Structural white composition and paint

Abstract

A resin composition or coating composition includes core-shell latex with core-shell particles in an aqueous solvent, the particles including a film-forming shell of a first polymer and a rigid core of a second polymer. The core-shell particles have an average particle size of 170 nm to 310 nm. Upon forming a coating, the coating composition exhibits whiteness without use of a white pigment, white dye, or white additive. A structural white coating includes a film-forming portion of a first polymer and core particles dispersed therethrough and including a second polymer and an average particle size of 150 nm to 250 nm.

Description

Attorney Docket Number: 0558.000089W001Applicant Docket Number: WO23101STRUCTURAL WHITE COMPOSITION AND PAINTCROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims the benefit of U.S. Provisional Application No.63 / 720,339, filed November 14, 2024, the disclosure of which are incorporated by reference herein its entirety.SUMMARY

[0002] Resin compositions, coating compositions, coatings, and methods of making and using the same are disclosed. A resin composition includes a monodisperse core-shell latex including first core-shell particles in an aqueous solvent, the first core-shell particles including a film-forming shell including a first polymer and a rigid core including a second polymer, wherein upon forming a coating, the coating composition exhibits whiteness without use of a white pigment, white dye, or white additive.

[0003] In another embodiment, a resin composition includes a film-forming shell including a first polymer; core particles including a second polymer; and an aqueous solvent, the shell and the core particles forming first core-shell particles dispersed in the aqueous solvent and having a poly dispersity index in a range of about 0.1 to about 0.4, wherein upon forming a coating, the composition exhibits whiteness without use of a white pigment, white dye, or white additive.

[0004] In another embodiment, a resin composition includes a film-forming shell including a first polymer having a glass transition temperature (Tg) in a range of -50 °C to 30 °C; core particles including a second polymer having a Tg in a range of 60 °C to 115 °C; and an aqueous solvent, the shell and the core particles forming first core-shell particles dispersed in the aqueous solvent, wherein upon forming a coating, the composition exhibits whiteness without use of a white pigment, white dye, or white additive.

[0005] In another embodiment, a resin composition includes a film-forming shell including a first polymer; core particles including a second polymer; and an aqueous solvent, the shell and the core particles forming first core-shell particles dispersed in the aqueous solvent and, the first polymer and the second polymer having a difference of refractive index (RI) in a range of 0.1 to0.35, wherein upon forming a coating, the coating composition exhibits whiteness without use of a white pigment, white dye, or white additive.

[0006] In another embodiment, a resin composition includes a fdm-forming shell including a first polymer; core particles including a second polymer; and an aqueous solvent, the shell and the core particles forming first core-shell particles dispersed in the aqueous solvent and having an average particle size in a range of 170 nm to 310 nm, wherein upon forming a coating, the coating composition exhibits whiteness without use of a white pigment, white dye, or white additive.

[0007] In another embodiment, a coating includes a film-forming portion including a first polymer having a Tg in a range of -50 °C to 30 °C and a first refractive index; and core particles dispersed throughout the film-forming portion and including a second polymer having a Tg in a range of 60 °C to 115 °C and a second refractive index, wherein the second refractive index is different from the first refractive index, the core particles having an average particle size in a range of 150 nm to 250 nm. The core particles may make up about 45 wt-% to about 75 wt-% of the coating composition. The film-forming portion may make up about 25 wt-% to about 55 wt-% of the coating composition.

[0008] In another embodiment, a coating including a film includes a binder including a first polymer having a Tg of 30 °C or lower, wherein the binder makes up 25 wt-% to 55 wt-% of the film; and core particles dispersed throughout the binder, the core particles including a second polymer having a Tg of 60 °C or greater, wherein the core particles make up 45 wt-% to 75 wt-% of the film. The film may exhibit an L* value of 80 or greater at a film thickness of 1 mil (25 pm) without a white pigment, white dye, or white additive. The film may exhibit a contrast ratio of 0.5 or greater against a black background at a film thickness of 1 mil (25 pm) without a white pigment, white dye, or white additive.

[0009] The resin composition or coating may be a structural white paint containing less than about 10 wt-% white pigment or filler.

