyl, phenyl-O-CH2-, phenyl-CH2-O-CH2-, or naphthyl-O-CH2-; phenyl, naphthyl, phenyl-O-CH2-, phenyl-CH2-O-CH2-, or naphthyl-O-CH2- substituted with 1 to 3 C1-C6 alkyl or alkoxy groups; and Ar 2 is phenyl, phenyl-OCH2CH2-, phenyl-(OCH2CH2) y -, benzyl, naphthyl, naphthyl-CH2-, naphthyl-OCH2CH2-, or naphthyl-(OCH2CH2) y -, where the phenyl or naphthyl moiety of Ar 2 is unsubstituted or substituted with 1 to 3 C1-C6 alkyl groups; where y is from 2 to 10; each R 1 is independently H or C1-C6-alkyl; X is O or NR 2 where R 2is H, C1-C6-alkyl, phenyl or benzyl; m is from 1 to 20; and n is from 0 to 100. The compounds of the present invention solve the needs in the art by providing viscosity stability during coloring of paints containing polymer particles comprising structural units of organophosphorus monomers and hydrophobically modified oxyalkylene-carbamate rheology modifiers. Detailed Description

[0006] The present invention is a composition comprising: (i) polymer particles comprising structural units of organophosphorus monomers and (ii) a hydrophobically modified oxyalkylene-carbamate polymer having a hydrophobic segment represented by Structure I:

[0007]

[0008] wherein the dashed line represents the point of attachment of the segment to the hydrophobically modified oxyalkylene-carbamate polymer; Ar 1 is unsubstituted phenyl, naphthyl, phenyl-O-CH2-, phenyl-CH2-O-CH2- or naphthyl-O-CH2-; phenyl, naphthyl, phenyl-O-CH2-, phenyl-CH2-O-CH2- or naphthyl-O-CH2- substituted with 1 to 3 C1-C6 alkyl or alkoxy groups; and Ar 2 is phenyl, phenyl-OCH2CH2-, phenyl-(OCH2CH2) y -, benzyl, naphthyl, naphthyl-CH2-, naphthyl-OCH2CH2- or naphthyl-(OCH2CH2) y -, wherein the phenyl or naphthyl moiety of Ar 2 is unsubstituted or substituted with 1 to 3 C1-C6 alkyl groups; wherein y is from 2 to 10; each R 1 is independently H or C1-C6-alkyl; X is O or NR 2 wherein R 2 is H, C1-C6-alkyl, phenyl or benzyl; m is from 1 to 20; and n is from 0 to 100.

[0009] As used herein, the term "oxyalkylene-carbamate polymer" refers to water-soluble polyethylene oxide polymers and water-soluble polyethylene oxide / polypropylene oxide and polyethylene oxide / polybutylene oxide copolymers. Preferably, the oxyalkylene-carbamate polymer is an oxyethylene-carbamate polymer.

[0010] As used herein, a hydrophobically modified oxyalkylene-carbamate polymer refers to a polyethylene oxide, polypropylene oxide or polybutylene oxide carbamate polymer, preferably a polyethylene oxide carbamate polymer (HEUR) modified with a hydrophobic segment having Structure I.

[0011] The fragment having Structure I is prepared using a capping agent, which is a compound represented by Structure II:

[0012]

[0013] Examples of suitable diisocyanates include 1,4-tetramethylene diisocyanate, 1,6-hexamethylene diisocyanate (HDI), 2,2,4-trimethyl-1,6-diisocyanatohexane, 1,10-decamethylene diisocyanate, 4,4'-methylenebis(isocyanatocyclohexane) (H 12 -MDI), 2,4'-methylenebis(isocyanatocyclohexane), 1,4-diisocyanatocyclohexane, 1-isocyanato-3-isocyanatomethyl-3,5,5-trimethylcyclohexane (IPDI), m-phenylene diisocyanate and p-phenylene diisocyanate, 2,6-toluene diisocyanate and 2,4-toluene diisocyanate (TDI), xylene diisocyanate, 4-chloro-1,3-phenylene diisocyanate, 4,4'-methylenediphenyl diisocyanate (MDI), 1,5-naphthalene diisocyanate, and 1,5-tetrahydronaphthalene diisocyanate. Examples of commercially available diisocyanates are Desmodur W cycloaliphatic diisocyanate (DesW) and Desmodur H (HDI).

