Rheological modifier composition and architectural paint composition derived therefrom

Abstract

The inventive concepts disclosed herein generally relate to rheology modifier compositions comprising 0.05 wt.% to 70.0 wt.% of an acrylamide polymer having a weight average molecular weight greater than 6 million Daltons, and 30.0 wt.% to 99.95 wt.% of at least one cellulose ether. Additionally, the inventive concepts disclosed herein relate to methods for preparing the rheology modifier compositions and aqueous coating compositions comprising the same.

Description

Technical Field

[0001] The processes, procedures, methods, products, results, and / or concepts disclosed herein (hereinafter collectively referred to as "the present disclosure") generally relate to rheology modifier compositions and their use. The present disclosure further relates to architectural coating compositions derived from rheology modifier compositions.

Background Art

[0002] Hydrophobically modified nonionic synthetic thickeners (NSATs), such as hydrophobically modified ethylene oxide-based polyurethanes (HEUR), generally known as associative rheology modifiers, are widely used for thickening or increasing the viscosity of paints in order to provide optimal application properties such as leveling (smoothness), sag resistance, etc. These rheology modifiers contain two or more hydrophobizing agents. The function of the hydrophobizing agent is to associate with the surface of the bound latex particles, as a result of which a network structure that binds the individual latex particles is formed, and thus the viscosity increases. Also used in the paint industry are another type of non-associative rheology modifiers. Examples of non-associative rheology modifiers include water-soluble polymers such as cellulose-based (HEC), starch, etc. Non-associative rheology modifiers increase the viscosity of paints and limit the mobility of paints by a thickening mechanism brought about by polymer molecules highly entangled in an aqueous solution. Although the individual use of polyacrylamide and cellulose ethers, such as hydroxyethyl cellulose, as non-associative thickeners is known in the relevant technical field, nevertheless, it is known to have some drawbacks such as, for example, a stringy or droopy rheology, poor leveling (smoothness), and dilution resistance.

[0003] Patent Document 1 (U.S. Patent No. 4,425,469) teaches the use of a water-soluble vinyl addition polymer of acrylamide containing a hydrophobic end group as an adsorbent and as a flow modifier in an aqueous system. The polymer of acrylamide is a homopolymer or copolymer having a terminal hydrophobic group introduced via a hydrophobic chain transfer agent.

[0004] Patent document 2 (Chinese Patent No. 1225934) teaches a high-viscosity powder building coating comprising sodium carboxymethylcellulose, hydroxypropylcellulose, and polyacrylamide.

[0005] Patent Document 3 (U.S. Patent No. 9,834,695), assigned to Hercules, discloses a rheological modifier composition for use in architectural coatings, which comprises a blend of cellulose ethers such as hydroxyethylcellulose, ethylhydroxyethylcellulose, and hydrophobic modified hydroxyethylcellulose, a cationic polymer such as acrylamidopropyltrimonium chloride, an acrylamidopropyltrimonium chloride / acrylamide copolymer, and a dispersant. [Prior art documents] [Patent Documents]

[0006] [Patent Document 1] U.S. Patent No. 4,425,469 [Patent Document 2] Chinese Patent No. 1225934 Specification [Patent Document 3] U.S. Patent No. 9,834,695 [Overview of the project] [Problems that the invention aims to solve]

[0007] Therefore, it has long been needed in the art to provide a rheological modifier composition that overcomes the drawbacks associated with the individual specifications of acrylamide polymers and cellulose ethers, resulting in a cost-effective rheological modifier composition that includes several unexpected advantages such as improved thickening effect, high sag resistance, dilution resistance, and cost in use.

[0008] In one embodiment, the Disclosure provides a rheological modifier composition comprising a blend of 0.05 wt.% to 70.0 wt.% of an acrylamide polymer having a weight-average molecular weight greater than 6 million daltons, and at least one 30.0 wt.% to 99.95 wt.% of a cellulose ether. In one non-limiting embodiment of the Disclosure, the acrylamide polymer is a nonionic homopolymer, an anionic copolymer, or a cationic copolymer. In one non-limiting embodiment of the Disclosure, the acrylamide polymer is a cationic polymer. In one non-limiting embodiment of the Disclosure, the weight-average molecular weight of the acrylamide polymer varies in the range of about 6 million daltons to about 15 million daltons, or about 8 million daltons to about 12 million daltons. In one non-limiting embodiment of the Disclosure, the cellulose ether is a glyoxal-treated cellulose ether or an untreated cellulose ether. In another non-limiting embodiment of the Disclosure, the cellulose ether is hydroxyethylcellulose or carboxymethylcellulose, either alone or in combination. In another non-limiting embodiment of the present disclosure, the cellulose ether is hydroxyethylcellulose that has not been treated with glyoxal. In yet another embodiment of the present disclosure, the cellulose ether is hydroxyethylcellulose that has been treated with glyoxal. In one non-limiting embodiment of the present disclosure, the rheological modifier composition is a dry powder blend.

[0009] In another embodiment, the Disclosure provides a method for preparing the rheological modifier composition of the Disclosure, comprising the steps of (i) blending 0.05 wt.% to 70.0 wt.% of an acrylamide polymer having a weight-average molecular weight greater than 6 million daltons, and (ii) 30.0 wt.% to 99.95 wt.% of at least one cellulose ether.

[0010] In yet another embodiment, the Disclosure provides applications for such rheological modifier compositions in aqueous-based coatings, the composition comprising (i) 0.05 wt.% to 70.0 wt.% of an acrylamide polymer having a weight-average molecular weight greater than 6 million daltons, and (ii) a blend of at least one 30.0 wt.% to 99.95 wt.% of a cellulose ether.