[0010] In another embodiment, a method of preparing a structural white coating includes applying a film of the resin composition of any one of claims 1 to 14 to a substrate at a dry film thickness ranging from about 15 pm to about 200 pm; and drying or curing or both drying andcuring the film to form the structural white coating. The method may further include curing the film, where during curing, the first polymer self-crosslinks. The film may be cured at ambient conditions, at an elevated temperature, by radiation, or a combination thereof.BRIEF DESCRIPTION OF DRAWINGS

[0011] FIG. 1A is a schematic detail view of a coating composition according to an embodiment.

[0012] FIG. IB is a schematic detail view of the coating composition of FIG. 1 A after drying according to an embodiment.

[0013] FIG. 2 is a schematic side view of a coating according to an embodiment.

[0014] FIG. 3A is a photograph of a sample of Example 1.

[0015] FIG. 3B is an SEM image of the sample of Example 1.DEFINITIONS

[0016] All scientific and technical terms used herein have meanings commonly used in the art unless otherwise specified. The definitions provided herein are to facilitate understanding of certain terms used frequently herein and are not meant to limit the scope of the present disclosure.

[0017] Unless otherwise indicated, the terms “polymer” and “polymeric material” include, but are not limited to, organic homopolymers, copolymers, such as for example, block, graft, random and alternating copolymers, terpolymers, etc., and blends and modifications thereof. Furthermore, unless otherwise specifically limited, the term “polymer” shall include all possible geometrical configurations of the material. These configurations include, but are not limited to, isotactic, syndiotactic, and atactic symmetries.

[0018] The term “substantially” as used here has the same meaning as “significantly,” and can be understood to modify the term that follows by at least about 95 %, at least about 98 %, or at least about 99 %. The term “substantially free” of a particular compound means that the compositions of the present invention contain less than 1,000 parts per million (ppm) of the recited compound.

[0019] The term “not substantially” as used here has the same meaning as “not significantly,” and can be understood to have the inverse meaning of “substantially,” i.e., modifying the term that follows by not more than 10 %, not more than 5 %, not more than 2 %, or not more than 1 %.

[0020] The term “about” is used here in conjunction with numeric values to include normal variations in measurements as expected by persons skilled in the art, and is understood to have the same meaning as “approximately” and to cover a typical margin of error, such as ±5 % of the stated value.

[0021] Terms such as “a,” “an,” and “the” are not intended to refer to only a singular entity, but include the general class of which a specific example may be used for illustration.

[0022] The terms “a,” “an,” and “the” are used interchangeably with the term “at least one.” The phrases “at least one of’ and “comprises at least one of’ followed by a list refers to any one of the items in the list and any combination of two or more items in the list.

[0023] As used here, the term “or” is generally employed in its usual sense including “and / or” unless the content clearly dictates otherwise. The term “and / or” means one or all of the listed elements or a combination of any two or more of the listed elements.

[0024] The recitations of numerical ranges by endpoints include all numbers subsumed within that range (e.g., 1 to 5 includes 1, 1.5, 2, 2.75, 3, 3.80, 4, 5, etc. or 10 or less includes 10, 9.4, 7.6, 5, 4.3, 2.9, 1.62, 0.3, etc.). Where a range of values is “up to” or “at least” a particular value, that value is included within the range.

[0025] As used here, “have,” “having,” “include,” “including,” “comprise,” “comprising,” or the like are used in their open-ended sense, and generally mean “including, but not limited to.” It will be understood that “consisting essentially of,” “consisting of,” and the like are subsumed in “comprising” and the like. As used herein, “consisting essentially of,” as it relates to a composition, product, method, or the like, means that the components of the composition, product, method, or the like are limited to the enumerated components and any other components that do not materially affect the basic and novel character! stic(s) of the composition, product, method, or the like.

[0026] The words “preferred” and “preferably” refer to embodiments that may afford certain benefits, under certain circumstances. However, other embodiments may also be preferred, under the same or other circumstances. Furthermore, the recitation of one or more preferred embodiments does not imply that other embodiments are not useful, and is not intended to exclude other embodiments from the scope of the disclosure, including the claims.DETAILED DESCRIPTION

[0027] Paint and coating compositions are typically provided whiteness and / or opacity by including titanium dioxide (TiO?) in the composition. In fact, titanium dioxide (TiO2) and resin are the main components of many paints and coatings, providing white coloration and binding / protection, respectively. Titanium dioxide (TiO ) makes up about 70 % of the total volume of pigments used in the world. In 2019, the paint industry consumed 3.5 million tons of TiC>2. Even a partial substitution of TiCh would, therefore, offer significant cost savings. As of now, various approaches have been explored to partially replace TiCh, such as inorganic materials (e.g., ZnO) or engineer-designed structures. However, these alternatives have not provided sufficient light scattering and / or are expensive. A need for alternative solutions for provided whiteness and / or opacity to paints and coatings exists.

