Quick-drying coating composition

Abstract

Binder containing opaque acrylic polymers can be used to prepare quick-drying coating formulations containing high levels of filler and having high viscosity suitable for EIFS applications.

Description

Technical Field

[0001] This invention relates to the field of architectural coating compositions. Background Technology

[0002] High-viscosity coating compositions are often used as finishing coatings on exterior insulation and finishing systems (EIFS) cladding for buildings, but they can also be used on other substrates.

[0003] EIFS is used on the exterior of buildings to provide good thermal insulation, weather resistance, and aesthetics at a low cost. EIFS consists of at least three layers:

[0004] 1. Insulation layer, which is usually a foam insulation board, such as STYROFOAM ™ Insulating materials are attached directly or indirectly to the wall substrate using adhesives or mechanical fasteners.

[0005] 2. A base coating layer, which is directly or indirectly attached to the insulating layer, the base coating layer comprising a fiber web embedded in the coating material; and

[0006] 3. A finishing coating layer, which is directly or indirectly attached to the base coating, the finishing coating comprising coating materials that provide weather resistance and desired appearance.

[0007] Other layers may also be included, such as water channels beneath the insulation layer to allow water to escape when it reaches below the EIFS, or a waterproof layer to protect the substrate from water reaching below the EIFS. The EIFS and the layers found therein are described in numerous published references, such as U.S. Patent Publications 2014 / 0373474 and 2015 / 0159008, and “Application Fast Facts: EIFS” Publication 832-00189-01 published by Dow Chemical Company, and are available at dow.com / en-us / market / mkt-building-construction / sub-build-wall-systems-insulation-facade.html.

[0008] Finishing coatings typically contain inorganic fillers, organic binders, and additives. Fillers generally include sand and other inorganic particles; they may include materials classified as inorganic pigments, such as titanium dioxide. Binders are typically emulsion polymers, such as acrylic polymers. In many cases, finishing coatings are designed to have high solar reflectivity to minimize solar heating of the underlying building and reduce the energy and cost required to keep the building cool. In these cases, fillers may contain high levels of white components, such as titanium dioxide and calcium carbonate. Other additives may include known additives used in exterior coatings, such as organic pigments, thickeners and flow modifiers, surfactants, antioxidants, and stabilizers.

[0009] Finishing coatings are typically applied as an aqueous slurry. The slurry usually has high solids and high viscosity, allowing the finishing coating to be applied to vertical surfaces with a trowel at a thickness of 0.1 cm to 2.5 cm. The appearance is generally similar to plaster, hence EIFS surfaces are sometimes referred to as "synthetic plaster."

[0010] Drying time is a concern for all architectural coatings, including finishes on EIFS. Coatings applied outdoors can be damaged if they come into contact with rain or accidental water splashes before drying. Users generally want architectural coatings to dry quickly after application to minimize the risk of water damage. Drying time is a particular concern for EIFS finishes because they are thicker than regular paint coatings and therefore require a longer drying time.

[0011] It is known that the drying of waterborne coating compositions can be accelerated by adding organic polyamines and ammonia to the coating composition. See, for example, U.S. Patent 5,527,853. However, this formulation produces an ammonia odor during drying, and the resulting coating may be prone to yellowing.

[0012] The goal is to produce high-solids coating compositions that can dry rapidly and are water-resistant without the need for organic polyamines. Summary of the Invention

[0013] One aspect of the present invention is a coating composition comprising:

[0014] a) Inorganic fillers;

[0015] b) An opaque film-forming acrylic polymer (OAP) binder comprising hollow spherical particles and present at a concentration that effectively binds the fillers and other solid components of the coating composition to the substrate; and

[0016] c) Water, in an amount sufficient to completely wet the dry components and provide a slurry.

[0017] The coating composition has a combined pigment volume concentration (PVC) of at least 65 for the inorganic filler and hollow spherical particles, and the coating composition has a viscosity of at least 100 g as measured using a Krebs Stormer Model KU-1 with a paste rotor.

[0018] A second aspect of the present invention is a method for coating a building substrate, the method comprising the following steps:

[0019] a) Applying the coating composition of the first aspect of the present invention directly or indirectly to a building substrate; and

[0020] b) Dry the coating composition.

[0021] A third aspect of the present invention is a coated building substrate comprising (1) a building substrate and (2) a dry coating material directly or indirectly adhered to the building substrate, wherein:

[0022] a) The dry coating comprises inorganic fillers and a film-forming opaque acrylic polymer (OAP) binder, which contains hollow spherical particles and is present at a concentration that effectively binds the fillers and other components of the dry coating to the substrate; and

[0023] b) The combined pigment volume concentration (PVC) of the inorganic filler and hollow spherical particles in the dry coating is at least 65; and

[0024] c) The dry coating layer is at least 0.05 cm thick.

[0025] In the high-solids coating compositions of the present invention, the OAP binder provides rapid drying without the need for organic polyamine desiccants. Detailed Implementation

[0026] This invention relates to a high-PVC coating composition containing fillers, binders, and water. The binder contains an opaque, film-forming acrylic polymer (OAP). This composition is particularly suitable for use as a finishing layer in EIFS coatings.

[0027] filler

[0028] Fillers used in coating compositions are water-insoluble powders and granules. Suitable fillers are known in the coatings industry and are commercially available. See, for example, Gysau, Fillers for Paints (3rd edition), published by VincenzNetwork GmbH (2017); and “Functional Silicate Fillers: Basic Principles”, Painting & Coatings Industry (August 1, 2002) (https: / / www.pcimag.com / articles / 84909-functional-silicate-fillers-basic-principles).