[0014] Water-soluble polyalkylene glycols refer to water-soluble polyethylene oxide, water-soluble polyethylene oxide / polypropylene oxide copolymers, and water-soluble polyethylene oxide / polybutylene oxide copolymers. Preferred water-soluble polyalkylene oxides are polyethylene glycols, especially polyethylene glycols having a weight average molecular weight in the range of 600 daltons to 12,000 daltons. Examples of suitable polyethylene glycols are PEG 8000 commercially available as CARBOWAX TM 8000 polyethylene glycol (PEG-8000, a trademark of The Dow Chemical Company ("Dow") or an affiliate of Dow, Midland, MI).

[0015] The diisocyanate, polyalkylene glycol, and capping agent having Structure II are contacted under reaction conditions to form a hydrophobically modified alkylene oxide-urethane polymer. Preferably, as determined by size exclusion chromatography (SEC) as described herein, the weight average molecular weight (M w ) of the hydrophobically modified alkylene oxide-urethane polymer is in the range of 2000 daltons, more preferably 4000 daltons to preferably 50,000 daltons, more preferably up to 25,000 daltons. Examples of preferred subclasses of the fragments of the present invention are represented by the following structures:

[0016]

[0017]

[0018] wherein R 1 ’ is H or CH3; and R 2 ’ is CH3 or benzyl.

[0019] Preferably, Ar 1 is phenyl-OCH2- or o-methylphenyl-OCH2-, more preferably phenyl-OCH2-. Preferably, when X = O, Ar 2 is phenyl, phenyl-OCH2CH2- or o-methylphenyl; preferably, when X = NR 2 , Ar 2 is phenyl; and R 2 is benzyl, methyl or ethyl. Preferably, m is in the range of 1, more preferably 2 to 10, more preferably up to 6; and n is in the range of 0 to 40, more preferably 1 to 30. Preferably, each R 1 is independently H, methyl or ethyl; more preferably H or methyl; most preferably, each R 1 is H. Preferably, X is O, N-CH3, N-phenyl or N-benzyl.

[0020] Preferably, as described in the Examples section below herein, as determined by matrix-assisted laser desorption / ionization - mass spectrometry (MALDI-MS), the number average molecular weight (M n ) of the fragment having structure I (and the compound having structure II) is in the range of 500 g / mol, more preferably 750 g / mol to 10,000, more preferably up to 2500 g / mol and most preferably up to 1500 g / mol.

[0021] The compound having structure II can be conveniently prepared by: first, in the presence of a catalytic amount of a suitable base such as KOH, under conditions sufficient to prepare an aryl alkoxy ether oligomer intermediate, contacting an aryl alcohol or arylamine with an aryl glycidyl ether, and then preferably under conditions sufficient to form the desired compound having structure II, contacting the intermediate with an alkylene oxide such as ethylene oxide. Preferably, the aryl alcohol is phenol, cresol or phenoxyethanol or a combination thereof; the arylamine is preferably N-methylbenzylamine or dibenzylamine or a combination thereof; and the aryl alkoxy ether is preferably phenyl glycidyl ether.