[0011] In yet another embodiment, the Disclosure provides an aqueous coating composition comprising (ia) 0.01 wt.% to 10.0 wt.% of a rheological modifier composition of the Disclosure, or (ib) 0.01 wt.% to 10.0 wt.% of an acrylamide polymer having a weight-average molecular weight greater than 6 million daltons, and at least one 0.01 wt.% to 10.0 wt.% of a cellulose ether, (ii) at least one 5.0 wt.% to 85.0 wt.% of a film-forming polymer, and (iii) 5.0 wt.% to 85.0 wt.% of water based on the total weight of the coating composition. In one non-limiting embodiment of the Disclosure, both the acrylamide polymer and the cellulose ether are present as a blend in the coating composition. In one non-limiting embodiment of the Disclosure, the aqueous coating composition further comprises at least one pigment. In one non-limiting embodiment of the Disclosure, the aqueous coating composition is an architectural coating composition. [Modes for carrying out the invention]

[0012] Before describing in detail at least one embodiment of the concept of the present invention using exemplary drawings, experiments, results, and experimental procedures, it should be understood that the concept of the present invention is not limited in scope to the details and arrangements of configurations described below or illustrated in the drawings, experiments, and / or results. The concept of the present invention can be carried out or implemented in other embodiments or in various ways. The language used herein is intended to give the broadest possible scope and meaning, and the embodiments are illustrative and not exhaustive. It should also be understood that the expressions and terms used herein are for illustrative purposes only and should not be considered limiting.

[0013] Unless otherwise defined herein, scientific and technical terms used in connection with this disclosure shall have meanings generally understood by those skilled in the art. Furthermore, unless otherwise specified in the context, singular terms shall include plural forms, and plural terms shall include singular forms. Generally, the nomenclature and chemical techniques used in connection with the chemistry described herein are publicly known and commonly used in the art. Reaction and purification techniques shall be carried out in accordance with the manufacturer's specifications, as commonly achieved in the art, or as described herein.

[0014] All patents, published patent applications, and non-patent literature referenced herein represent the level of skill of those skilled in the art to which this disclosure relates. All patents, published patent applications, and non-patent publications referenced in any part of this application are expressly incorporated herein in whole by reference to the same extent as when individual patents or publications are indicated to be incorporated specifically and individually by reference.

[0015] All compositions and / or methods disclosed and claimed herein can be manufactured and performed without undue experimentation in light of this disclosure. While the compositions and methods of the present invention have been described in terms of preferred embodiments, it will be apparent to those skilled in the art that modifications can be applied to the compositions and / or methods described herein, as well as to the steps or sets of steps of the methods, without departing from the concept, spirit, and scope of the invention. All such similar substitutes and modifications that are apparent to those skilled in the art shall be deemed to be within the spirit, scope, and concept of the invention as defined by the appended claims.

[0016] When used in accordance with this disclosure, the following terms shall be understood to have the following meanings unless otherwise indicated.

[0017] When used in the claims and / or specification in combination with the term “comprising”, the use of the words “a” or “an” may mean “one”, but also coincide with the meanings of “one or more”, “at least one”, and “one or more than one”. The use of the term “or” in the claims is used to mean “and / or”, but unless it is explicitly indicated that it refers only to substitutes or that the substitutes are mutually exclusive, this disclosure supports the definition that it refers only to substitutes and “and / or”. Throughout this application, the term “about” indicates that the value includes the variation in errors inherent in the apparatus, the apparatus employed to determine the value, and / or the variation present among the subjects under investigation. The use of the term “at least one” will be understood to include, but not limited to, any number greater than or equal to one, including 2, 3, 4, 5, 10, 15, 20, 30, 40, 50, 100, etc. The term "at least one" can be extended to 100, 1000, or even more, depending on the word it is attached to, and furthermore, the numbers 100 / 1000 are not limiting, and even greater limits may yield sufficient results. In addition, the use of the term "at least one of X, Y, and Z" is understood to include X alone, Y alone, Z alone, and any combination of X, Y, and Z.

[0018] As used herein and in the claims, the words “comprising” (and any variations of “comprising,” such as “comprise,” “comprises,” etc.), “having” (and any variations of “having,” such as “have,” “has,” etc.), “including” (and any variations of “including,” such as “includes,” “include,” etc.), or “containing” (and any variations of “containing,” such as “contains,” “contain,” etc.) are inclusive or non-exclusive and do not exclude additional unreproduced elements or steps of the method.

[0019] As used herein, the terms "or combinations thereof" refer to all permutations and combinations of the items listed before the term. For example, "A, B, C, or any combination thereof" is intended to include at least one of A, B, C, AB, AC, BC, or ABC, and also includes BA, CA, CB, CBA, BCA, ACB, BAC, or CAB if the order is important in the particular context. Continuing this example, combinations explicitly include those containing repetitions of one or more items or terms, such as BB, AAA, MB, BBC, AAABCCCC, CBBAAA, CABABB, etc. A person skilled in the art will understand that, unless otherwise evident from the context, there is typically no limit to the number of items or terms in any combination.

[0020] As used herein, the term "acrylamide polymer" means a polymer formed by polymerizing an acrylamide system as repeating units, which may be an acrylamide system repeating unit, acrylamide, or an acrylamide substituted on an α-carbon or nitrogen atom.