[0029] In some implementations, the filler is inorganic. In some embodiments, the inorganic filler contains oxides, carbonates, and sulfates of silicon, calcium, titanium, and / or aluminum. Examples of commonly used inorganic fillers include silica, titanium dioxide, calcium carbonate, dolomite, kaolin, barium sulfate, wollastonite, mica, talc, feldspar, and glass particles.

[0030] In some embodiments, the filler contains materials classified as inorganic pigments or pigment extenders. Examples of light-colored inorganic pigments and pigment extenders that may be present in the filler include titanium dioxide, antimony white, titanium white, zinc white, or barium sulfate, chrome yellow, cobalt yellow, and titanium yellow. The filler may also contain dark-colored inorganic pigments, such as oxides of iron and copper, as well as carbon black.

[0031] In the fields of coatings and EIFS, it is known to select fillers having particle sizes suitable for coating compositions. Some examples of coarse fillers may have an average particle size of at least 100 micrometers, or at least 200 micrometers, or at least 300 micrometers, or at least 500 micrometers, and may have an average particle size of at most 3 mm, or at most 2 mm, or at most 1.5 mm, or at most 1 mm, or at most 800 micrometers, or at most 600 micrometers. Some examples of fine fillers and pigment extenders may have smaller particle sizes, such as an average particle size of at least 1 micrometer and at most 100 micrometers.

[0032] Fillers are generally insoluble in water. Dispersants and wetting agents help maintain the stability of the filler in water as a slurry or dispersion. Suitable dispersants and wetting agents are known and commercially available, such as those under the trademark TAMOL. ™ Calgon and Dispex. In some embodiments, the dispersant is a polycarboxylate, polyphosphate, or a block copolymer having blocks that interact with water and blocks that interact with fillers / pigments. In some embodiments, the wetting agent is a surfactant, such as a fatty acid salt, a poly(ethylene oxide) surfactant, or a silicone-based surfactant.

[0033] The amount of filler in a coating formulation can be described using pigment volume concentration (“PVC”), which is the percentage of the volume of pigments and fillers relative to the total volume of solid components in the coating formulation. PVC is calculated using Equation 1:

[0034] (1)

[0035] Where V p V is the dry volume of the pigment. e It is the dry volume of the packing, and V b Dry refers to the dry volume of the binder. In this paper, the hollow spherical particles in the binder are included in "p" as part of the pigment.

[0036] The coating compositions of the present invention have a PVC of at least 65. In some embodiments, the PVC of the coating composition is at least 70, or at least 71, or at least 73, or at least 75, or at least 77, or at least 79 or 80. In some embodiments, the PVC of the coating composition is at most 90, or at most 88, or at most 86, or at most 84, or at most 82. For example, the PVC of the coating composition may be 71 to 90, or 73 to 88, or 75 to 86, or 77 to 84.

[0037] In some embodiments, the hollow spherical particles in the adhesive provide at least 20%, or at least 25%, or at least 30%, or at least 35% PVC. In some embodiments, the hollow spherical particles in the adhesive provide at most 50%, or at most 45%, or at most 40% PVC.

[0038] The amount of filler can also be described as a weight percentage. In some embodiments, the coating composition contains at least 70% by weight, or at least 75% by weight, or at least 80% by weight, or at least 82% by weight, or at least 84% by weight of filler, based on the weight of the dry component excluding water. (“Dry component” refers to inorganic fillers, binders, and other solid additives in the coating composition. The weight of the dry component is the dry weight of the dry component.) In some embodiments, the coating composition contains at most 94% by weight, or at most 93% by weight, or at most 92% by weight, or at most 91% by weight, or at most 90% by weight of filler, based on the weight of the dry component excluding water. For example, the coating composition may contain 75% to 93% by weight, or 80% to 92% by weight, or 84% to 90% by weight of filler, based on the dry component excluding water.

[0039] In some embodiments, based on all components including water, the coating composition implies at least 50% by weight, or at least 60% by weight, or at least 64% by weight, or at least 67% by weight of filler. In some embodiments, based on all components including water, the coating composition contains at most 85% by weight, or at most 80% by weight, or at most 78% by weight, or at most 76% by weight of filler. For example, based on all components including water, the coating composition may contain 50% to 85% by weight, or 60% to 70% by weight, or 64% to 78% by weight, or 67% to 76% by weight of filler.

[0040] adhesive

[0041] The coating composition contains an OAP binder. The OAP binder comprises (1) a rigid high-Tg polymer shell (“hollow spherical particles”) encapsulating the void space; and (2) a film-forming low-Tg polymer surrounding the rigid high-Tg polymer shell.

[0042] OAP binders and their preparation methods are known and reported in references such as U.S. Patents US 6,020,435, US 7,939,572 B2 and US 7,629,414 B2, and U.S. Patent Publications US 2010 / 0010118A1 and US 2008 / 0171810 A1. They can be prepared by multi-step emulsion polymerization.

[0043] • First, a high Tg shell is polymerized on an acidic polymer core in an aqueous emulsion.

[0044] • Secondly, a low-Tg film-forming polymer is polymerized on a high-Tg shell. Monomers are selected for preparing the film-forming polymer to plasticize the high-Tg shell.

[0045] • Third, the alkali in the aqueous emulsion reacts with the acidic polymer core, drawing water into the plasticized high Tg shell and causing the plasticized shell to expand to create water-filled voids.

[0046] • Fourth, the monomers that plasticize the high Tg shell are further polymerized, so that the high Tg shell is no longer plasticized but becomes rigid.