[0028] Conventional colorants in paints and coatings are based on pigments and dyes, in which the coloration mainly originates from the absorption of certain wavelength of visible light depending on chemical structure of the colorant. In contrast, structural color is a phenomenon by which an object is perceived to have a color due to the reflection or deflection of light because of the interaction of light with the structure of the object. Structural color is distinct from colors caused by absorption of light by pigments or dyes. An example of a source of structural color is thin-film interference, which may occur when light is incident on a thin film of material that has a different refractive index than its surroundings. When a light wave is reflected by the boundaries of the thin film, the reflected waves interfere with each other, forming a new wave. The color perceived on a soap bubble is a manifestation of thin-film interference. More complicated systems include multilayer interference and photonic crystals, which include multiple interfaces between media having different refractive indices. Structural color systems are typically known for their inherent regular structures and exhibiting non-equilibrium order formation.

[0029] It has surprisingly been discovered that a coating with controlled disordered micro- / nanostructures within the coating can be used to provide a structural white color. The degree of whiteness and the hiding power of the coated film may be adjusted or enhanced by controlling factors that contribute to creating the controlled disordered micro- / nanostructures. Such factors include, for example, the glass transition temperature (Tg) of the film-forming binder, and the particle size and distribution of the core particles. Thus, according to an embodiment, the coating composition and coating of the present disclosure includes controlled disordered micro- / nanostructures that provide the coating whiteness. The coating may include a reduced amount or may be free or substantially free of white pigments, white dyes, and white additives. Such controlled disordered micro- / nanostructures may be achieved by providing a core-shell latex having a relatively low poly dispersity index (e.g., being substantially monodisperse), where the shell is made up of a film-forming polymer.

[0030] By using structural color (e.g., structural white), coating compositions can be simplified by reducing or eliminating the need for pigments and dyes. Such simplified formulations may offer cost savings, less toxicity, more sustainable coating raw materials, and enhanced environmental stability of the coating composition. The coating compositions of the present disclosure may include a reduced amount of titanium dioxide (TiCh) compared to conventional coating compositions having the same whiteness. The coating compositions of the present disclosure may be free or substantially free of titanium dioxide (TiCh). The coating compositions of the present disclosure may be free or substantially free of pigments and dyes. The coating compositions of the present disclosure may be formulated as waterborne compositions. The coating compositions of the present disclosure is suitable for use as architectural coatings, industrial coatings, and wood coatings. The coating compositions of the present disclosure may be formulated as a one-component (“IK”) or a two-component (“2K”) system. The coating compositions of the present disclosure may be combined with common coating additives. The coating compositions of the present disclosure may be applied using any common application methods, such as brushing, spraying, rolling, etc.

[0031] The coating compositions of the present disclosure may also be referred to as resin compositions. The coating composition may be a latex and include a resin and an aqueoussolvent. The coating composition may be formulated as a paint. The coating composition may be applied onto a substrate and allowed to dry or cure (or both dry and cure), to form a coating.

[0032] According to an embodiment, the coating composition includes a core-shell latex. That is, the coating composition includes polymeric core-shell particles in an aqueous solvent. The core may be a hard, cured polymer particle that maintains its shape both in the liquid form of the coating composition and in the solid form of the coating. The shell may be a flowable polymer that forms a fdm as the coating composition is dried and the solvent is removed. The shell may further include a self-crosslinking polymer that crosslinks (e.g., cures) as the coating composition is dried and the solvent is removed. As the coating composition dries, it forms a coating that exhibits whiteness without the use of a white pigment, white dye, or white additive.

[0033] According to an embodiment, the core-shell particles include a fdm-forming shell. The shell is made of a suitable film-forming polymer. The shell may be made of a polymer that has a glass transition temperature (Tg) of -50 °C or greater, -40 °C or greater, -30 °C or greater, -20 °C or greater, -10 °C or greater, or 0 °C or greater. The shell may be made of a polymer that has a Tg of 30 °C or lower, 20 °C or lower, 15°C or lower, 10 °C or lower, or 0 °C or lower. The Tg of the shell polymer may be in a range of -50 °C to 30 °C, -30 °C to 20 °C, or -20 °C to 15 °C.