[0022] The hydrophobically modified alkylene oxide - urethane polymers of the present invention can advantageously be dissolved in water together with various other additives to prepare aqueous thickener compositions. The aqueous thickener compositions contain 1 weight percent, and more preferably 5 weight percent to 60 weight percent, and more preferably up to 40 weight percent of thickener solids based on the total weight of the aqueous thickener composition. Other additives can be included in the aqueous thickener compositions to inhibit the viscosity of the aqueous thickener compositions. Such other additives include water - miscible solvents such as propylene glycol and diethylene glycol butyl ether. Examples of other additives include cyclodextrin and various non - ionic and anionic surfactants. Examples of preferred non - ionic surfactants include C6 - C 18 alcohol ethoxylates, lauryl alcohol ethoxylates, Guerbet alcohol ethoxylates, and castor oil ethoxylates. The TERGITOL TM surfactant (a trademark of The Dow Chemical Company or its affiliates) is also suitable. Examples of suitable anionic surfactants include C6 - C 18 alcohol sulfates, sulfonates, sulfosuccinates, phosphates, and their ethoxylates, including sodium lauryl sulfate, sodium 2 - ethylhexyl sulfate, sodium dodecylbenzenesulfonate, and sodium dioctyl sulfosuccinate.

[0023] For the hydrophobically modified alkylene oxide - urethane polymers where X = NR 2 , preferably sufficient acid is added to the corresponding aqueous thickener composition to adjust its pH to the range of 2.1 to 6.0. Any acid compound that can lower the pH to this range is suitable. Examples of preferred acids include gluconic acid, phosphoric acid, hydrochloric acid, sulfuric acid, lactic acid, and poly(acrylic acid).

[0024] The hydrophobically modified alkylene oxide - urethane polymers can be used as rheology modifiers in pigmented coating formulations.

[0025] An aqueous dispersion of polymer particles comprising structural units of an organophosphorus monomer (i.e., a latex) is preferably a dispersion of polymer particles comprising structural units of an acrylate or methacrylate monomer and structural units of an organophosphorus monomer.

[0026] The term "structural unit" of a specified monomer refers to the residue of the monomer after polymerization. For example, the structural unit of methyl methacrylate is shown below:

[0027]

[0028] where the dashed line represents the point of attachment of the structural unit to the polymer backbone.

[0029] Preferably, the organophosphorus monomer is a compound represented by Structure III:

[0030]

[0031] wherein R 3 is H or -CH3; R 4 is a C1-C6 alkyl group; R 5 is H or

[0032]

[0033] wherein the dashed line represents the point of attachment to the oxygen atom; and p is from 1 to 5. Preferably, R 3 is -CH3, R 4 is -CH2CH2- or -CH2CH2CH2-, R 5 is H, and p is 1 or 2. More preferably, R 3 is -CH3, R 4 is -CH2CH2-, R 5 is H, and p is 1.

[0034] Preferably, the polymer particles comprise structural units of an organophosphorus monomer in an amount of at least 1 weight percent, more preferably at least 3 weight percent, and even more preferably at least 5 weight percent and not more than 15 weight percent, more preferably not more than 12 weight percent, and even more preferably not more than 10 weight percent based on the total weight of the polymer particles.

[0035] Preferably, the polymer particles comprise structural units of acrylate and methacrylate monomers in an amount of at least 30 weight percent, more preferably at least 50 weight percent, and not more than 98 weight percent, preferably not more than 90 weight percent based on the total weight of the polymer particles. Examples of suitable acrylate and methacrylate monomers include methyl methacrylate, ethyl methacrylate, butyl methacrylate, ureido methacrylate, ethyl acrylate, butyl acrylate, 2-ethylhexyl acrylate, and 2-propylheptyl acrylate. Preferred combinations of acrylate and methacrylate monomers include methyl methacrylate and one or more monomers selected from the group consisting of ethyl acrylate, butyl acrylate, ureido methacrylate, 2-propylheptyl acrylate, and 2-ethylhexyl acrylate. More preferred combinations of acrylate monomers include methyl methacrylate and butyl acrylate; methyl methacrylate and 2-ethylhexyl acrylate; and methyl methacrylate, butyl acrylate, and ethyl acrylate, with the combination of methyl methacrylate and butyl acrylate being most preferred. Examples of vinyl ester monomers include vinyl acetate, vinyl versatate. An example of a vinyl ester copolymer is vinyl acetate-ethylene (VAE).