[0047] When the OAP adhesive dries, water migrates out of the void space, leaving voids encapsulated by a high Tg shell.

[0048] OAP binders comprise a rigid, high-Tg polymer shell that encapsulates the voids. In some embodiments, such as when the OAP binder is suspended in an emulsion, the voids may also contain water in addition to residues of the acid polymer core. In some embodiments, such as when the OAP binder dries, the voids may also contain air in addition to residues of the acid polymer core.

[0049] In some embodiments, the high Tg polymer has a glass transition temperature of at least 55°C, or at least 60°C, or at least 70°C, or at least 80°C. There is no maximum desired glass transition temperature, but it is rarely required to be higher than 150°C, 120°C, or 105°C.

[0050] Examples of suitable high Tg polymers that can be used for the shell include polystyrene, styrene-acrylic acid copolymers, and acrylic polymers.

[0051] In some embodiments, the high Tg polymer comprises a polystyrene polymer, which may be a homopolymer or a copolymer. In some embodiments, the polystyrene polymer contains at least 80% by weight, at least 85% by weight, or at least 90% by weight of units derived from styrene monomers. In some embodiments, the polystyrene polymer contains up to 100% by weight of units derived from styrene monomers. Comonomers of polystyrene copolymers are known, and common examples include, but are not limited to, vinyltoluene, acrylonitrile, and methyl methacrylate. Emulsion polymerization of polystyrene is known and described in publications such as US3914338A, US4427836A, US4469825A, US4594363A, US7939572B2, US20010009929A1, and Ramli, “Hollow Polymer Particles: a Review” RSC Adv., 2017, 7, 52632. (Published at https: / / pubs.rsc.org / en / content / articlepdf / 2017 / ra / c7ra10358a)

[0052] In some embodiments, the high Tg polymer comprises an acrylic polymer. An acrylic polymer is a homopolymer or copolymer containing repeating units derived from acrylic monomers. Acrylic monomers include acrylic acid, methacrylic acid, and their esters. Exemplary esters used in acrylic monomers include alkyl esters, such as alkyl groups containing 1 to 8 carbon atoms or 1 to 4 carbon atoms, or in some cases methyl or ethyl groups. Particularly useful acrylic monomers are acrylic acid, methacrylic acid, acrylonitrile, butyl acrylate, 2-ethylhexyl acrylate, methyl acrylate, ethyl acrylate, methyl methacrylate, and ethyl methacrylate.

[0053] Exemplary acrylic polymers may contain at least 70% by weight, or at least 80% by weight, or at least 90% by weight, or at least 95% by weight of repeating units derived from acrylic monomers. Exemplary acrylic polymers may contain up to 100% repeating units derived from acrylic monomers. Some exemplary acrylic polymers are copolymers containing units derived from two or more acrylic monomers, such as copolymers of butyl acrylate with methyl methacrylate and / or methacrylic acid. Some exemplary acrylic polymers may also contain repeating units derived from non-acrylate-bonded unsaturated comonomers (such as styrene, vinyl acetate, and similar vinyl esters) and crosslinking monomers (such as divinylbenzene). The choice of monomers is known to affect the Tg of the resulting acrylic polymer. It is known that increasing the content of certain monomers (such as methyl methacrylate, acrylonitrile, and styrene) increases the Tg of the resulting polymer, and it is known that increasing the content of other monomers (such as butyl acrylate) decreases the Tg of the resulting polymer.

[0054] Emulsion polymerization of acrylic monomers is well known. See, for example, U.S. Patent 7,629,414 B2 and Emulsion Polymerization of Acrylic Monomers (1966) published by Rohm & Haas Company.

[0055] OAP binders also contain a film-forming low-Tg polymer surrounding a rigid, high-Tg polymer shell.

[0056] The concept of "film-forming" polymers is well-known. "Film-forming" refers to the ability of a substance to form a film when applied to a solid surface. The ability of polymers and their solutions or emulsions to form films is known and described in publications such as: PASteward et al., "An Overview of Polymer Latex Film Formation and Properties", 86 Advances in Colloid and Interface Science, pp. 195-267 (2000); and J. Guerts et al., "New Waterborne Acrylic Binders for Zero VOC Paints", 5 J. Coating Technol. Res., pp. 57-63 (2008). Film-forming polymer latexes typically contain suspended particles that can aggregate upon drying. Aggregation can occur by the compaction, deformation, adhesion, and / or diffusion of polymer chains between individual particles. Generally, the film-forming ability of a polymer increases with lower molecular weight and / or lower Tg, and decreases with higher molecular weight and / or higher Tg.

[0057] In some embodiments, the low-Tg polymer has a glass transition temperature of up to 50°C, or up to 45°C, or up to 40°C, or up to 30°C, or up to 20°C, or up to 10°C. There is no minimum required Tg, but it is rarely required to have a Tg below -50°C, or -30°C, or -15°C, or 0°C.

[0058] In some embodiments, the low-Tg polymer comprises an acrylic polymer, as already described, wherein the monomers are selected to produce the low-Tg film-forming polymer. In some embodiments, the low-Tg polymer contains at least 7% by weight, or at least 10% by weight, or at least 12% by weight of units derived from methyl methacrylate. In some embodiments, the low-Tg polymer contains at most 50% by weight, or at most 45% by weight, or at most 40% by weight, or at most 35% by weight, or at most 30% by weight, or at most 25% by weight of units derived from methyl methacrylate. In some embodiments, the low-Tg polymer contains at least 40% by weight, or at least 50% by weight, or at least 60% by weight, or at least 65% by weight, or at least 65% by weight, or at least 65% by weight of units derived from butyl acrylate. In some embodiments, the low-Tg polymer contains at most 93% by weight, or at most 90% by weight, or at most 86% by weight, or at most 84% by weight, or at most 82% by weight, or at most 80% by weight of units derived from butyl acrylate.

