Acrylamide polymer reverse emulsion containing rheological modifiers and building coating compositions derived therefrom

Abstract

The inventive concepts disclosed herein generally relate to rheology modifier compositions comprising 0.05% to 70.0% by weight of an inverse emulsion of an acrylamide polymer and 30.0% to 99.95% by weight of at least one cellulose ether, where the cellulose ether can be in dry powder form or in fluidized polymer suspension form. Additionally, the inventive concepts disclosed herein also relate to methods of making the rheology modifier compositions and aqueous coating compositions comprising the rheology modifier compositions.

Description

Technical Field

[0001] The processes, procedures, methods, products, results, and / or concepts disclosed herein (collectively hereinafter referred to as "the present disclosure") generally relate to a rheology modifier composition containing an inverse emulsion of an acrylamide polymer and its applications. The present disclosure further relates to an architectural coating composition obtained from the rheology modifier composition.

Background Art

[0002] Hydrophobically modified nonionic synthetic thickeners (NSATs), such as hydrophobically modified ethylene oxide-based polyurethanes (HEUR), are generally known as associative rheology modifiers (modifiers) and are widely used to thicken the viscosity of paints, providing optimal application performance (applicability) such as leveling and sag resistance. These rheology modifiers contain two or more hydrophobic substances. The function of the hydrophobic substances is to bind (associate) with the surface of the binder latex particles, resulting in a network structure that binds the individual latex particles, thereby increasing the viscosity. Also, in the coating industry, non-associative rheology modifiers are used. Examples of non-associative rheology modifiers include water-soluble polymers such as cellulose (HEC), starch, etc. Non-associative rheology modifiers increase the viscosity of paints through a thickening mechanism introduced by highly entangled polymer molecules in an aqueous solution, thereby restricting the mobility of the paints. The individual use of polyacrylamide and cellulose ethers, such as hydroxyethyl cellulose, as non-associative thickeners is known in the related art, but nevertheless, they are known to have certain defects such as a stringy or gloppy rheology, insufficient leveling, and dilution resistance.

[0003] Scott Bader Co. Ltd.'s European Patent No. 0042678 discloses a thickener for aqueous-based compositions, which is a water-in-oil emulsion containing a water-soluble polyacrylamide or polymethacrylamide homopolymer (homopolymer), or a copolymer (polymer) with other suitable monomers such as acrylic acid or methacrylic acid.

[0004] U.S. Patent No. 5,521,234 teaches the use of hydroxyethylcellulose and / or alkyl or arylalkyl hydrophobic modified hydroxyethylcellulose as a fluidized polymer suspension (FPS) thickener and in aqueous coating compositions.

[0005] Therefore, there has long been a need in the art to provide a rheological modifier composition that overcomes the shortcomings of conventional compositions and offers cost-effective rheological modifier compositions with unexpected benefits such as improved thickening efficiency, high sag resistance and dilution resistance, and lower costs in use. [Overview of the Initiative]

[0006] One aspect of the present disclosure provides a rheology modifier composition comprising (i) a reverse emulsion of an acrylamide polymer in an amount of 0.05 to 70.0 wt.%, and (ii) a blend of at least one cellulose ether in an amount of 30.0 to 99.95 wt.%. In one non-limiting embodiment of the present disclosure, the acrylamide polymer includes a nonionic homopolymer, an anionic copolymer, or a cationic copolymer. In one non-limiting embodiment of the present disclosure, the acrylamide polymer is a cationic polymer. In one non-limiting embodiment of the present disclosure, the weight-average molecular weight of the acrylamide polymer varies in the range of about 50,000 daltons to about 15,000,000 daltons. In one non-limiting embodiment of the present disclosure, the cellulose ether is glyoxal-treated cellulose ether or unglyoxal-treated cellulose ether. In another non-limiting embodiment of the present disclosure, the cellulose ether is hydroxyethylcellulose or carboxymethylcellulose, either alone or in combination thereof. In another non-limiting embodiment of the present disclosure, the cellulose ether is unglyoxal-treated hydroxyethylcellulose. In yet another embodiment of the present disclosure, the cellulose ether is glyoxal-treated hydroxyethylcellulose. In one non-limiting embodiment of the present disclosure, the cellulose ether is in the form of a dry powder or a fluidized polymer suspension.

[0007] Another aspect of the present disclosure provides a method for preparing the above-mentioned rheology modifier composition, the method comprising the steps of (i) blending a reverse emulsion of an acrylamide polymer in an amount of 0.05% to 70.0% by weight; and (ii) blending at least one cellulose ether in an amount of 30.0% to 99.95% by weight, wherein the cellulose ether is in the form of a dry powder or a fluidized polymer suspension.

[0008] A further aspect of the present disclosure is intended for use in aqueous-based coatings (films) comprising (i) a blend of 0.05% to 70.0% by weight of an acrylamide polymer in reverse emulsion, and (ii) 30.0% to 99.95% by weight of at least one cellulose ether, wherein the cellulose ether is in the form of a dry powder or a fluidized polymer suspension.