[0036] The polymer particles may also include other monomers, such as structural units of styrene, acetoacetoxyethyl methacrylate, acrylonitrile, acrylamide, and 2-acrylamido-2-methylpropanesulfonic acid. In addition, the polymer particles preferably include structural units of ethylenically unsaturated carboxylic acid monomers in an amount of 0.2 weight percent, more preferably 0.5 weight percent, and most preferably 1 weight percent to preferably 5 weight percent and more preferably up to 3 weight percent, such as acrylic acid, methacrylic acid, and itaconic acid.

[0037] The polymer particles can have any morphology known in the art. The polymer particles can be block or random copolymers including structural units of organophosphorus monomers. Alternatively, the polymer particles can be composite polymers including structural units of organophosphorus monomers. Examples of composite polymers include spherical core-shell particles and particles having an acorn morphology, where the particles include small protuberances of larger spherical particles. Such composite polymers are disclosed in U.S. Patent No. 9,745,492 and U.S. Patent No. 9,745,478, respectively.

[0038] The composition of the present invention can be formed into an aqueous dispersion of: a) 10 weight percent to 60 weight percent of polymer particles based on the weight of the composition; b) and 0.05 weight percent to 2 weight percent of a hydrophobically modified alkylene oxide-urethane polymer containing a hydrophobic segment having Structure I based on the weight of the composition.

[0039] The composition of the present invention can be contacted with a coloring agent in a sufficient concentration to impart a desired color. As used herein, "coloring agent" refers to a liquid dispersion of a colored pigment. The concentration of the coloring agent is generally present in the range of 5 volume percent to 20 volume percent of the total volume of the paint and the coloring agent. Examples of colored pigments include phthalocyanine blue, phthalocyanine green, monoarylide yellow, diarylide yellow, benzimidazolone yellow, heterocyclic yellow, DAN orange, quinacridone magenta, quinacridone violet, organic reds (including metallized azo reds and non-metallized azo reds), carbon black, lamp black, black iron oxide, yellow iron oxide, brown iron oxide, and red iron oxide.

[0040] In another aspect, the composition contains TiO2 or BaSO4 particles with less than 15 PVC; in yet another aspect, the composition contains TiO2 and BaSO4 particles with less than 10 PVC. For deep base formulations, the PVC of the TiO2 and BaSO4 particles is <1. PVC is defined by the following formula:

[0041]

[0042] wherein binder solids refer to the contribution of the polymer from the aqueous dispersion of polymer particles that bind the pigment and extender particles together.

[0043] The composition may also include any one or all of the following materials: binder, dispersant, pigment, defoamer, surfactant, solvent, extender, coalescent, biocide, and opacifying polymer.

[0044] Example

[0045] Preparation of aminophenyl glycidyl ether ethoxylate block copolymer and HEUR

[0046] The aminophenyl glycidyl ether ethoxylate block copolymer intermediate and the corresponding HEUR (Inventive HEUR 1) are prepared in a manner similar to that described in U.S. Patent Application Publication No. US2020 / 0262975. Then, Inventive HEUR 1 and Comparative HEUR 1 (prepared in a manner similar to that described for Comparative Example 1 in U.S. Patent Application Publication No. US2021 / 0017380, except that the polymer is dissolved in water together with gluconic acid to form a final aqueous mixture of 20 wt% Comparative HEUR 1, 3.5 wt% gluconic acid, and 76.5 wt% water) are used as KU builders and various latexes with and without structural units of organophosphorus monomers are used to prepare the deep paint formulations according to Table 1.

[0047] Latex 1 is an acrylic latex that does not include structural units of organophosphorus monomers and is prepared in a manner similar to that described in U.S. Patent No. 7,695,770.

[0048] Latex 2 is an acrylic latex that includes structural units of organophosphorus monomers and is prepared in a manner similar to that described in U.S. Patent No. 8,318,848.