[0059] In some embodiments, the low-Tg acrylic polymer may contain crosslinking monomers. Examples of crosslinking monomers include, but are not limited to, acetoacetoxyethyl methacrylate (AAEM), diacetone acrylamide (DAAM, which can be crosslinked with adipate dihydrazide), and glycidyl methacrylate and other epoxy resins that can be crosslinked in the presence of amine functional groups. The amount of crosslinking should be kept sufficiently low so that the resulting polymer remains film-forming. In some embodiments, the acrylic polymer contains no more than 10% by weight, or no more than 6% by weight, or no more than 4% by weight, or no more than 2% by weight of crosslinking monomers. In some embodiments, the acrylic polymer contains 0% by weight, or at least 0.5% by weight, or at least 1% by weight of crosslinking monomers.

[0060] It may also be useful for low-Tg polymers to remain non-melting at temperatures where the external coating is typically exposed. In some embodiments, the low-Tg polymer has a melt temperature of at least 60°C, or at least 75°C, or at least 80°C, or at least 95°C, or at least 110°C. There is no single highest desired melt temperature, but temperatures above 200°C are rarely required.

[0061] In some embodiments, the low-Tg polymer comprises at least 50% by weight, or at least 60% by weight, or at least 65% by weight of the dry components of the OAP adhesive excluding water. In some embodiments, the low-Tg polymer comprises at most 90% by weight, or at most 80% by weight, or at most 75% by weight, or at most 70% by weight of the dry components of the OAP adhesive excluding water.

[0062] In some embodiments, the OAP binder is the only binder in the coating composition. In some embodiments, the binder of the coating composition comprises a blend of the OAP binder and another binder polymer. Other binders are known and commercially available. They are described in publications such as “Paints” (March 18, 2013) published by the Department of Chemistry, University of York at https: / / www.essentialchemicalindustry.org / materials-and-applications / paints.html. Examples of other binders include certain acrylic polymers, polyurethane polymers, styrene-acrylic polymers, and vinyl-acrylic polymers. Examples of commercially available binders include those using RHOPLEX... ™ PRIMAL ™ Paraloid ™ and MAINCOTE ™ The trademarks are derived from acrylic polymers and polymer dispersions obtained from Dow Chemical Company.

[0063] In some embodiments, the OAP adhesive comprises at least 20% by weight, or at least 40%, or at least 60%, or at least 80% by weight of the adhesive. In some embodiments, the OAP adhesive constitutes 100% of the adhesive.

[0064] In some embodiments, the binder comprises at least 5% by weight, or at least 7% by weight, or at least 8% by weight, or at least 9% by weight, or at least 10% by weight of the dry components of the coating composition. In some embodiments, the binder comprises at most 25% by weight, or at most 20% by weight, or at most 18% by weight, or at most 16% by weight of the dry components of the coating composition. For example, the binder may comprise from 5% to 25% by weight, or 8% to 20% by weight, or 10% to 16% by weight of the dry components.

[0065] In some embodiments, the binder comprises at least 4% by weight, or at least 5% by weight, or at least 6% by weight, or at least 7% by weight, or at least 8% by weight of the total coating composition comprising water. In some embodiments, the binder comprises at most 20% by weight, or at most 18% by weight, or at most 16% by weight, or at most 14% by weight of the total coating composition comprising water. For example, the binder may comprise from 5% by weight to 20% by weight, or 7% by weight to 18% by weight, or 8% by weight to 14% by weight of the total coating composition.

[0066] Other additives

[0067] In addition to fillers, binders, and water, coating compositions may optionally contain other additives suitable for EIFS finishing coatings. Commercial implementations of EIFS finishing coatings typically contain a variety of additives. Many such components are described in the publication Johan Bieleman (ed.), *Additives for Coatings*, published by WILEY-VCH Verlag GmbH (2000). Some examples of commonly used additives are listed below. All additives listed below are commercially available and accompanied by usage recommendations.

[0068] The coating composition may optionally contain an amount of organic dyes and pigments that effectively color the resulting coating. Examples of suitable organic dyes and pigments include phthalocyanines (blue / green), quinacridones (red / yellow), quinone derivatives, and azo compounds.

[0069] The coating composition may optionally contain a thickener to make it easier to handle and apply. Examples of thickeners include inorganic materials (such as certain clays) and polymeric thickeners (such as cellulose ethers, starches, and acrylic polymers).

[0070] For a variety of purposes, coating compositions may optionally contain surfactants. Some surfactants are emulsifiers, wetting agents, and dispersants, which facilitate the entry and retention of insoluble components in emulsions or dispersions containing aqueous solvents. Some surfactants are defoamers. Some surfactants promote the adhesion of the coating composition to the substrate.

[0071] The coating composition may optionally contain hydrophobic additives to improve the resulting coating's resistance to water penetration. Examples of hydrophobic components may include waxes and polymers (such as polypropylene), as well as silicone, silane, or siloxane components.