[0009] Another aspect of this disclosure is, (ia) 0.01% to 10.0% by weight of a rheology modifier composition of the present disclosure, or (ib) 0.01% to 10.0% by weight of an inverse emulsion of an acrylamide polymer and 0.01% to 10.0% by weight of at least one cellulose ether, (ii) at least one film-forming polymer in an amount of 5.0% to 85.0% by weight, and (iii) Provide an aqueous coating composition comprising 5.0% to 15.0% by weight of water, based on the total weight of the aqueous coating composition. In one non-limiting embodiment of the present disclosure, the aqueous coating composition is a building coating composition. [Modes for carrying out the invention]

[0010] Before describing in detail at least one embodiment of the concept of the present invention with illustrative drawings, experiments, results, and experimental procedures, it should be understood that the application of the concept of the present invention is not limited to the detailed configuration and arrangement of components described or shown in the following description or in the drawings, experiments, and / or results. The concept of the present invention can be carried out in other embodiments or in a variety of ways. Accordingly, 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 language and terminology used herein are for illustrative purposes only and should not be considered limiting.

[0011] Unless otherwise defined herein, scientific and technical terms used in connection with this disclosure have meanings generally understood by those skilled in the art. Furthermore, unless otherwise specified in the context, singular terms include plural forms, and plural terms include singular forms. Generally, the nomenclature used in connection with the chemical techniques described herein is well known and commonly used in the art. Reaction and purification techniques are carried out according to the manufacturer's specifications, as commonly achieved in the art, or as described herein.

[0012] All patents, published patent applications, and non-patent publications described in this specification represent the state of the art for those skilled in the art to which this disclosure relates. All patents, published patent applications, and non-U.S. patent publications referenced in any part of this application are expressly incorporated by reference in whole to the same extent as each individual patent or publication is specifically and individually directed to be incorporated by reference.

[0013] All compositions and / or methods disclosed and claimed herein can be prepared and performed without undue experimentation in light of this disclosure. While the compositions and methods of the present invention are described in relation to preferred embodiments, it will be apparent to those skilled in the art that modifications can be made to the compositions and / or methods described herein, as well as to the steps or sequences of steps of such methods, without departing from the concept, intent, and scope of the invention. All such similar substitutes and modifications, which will be apparent to those skilled in the art, are deemed to fall within the spirit, scope, and concept of the invention as defined by the appended claims.

[0014] When used in accordance with this disclosure, unless otherwise indicated, the following terms shall be understood to have the following meanings:

[0015] The use of the terms “one (a)” or “one (an)” in the claims and / or specification in connection with the term “including” may mean “one,” but also coincide with the meanings of “one or more,” “at least one,” and “one or more.” The use of the term “or” in the claims is used to mean “and / or,” unless it is explicitly indicated that it refers only to the options, or that the options are mutually exclusive, although this disclosure supports definitions that refer only to the options and “and / or.” Throughout this application, the term “about” is used to indicate that the value includes device-specific error variability, the method used to determine the value, and / or variability that exists between the subjects of study. The use of the term “at least one” is understood to include one and two or more quantities, including but not limited to 2, 3, 4, 5, 10, 15, 20, 30, 40, 50, 100, etc. The term "at least one" can extend to 100 or 1000 or more, depending on the term it is attached to, and moreover, higher limits may yield satisfactory results. Furthermore, a quantity of 100 / 1000 is not considered a limitation, as a higher limitation may also yield satisfactory results. Additionally, 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.

[0016] As used herein and in the claims, the words “compriss” (and any form of “compriss,” such as “compriss” and “comprises”), “have” (and any form of “have,” such as “have” and “has”), “includes” (and any form of “includes,” such as “includes” and “include”), or “contains” (and any form of “contains,” such as “contains” and “contain”) are comprehensive or open-ended and do not exclude additional, unquoted elements or method steps.

[0017] As used herein, the terms "or combination thereof" mean all permutations and combinations of the items listed before the term. For example, "A, B, C, or 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, where the order is important in a particular context. Following this example, combinations containing repetitions of one or more items or terms are explicitly included, such as BB, AAA, MB, BBC, AAABCCCC, CBBAAA, CABABB, etc. Those 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.

[0018] As used herein, the term "acrylamide polymer" means a polymer formed by polymerizing repeating monomer units based on acrylamide, where the repeating units based on acrylamide may be acrylamide or acrylamide substituted on an alpha carbon atom or a nitrogen atom.

[0019] As used herein, the term “reverse emulsion” means a water-in-oil emulsion comprising an oil as a continuous phase and an aqueous solution or gel as a discontinuous / dispersed phase, wherein the aqueous phase comprises one or more water-soluble or water-dispersible polymers, such as an acrylamide polymer.

[0020] As used herein, the term “aqueous coating” has its technically recognized meaning, which allows for the inclusion of small amounts of cosolvents and other volatile organic materials; however, since water constitutes more than 50%, preferably at least 80%, of the volatile phase, and even in the presence of organic solvents, these coatings are still considered aqueous because the majority of the volatile solvent present in the liquid coating composition is water.

[0021] As used herein, the term “architectural coating” refers to an aqueous coating characterized by a resinous binder being solubilized, dispersed, or emulsified in an aqueous phase, generally called the continuous phase, which is primarily water. Suitable aqueous binders may 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, and polyacrylonitrile. Suitable and non-limiting examples of non-water-soluble binders include polyacrylate, methacrylate, vinyl-acrylic, and styrene-acrylic.

[0022] One aspect of the present disclosure provides a rheological modifier composition. The rheological modifier composition of the present disclosure comprises a blend of an inverse emulsion of an acrylamide polymer and at least one cellulose ether.

[0023] The inverse emulsion of the acrylamide polymer used in the rheology modifier composition of the present disclosure is a water-in-oil emulsion of an acrylamide polymer containing water as a discontinuous phase dispersed in at least one oil phase as a continuous phase. The acrylamide polymer is solubilized in the discontinuous aqueous phase. The inverse emulsion or water-in-oil emulsion of the acrylamide polymer can further contain one or more emulsifying surfactants and one or more inversion surfactants.