[0049] Latex 3 is an acrylic latex that includes structural units of organophosphorus monomers and is prepared according to Example 1 in U.S. Patent No. 9,920,194.

[0050] Table 1 is the formulation of a deep base paint (i.e., a paint without colorant).

[0051] Table 1 - Deep base paint formulation

[0052]

[0053]

[0054] TAMOL, TERGITOL, and ACRYSOL are all trademarks of The Dow Chemical Company or its affiliates.

[0055] Coloring

[0056] Place 40 g of the base paint in a small FlakTek cup and add an appropriate amount of colorant to achieve a short-fill color level between 12 oz / gal. Mix the paint and colorant on a Flak Tek Speed Mixer (DAC 150FVZ) at 2500 RPM for 3 minutes, and before any rheological testing, let the colored paint stand overnight and stir it manually with a wooden applicator.

[0057] Color the paint with a universal colorant from Chromaflow Technologies, which includes: 808 Phthalocyanine Blue (808 - 7214), a low-VOC colorant with an organic pigment; 808 Yellow Iron Oxide (808 - 1810), a low-VOC colorant with an inorganic pigment; equal weight parts of 808 Phthalocyanine Blue (808 - 7214), 808 Yellow Iron Oxide (808 - 1810), 808 Titanium White (808 - 0018), 808 Lamp Black (808 - 9907); and a blend of 888 Phthalocyanine Blue (888 - 7214), a high-VOC colorant with an organic pigment.

[0058] Viscosity test

[0059] Measure the viscosity of the paint before and after coloring on a TA Instruments DHR-3 rheometer equipped with a 2-degree, 40-mm cone-on-plate geometry, a Peltier-controlled temperature lower plate, and a solvent trap to minimize sample evaporation. Deliver approximately 0.7 mL of the paint to the lower plate via a syringe, and lower and seal the sample geometry without trimming. Apply a shear rate of 75 s -1 for 90 seconds and record the steady-state "mid-shear" viscosity η MS . The calculation of the mid-shear viscosity drop upon coloring is:

[0060]

[0061] Test

[0062] The mid-shear viscosity drop during the coloring of a deep base paint formulated with latex having structural units with and without organophosphorus monomers and a conventional KU co-detergent (Comparative HEUR 1) relative to the inventive KU co-detergent (Inventive HEUR 1), with 35PVC relative to 8PVC. The paint was colored with a 12 oz / gal colorant by adding a specified mass of the colorant to 40 g of the base paint. The value is expressed as a percentage of the base paint viscosity and represents the mid-shear viscosity drop after coloring.

[0063] Coloring was carried out using two low-VOC colorants (phthalocyanine blue - organic colorant, yellow oxide - inorganic colorant), a low-VOC colorant blend (equal weight portions of 4 colorants), and a high-VOC organic colorant. The viscosity drop and average value for each colorant are recorded in Table 2 below.

[0064] Table 2 - Drop in viscosity of colorant ( Δη MS )

[0065]

[0066]

[0067] In the case of two different HEUR chemicals (Comparative HEUR 1 and Inventive HEUR 1), when combined with a latex without structural units of organophosphorus monomers (Latex 1), Comparative Example 1 and Comparative Example 2 exhibited similar viscosity drops during coloring.

[0068] Comparative Example 3 and Comparative Example 4 show that when paired with Latex 2 or Latex 3 (both containing structural units of organophosphorus monomers) as compared to Latex 1 used in Comparative Example 1, Comparative HEUR 1 has a more problematic viscosity drop during coloring.

[0069] Surprisingly, Inventive Example 1 and Inventive Example 2 produced significantly opposite results when using Latex 2 or Latex 3 instead of Latex 1. In contrast to Comparative Example 3 and Comparative Example 4, which had a greater average viscosity drop when using Latex 2 or Latex 3 instead of Latex 1, Inventive Example 1 and Inventive Example 2 had a lower average viscosity drop when using Latex 2 or Latex 3 instead of Latex 1.