[0072] The coating composition may optionally include leveling agents and coalescing agents. Examples of leveling additives include certain polyacrylate polymers having a low glass transition temperature, such as 20°C or lower. Coalescing agents promote the interaction of binder molecules as the coating dries on the substrate to form a solid, homogeneous film that no longer dissolves upon exposure to fresh water. Examples of coalescing agents include:

[0073] • Certain branched and cyclic alkanes,

[0074] • Certain esters, such as 3-hydroxy-2,2,4-trimethylpentyl isobutyrate (TPiB), adipic acid diester (ADE), dimethyl phthalate (DMP), 2-hydroxypropyl ethylhexanoate (HPE), and benzyl benzoate, and

[0075] • Certain ether alcohols, such as ethylene glycol butyl ether, propylene glycol butyl ether, dipropylene glycol butyl ether (DPB), and propylene glycol and ethylene glycol phenyl ethers (PPH and EPH).

[0076] The coating composition may optionally contain antioxidants. The antioxidants may contain primary antioxidants (such as certain amines or sterically hindered phenols) and / or secondary antioxidants (such as certain organophosphates or thioesters).

[0077] The coating composition may optionally contain light and ultraviolet (UV) stabilizers. Examples of light and ultraviolet (UV) stabilizers may include:

[0078] • UV absorbers, such as benzotriazole and other compounds with coordinating double bonds; and

[0079] • Stericly hindered amines, such as compounds containing a 2,2,6,6-tetramethylpiperidine group.

[0080] The coating composition may optionally contain other additives to improve the stain resistance (DPUR) of the resulting coating. Examples of DPUR additives include some aromatic compounds (such as benzophenone and methyl 2-benzoylbenzoate), some fluorinated surfactants, some waxes, and some silicones (such as polydimethylsiloxane (PDMS)).

[0081] In some embodiments, based on the dry weight excluding water, the amount of additive does not exceed 8% by weight, or 6% by weight, or 5% by weight, or 4% by weight, or 3% by weight of the coating composition. The amount of additive can be 0% by weight, but in some embodiments, based on the dry weight excluding water, the amount of other additives is at least 0.2% by weight, or at least 0.5% by weight, or at least 0.8% by weight, or at least 1% by weight, or at least 1.5% by weight, or at least 2% by weight. In some embodiments, the amount of additive is low enough that the volume percentage, the weight percentage excluding water, and the weight percentage including water are substantially the same, so the previously described concentrations are also applicable to the weight percentage including water. For example, in some embodiments, based on the dry weight of the ingredients and excluding water, the coating composition contains 0.2% by weight to 8% by weight, or 0.5% by weight to 5% by weight, or 1% by weight to 3% by weight of additive. In some embodiments, based on all components including water, the coating composition contains 0.2% by weight to 8% by weight, or 0.5% by weight to 5% by weight, or 1% by weight to 3% by weight of additive.

[0082] The coating compositions of the present invention can dry rapidly without the need for organic polyamines, but can dry even faster if they contain both organic polyamines and volatile amines. Suitable organic polyamines and volatile amines and their use in fast-drying formulations are described in U.S. Patent Application 2008 / 0171810 A1 and U.S. Patent 5,804,627. Organic polyamines are polymers containing 20% ​​to 100% by weight repeating units having side amine groups. In some embodiments, the polyamine has a weight-average molecular weight of at least 1000 Da. Examples of volatile amines include ammonia, morpholine, lower alkylamines, 2-dimethylaminoethanol, and ethylenediamine.

[0083] In some embodiments, faster drying with organic polyamines is not desirable. In some embodiments, based on the dry composition excluding water, the coating composition contains less than 0.1% by weight, or no more than 0.08% by weight, or no more than 0.05% by weight, or no more than 0.01% by weight of organic polyamines. In some embodiments, the coating composition does not contain a measurable amount of organic polyamines (0% by weight).

[0084] In some embodiments, faster drying with organic polyamines is desirable. In some embodiments, the coating composition contains at least 0.1% by weight, or at least 0.2% by weight, or at least 0.5% by weight of organic polyamines based on the dry composition excluding water. In some embodiments, the coating composition contains no more than 10% by weight, or no more than 5% by weight, or no more than 2% by weight of organic polyamines based on the dry composition excluding water.

[0085] water

[0086] The coating composition contains water. The amount of water is sufficient to completely wet the dry components and form a slurry.

[0087] In this invention, the slurry has a sufficiently low viscosity to allow for smooth application and a sufficiently high viscosity to allow for thick application to vertical surfaces and drying without substantially flowing down the surface. In EIFS, the slurry is typically applied with a trowel, rather than with sprayers and brushes typically used for applying paint. The coating composition has a viscosity of at least 100 g, as measured using a Krebs Stormer Model KU-1 with a paste rotor. In some embodiments, the viscosity of the coating composition is at least 150 g, or at least 200 g, or at least 250 g, or at least 300 g, or at least 400 g, or at least 500 g. In some embodiments, the viscosity exceeds 1099 g, which is the measurement capacity of some measuring units.

[0088] In some embodiments, the coating composition contains at least 5% by weight, or at least 10% by weight, or 12% by weight, or at least 15% by weight of water. In some embodiments, the coating composition contains up to 30% by weight, or up to 25% by weight, or up to 22% by weight, or up to 20% by weight, or up to 18% by weight of water. For example, in some embodiments, the coating composition contains 5% to 30% by weight, or 10% to 25% by weight, or 12% to 20% by weight, or 15% to 18% by weight of water. It should be noted that in some cases, acrylic polymer binders, fillers, and / or other additives in the coating composition may be added as aqueous solutions, emulsions, or suspensions; in such cases, only a small amount of additional water may be required to achieve the desired water content in the overall coating composition.