[0034] Examples of suitable polymers for the shell include latex polymers derived from monomers selected from N-substituted (meth)acrylamide, octyl (meth)acrylate, nonylphenol ethoxylate (meth)acrylate, isononyl (meth)acrylate, 1,6-hexanediol (meth)acrylate, isobornyl (meth)acrylate, 2-(2-ethoxyethoxy)ethyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, lauryl (meth)acrylate, beta-carboxyethyl (meth)acrylate, butyl (meth)acrylate; isobutyl (meth)acrylate, cycloaliphatic epoxide, alpha-epoxide, 2-hydroxyethyl (meth)acrylate, (meth)acrylonitrile, maleic anhydride, itaconic acid, isodecyl (meth)acrylate, dodecyl (meth)acrylate, n-butyl (meth)acrylate, methyl (meth)acrylate, hexyl (meth)acrylate, (meth)acrylic acid, N-vinylcaprolactam, stearyl (meth)acrylate, hydroxy functional caprolactone ester (meth)acrylate, octadecyl (meth)acrylate, isooctyl (meth)acrylate, hydroxyethyl (meth)acrylate, hydroxymethyl (meth)acrylate, hydroxypropyl (meth)acrylate, hydroxyisopropyl (meth)acrylate, hydroxybutyl (meth)acrylate, hydroxyisobutyl (meth)acrylate, tetrahydrofurfuryl (meth)acrylate, and mixtures or combinations thereof. In some embodiments, the shell may be made of a polymer derivedfrom monomers selected from (meth)acrylic acid, sorbic acid maleic anhydride, maleic acid, crotonic acid, itaconic acid, cinnamic acid, palmitoleic acid, oleic acid, linoleic acid, arachidonic acid, benzoic acid, fumaric acid, and mixtures or combinations thereof. In some embodiments, the shell may include a copolymer derived from the reaction of at least one vinyl ester monomer with at least one ethylenically unsaturated or free radically polymerizable monomer. In some embodiments, the shell may include a copolymer of two or more of butyl (meth)acrylate, methacrylic acid, methyl methacrylate, hydroxyethyl methacrylate, and 2-ethylhexyl acrylate. In some embodiments, the shell may include a copolymer that is functionalized. In some embodiments, the shell includes a self-crosslinking polymer. In some embodiments, the shell may include a chain transfer agent, optionally wherein the chain transfer agent comprises N-dodecyl mercaptan, T-dodecyl mercaptan, 2-mercaptoethanol, 1 -propanethiol, 2-mercaptopropionic acid, 3-mercaptopropionic acid, 2-methyl2propanethiol, 2-mercaptobutyric acid, 3 -mercaptobutyric acid, 4-mercaptobutyric acid, or a combination of two or more thereof.

[0035] According to an embodiment, the polymer of the shell and the polymer of the core have different refractive indices. The difference in the refractive index (RI) of the shell polymer compared to the core polymer may be 0.05 or greater, 0.08 or greater, 0.1 or greater, or 0.12 or greater. The difference in the RI may be 0.5 or less, 0.4 or less, 0.38 or less, 0.35 or less, 0.32 or less, 0.3 or less, or 0.28 or less. The difference in the RI may be in a range of 0.05 to 0.4, 0.08 to 0.38, or 0.1 to 0.35.

[0036] According to an embodiment, the core-shell particles include a core particle made of a different polymer than the shell. The core may be made of a polymer that has a Tg of 60 °C or greater, 65 °C or greater, 70 °C or greater, 80 °C or greater, or 90 °C or greater. The core may be made of a polymer that has a Tg of 115 °C or lower, 110 °C or lower, 100 °C or lower, or 90 °C or lower. The core may be made of a polymer that has a Tg in a range of 60 °C to 115 °C, 65 °C to 110 °C, or 70 °C to 100 °C.