[0024] The inverse emulsion of the acrylamide polymer useful for the purposes of the present disclosure can be prepared by conventional methods known in the relevant technical fields. Alternatively, commercially available polymer products can also be procured. Suitable examples of such products include, but are not limited to, PRAESTOL N3100 LTR, PRAESTOL N3100 L, PRAESTOL A3040 LAD, PRAESTOL A3015 L, PRAESTOL 3019L (available from Solenis), and FLOPAM EM 230 and FLOPAM DW 230 from SNF.

[0025] The relative amounts of the components of the inverse emulsion of the acrylamide polymer can vary over a wide range. In one non-limiting embodiment of the present disclosure, the inverse emulsion of the acrylamide polymer contains from about 5.0 wt% to about 90.0 wt% water, from about 5.0 wt% to about 90.0 wt% oil phase, from about 2.0 wt% to about 90.0 wt% acrylamide polymer solids, and from about 0.1 wt% to about 10.0 wt% surfactant, where all wt% values are based on the total weight of the inverse emulsion of the acrylamide polymer.

[0026] In one embodiment of the present disclosure, the oil phase of the inverse emulsion of the acrylamide polymer can be selected from a large group of organic liquids that can include liquid hydrocarbons or substituted liquid hydrocarbons. Further, both the hydrocarbon liquid and / or the substituted hydrocarbon liquid can be aliphatic hydrocarbons and aromatic hydrocarbons. Suitable examples of such organic liquids can include, but are not limited to, benzene, xylene, toluene, mineral oil, kerosene, naptha, petroleum, blends of aromatic and aliphatic hydrocarbons containing 4 or more carbon atoms, vegetable oils, paraffinic hydrocarbon oils, and combinations thereof.

[0027] In one non-limiting embodiment of the present disclosure, the oil phase can be present in an amount of about 5.0 wt% to about 90.0 wt% of the inverse emulsion of the acrylamide polymer. In another non-limiting embodiment of the present disclosure, the amount can vary from about 10.0 wt% to about 20.0 wt%, or from about 20.0 wt% to about 30.0 wt%, or from about 30.0 wt% to about 40.0 wt%, or from about 50.0 wt% to about 60.0 wt%, or from about 60.0 wt% to about 70.0 wt%, or from about 70.0 wt% to about 80.0 wt%, or from about 80.0 wt% to about 90.0 wt% based on the total weight of the inverse emulsion of the acrylamide polymer.

[0028] In one non-limiting embodiment of the present disclosure, any suitable surfactant that provides a stable water-in-oil emulsion polymer can be used in the present inverse emulsion of the acrylamide polymer. Suitable examples of such surfactants include alkanolamides, polyoxyethylene derivatives of sorbitan esters, sorbitan monooleate, sorbitan monostearate, C6-C with 1 to 30 oxyethylene units 22 linear or branched alkyl ethoxylates, C6-C with 1 to 30 oxypropylene units 22 linear or branched alkyl propoxylates, C6-C with a combination of 1 to 30 oxyethylene and propoxylate units 22Linear or branched alkyl ethoxylate / propoxylate, C6-C having 1 to 30 oxyethylene units 22 Examples of suitable surfactant systems include, but are not limited to, alkylaryl ethoxylates containing aryl groups, sodium hexadecyl phthalate, sodium cetyl phthalate, sodium stearyl phthalate, ethylene oxide condensates of fatty acid amides, and mixtures thereof. Other non-limiting examples of suitable surfactant systems may include the surfactants disclosed in U.S. Patents 4,672,090, 4,772,659, 4,935,456, 3,826,771, 3,278,506, 3,284,393, and 4,070,323.

[0029] In one non-limiting embodiment of the present disclosure, the surfactant may be present in an amount of about 0.1% to about 10.0% by weight of the acrylamide polymer reverse emulsion. In another non-limiting embodiment of the present disclosure, the amount of the total acrylamide polymer reverse emulsion may vary from about 0.5% to about 8.0% by weight, or from about 0.75% to about 7.0% by weight, or from about 1.0% to about 6.0% by weight, or from about 1.0% to about 5.0% by weight.

[0030] In one non-limiting embodiment of the present disclosure, the aqueous phase may be present in an amount of about 5.0% to about 90.0% by weight of the total weight of the acrylamide polymer reverse emulsion. In another non-limiting embodiment of the present disclosure, based on the total weight of the acrylamide polymer reverse emulsion, the amount of the aqueous phase may vary from about 10.0% to 20.0% by weight or from about 20.0% to about 30.0% by weight or from about 30.0% to about 40.0% by weight or from about 40.0% to about 50.0% by weight or from about 50.0% to about 60.0% by weight or from about 60.0% to about 70.0% by weight or from about 70.0% to about 80.0% by weight or from about 80.0% to about 90.0% by weight.

[0031] Furthermore, the acrylamide polymer constitutes at least 2% of the total reverse emulsion of the acrylamide polymer. In one non-limiting embodiment of the present disclosure, the acrylamide polymer may be present in an amount ranging from about 5.0% by weight to about 90.0% by weight, or about 5.0% by weight to about 10.0% by weight, or about 10.0% by weight to about 20.0% by weight, or about 20.0% by weight to about 30.0% by weight, or about 30.0% by weight to about 40.0% by weight, or about 40.0% by weight to about 50.0% by weight, or about 50.0% by weight to about 60.0% by weight, or about 60.0% by weight to about 70.0% by weight, or about 70.0% by weight to about 80.0% by weight, or about 80.0% by weight to about 90.0% by weight, based on the total weight of the reverse emulsion of the acrylamide polymer.