[0089] In some embodiments, the coating composition has a pH of at least 6, at least 7, or at least 8. In some embodiments, the coating composition has a pH of at most 9, at most 10, or at most 11. Acids such as acetic acid, formic acid, and citric acid, or bases such as ammonia or potassium hydroxide, may be added to the coating composition to provide the desired pH.

[0090] In some embodiments, the coating composition also contains a water-miscible organic solvent. Examples of suitable organic solvents include alcohols and glycols. In some embodiments, the amount of organic solvent does not exceed 8% by weight, or 6% by weight, or 5% by weight, or 4% by weight, or 3% by weight of the coating composition (including water). The amount of organic solvent can be 0% by weight, but in some embodiments, the amount of organic solvent is at least 0.5% by weight, or at least 1% by weight, or at least 1.5% by weight, or at least 2% by weight. In some embodiments, the amount of organic solvent is low enough that there is no substantial difference between volume percentage and weight percentage, so the previously described concentrations are also applicable to volume percentage.

[0091] Uses of coating compositions and resulting coatings

[0092] In other applications, the coating composition can be used to form an external coating on a substrate, and particularly for forming a finishing coating on the exterior of EIFS. First, the coating composition is applied directly or indirectly to the substrate. Second, the aqueous composition is allowed to dry and harden. Each of these steps is well known.

[0093] In some embodiments, the substrate is a vertical surface, such as a wall, or more specifically, the exterior wall of a building. Examples of suitable substrates for walls include any known building surface material, such as wood, plaster, concrete, or composite board. In a specific embodiment, the substrate comprises an insulation layer and a primer layer of EIFS, and a coating composition is used to form a finishing coating of the EIFS.

[0094] This coating composition can be applied by known means. For example, depending on viscosity, it can be applied and spread with a trowel, or it can be brushed or rolled. If the coating composition is applied with a trowel, it can be smooth or textured, and designs can be added. Some weather conditions, such as rain, extreme cold, or humidity, are known to be unsuitable for applying the coating composition and can be avoided.

[0095] In some embodiments, the coating composition is applied with an average thickness of at least 0.05 cm, or at least 0.1 cm, or at least 0.15 cm. In some embodiments, the coating composition is applied with an average thickness of at most 3 cm, or at most 1 cm, or at most 0.5 cm, or at most 0.4 cm, or at most 0.3 cm.

[0096] After application, the coating composition is allowed to dry and harden. The drying time required for the coating composition can vary depending on the water content of the coating composition, the thickness of the coating, and environmental conditions such as temperature and humidity. In some embodiments, a 1 / 16-inch (0.16 cm) layer of the coating composition reaches touch dryness within 2 hours, 1.5 hours, 1 hour, 45 minutes, or 30 minutes after application, under the conditions of the test method. In some embodiments, a 1 / 16-inch layer of the coating composition reaches touch dryness within at least 5 minutes, 10 minutes, 15 minutes, 20 minutes, or 30 minutes after application, under the conditions of the test method. In some embodiments, a 1 / 16-inch layer of the coating composition dries completely within 4 hours, 3.5 hours, 3 hours, or 2.5 hours after application, under the conditions of the test method. In some embodiments, a 1 / 16-inch layer of the coating composition dries completely within at least 1 hour, 1.5 hours, or 2 hours after application, under the conditions of the test method. In some embodiments, these objectives can be met even when the composition contains no more than 0.1% by weight of polyamine.

[0097] After drying, the coating composition produces a dry coating that is directly or indirectly attached to the selected substrate. In an EIFS, the dry coating can be a finishing layer on the EIFS, which includes an insulating layer and a base coat as described above.

[0098] The dry coating has a content derived from the solids content of the coating composition. For example, based on the total weight of the dry components, the dry coating may contain:

[0099] a) Fillers, described and in quantity as previously described, excluding aqueous solvents;

[0100] b) OAP adhesive, in an amount suitable for adhering the filler to the substrate;

[0101] c) Other additives ranging from 0% to 8% by weight.

[0102] Its thickness is approximately equal to the thickness of the coating composition being applied.

[0103] The amounts and descriptions of these components in a dry coating are similar to those for a paint composition, excluding water. Dry coatings typically contain less than 5% by weight, or less than 3% by weight, or less than 1% by weight of water.

[0104] In some embodiments, after drying at 25°C for no more than 5 hours, or no more than 4 hours, or no more than 3 hours, or no more than 2 hours, the dry coating did not suffer visible damage in a rain test (as described in the test method). In some embodiments, after drying at 25°C for only 30 minutes or only 1 hour, the dry coating showed visible damage in a rain test (as described in the test method).

[0105] Test methods

[0106] Unless otherwise stated, the measurements listed in this application are performed using the following test methods:

[0107]

[0108] Kubelka-Munk scattering coefficient measurement

[0109] The scattering coefficient (S / Mil) is a measure of the opacity of OAP. A 7-mil wet OAP film was dragged over a black vinyl sheet, and the thickness was measured in four small, defined regions using an Ames gauge. The film was dried at low relative humidity (<40% RH) for 2 hours. The reflectance of the dry film was measured in the four defined regions using a Gardner Instrument reflectometer. The thickness of the dry film was also determined in the same defined regions using an Ames gauge. The scattering coefficient for each defined region was calculated:

[0110]

[0111] Where R is the reflectance and T is the film thickness in mils. The average of the four S / Mil measurements is then taken to obtain the film's S / Mil.