[0037] Examples of suitable polymers for the core includes a polymer or copolymer derived from reactants including (a) at least one aromatic reactant comprising pendant free-radically-polymerizable functionality; optionally (b) at least one free-radically-polymerizable reactant having pendant acid functionality (or a salt or ester thereof); and optionally (c) at least one other copolymerizable reactant with free-radically-polymerizable functionality. In some embodiments,the core includes a polymer or copolymer derived from monomers selected from styrene, alphamethyl styrene, t-butyl styrene, 1,3-diisopropenylbenzene, 2,4, 6-trimethyl styrene, 2,4-dimethyl styrene, 2,4-diphenyl-4-methyl-l -pentene, 2,5-dimethylstyrene, 2-vinylnaphthalene, 3-methylstyrene, 4-benzyloxy-3 -methoxy styrene, 9-vinylanthracene, a,2-dimethylstyrene, benzyl (meth)acrylate, phenoxy ethyl (meth)acrylate, phenoxy ethylene glycol (meth)arylate, phenoxy diethylene glycol (meth)acrylate, 2-hydroxy 3-phexoxy propyl (meth)acrylate, 2-hydroxy o-phenylphenol propyl (meth)acrylate, ethoxylated o-phenylphenol (meth)acrylate, combinations of these, and mixtures or combinations thereof. In some embodiments, the core includes a polystyrene.

[0038] The core particles may be spherical or substantially spherical. In some embodiments, the core particles may have an average particle size of 150 nm or greater, 160 nm or greater, 170 nm or greater, 180 nm or greater, 190 nm or greater, or 200 nm or greater. The core particles may have an average particle size of 250 nm or less, 230 nm or less, 210 nm or less, or 200 nm or less. The core particles may have an average particle size in a range of 150 nm to 250 nm, 160 nm to 230 nm, or 170 nm to 210 nm.

[0039] Average particle size refers here to a volume average, and may be measured by dynamic light scattering.

[0040] In some embodiments, the core-shell particles have an average particle size of 170 nm or greater, 180 nm or greater, 190 nm or greater, 200 nm or greater, or 210 nm or greater. The core-shell particles may have an average particle size of 310 nm or less, 300 nm or less, 290 nm or less, 280 nm or less, 270 nm or less, 260 nm or less, 250 nm or less, 230 nm or less, or 210 nm or less. The core-shell particles may have an average particle size in a range of 170 nm to 310 nm, 180 nm to 280 nm, or 190 nm to 260 nm. The core-shell particles in the coating composition may have a relatively narrow particle size distribution. For example, the core-shell particles may have a poly dispersity index of 0.01 or greater, 0.05 or greater, 0.1 or greater, 0.15 or greater, or 0.2 or greater. The core-shell particles may have a poly dispersity index of 0.4 or lower, 0.35 or lower, or 0.3 or lower. The core-shell particles may have a poly dispersity index in a range of 0.1 to 0.4, or 0.15 to 0.35. In some embodiments, the core-shell particles may be characterized as monodisperse. The term “monodisperse” is used here to refer to a particle size distribution with a poly dispersity index of 0.2 or lower.

[0041] According to an embodiment, the core particles make up about 45 wt-% or more, 50 wt-% or more, 55 wt-% or more, 60 wt-% or more, or 65 wt-% or more of the total weight of the resins in the coating composition. The core particles may make up about 80 wt% or less, 75 wt-% or less, 70 wt-% or less, 65 wt-% or less, or 60 wt-% or less of the total weight of the resins in the coating composition. The core particles may make up about 45 wt-% to about 75 wt-%, or 50 wt-% to 70 wt-% of the total weight of the resins in the coating composition.

[0042] According to an embodiment, the shell makes up about 20 wt-% or more, 25 wt-% or more, 30 wt-% or more, 35 wt-% or more, or 40 wt-% or more of the total weight of the resins in the coating composition. The shell may make up about 55 wt-% or less, 50 wt-% or less, 45 wt-% or less, or 40 wt-% or less of the total weight of the resins in the coating composition. The shell may make up about 25 wt-% to about 55 wt-%, or 30 wt-% to 50 wt-% of the total weight of the resins in the coating composition.

[0043] The core-shell particles may make up about 25 wt-% or more, 50 wt-% or more, 60 wt-% or more, 70 wt-% or more, 80 wt-% or more, 90 wt-% or more, 95 wt-% or more, or all or substantially all of the resins in the coating composition. The core-shell particles may make up about 100 wt-% or less, 95 wt-% or less, 90 wt-% or less, 80 wt-% or less, or 50 wt-% or less of the resins in the coating composition.

[0044] The core-shell particles may make up about 10 wt-% or more, 20 wt-% or more, 25 wt-% or more, 30 wt-% or more, 35 wt-% or more, or 40 wt-% or more of the total weight of the coating composition. The core-shell particles may make up about 95 wt-% or less, 90 wt-% or less, 80 wt-% or less, 70 wt-% or less, 60 wt-% or less, 50 wt-% or less, 45 wt-% or less, or 40 wt-% or less of the total weight of the coating composition. The core-shell particles may make up about 25 wt-% to about 55 wt-%, or 30 wt-% to 50 wt-% of the total weight of the coating composition.