[0032] The acrylamide polymers according to this disclosure may be nonionic homopolymers, anionic copolymers, or cationic copolymers. In one non-limiting embodiment of this disclosure, the acrylamide polymer may be a homopolymer. In another non-limiting embodiment of this disclosure, the acrylamide polymer may be an anionic copolymer. In yet another non-limiting embodiment of this disclosure, the acrylamide polymer may be a cationic polymer. The anionic copolymers according to this disclosure comprise at least one monomer unit having one or more acidic functional groups or anhydride functional groups, or any combination thereof, together with one or more heteroatoms selected from the group consisting of S, N, O, and P. Suitable examples of such monomers may include, but are not limited to, acrylic acid, methacrylic acid, maleic acid or anhydride, itaconic acid or anhydride, acrylamidepropanesulfonic acid, vinylphosphonic acid, and the like. Similarly, suitable examples of cationic polymers include, but are not limited to, 3-acrylamidopropyltrimethylammonium chloride and 3-methacrylamidopropyltrimethylammonium chloride.

[0033] The acrylamide polymer present in the water-in-oil emulsion of this disclosure can have a wide molecular weight range. In one non-limiting embodiment of this disclosure, the acrylamide polymer can have an average molecular weight in the range of about 50,000 daltons to about 15 million daltons. In one non-limiting embodiment of this disclosure, the molecular weight of the acrylamide polymer can vary in the range of about 1 million daltons to about 4 million daltons, or about 4 million daltons to about 8 million daltons, or about 8 million daltons to about 12 million daltons.

[0034] The reverse emulsion of acrylamide polymers may optionally contain one or more additional components. Examples of such components include, but are not limited to, surfactants, dispersants, suspending agents, chelating agents, insecticides, and stabilizers.

[0035] The reverse emulsions of acrylamide polymers used in the compositions of this disclosure can be prepared by methods known to those skilled in the art. Furthermore, those skilled in the art will understand how to appropriately formulate reverse emulsion compositions to provide required or desired features or properties.

[0036] Furthermore, the cellulose ether used in the rheological modifier compositions of the present disclosure may be glyoxal-treated cellulose ether or un-glyoxal-treated cellulose ether. In one non-limiting embodiment of the present disclosure, the cellulose ether is glyoxal-treated cellulose ether. In another non-limiting embodiment of the present disclosure, the cellulose ether is un-glyoxal-treated cellulose ether. Suitable examples of such cellulose ethers are hydroxyethylcellulose (HEC), hydroxypropylcellulose (HPC), ethylhydroxyethylcellulose (EHEC), carboxymethylcellulose (CMC), carboxymethylhydroxyethylcellulose (CMHEC), hydroxypropylhydroxyethylcellulose (HPHEC), methylcellulose (MC), methylhydroxypropylcellulose (MHPC), methylhydroxyethylcellulose (MHEC), carboxymethylmethylcellulose (CMMC), hydrophobically modified carboxymethylcellulose (HMCMC), and hydrophobically modified hydroxyethylcellulose (HMHEC). This may include, but is not limited to, hydrophobically modified hydroxypropyl cellulose (HMHPC), hydrophobically modified ethyl hydroxyethyl cellulose (HMEHEC), hydrophobically modified carboxymethyl hydroxyethyl cellulose (HMCMHEC), hydrophobically modified hydroxypropyl hydroxyethyl cellulose (HMHPHEC), hydrophobically modified methyl methyl hydroxypropyl cellulose (HMMHPC), hydrophobically modified methyl hydroxyethyl cellulose (HMMHEC), hydrophobically modified carboxymethyl methyl cellulose (HMCMMC), cationic hydroxyethyl cellulose (cationic HEC), cationic hydrophobically modified (cationically hydrophobically modified) hydroxyethyl cellulose (cationic HMHEC), and any combination thereof. In one non-limiting embodiment of this disclosure, the cellulose ether may be glyoxal-treated hydroxyethyl cellulose. In another non-limiting embodiment of this disclosure, the cellulose ether may be unglyoxal-treated hydroxyethyl cellulose.In another non-limiting embodiment of the present disclosure, the cellulose ether may be hydroxyethylcellulose or carboxymethylcellulose, either alone or in combination thereof.

[0037] Furthermore, the cellulose ether present in the rheological modifier compositions of this disclosure may be in the form of a dry powder. Alternatively, the cellulose ether may be in the form of a fluid polymer suspension (FPS). In one non-limiting embodiment of this disclosure, the cellulose ether is in the form of a dry powder. In another non-limiting embodiment of this disclosure, the cellulose ether is in the form of a fluid polymer suspension (FPS). Any commercially available cellulose ether can be suitably used in this disclosure. Suitable examples of such products include, but are not limited to, FPS Natrosol HEC250 HHRP, FPS Natrosol HEC250 HHBR, FPS Natrosol Plus 330, FPS Natrosol 250H4BR, FPS Natrosol 250HBR (available from Ashland LLC in FPS form), and Natrosol HEC H4BR (available from Ashland LLC in dry powder form). Furthermore, fluidized polymer suspensions of cellulose ethers such as hydroxyethylcellulose can also be prepared by methods known to those skilled in the art, for example, by methods described in U.S. Patent No. 5,521,234, transferred to Aqualon.