[0112] Collapse

[0113] Slump indicates the ability of an opaque polymer to resist drying forces acting on the walls of its internal micropores. These forces are greatest at high humidity, which causes the particles to dry slowly. Slump was determined using essentially the same procedure used to determine the S / Mil, except that the second coat was dried overnight at 75% RH and then for 1 hour at <40% RH.

[0114]

[0115] Example

[0116] The following examples illustrate specific implementations of the present invention, but do not limit the widest scope of the invention.

[0117] The materials in Table 1 are used in the examples:

[0118]

[0119] Preparation of OAP Adhesive 1 (OAP1)

[0120] Core #1 is an aqueous dispersion of polymer particles (66 wt% methyl methacrylate / 34 wt% methacrylic acid, 32.0% solids, z-average particle size 135 nm) prepared essentially as described in US 6,020,435.

[0121] Monomer emulsion 1 (ME 1) was prepared by mixing deionized water (125.0 g), Disponil FES-32 emulsifier (10.0 g), styrene (424.2 g), methacrylic acid (7.0 g), linseed oil fatty acid (2.8 g), acrylonitrile (112.0 g), and divinylbenzene (14.0 g).

[0122] Monomer emulsion 2 (ME 2) was prepared by mixing deionized water (240 g), Disponil FES-32 emulsifier (17.0 g), butyl acrylate (431.46 g), methyl methacrylate (430.54 g), 2-ethylhexyl acrylate (124.44 g), acetyl acetoxyethyl methacrylate (25.5 g), and methacrylic acid (7.96 g).

[0123] Monomer emulsion 3 (ME 3) was prepared by mixing DI water (54.0 g), Disponil FES-32 emulsifier (3.0 g), butyl acrylate (104.4 g), methyl methacrylate (75.6 g), and 4-hydroxy TEMPO (3.0 g), and fed into the reactor within 5 minutes.

[0124] A 5-liter four-necked round-bottom flask was equipped with a paddle stirrer, thermometer, N2 inlet, and reflux condenser. Deionized water (475 g) was added to the vessel and heated to 89°C under N2. Sodium persulfate (NaPS, 3 g in 25 g water) was immediately added to the vessel, followed by core #1 (125 g). Monomer emulsion 1 was added to the vessel over 45 minutes. The temperature of the reaction mixture was raised to 84°C after 15 minutes and to 92°C after 25 minutes. Two minutes after the initial addition of ME 1, a solution of acrylic acid (5.6 g) in DI water (40 g) was added to the flask. After the ME 1 feed was complete, the reaction was cooled to 60°C.

[0125] When the reactor temperature reaches 80°C, an aqueous mixture of ferrous sulfate and EDTA (20 g, 0.1 wt% FeSO4 and 2 g, 1 wt% EDTA) is added to the reactor. When the reactor temperature reaches 60°C, two co-feeds are simultaneously added to the reactor at a rate of 1.2 g / min: (a) a solution of tert-butyl hydroperoxide (t-BHP 1.9 g) and NaPS (5.0 g) mixed with deionized water (100 g); and (b) a separate solution of isoascorbic acid (IAA, 2.6 g in 100 g water). Two minutes after the start of the co-feed solution loading, ME2 is added to the reactor over 55 minutes while the temperature is raised to 86°C without providing any external heat. After the ME2 addition is complete, the addition of the co-feed solution is stopped, and the batch is maintained at 80°C to 86°C for 5 minutes. Add the ammonium hydroxide solution (5 g, 28% by weight aqueous solution) mixed with deionized water (5.0 g) along with hot (90°C) deionized water (175 g) to the reactor.

[0126] ME 3 was fed into the reactor over 5 minutes. Immediately after the ME 3 feed was completed, ammonium hydroxide (35.0 g, 28% wt% aqueous solution) mixed with deionized water (35 g) was added to the reactor over 2 minutes. After the ammonium hydroxide was added, the batch was held for 5 minutes. The co-feed solution was then restarted at 1.2 g / min until complete, and the dispersion was then cooled to 25°C. While cooling, additional co-feeds were simultaneously added to the reactor at a rate of 1.30 g / min: (a) a solution of tert-butyl hydroperoxide (1.5 g) in deionized water (25 g); and (b) a separate solution of IAA (0.7 g) in water (25 g). After the second co-feed was added, the dispersion was filtered to remove any condensation. The filtered opaque acrylic acid dispersion (OAP) had a solids content of 48.7%. The measured S / Mil was 1.03, and the collapse rate was 0.0%.

[0127] Synthesis of OAP Adhesive 2

[0128] The procedure used to prepare OAP binder 1 was repeated, but: ME 2 contained deionized water (240 g), Disponil FES-32 emulsifier (17.0 g), butyl acrylate (679.8 g), methyl methacrylate (316.2 g), diacetone acrylamide (DAAm, 12.0 g), and methacrylic acid (12.0 g). When the flask reached 45°C, ACRYSOL was added... ™ Prior to ASE-60, a slurry solution of adipic acid dihydrazide (ADH, 6 g in 30 g water) was added to the flask. The filtered opaque OAP binder 2 dispersion had a solids content of 48.3%.

[0129] Synthesis of OAP Adhesive 3

[0130] Repeat the procedure used to prepare OAP binder 2, but add an additional 0.975 g ADH before formulating the EIFS coating.

[0131] Synthesis of OAP Adhesive 4

[0132] The procedure used to prepare OAP binder 1 was repeated, but ME 2 contained DI water (240 g), Disponil FES 32 emulsifier (17.0 g), butyl acrylate (679.8 g), methyl methacrylate (305.4 g), acetyl methacrylate (22.8 g), and methacrylic acid (12.0 g). The filtered OAP binder 4 dispersion had a solids content of 48.6%.