[0045] In some embodiments, the coating composition includes another plurality of core¬ shell particles (e.g., second core-shell particles) that are different from the first core-shell particles. The second core-shell particles may, for example, have one or more of a different particle size, different core-particle particle size, or different chemical composition, than the first core-shell particles. In one embodiment, the second core-shell particles have a different particle size than the first core-shell particles. For example, the coating composition may include firstcore-shell particles having a particle size in a range of 200 nm to 250 nm, and second core-shell particles having a particle size in a range of 250 nm to 300 nm. The particle size, the coreparticle particle size, and chemical composition of the core and the shell of the second core-shell particles may be selected within the same ranges as the first core-shell particles as described herein.

[0046] The coating composition may include one or more additional resins. For example, the core-shell particles described herein may be included or mixed with a conventional coating composition, such as a conventional water-based coating composition (e.g., a latex-based paint). Conventional coating compositions may include interior and exterior architectural paints, stains, industrial paints (e.g., alkyd, polyester, epoxy, acrylic, and urethane chemistries), primers, caulks, and sealants. Including the core-shell particles in a conventional coating composition can be used to increase whiteness of the composition and improve coverage (e g., increased opacity). The amount of other white pigments, white dyes, and white additives in the conventional coating composition can be reduced by including the core-shell particles of the present disclosure. A typical white coating composition may include about 2.3 Ib / gal (about 0.28 kg / L) of titanium dioxide (TiCh). The amount of TiCh may be reduced by 10 % or more, 20 % or more, 25 % or more, or 30 % or more, by including the core-shell particles of the present disclosure. In some embodiments, the coating composition includes about 20 kg / L or less, about 15 kg / L or less, or about 10 kg / L or less of white pigment (such as TiCh) or fdler. In some embodiments, the coating composition includes less than about 20 wt-%, less than about 15 wt-%, or less than about 10 wt-% of white pigment (such as TiCh) or fdler. In some embodiments, the coating composition is a structural white paint containing less than about 10 wt-% white pigment (such as TiCh) or fdler. On the other hand, mixing a conventional coating composition with the coreshell particle coating composition can be used to increase the durability of the core-shell particle coating composition.

[0047] The coating composition may include various additional ingredients. Such additional ingredients may include any suitable additives typically used in the industry, such as pigments, matting agents, fdlers, wetting agents, defoamers, rheological modifiers, ultraviolet (UV) light stabilizers, UV absorbers, dispersing agents, flow and leveling agents, optical brighteners, gloss additives, radical inhibitors, radical initiators, adhesion promotors, plasticizers, co-solvents,coalescing agents, reducers, reactive diluents, co-binders, photo-initiators, hardeners, catalysts, corrosion inhibitors, biocides, fungicides, surfactants, and waxes. When used, the additives preferably enhance and preferably do not adversely affect the coating composition, or a cured coating formed from the coating composition. For example, additives may be included in the coating composition to enhance composition aesthetics, to facilitate manufacturing, processing, handling, and application of the composition, and to further improve a particular functional property of the coating composition or a cured coating resulting therefrom. Each optional additive is preferably included in a sufficient amount to serve its intended purpose, but not in such an amount to adversely affect the coating composition or a cured coating resulting therefrom.

[0048] The coating composition may be made by typical seeded or unseeded 2-stage or 3-stage emulsion polymerization process. The particle size of core-shell latex can be adjusted by changing the type and the level of surfactant used in the recipe. The core particle size can also be controlled by changing the ratio of core / shell of the latex.

[0049] The coating composition may be formulated as a one-component system or as a two-component system. In other words, the coating composition may be a one-part system or a two-part system. The coating composition being a one-part system refers to the ingredients of the coating system being in a pre-mixed form, i.e., the reagents are provided as a pre-mixed mixture. The coating composition being a two-part coating system refers to the composition of the coating system not being in a pre-mixed form. It refers to the coating system being comprised of two mixtures of the reagents of the coating system. A two-component system is typically mixed immediately before or during application to form the coating.