[0038] In one non-limiting embodiment of the present disclosure, the acrylamide polymer reverse emulsion may be present in an amount of about 0.05% to about 50.0% by weight, or about 0.05% to about 30.0% by weight, based on the total weight of the rheology modifier composition. In another non-limiting embodiment of the present disclosure, the acrylamide polymer reverse emulsion is a cationic polymer and may be present in an amount of about 0.05% to about 50.0% by weight, or about 0.05% to about 30.0% by weight, based on the total weight of the rheology modifier composition. In another non-limiting embodiment of the present disclosure, the cellulose ether may be present in an amount of about 50.0% to about 99.95% by weight, or about 70.0% to about 99.95% by weight, based on the total weight of the rheology modifier composition. In embodiments of this disclosure in which the cellulose ether is a combination of hydroxyethylcellulose and carboxymethylcellulose, the total amount of these cellulose ethers may vary in the range of about 50.0% to about 99.95% by weight, or about 70.0% to about 99.95% by weight, based on the total weight of the rheological modifier composition.

[0039] The rheological modifier compositions of the present disclosure may further comprise at least one associative polymer selected from the group consisting of hydrophobically modified (hydrophobically modified) ethoxylated urethane polymers, hydrophobically modified polyacetal-polyether polymers, hydrophobically modified alkali-swellable emulsions, hydrophobically modified aminoplasts, alkali-swellable emulsions, and combinations thereof. In one non-limiting embodiment of the present disclosure, the associative polymer is a hydrophobically modified polyacetal-polyether polymer.

[0040] The rheological modifier compositions of the present disclosure may further comprise at least one additive selected from the group consisting of surfactants; dispersants; thickeners; anti-caking agents; defoamers; preservatives; hydrophobic agents including waxes, silicones, and hydrocarbons; compatibilizers; adhesion promoters; stabilizers, crosslinkers; and combinations thereof.

[0041] Suitable examples of dispersants may include, but are not limited to, polycarboxylic acids, carboxylated polymer electrolytes, tripolyphosphates and tetrapotassium pyrophosphate, ethoxylated fatty alcohols, amino alcohols, acrylic copolymers, naphthalene sulfonic acid-formaldehyde adducts, sulfonated fatty acids, polyethylene glycol diroates, soy lecithin, PEG diroates, polyethylene glycol, polypropylene glycol, methoxypolyethylene glycol, monostearate polyethylene glycol, distearate polyethylene glycol, and combinations thereof.

[0042] Furthermore, the rheological modifier compositions of this disclosure may be liquid blends of a reverse emulsion of an acrylamide polymer and a cellulose ether. Liquid blends of a reverse emulsion of an acrylamide polymer and a cellulose ether can be prepared by blending a cellulose ether with a reverse emulsion of an acrylamide polymer.

[0043] Another aspect of the present disclosure provides a method for preparing the rheology modifier composition, the method comprising blending an acrylamide polymer reverse emulsion with at least one cellulose ether. In one non-limiting embodiment of the present disclosure, the cellulose ether may be in the form of a dry powder. In another non-limiting embodiment of the present disclosure, the cellulose ether may be in the form of a fluid polymer suspension. Any known blending technique or apparatus well known to those skilled in the art can be appropriately used to blend the acrylamide polymer reverse emulsion with the cellulose ether to prepare the rheology modifier composition of the present disclosure. In embodiments of the present disclosure where the cellulose ether is a fluid polymer suspension formation, the blending of the acrylamide polymer reverse emulsion with the fluid polymer suspension (FPS) of the cellulose ether can be carried out during the design and manufacture of the FPS formation of the cellulose ether.

[0044] Furthermore, cellulose ether can be used in amounts ranging from about 30.0% to about 99.95% by weight, or about 50% to about 99.97% by weight, or about 70% to about 99.95% by weight, based on the total weight of the rheology modifier composition. Similarly, the reverse emulsion of the acrylamide polymer can be used in amounts ranging from about 0.05% to about 70.0% by weight, or from about 0.05% to about 50.0% by weight, or from about 0.05% to about 30.0% by weight, based on the total weight of the rheology modifier composition of the present invention.

[0045] Furthermore, additional additives may be added during the preparation of the rheological modifier composition. These additives may include at least one additive selected from the group consisting of surfactants, dispersants, thickeners, anti-caking agents, defoaming agents, preservatives, waxes, silicones, hydrophobic agents including hydrocarbons, compatibilizers, adhesion promoters, crosslinking agents, and any combination thereof.

[0046] 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, as well as paper coatings. Aqueous protective coating compositions are commonly known as latex coatings or dispersion coatings and have been known for a considerable number of years. 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 preferably provide good leveling and excellent sag resistance through careful selection of rheological modifiers. Another embodiment of this disclosure provides the use of the rheological modifier compositions of this disclosure in aqueous-based coatings comprising (i) a reverse emulsion of an acrylamide polymer in an amount of 0.05% to 70.0% by weight and (ii) a blend of at least one cellulose ether in an amount of 30.0% to 99.95% by weight.

[0047] Another aspect of the present disclosure provides an aqueous coating composition comprising the rheology modifier composition of the present disclosure described above. The aqueous coating composition comprises a reverse emulsion of an acrylamide polymer and at least one cellulose ether; at least one film-forming polymer; and a rheology modifier composition comprising water.

[0048] 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 thickness 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 liquid blend containing an acrylamide polymer and an inverse emulsion of at least one cellulose ether. Alternatively, the acrylamide polymer and the inverse emulsion of cellulose ether may be added individually to the aqueous coating composition of this disclosure.