[0133] Synthesis of OAP Adhesive 5

[0134] Repeat the procedure used to prepare OAP binder 4, but add 0.466 g of amine before formulating the EIFS coating.

[0135] Finishing coating formulations

[0136] The ingredients shown in Table 2 were mixed in the following order to form eight homogeneous coating formulations: first, the binder solution, defoamer, and TiO2 were mixed; then, pigments and fillers were mixed; next, a thickener mixed in water was added; then, other ingredients, water, and finally ammonia. Examples 2 to 11 are embodiments of the present invention. Example 1 is a comparative example using a commercial binder used in the EIFS industry.

[0137] Drying time test

[0138] Each paint formulation was applied to a metal plate at a thickness of 1 / 16”. Touch-dry time was tested at 15-minute, 30-minute, and subsequent 30-minute intervals. Complete-dry time was tested at 30-minute intervals after the coating had reached touch-dry. Touch-dry time was the time it took for no paint to adhere to a finger after lightly pressing the coating. Complete-dry time was the time it took for no trace to remain on the coating after pressing it with the thumb at a 90° angle. The results are recorded in Table 2.

[0139] Rain test

[0140] The EIFS blend contains 287 lbs of EI-2000 binder solution and 8.21 lbs of WALOCEL dissolved in 247.48 lbs of water. ™The thickener consists of MT 40000PV (with a few drops of ammonium hydroxide to initiate thickening), 1.99 lbs Nopco NXZ defoamer, 789.94 lbs Unimin 50-30 sand, 1.8 lbs Kathon LX 1.5% corrosion inhibitor, and 2.00 lbs Texanol coalescing agent. The cementitious undercoat contains equal weights of EIFS admixtures and Portland cement, plus 7% by weight of water. The EIFS substrate was prepared by spreading a cementitious primer on top of a 1" foam block. The mesh was then embedded into the admixture / cement mixture using a hand trowel. The substrate was allowed to dry completely. Each coating formulation was applied to the prepared EIFS substrate at a thickness of 1 / 16 inch. The sample was allowed to cure for 2 hours (2-hour rain test) or 4 hours (4-hour rain test), then placed under a nozzle spraying water onto the coating at a flow rate of approximately 3 gallons per minute. In the 4-hour rain test, the coating was left in the water spray for 2 hours, or in the 2-hour rain test, for 3 hours. Damage to the coating was visually inspected.

[0141]

Claims

1. A coating composition comprising: (a) Inorganic fillers; (b) A film-forming opaque acrylic polymer binder comprising hollow spherical particles and present at a concentration that effectively binds the fillers and other solid components of the coating composition to the substrate; and (c) Water, in an amount sufficient to completely wet the dry components and provide a slurry. The paint composition wherein the combined pigment volume concentration of inorganic filler and hollow spherical particles is at least 65, and the paint composition has a viscosity of at least 100g.

2. The coating composition according to claim 1, wherein the combined pigment volume concentration of the inorganic filler and hollow spherical particles in the coating composition is 71 to 90.

3. The coating composition according to claim 1, wherein the coating composition has a viscosity of at least 200g.

4. The coating composition according to claim 1, wherein the coating composition contains 8% to 20% by weight of an opaque acrylic polymer binder.

5. The coating composition according to claim 1, wherein the opaque acrylic polymer binder comprises (a) 10% to 50% by weight of a film-forming low-Tg acrylic polymer having a glass transition temperature not exceeding 45°C; and (b) a shell of a high-Tg polymer having a glass transition temperature of at least 55°C and encapsulating void spaces, and wherein the weight percentages are based on the dry weight of the binder excluding water.

6. The coating composition of claim 5, wherein the film-forming low Tg acrylic polymer comprises repeating units from crosslinking monomers.

7. The coating composition according to claim 1, wherein, based on the dry weight of the coating composition excluding water, the coating composition contains less than 0.1% by weight of organic polyamine.

8. The coating composition according to claim 1, wherein the coating composition has a viscosity of at least 300 g.

9. The coating composition according to claim 1, wherein: (a) The volume concentration of the combined pigment, consisting of inorganic fillers and hollow spherical particles, in the coating composition is 75 to 86. (b) The coating composition contains 8% to 20% by weight of an opaque acrylic polymer binder, wherein the opaque acrylic polymer binder contains (a) 10% to 50% by weight of a film-forming low-Tg acrylic polymer having a glass transition temperature not exceeding 45°C; and (b) a shell of a high-Tg polymer having a glass transition temperature of at least 55°C and encapsulating void spaces; and (c) The coating composition has a viscosity of at least 200g; The weight percentages are based on dry weight excluding water.

10. The coating composition of claim 9, wherein the film-forming low Tg acrylic polymer comprises repeating units from crosslinking monomers.

11. The coating composition according to claim 9, wherein, based on the dry weight of the coating composition excluding water, the coating composition contains less than 0.1% by weight of an organic polyamine.

12. The coating composition according to claim 11, wherein the 0.16 cm thick coating dries within 3 hours after application.

13. A method for coating a building substrate, the method comprising the following steps: (a) applying the coating composition of any one of claims 1 to 12 directly or indirectly to the building substrate; and (b) Dry the coating composition.

14. The method of claim 11, wherein the coating composition is applied at a thickness of 0.1 cm to 3 cm.

15. The method of claim 11, wherein the building substrate comprises an insulating layer and a base coat of an external insulation and finishing system (EIFS), and the coating composition is used to form a finishing coating of the EIFS.

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