[0021] As used herein, the term "aqueous coatings" has the meaning recognized in the art, which allows for the inclusion of small amounts of co-solvents and other volatile organic materials, provided that water constitutes more than 50%, preferably at least 80%, of the volatile phase, so that even if organic solvents are present, most of the volatile solvents present in the liquid coating composition are water, and these coatings are still considered aqueous.

[0022] As used herein, the term "architectural coatings" refers to aqueous coatings characterized in that the resin binder is solubilized, dispersed or emulsified (emulsified) in an aqueous phase, which is generally a continuous phase mainly consisting of water. Suitable aqueous binders include materials such as starch, modified starch, polyvinyl alcohol, polyvinyl acetate, polyethylene / acrylic acid copolymer, acrylic acid polymer, polyacrylate, polyacrylamide copolymer, acrylonitrile / butadiene / styrene copolymer / polyacrylonitrile. Preferred and non-limiting examples of water-insoluble binders include polyacrylate, methacrylate, vinyl-acrylic, styrene-acrylic, etc.

[0023] One aspect of the present disclosure provides a rheology modifier composition. The rheology modifier composition of the present disclosure comprises a blend of an acrylamide polymer having a weight average molecular weight exceeding 6 million daltons and at least one type of cellulose ether. In one non-limiting embodiment of the present disclosure, the polyacrylamide polymer may be present in an amount of about 0.05 wt.% to about 70.0 wt.%. The cellulose ether may be present in an amount of about 30.0 wt.% to about 99.95 wt.% based on the total weight of the rheology modifier composition.

[0024] The acrylamide polymers according to the present disclosure can be nonionic homopolymers, anionic copolymers or cationic copolymers. In one non-limiting embodiment of the present disclosure, the acrylamide polymer is a homopolymer. In another non-limiting embodiment of the present disclosure, the acrylamide polymer is an anionic copolymer. In yet another non-limiting embodiment of the present disclosure, the acrylamide polymer is a cationic polymer. The anionic copolymer according to the present disclosure includes at least one monomer unit having one or more acidic functional groups or anhydride functional groups, or any combination thereof, having one or more heteroatoms selected from the group consisting of S, N, O, and P. Suitable examples of such monomers include, but are not limited to, acrylic acid, methacrylic acid, maleic acid or anhydride, itaconic acid or anhydride, acrylamidopropanesulfonic acid, vinylphosphonic acid, and the like. Similarly, suitable examples of the cationic polymer include, but are not limited to, 3-acrylamidopropyltrimethylammonium chloride, 3-methylacrylamidopropyltrimethylammonium chloride, and the like.

[0025] The acrylamide polymers according to the present disclosure can have an average molecular weight in the range of about 6 million daltons to about 15 million daltons. In one non-limiting embodiment of the present disclosure, the molecular weight of the acrylamide polymer varies in the range of 8 million daltons to 12 million daltons.

[0026] Acrylamide polymers useful for the purposes of this disclosure can be prepared by conventional methods known in the relevant art. Alternatively, commercially available polymers can be procured. Suitable examples of such commercially available polymers include, but are not limited to, FLOPAM® (registered trademark) (available from SNF) such as FA 920 VHM, FA 920 VHR, FA 920 SH, FA 920 SHR, FA 920 SD, FA 920 SHD, FA 920, FA 920 HD, AN 905 SH, AN 905 SHU, AN 910 SH, AN 910 SHU, AN 913 SH, AN 913 SHU, AN 923 SH, AN 923 SHU, and AN 926 SH, and PRAESTOL (available from Solenis) such as 2500 / 2500TR, 2510, 2515 / 2515TR, 2520, 2525, 2530 / 2530TR, 2540 / 2540TR, 2640, 644BC, and 650BC.

[0027] The cellulose ether used in the rheological modifier compositions of this disclosure may be a hydroxyalkyl cellulose ether. Furthermore, cellulose ethers useful for the purposes of this disclosure may be glyoxal-treated cellulose ethers or glyoxal-untreated cellulose ethers. Suitable examples of such cellulose ethers include hydroxyethylcellulose (HEC), hydroxypropylcellulose (HPC), ethylhydroxyethylcellulose (EHEC), carboxymethylcellulose (CMC), carboxymethylhydroxyethylcellulose (CMHEC), hydroxypropylhydroxyethylcellulose (HPHEC), methylcellulose (MC), methylhydroxypropylcellulose (MHPC), methylhydroxyethylcellulose (MHEC), carboxymethylmethylcellulose (CMMC), hydrophobic modified carboxymethylcellulose (HMCMC), hydrophobic modified hydroxyethylcellulose (HMHEC), hydrophobic modified hydroxypropylcellulose (HMHPC), hydrophobic modified ethylhydroxyethylcellulose (HMEHEC), hydrophobic modified carboxymethylhydroxyethylcellulose (HMCMHEC), hydrophobic modified hydroxypropylhydroxyethylcellulose (HMHPHEC), and hydrophobic modified methylcellulose (HM Examples include, but are not limited to, cellulose ethers (MC), hydrophobic modified methylhydroxypropylcellulose (HMMHPC), hydrophobic modified methylhydroxyethylcellulose (HMMHEC), hydrophobic modified carboxymethylmethylcellulose (HMCMMC), cationic hydroxyethylcellulose (cationic HEC), cationic hydrophobic modified hydroxyethylcellulose (cationic HMHEC), and any combination thereof. In one non-limiting embodiment of this disclosure, the cellulose ether may be hydroxyethylcellulose treated with glyoxal. In another non-limiting embodiment of this disclosure, the cellulose ether may be hydroxyethylcellulose that has not been treated with glyoxal. In another non-limiting embodiment of this disclosure, the cellulose ether may be either hydroxyethylcellulose or carboxymethylcellulose, or a combination thereof.