[0049] In embodiments of the present disclosure in which a rheological modifier composition may be added as a liquid blend in an aqueous coating composition, the amount of the rheological modifier composition added may vary in the range of about 0.01% to 10.0% by weight, 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% to about 5% by weight of the total weight of the aqueous coating composition.

[0050] 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% by weight to about 10.0% by weight of 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. Even in this case, their combined weight ratio varies in the range of about 0.01% by weight to about 10.0% by weight, or about 0.05% by weight to about 5.0% by weight of the total weight of the aqueous coating composition.

[0051] 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 relevant 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, ureidomethacrylate, vinyl acetate, vinyl esters of branched tertiary monocarboxylic acids, itaconic acid, crotonic acid, maleic acid, fumaric acid, and ethylene. It is also possible to include C4-C8 conjugated dienes such as 1,3-butadiene, isoprene, and chloroprene. The film-forming polymer may also be a copolymer product of two or more monomers to achieve several desired properties, particularly for applications in latex coatings with very little or no volatile organic compounds (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 esters of versatic acid (VeoVa), vinyl propionate, butadiene, acrylonitrile, maleate, and fumaric acid. 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 esters of versatic acid (VeoVa), and polyester.

[0052] Other suitable examples of film-forming polymers may include, but are not limited to, alkyds, cellulose (cellulose nitrate and cellulose esters), coumarone-indene, epoxy, esters, hydrocarbons, melamine, natural resins, oleoresins, phenolic resins, polyamides, polyesters, rosin, silicones, terpenes, ureas, and urethanes.

[0053] The amount of film-forming polymer in the aqueous coating composition of this disclosure varies from about 5.0% by weight to about 85.0% by weight, based on the total weight of the aqueous coating composition. In one non-limiting embodiment, the amount of film-forming polymer can be varied from about 40.0% by weight to about 70.0% by weight, or from about 50.0% by weight to about 70.0% by weight, based on the total weight of the aqueous composition.

[0054] The aqueous coating compositions of this disclosure may further comprise at least one pigment. The pigments 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 grade of titanium dioxide used in aqueous coating compositions is surface-modified with various inorganic oxides such as silicates, aluminates, and zirconates. Aluminum silicate, nepeline syenite, mica, calcium carbonate, and / or diatomaceous earth may also be used.

[0055] The type and amount of pigment present in the aqueous coating compositions of this disclosure determine the performance characteristics of the dried film, such as gloss, transparency, scrub resistance, and tensile strength. Therefore, the coatings are characterized by their pigment volume concentration (PVC). PVC is a percentage representing the volume ratio of pigment to the total solids present in the dried film. Polyvinyl chloride is defined as follows:

[0056] PVC% = Pigment volume / (Pigment volume + Latex volume) × 100

[0057] 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).

[0058] 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 the coating is a flat 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.

[0059] The balance of the aqueous coating composition is water. Water can be present in the film-forming polymer dispersion and in the other components of the aqueous coating composition. Alternatively, water can be added separately to the aqueous coating composition.

[0060] 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-caking agents; defoamers such as non-silicone and silicone types; plasticizers; extenders (inert fillers); preservatives; hydrophobic agents including waxes, silicones, and hydrocarbons; compatibilizers; adhesion promoters; crosslinking agents; bactericides; antifungal agents, defoamers such as non-silicone and silicone types; 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.

[0061] The aqueous coating compositions described herein can be used for a variety of applications. In particular, the rheological modifier compositions of this disclosure are useful for all kinds of coatings, such as decorative and protective coatings for architectural surfaces such as walls, ceilings, doors, and trims; paper coatings; and coatings for dry walls, masonry, wood, metal, plastic, and primed surfaces. In one non-limiting embodiment of this disclosure, the coating composition is an architectural coating composition for interior and / or exterior architectural surfaces.

[0062] Another aspect of the present disclosure provides a method for preparing the aqueous coating composition of the present disclosure, the method comprising mixing or blending, under stirring, at least one film-forming polymer, the rheological modifier composition of the present disclosure, and water. Pigments may be added advantageously to provide an aqueous building coating. The additives described above may also be added to the film-forming polymer, the rheological modifier composition of the present disclosure, the pigment, or a combination thereof, in any suitable order.

[0063] Aqueous coating compositions are stable fluids that can be applied as protective coatings to a wide range of surface materials. Examples of such materials include, but are not limited to, paper, wood, concrete, metal, glass, ceramics, plastics, plaster, asphalt coatings, roofing substrates such as roofing felt and foamed polyurethane insulators, or pre-painted, primed, undercoated, abraded, or weathered substrates.

[0064] Further aspects of the present disclosure provide methods 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, aerosol sprays, brushes, rollers, airless sprays, air-assisted sprays, electrostatic sprays, and high-volume low-pressure (HVLP) sprays.

[0065] The rheological modifier compositions of this disclosure favorably influence specific rheological properties of paint formulations, such as thickening efficiency and sag resistance. The inventors have surprisingly found that these compositions, including blends of acrylamide polymer reverse emulsions and cellulose ethers, exhibit several unique and unexpected attributes, such as improved efficiency (cost in use) and thickening efficiency, with similar or improved application performance, such as better dilution resistance and improved hiding, compared to conventional non-associative thickeners such as pure acrylamide polymer or cellulose. These rheological modifier compositions enhance or improve the overall thickening efficiency (Stormer, Brookfield, 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, the rheological modifier compositions of the present invention provide many structural advantages to architectural paints, such as improved sag resistance.