Claims

1. A composition, the composition comprising: (i) Polymer particles comprising structural units of an organophosphorus monomer; and (ii) A hydrophobically modified oxyalkylene-carbamate polymer having a hydrophobic moiety represented by Structure I: wherein the dashed line represents the point of attachment of the moiety to the hydrophobically modified oxyalkylene-carbamate polymer; Ar 1 is an unsubstituted phenyl, naphthyl, phenyl-O-CH2-, phenyl-CH2-O-CH2- or naphthyl-O-CH2-; phenyl, naphthyl, phenyl-O-CH2-, phenyl-CH2-O-CH2- or naphthyl-O-CH2- substituted by 1 to 3 C1-C6 alkyl or alkoxy groups; Ar 2 is phenyl, phenyl-OCH2CH2-, phenyl-(OCH2CH2) y -, benzyl, naphthyl, naphthyl-CH2-, naphthyl-OCH2CH2- or naphthyl-(OCH2CH2) y -, wherein Ar 2 phenyl or naphthyl moiety is unsubstituted or substituted with 1 to 3 C1-C6 alkyl groups, and wherein y is from 2 to 10; Each R 1 independently is H or C1-C6-alkyl; X is O or NR 2 , where R 2 is H, C1-C6-alkyl, phenyl or benzyl; m is from 1 to 20; and n is from 0 to 100.

2. The composition according to claim 1, wherein the organophosphorus monomer is a compound represented by Structure III: wherein: R 3 is H or -CH3; R 4 is a C1-C6 alkyl group; R 5 is H, or wherein the dashed line represents the point of attachment to the oxygen atom; and p is from 1 to 5.

3. The composition according to claim 2, wherein R 3 is -CH3, R 4 is -CH2CH2-, R 5 is H, and p is 1.

4. The composition according to any one of the preceding claims, wherein the polymer particles comprise at least 2 weight percent to 10 weight percent of the structural units of the organophosphorus monomer relative to the total weight of the polymer particles.

5. The composition according to any one of the preceding claims, wherein the polymer particles further comprise at least 30 weight percent to 98 weight percent of the structural units of acrylate and methacrylate monomers relative to the total weight of the polymer particles.

6. The composition according to any one of the preceding claims, wherein: Ar 1 is phenyl-O-CH2- or o-tolyl-O-CH2-; Ar 2 is phenyl, phenyl-OCH2CH2-, or o-methylphenyl; Each R 1 is independently H or CH3; m is from 1 to 10; and n is from 0 to 40.

7. A compound according to any one of the preceding claims, wherein the hydrophobic moiety has a number average molecular weight (M n ) in the range of 500 g / mol to 10,000 g / mol; and X is O or N-CH3, N-phenyl or N-benzyl.

8. The compound according to claim 7, wherein the hydrophobic moiety has an M in the range of 500 g / mol to 2500 g / mol n and is selected from the group consisting of: wherein R 1 ’ is H or CH3; and R 2 ’ is CH3 or benzyl.

9. The composition according to any one of the preceding claims, comprising an aqueous dispersion of the polymer particles in an amount of 10 weight percent to 60 weight percent based on the weight of the composition; and the hydrophobically modified oxyalkylene-carbamate polymer in an amount of 0.05 weight percent to 2 weight percent based on the weight of the composition.

10. The composition according to any one of the preceding claims, comprising TiO2 or BaSO4 particles with less than 10 PVC.

11. The composition according to any one of the preceding claims, further comprising one or more materials selected from the group consisting of binders, dispersants, pigments, defoamers, surfactants, solvents, extenders, coalescing agents, biocides, and opacifying polymers.

12. The composition according to any one of the preceding claims, wherein the hydrophobically modified oxyalkylene-carbamate polymer is a hydrophobically modified oxyethylene-carbamate polymer.

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