[0028] Furthermore, cellulose ethers useful for the purposes of this disclosure can be prepared by methods known in the art, or by using any commercially available product such as NATROSOL 250 HHBR, NATROSOL 250 H4BR, or NATROSOL 250 MHBR (available from Ashland LLC).

[0029] In one non-limiting embodiment of this disclosure, the acrylamide polymer may be present in an amount ranging from about 0.05 wt.% to about 50.0 wt.% or about 0.05 wt.% to about 30.0 wt.% relative to the total weight of the rheological modifier composition. In another non-limiting embodiment of this disclosure, the acrylamide polymer is a cationic polymer and may be present in an amount ranging from about 0.05 wt.% to about 50.0 wt.% or about 0.05 wt.% to about 30.0 wt.% relative to the total weight of the rheological modifier composition. In one non-limiting embodiment of this disclosure, the amount of cellulose ether may vary in an amount ranging from about 50.0 wt.% to about 99.95 wt.% or about 70.0 wt.% to about 99.95 wt.% relative to the total weight of the rheological modifier composition. In embodiments of this disclosure in which the cellulose ether is a combination of hydroxyethylcellulose and carboxymethylcellulose, the total amount thereof may vary in the range of about 50.0 wt.% to about 99.95 wt.% or about 70.0 wt.% to about 99.95 wt.% relative to the total weight of the rheological modifier composition.

[0030] The rheological modifier compositions of the present disclosure may further comprise at least one associative polymer selected from the group consisting of hydrophobic modified ethoxylated urethane polymers, hydrophobic modified polyacetal polyether polymers, hydrophobic modified alkali-swellable emulsions, hydrophobic modified aminoplasts, alkali-swellable emulsions, and combinations thereof. In one non-limiting embodiment of the present disclosure, the associative polymer is a hydrophobic modified polyacetal polyether polymer.

[0031] The rheological modifier composition may further include at least one additive selected from the group consisting of surfactants, dispersants, thickeners, anti-caking agents, defoaming agents, preservatives, waxes, hydrophobic agents including silicones and hydrocarbons, compatibilizers, adhesion promoters, stabilizers, crosslinking agents, and any combination thereof.

[0032] Suitable examples of dispersants include, but are not limited to, polycarboxylic acids, carboxylated polymer electrolytes, tripolyphosphates and potassium pyrophosphate, ethoxylated fatty alcohols, amino alcohols, acrylic copolymers, naphthalene sulfonic acid-formaldehyde adducts, sulfonated fatty acids, soy lecithin, polyethylene glycol dioleate, soy lecithin, PEG dioleate, polyethylene glycol, methoxypolyethylene glycol, polyethylene glycol monostearate, polyethylene glycol distearate, and combinations thereof.

[0033] The rheological modifier compositions of this disclosure are dry powder blends of an acrylamide polymer and a cellulose ether. The dry powder blends of the acrylamide polymer and cellulose ether according to this disclosure can be prepared by blending the acrylamide polymer and the cellulose ether. Another aspect of this disclosure provides a method for preparing the rheological modifier compositions of this disclosure, comprising (i) 0.05 wt.% to 70.0 wt.% of an acrylamide polymer having a weight-average molecular weight greater than 6 million daltons, and (ii) 30.0 wt.% to 99.95 wt.% of at least one type of cellulose ether. Any dry blending techniques or apparatus known as related techniques for preparing dry powder blends can be publicly used to blend the acrylamide polymer and cellulose ether according to this disclosure. Preferred examples of such dry blending techniques or apparatus include, but are not limited to, dry blending in a mortar and pestle, ball mill, or attritor mill.

[0034] In another non-limiting embodiment of this disclosure, cellulose ether may be used in amounts of about 50.0 wt.% to about 99.95 wt.% or about 70.0 wt.% to about 99.95 wt.% based on the total weight of the rheological modifier composition. Similarly, acrylamide polymer may be used in amounts of about 0.05 wt.% to about 50.0 wt.% or about 0.05 wt.% to about 30.0 wt.% based on the total weight of the rheological modifier composition of the present invention.

[0035] Furthermore, additional additives may be added during the preparation of the rheological modifier composition. Such additives may include at least one additive selected from the group consisting of surfactants, dispersants, thickeners, anti-caking agents, defoaming agents, preservatives, waxes, hydrophobic agents including silicones and hydrocarbons, compatibilizers, adhesion promoters, stabilizers, crosslinking agents, and any combination thereof.

[0036] The rheological modifier compositions of this disclosure can be used in aqueous coating compositions. In particular, the rheological modifier compositions of this disclosure are useful in all kinds of coatings, such as decorative and protective coatings and paper coatings. Aqueous protective coating compositions have been commonly known for many years as latex coatings or dispersion coatings. Rheological modifiers used in aqueous coating compositions increase and maintain viscosity to the required level under specific processing conditions and end-use conditions. Aqueous protective coating compositions need to provide good leveling and excellent sag resistance through the selection of rheological modifiers. Another aspect of this disclosure provides the use of the rheological modifier compositions of this disclosure in aqueous-based coatings, the composition comprising (i) about 0.05 wt.% to about 70.0 wt.% of an acrylamide polymer and (ii) a blend of at least one cellulose ether in about 30.0 wt.% to about 99.95 wt.%.