[0066] The following embodiments, unless otherwise specified, represent the currently disclosed and / or claimed inventive concept, parts by weight, and percentages. Each embodiment is provided as an explanation of the currently disclosed and / or claimed inventive concept, not as a limitation of the currently disclosed and / or claimed inventive concept. Indeed, it will be apparent to those skilled in the art that various modifications and changes can be made to the currently disclosed and / or claimed inventive concept without departing from the scope or spirit of the invention. For example, a feature illustrated or described as part of one embodiment may be used in another embodiment to produce yet another embodiment. Thus, the currently disclosed and / or claimed inventive concept is intended to cover modifications and variations that fall within the scope of the appended claims and their equivalents. Examples

[0067] Test method Unless otherwise specified, the following test methods were used in the examples.

[0068] Thickening Efficiency Measurement The thickening efficiency was measured by adding 0.15% by weight of the activator from the polymer sample obtained from the examples to the building coating agent shown in Table 2. The thickening efficiency was measured by the Brookfield viscosity and Stormer viscosity (KU) of the thickened building coating composition.

[0069] Brookfield viscosity was measured using a Brookfield viscometer with a spindle #5 at 30 RPM / min and 25°C. It is expressed in mPa·s.

[0070] The Stormer viscosity was measured using a Stormer viscometer according to the standard test method ASTM D562. It is expressed in Kleb units (KU).

[0071] ICI viscosity was measured using an ICI cone and plate viscometer according to the standard test method ASTM D4287. It is expressed in mPa·s.

[0072] Different samples of the rheological modifier compositions of this disclosure were prepared by blending a wide variety of reverse emulsions of acrylamide polymers (PAM) and hydroxyethylcellulose (HEC) polymers, as shown in Table 1.

[0073] [Table 1]

[0074] Example 1: Different samples of the rheology modifier composition of Example 1 were prepared by blending a reverse emulsion of acrylamide polymer (Flopam EM 230, available from SNF) and a fluidized polymer suspension of hydroxyethylcellulose (FPS HEC HHRP, available from Ashland LLC) in the weight proportions shown in Table 3. The weight proportions are based on the active polymer solids content of the acrylamide polymer and HEC polymer. In a typical experiment, the fluidized polymer suspension of hydroxyethylcellulose (FPS HHRP, available from Ashland LLC) was mixed (blended) with the reverse emulsion of acrylamide polymer in an 8-ounce glass jar and blended using a Harbil mixer until a homogeneous mixture was obtained. The rheology modifier composition of Example 1 was added to paint formulations (shown in Tables 2A and 2B) at a concentration of 0.15% by weight based on the active polymer content.

[0075] The formulated aqueous coating compositions were equilibrated overnight before measuring the Brookfield and Stormer viscosity responses. Brookfield viscosity, Stormer viscosity (KU), and ICI viscosity data are shown in Table 3.

[0076] [Table 2-1] [Table 2-2]

[0077] [Table 3]

[0078] Example 2 In this example, a nonionic acrylamide polymer reverse emulsion (PAM N3100 L) was blended with a hydroxyethyl cellulose fluid polymer suspension (FPS HHRP) in the weight proportions shown in Table 4 to form different rheological modifier compositions. These compositions were added to paint formulations at 0.15% by weight (shown in Tables 2A and 2B). The stoma viscosity, Brookfield viscosity, and ICI viscosity data for paint formulations using these compositions are shown in Table 4.

[0079] [Table 4]

[0080] Example 3 The rheology modifier compositions of this example were prepared in the same manner as described in Example 1, except that a nonionic acrylamide polymer reverse emulsion (PAM N3100LTR) was used. The acrylamide polymer and hydroxyethylcellulose fluidized polymer suspension (FPS HHRP) were blended in the weight ratios shown in Table 5. These rheology modifier compositions were added to the paint formulation at a concentration of 0.15% by weight (as shown in Tables 2A and 2B). The stoma viscosity (KU), Brookfield viscosity, and ICI viscosity data for paint formulations using these compositions are shown in Table 5.

[0081] [Table 5]

[0082] Example 4 The rheology modifier compositions of this example were prepared in the same manner as described above in Example 1, except that an anionic acrylamide polymer reverse emulsion (PAM A3015 L) was used. PAM A3015 L and FPS HEC HHRP were blended in the weight ratios shown in Table 6. These rheology modifier compositions were added to the paint formulation at a concentration of 0.15% by weight (as shown in Tables 2A and 2B). The Stormer viscosity (KU), Brookfield viscosity, and ICI viscosity data for paint formulations using these compositions are shown in Table 6.

[0083] [Table 6]

[0084] Example 5 The rheology modifier compositions of this example were prepared in the same manner as described above in Example 1, except that an anionic acrylamide polymer reverse emulsion (PAM A3040 LAD) was used. PAM A3040 LAD and FPS HEC HHRP were blended in the weight ratios shown in Table 7. These rheology modifier compositions were added to the paint formulation at a concentration of 0.15% by weight (as shown in Tables 2A and 2B). The Stormer viscosity (KU), Brookfield viscosity, and ICI viscosity data for the paint formulations using these compositions are shown in Table 7.

[0085] [Table 7]

[0086] Example 6 The rheology modifier compositions of this example were prepared by blending acrylamide polymer reverse emulsion (PAM N3100L) and dry hydroxyethylcellulose powder (HEC H4BR, available from Ashland LLC) in various weight proportions as shown in Table 8. These rheology modifier compositions were added to paint formulations at 0.15% by weight (as shown in Tables 2A and 2B). The Stormer viscosity (KU), Brookfield viscosity, and ICI viscosity data for paints using these compositions are shown in Table 8.