[0037] Another aspect of the present disclosure provides an aqueous coating composition comprising the rheological modifier composition of the present disclosure as described herein. The aqueous coating composition comprises, or substantially comprises, a rheological modifier composition comprising an acrylamide polymer having a molecular weight greater than 6 million daltons, at least one cellulose ether, at least one film-forming polymer, and water.

[0038] The amount of the rheology modifier composition used in the aqueous coating composition of this disclosure is an effective amount to provide the aqueous coating composition with the desired viscosity and rheological properties, and therefore depends on both the desired rheological properties and the dispersion used. Furthermore, the rheology modifier composition may be added to the aqueous coating composition of this disclosure as a dry powder blend of an acrylamide polymer having a molecular weight of more than 6 million daltons and at least one cellulose ether. Alternatively, the acrylamide polymer having a molecular weight of more than 6 million daltons and at least one cellulose ether may be added individually to the aqueous coating composition of this disclosure.

[0039] In embodiments of the present disclosure in which the rheological modifier composition may be added to an aqueous coating composition as a dry powder blend, the amount of the rheological modifier composition may vary in the range of about 0.01 wt.% to about 10.0 wt.% based on the total weight of the aqueous coating composition. In another non-limiting embodiment of the present disclosure, the amount may vary in the range of about 0.05 wt.% to about 5.0 wt.% based on the total weight of the aqueous coating composition.

[0040] In embodiments of this disclosure in which the acrylamide polymer and cellulose ether are added individually, the amount of each typically varies in the range of about 0.01 wt.% to about 10.0 wt.% relative to the total weight of the aqueous coating composition. When the acrylamide polymer and cellulose ether are added individually to the aqueous coating composition, they exist as a synergistic dry blend. In this case, their combined weight percentage may vary in the range of about 0.01 wt.% to about 10.0 wt.% or about 0.05 wt.% to about 5.0 wt.% relative to the total weight of the aqueous coating composition.

[0041] The aqueous coating compositions of this disclosure are aqueous polymer dispersions comprising at least one film-forming polymer. The film-forming polymers used in the aqueous coating compositions of this disclosure can be selected from a wide variety of polymers known in the related art. For example, these film-forming polymers can be obtained from various ethylenically unsaturated monomers such as ethylene, vinyl, and acrylic monomers. Examples of such monomers include, but are not limited to, acrylic acid, methacrylic acid, methacrylic acid esters, styrene, α-methylstyrene, vinyl chloride, acrylonitrile, methacrylonitrile, methacrylate ureid, vinyl acetate, vinyl esters of branched tertiary monocarboxylic acids, itaconic acid, crotonic acid, maleic acid, fumaric acid, and ethylene. They can also include C4-C8 conjugated dienes such as 1,3-butadiene, isopropylene, and chloropyrene. The film-forming polymers can also be one or more copolymer products, particularly for applications in latex coatings that are volatile organic compound (VOC)-free or contain little to no VOCs. Examples of suitable film-forming polymers include, but are not limited to, homopolymers or copolymers of vinyl acetate, methacrylic acid, methyl acrylate, methyl methacrylate, ethyl acrylate, butyl acrylate, styrene, ethylene, vinyl chloride, vinyl versatate (VeoVa), vinyl propionate, butadiene, acrylonitrile, maleate, and fumarate. In one non-limiting embodiment of the present disclosure, the film-forming polymer is selected from the group consisting of acrylic, vinyl-acrylic and styrene-acrylic, styrene-butadiene copolymer, vinyl acetate ethylene, butadiene-acrylonitrile copolymer, epoxide, urethane, polyamide, vinyl versatate (VeoVa), and polyester.

[0042] Other suitable film-forming polymers include, but are not limited to, alkyds, cellulosins (nitrocellulose and cellulose esters), coumarone indene, epoxy, hydrocarbons, melamine, natural resins, oleoresins, phenols, polyamides, polyesters, rosin, silicones, terpenes, ureas, urethanes, and vinyls.

[0043] The amount of film-forming polymer in the aqueous coating composition of this disclosure may vary in the range of about 5.0 wt.% to about 85.0 wt.% based on the total weight of the aqueous coating composition. In one non-limiting embodiment of this disclosure, the amount of film-forming polymer may vary in the range of about 40.0 wt.% to about 70.0 wt.% or about 50.0 wt.% to about 70.0 wt.% based on the total weight of the aqueous coating composition.

[0044] The aqueous coating compositions of this disclosure may further comprise at least one pigment. The pigment can be selected from the group consisting of phthalocyanine, iron oxide, titanium dioxide, zinc oxide, indigo, hydrated aluminum oxide, barium sulfate, calcium silicate, clay, silica, talc, calcium carbonate, and mixtures thereof. Often, the titanium oxide grade used in the aqueous coating compositions is surface-modified with various inorganic oxides such as silicates, aluminates, and zirconates. Aluminum silicate, nepheline syenite, mica, calcium carbonate, and / or diatomaceous earth can also be employed.

[0045] The type and amount of pigment present in the aqueous coating compositions of this disclosure define the performance characteristics of the dried film, such as gloss, penetration, scrub resistance, and tensile strength. Therefore, the coating is characterized by its pigment volume concentration (PVC). PVC is a percentage representing the volume ratio of pigment to the total solids present in the dried film. PVC is defined as follows:

[0046] PVC% = Pigment volume / (Pigment volume + Latex volume) × 100

[0047] The point at which all the voids between pigment particles are filled with the film-forming polymer is called the critical pigment volume concentration (CPVC).

[0048] The aqueous coating compositions of this disclosure have a PVC upper limit of about 85% by weight. In one non-limiting embodiment of this disclosure, the aqueous coating composition has a PVC upper limit of about 75% by weight. In another non-limiting embodiment of this disclosure, the aqueous protective coating has a PVC upper limit of about 65% by weight. Similarly, the aqueous coating compositions of this disclosure have a PVC lower limit of about 10% by weight. In another non-limiting embodiment of this disclosure, the aqueous coating composition has a PVC lower limit of about 20% by weight. More specifically, if the latex coating is a high-gloss coating, the PVC is about 15% to about 30% by weight; if the coating is a semi-gloss coating, the PVC is about 20% to about 35% by weight; and if it is a matte coating, the PVC is about 40% to about 85% by weight. Pigments can be added to the aqueous coating composition in the form of a dry powder or a slurry.

[0049] The remainder of the aqueous paint composition is water. Water can be present in the film-forming polymer dispersion and in the other components of the aqueous paint composition. Alternatively, water can be added separately to the aqueous paint composition.

[0050] The aqueous coating compositions of this disclosure may further include at least one additive. Examples of such additives include, but are not limited to, surfactants, dispersants such as polyphosphates, amino alcohols and acrylic copolymers, thickeners, anti-solidifying agents, antifoaming agents such as non-silicone and silicone-based ones, plasticizers, fillers, preservatives, waxes, hydrophobic agents including silicones and hydrocarbons, compatibilizers, adhesion promoters, crosslinking agents, biocides, antifungal agents, non-silicone and silicone-based antifoaming agents, cosolvents, bonding agents such as glycol ethers / esters, and any combination thereof. These additives may be used in methods and amounts known in the art of conventional aqueous coating compositions.

[0051] The aqueous coating compositions described herein can be used in a variety of applications. In particular, the rheological modifier compositions of this disclosure are useful in decorative and protective coatings for walls, ceilings, doors, trims, etc., and in all kinds of coatings such as paper coatings, drywall, masonry, wood, metal, plastic, and primer surfaces. In one non-limiting embodiment of this disclosure, the coating composition is an architectural coating composition for interior and / or exterior surfaces of buildings.

[0052] Another aspect of the present disclosure further provides a method for preparing an aqueous coating composition of the present disclosure, the method comprising the step of mixing or blending at least one film-forming polymer, a rheological modifier composition of the present disclosure, and water under stirring. Pigments may be added advantageously to obtain an aqueous architectural coating. The additives described herein may also be added to the film-forming agent, rheological modifier, pigment, or combination thereof in any suitable order.

[0053] Water-based coating compositions are stable fluids that can be applied as protective coatings to a wide variety of surface materials. Examples of such materials include, but are not limited to, paper, wood, concrete, metal, glass, ceramic, plastic, gypsum, asphalt coatings, roofing felt, foamed polyurethane insulation and other roofing substrates, or substrates that have been previously painted, primed, undercoated, worn, or weathered.

[0054] A further aspect of the present disclosure provides a method for applying the aqueous coating compositions of the present disclosure to various surfaces. The aqueous coating compositions can be applied to one or more surfaces by various conventional methods known to those skilled in the art. Examples of such application methods include, but are not limited to, application by aerosol spray, brush, roller, airless spray, air-assisted spray, electrostatic spray, high volume low pressure (HVLP) spray, and the like.

[0055] The rheological modifier compositions of this disclosure have beneficial effects on specific rheological properties of paint formulations, such as thickening efficiency and sag resistance. To our surprise, we have found that compositions comprising a blend of acrylamide polymer and cellulose ether exhibit several unique and unexpected properties, such as improved efficiency (cost of use) and thickening efficiency, as well as better dilution resistance and improved opacity, compared to conventional non-associative thickeners such as pure acrylamide polymer or cellulose-based thickeners, with equivalent or improved application performance. These rheological modifier compositions improve or enhance the overall thickening efficiency (Stormer viscosity, Brookfield viscosity, and ICI viscosity) of paint formulations and are particularly suitable for paint formulations that are difficult to thicken, such as vinyl acetate ethylene (VAE) latex paints. In addition, these rheological modifier compositions provide a considerable number of structural advantages to architectural coatings, including improved sag resistance.

[0056] The following examples illustrate the inventive concept disclosed and / or claimed herein, and unless otherwise noted, proportions or percentages are in weight percent. Each example is presented for illustrative purposes of the inventive concept currently disclosed and / or claimed herein, and is not intended to limit the inventive concept currently disclosed and / or claimed herein. Indeed, it will be apparent to those skilled in the art that various modifications and variations can be made to the inventive concept currently disclosed and / or claimed without departing from the scope or spirit of the invention. For example, features illustrated or described as part of one embodiment can be used in another embodiment to obtain yet another embodiment. Thus, the inventive concept currently disclosed and / or claimed herein is intended to encompass modifications and variations that fall within the scope of the appended claims and their equivalents. [Examples]

[0057] [Test Method] Unless otherwise specified, the following test methods were used in the examples.

[0058] [Measurement of thickening efficiency] The thickening efficiency was measured by adding 0.15% by weight of the activator from the polymer sample obtained in the example to the architectural coating formulations shown in Table 2. The thickening efficiency was measured by the Stormer viscosity (KU), Brookfield viscosity, and ICI viscosity of the thickened architectural coating composition.