[0087] [Table 8]

[0088] Example 7 The rheology modifier compositions of this example were prepared by blending a fluidized polymer suspension of hydroxyethylcellulose and 20% active solids (FPS HEC HHBR) with an acrylamide polymer (PAM N3100L) in various weight proportions as shown in Table 9. These rheology modifier compositions were added to paint formulations at a concentration of 0.15% by weight (as shown in Tables 2A and 2B). The Stormer viscosity (KU), Brookfield viscosity, and ICI viscosity data for paint formulations using these compositions are shown in Table 9.

[0089] [Table 9]

Claims

1. A rheological modifier composition, (i) a reverse emulsion of acrylamide polymer in an amount of 0.05% to 70.0% by weight, based on the total weight of the rheology modifier composition, and (ii) 30.0% to 99.95% by weight of at least one cellulose ether, in the form of a dry powder or a fluidized polymer suspension, based on the total weight of the rheology modifier composition. Includes a blend of A rheology modifier composition wherein the weight-average molecular weight of the acrylamide polymer is in the range of 50,000 Daltons to 15,000,000 Daltons.

2. The acrylamide polymer (i) Nonionic homopolymers, (ii) Cationic copolymer, or (iii) An anionic copolymer, The anionic copolymer comprises at least one monomer having one or more acid or anhydride functional groups or combinations thereof, each having one or more heteroatoms selected from the group consisting of S, N, O, and P. The rheology 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 anhydride, crotonic acid, fumaric acid, and citraconic acid.

3. The cellulose ethers include hydroxyethylcellulose (HEC), hydroxypropylcellulose (HPC), ethylhydroxyethylcellulose (EHEC), carboxymethylcellulose (CMC), carboxymethylhydroxyethylcellulose (CMHEC), hydroxypropylhydroxyethylcellulose (HPHEC), methylcellulose (MC), methylhydroxypropylcellulose (MHPC), methylhydroxyethylcellulose (MHEC), carboxymethylmethylcellulose (CMMC), hydrophobically modified carboxymethylcellulose (HMCMC), hydrophobically modified hydroxyethylcellulose (HMHEC), hydrophobically modified hydroxypropylcellulose (HMHPC), hydrophobically modified ethylhydroxyethylcellulose (HMEHEC), and hydrophobically modified hydroxyethylcellulose (HMEHEC). The rheology modifier composition according to claim 1, which is a glyoxal-treated cellulose ether or a non-glyoxal-treated cellulose ether selected from the group consisting of modified carboxymethyl hydroxyethyl cellulose (HMCMHEC), hydrophobically modified hydroxypropyl hydroxyethyl cellulose (HMHPHEC), hydrophobically modified methyl methyl hydroxyethyl cellulose (HMMHPC), hydrophobically modified carboxymethyl methyl cellulose (HMCMMC), cationic hydroxyethyl cellulose (cationic HEC), cationic hydrophobically modified hydroxyethyl cellulose (cationic HMHEC), and combinations thereof.

4. The reverse emulsion of the acrylamide polymer is present in an amount of 0.05% to 50.0% by weight. The rheology modifier composition according to claim 1, wherein the cellulose ether is present in an amount of 50.0% to 99.95% by weight.

5. The rheology modifier composition according to claim 1, further comprising at least one associative polymer selected from the group consisting of hydrophobically modified ethoxylated urethane polymers, hydrophobically modified polyacetal-polyether polymers, hydrophobically modified alkali-swellable emulsions, hydrophobically modified aminoplasts, alkali-swellable emulsions, and combinations thereof.

6. The rheology modifier composition according to claim 1, wherein the composition further comprises a surfactant, a dispersant, a thickener, an anticaking agent, an antifoaming agent, a preservative, and at least one additive selected from the group consisting of a hydrophobic agent including waxes, silicones, and hydrocarbons, a compatibilizer, an adhesion promoter, a crosslinking agent, and combinations thereof.

7. The rheological modifier composition according to claim 1, wherein the composition is a liquid blend.

8. (i) a reverse emulsion of acrylamide polymer in an amount of 0.05% to 70.0% by weight, and (ii) 30.0% to 99.95% by weight of at least one cellulose ether, A method for preparing the composition according to claim 1, comprising the step of blending, The method wherein the cellulose ether is in the form of a dry powder or a fluidized polymer suspension.

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

10. An aqueous coating composition, (i) 0.01% to 10.0% by weight of the rheology modifier composition according to claim 1, based on the total weight of the aqueous coating composition, (ii) At least one film-forming polymer in an amount of 5.0% to 85.0% by weight, based on the total weight of the aqueous coating composition. Includes, and further (iii) 5.0% to 15.0% by weight of water, based on the total weight of the aqueous coating composition. A water-based coating composition containing [a specific substance].

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

12. The coating composition further comprises at least one additive selected from the group consisting of surfactants, dispersants, pigments, thickeners, anti-solidification agents, defoaming agents, plasticizers, bulking agents, preservatives, and hydrophobic agents including waxes, silicones, and hydrocarbons, compatibilizers, adhesion promoters, crosslinking agents, biocides, fungicides, anti-foaming agents, cosolvents, combining agents, and combinations thereof. The aqueous coating composition according to claim 10, wherein the pigment is selected from the group consisting of phthalocyanine, iron oxide, titanium dioxide, zinc oxide, blue, hydrated aluminum oxide, barium sulfate, calcium silicate, clay, silica, talc, and mixtures thereof.

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

14. The aqueous coating composition according to claim 10, wherein the coating composition is a coating composition for building applications.

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