[0059] Brookfield viscosity was measured using a Brookfield viscometer at spindle #5, 30 RPM, and 25°C. The unit is mPa.s.

[0060] Stomer viscosity was measured using a stomer viscometer according to the standard test method ASTM D562. The unit is Kleb units (KU).

[0061] ICI viscosity was measured using an ICI cone plate according to the standard test method ASTMD4287. The unit is mPa.s.

[0062] Sag resistance was measured by drawing down the paint using a multi-notch drawdown applicator (Leneta anti-sag meter) with various clearances, in accordance with ASTM D4400. Sag resistance is reported as a sag index in mils.

[0063] [Example 1: Blend of HEC and acrylamide polymer (FLOPAM AN 923SH)] The complete samples of the rheology modifier composition for Example 1 were prepared by blending dry granular hydroxyethylcellulose (HEC HBR 250PA, available from Ashland), a type of moderately anionic acrylamide polymer with a dalton Mw of 12 to 14 million, in the weight ratios shown in Table 1, and acrylamide polymer (FLOPAM AN 923SH, available from SNF). In a typical experiment, hydroxyethylcellulose (HEC HBR 250PA) was mixed with the acrylamide polymer (AN 923SH) in an 8-ounce glass jar and blended using a Harville mixer until a homogeneous mixture was obtained.

[0064] [Control Example 1: Control Rheology Modifier Compositions (CE.1A and CE.1B)] Two different control rheology modifier compositions (CE.1A and CE.1B) were prepared using 100 wt.% acrylamide polymer (FLOPAM AN 923SH) or 100 wt.% HECHBR250PA in the same manner as described in Example 1, and were compared with the rheology modifier composition of Example 1. [Table 1]

[0065] The rheological modifier composition of Example 1 was added to the paint formulation (shown in Tables 2A and 2B) at a concentration of 0.15 wt.%. The formulated aqueous paint composition was allowed to equilibrate overnight before measuring Brookfield viscosity, Stormer viscosity reaction, and ICI viscosity. Sag resistance, which is the ability of the architectural paint composition to resist sagging and dripping of a wet paint film, was also measured. A higher sag index number indicates a greater ability of the paint composition to prevent dripping of freshly applied wet paint. [Table 2A] Proxel GXL: A biocide commercially available from Lonza Corporation. Drewplus™ L-475: An antifoaming agent commercially available from Ashland. Tamol™ 731A: A dispersant commercially available from Dow Chemical Company. Strodex™ PK-90: ​​A surfactant commercially available from Ashland. Strodex™ TH-4427: A surfactant commercially available from Ashland Corporation. Tronox(registered trademark) CR-828: A rutile-type titanium dioxide pigment commercially available from Tronox Limited. Optiwhite MX: A calcined alumina silicate pigment commercially available from Burgues Pigments. AMP-95: A neutralizing agent commercially available from Angus Chemical Company. [Table 2B] *Acronal 296D: A styrene-butyl acrylate emulsion commercially available from Dow Chemicals. **Optifilm™ Enhancer 400: A combination agent commercially available from Eastman Chemical Company.**

[0066] [Example 2: Blend of HEC and acrylamide polymer (PRAESTOL A 2530)] The rheological modifier composition of this example was prepared in the same manner as described in Example 1, using the weight proportions shown in Table 3 for acrylamide polymer (PRAESTOL A 2530 anionic polymer, available from Solenis) and hydroxyethylcellulose (HEC HBR 250PA) powder.

[0067] These compositions were added to the paint formulations (shown in Tables 2A and 2B) at a concentration of 0.15 wt.%. The Stormer viscosity, Brookfield viscosity, ICI viscosity, and sag index data for paint formulations using these compositions are shown in Table 3. [Table 3]

[0068] [Example 3: Blend of HEC and acrylamide polymer (FLOPAM 920 VHM)] The rheological modifier compositions of this example were prepared in the same manner as described in Example 2 above, except that an acrylamide polymer (FLOPAM 920 VHM, available from SNF) was used. The acrylamide polymer and hydroxyethylcellulose powder were dry-blended in the weight percentages shown in Table 4. These rheological modifier compositions were added to the paint formulations (shown in Tables 2A and 2B) at a concentration of 0.15 wt.%. Stomer viscosity, Brookfield viscosity, and ICI viscosity, and sag index data are shown in Table 4. [Table 4]

[0069] [Example 4: Effect of acrylamide polymer on paint thickening efficiency] In this example, acrylamide polymers with different molecular weights (Mw) were used to evaluate the effect of acrylamide polymers on the thickening efficiency of paint formulations. Table 5 lists acrylonitrile copolymers (FLOPAM polymers available from SNF) with molecular weights (Mw). These polymers were added to 47PVC acrylate styrene-butyl paint formulations at a concentration of 0.34 wt.% (single weight) (Tables 2A and 2B). [Table 5]

[0070] As is clear from Table 5, the viscosity of paint formulations (KU, Brookfield, and ICI viscosity) also decreases as the Mw of the acrylamide polymer, especially nonionic acrylamide polymers, decreases.

Claims

1. (i) an acrylamide polymer having a weight-average molecular weight of over 6 million daltons in an amount of 0.05 wt.% to 70.0 wt.% relative to the blend, and (ii) 30.0 wt.% to 99.95 wt.% of the blend, A rheological modifier composition comprising a blend of, The acrylamide polymer is (i) a nonionic homopolymer, (ii) an anionic copolymer having one or more acidic functional groups or anhydride functional groups or combinations thereof, with at least one monomer having one or more heteroatoms selected from the group consisting of S, N, O, and P, (iii) a cationic polymer, or (iv) a cationic copolymer. The aforementioned composition is a rheological modifier composition, which is a dry powder blend.

2. A rheological modifier composition according to claim 1, wherein the monomer is selected from the group consisting of acrylic acid, methacrylic acid, maleic acid or anhydride, itaconic acid or aqueous solution, crotonic acid, fumaric acid, and citraconic acid.

3. A rheological modifier composition according to claim 1, wherein the weight-average molecular weight of the acrylamide polymer varies in the range of 6 million daltons to 15 million daltons.

4. In the rheological modifier composition according to claim 1, the cellulose ether is hydroxyethylcellulose (HEC), hydroxypropylcellulose (HPC), ethylhydroxyethylcellulose (EHEC), carboxymethylcellulose (CMC), carboxymethylhydroxyethylcellulose (CMHEC), hydroxypropylhydroxyethylcellulose (HPHEC), methylcellulose (MC), methylhydroxypropylcellulose (MHPC), methylhydroxyethylcellulose (MHEC), carboxymethylmethylcellulose (CMMC), hydrophobic modified carboxymethylcellulose (HMCMC), hydrophobic modified hydroxyethylcellulose (HMHEC), hydrophobic modified hydroxypropylcellulose (HMHPC), hydrophobic modified ethyl hydroxyethylcellulose A rheology modifier composition comprising a glyoxal-treated or untreated cellulose ether selected from the group consisting of roxyethylcellulose (HMEHEC), hydrophobic modified carboxymethylhydroxyethylcellulose (HMCMHEC), hydrophobic modified hydroxypropylhydroxyethylcellulose (HMHPHEC), hydrophobic modified methylcellulose (HMMC), hydrophobic modified methylhydroxypropylcellulose (HMMHPC), hydrophobic modified methylhydroxyethylcellulose (HMMHEC), hydrophobic modified carboxymethylmethylcellulose (HMCMMC), cationic hydroxyethylcellulose (cationic HEC), cationic hydrophobic modified hydroxyethylcellulose (cationic HMHEC), and any combination thereof.

5. A rheological modifier composition according to claim 1, wherein the acrylamide polymer is present in an amount of 0.05 wt.% to 50.0 wt.%, and the cellulose ether is present in an amount of 50.0 wt.% to 99.95 wt.%.

6. A rheology modifier composition according to claim 1, further comprising at least one associative polymer selected from the group consisting of a hydrophobic modified ethoxylated urethane polymer, a hydrophobic modified polyacetal polyether polymer, a hydrophobic modified alkali-swellable emulsion, a hydrophobic modified aminoplast, an alkali-swellable emulsion, and combinations thereof.

7. A rheological modifier composition according to claim 1, wherein the composition further comprises at least one additive selected from the group consisting of surfactants, dispersants, thickeners, anti-solidification agents, defoaming agents, preservatives, waxes, hydrophobic agents including silicones and hydrocarbons, compatibilizers, adhesion promoters, crosslinking agents, and any combination thereof.

8. A method for preparing the composition described in claim 1, (i) an acrylamide polymer having a weight-average molecular weight of over 6 million daltons in an amount of 0.05 wt.% to 70.0 wt.% relative to the blend, and (ii) 30.0 wt.% to 99.95 wt.% of the blend, A method that includes a step for blending.

9. The method according to claim 8, further, A method comprising the step of blending at least one additive selected from the group consisting of surfactants, dispersants, thickeners, anti-caking agents, defoaming agents, preservatives, waxes, hydrophobic agents including silicones and hydrocarbons, compatibilizers, adhesion promoters, crosslinking agents, and any combination thereof.

10. A water-based paint composition, Based on the total weight of the paint composition, (ia) The composition of claim 1 in an amount of 0.01 wt.% to 10.0 wt.%, (ii) At least one film-forming polymer in an amount of 5.0 wt.% to 85.0 wt.%, (iii) 5.0 wt.% to 15.0 wt.% water and A water-based paint composition containing the following:

11. The aqueous coating composition according to claim 10, wherein the film-forming polymer is selected from the group consisting of acrylic, vinyl-acrylic and styrene-acrylic, styrene-butadiene copolymer, vinyl acetate ethylene, butadiene-acrylonitrile copolymer, epoxide, urethane, polyamide, vinyl ester versaticate (VeoVa), and polyester.

12. The aqueous paint composition according to claim 10, wherein the paint composition further comprises at least one pigment selected from the group consisting of phthalocyanine, iron oxide, titanium dioxide, zinc oxide, indigo, hydrated aluminum oxide, barium sulfate, calcium silicate, clay, silica, talc, calcium carbonate, and mixtures thereof.

13. The aqueous paint composition according to claim 12, wherein the paint composition has a pigment volume concentration (PVC) in the range of 15% to 85%.

14. The aqueous paint composition according to claim 10, wherein the paint composition further comprises at least one additive selected from the group consisting of surfactants, dispersants, thickeners, anti-solidifying agents, defoaming agents, plasticizers, bulking agents, preservatives, waxes, hydrophobic agents including silicones and hydrocarbons, compatibilizers, adhesion promoters, crosslinking agents, biocides, antifungal agents, defoaming agents, cosolvents, bonding agents, and any combination thereof.

15. The aqueous paint composition according to claim 10, wherein the aqueous paint composition is an architectural paint composition.

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