[0050] The coating composition may be applied to any suitable substrate by any suitable means. For example, the coating composition may be applied to wood, metal, plastic, concrete, cellulosic, composite, and like substrates, and combinations thereof. In some embodiments, the coating composition is an architectural paint intended for application onto building surfaces. The coating composition may be applied using any suitable method. For example, the coating composition may be applied by spraying, brushing, roll coating, pouring, dipping, etc.

[0051] After application onto a substrate, the coating composition may be dried. The drying of the coating composition may involve removing at least some of the solvent. As the solvent isremoved, the flowable shell polymer flows such that the shells of adjacent core-shell particles merge, forming a film of the shell polymer in which the core particles are dispersed. This mechanism is schematically illustrated in FIGS. 1 A and IB. FIG. 1A shows the coating composition 1 prior to drying. The coating composition 1 includes core-shell particles 20 in a solvent 50. The core-shell particles 20 are made up of a core particle 30 and a shell 40. The coreshell particle 20 has a diameter D20. The core particle 30 has a diameter D30. As the solvent is removed during drying, the coating composition 1 forms a coating 100. In the coating, the flowable shell polymer flows such that the shells 40 of adjacent core-shell particles 20 merge, forming a film 60 of the shell polymer in which the core particles 30 are dispersed, as shown in FIG. IB. The core particles become arranged in a disordered arrangement within the film formed by the shell polymer. The coating 100, including core particles 30 dispersed within the film 60, applied onto a substrate 80, is schematically shown in FIG. 2. The removal of the solvent may occur at ambient conditions, or at an elevated temperature. Ambient conditions are understood to mean outdoor ambient temperatures above freezing, e.g., from about 0 °C to about 40 °C, including temperatures in a range of 10 °C to 40 °C. An elevated temperature is understood to mean temperatures above 40 °C, including oven baking temperatures. In some embodiments it may be desirable to maintain the elevated temperature at 80 °C or below. The drying of the coating composition may involve curing. In particular, the drying of the coating may involve curing of the shell polymer. The coating composition may include a cross-linking agent or a selfcrosslinking polymer. In some embodiments, the shell polymer is or includes a self-crosslinking and / or radiation curable polymer. Curing or crosslinking may be initiated by drying or by radiating the composition by, for example, ultraviolet (“UV”), light emitting diode (“LED”), or electron beam (“EB”) radiation, or by both drying and radiation.

[0052] A method of preparing a coating (e.g., a structural white coating) may include applying a film of the coating composition of the present disclosure to a substrate at a dry film thickness ranging from about 15 pm to about 200 pm; and drying or curing or both drying and curing the film to form the structural white coating. The coating may be applied by brushing, spraying, roll coating, or a combination thereof. The film may be cured at ambient conditions, at an elevated temperature, by radiation, or a combination thereof. During curing, the shell polymer of the core-shell particles may self-crosslink.

[0053] The coating composition may be applied at any suitable or desired thickness. In some embodiments, the coating composition may be applied at a dry coat thickness of about 0.5 mil (about 12 pm) to about 4 mil (about 100 pm), about 0.5 mil (about 12 pm) to about 3 mil (about 75 pm), 0.75 mil (about 19 pm) to 2 mil (about 50 pm), or about 1 mil (about 25 pm). Coating composition thicknesses below 3 mil (about 75 pm) or below 2 mil (about 50 pm) may be desired to avoid cracking of the dry coating. Thicker coatings (without cracks) may also be achieved by applying multiple layers of the coating composition, if desired. Additional methods to achieve thicker coatings (without cracks) include blending the coating composition with a conventional resin having good film formation ability, and adding a suitable coalescing agent to the coating composition.

[0054] According to an embodiment, the coating composition is a structural white paint. Further according to an embodiment, the coating formed by the coating composition is a structural white coating having a white appearance. The whiteness of a material, such as a coating, may be measured using a spectrophotometer. The whiteness of the material may be expressed, for example, using L* values of the CIELAB color space. L* values range from 0 to 100, with higher values indicating greater whiteness. In some embodiments, the coating, when applied as a film having a film thickness of 1 mil (25 pm), exhibits an L* value of 80 or greater, 85 or greater, 90 or greater, or 95 or greater, without a white pigment, white dye, or white additive.

[0055] According to an embodiment, the coating composition exhibits good opacity. Opacity may be measured, for example, by applying the coating as a film on a test substrate that includes both a black surface and a white surface, and measuring the contrast ratio using a spectrophotometer. The contrast ratio is calculated as the ratio of the reflectance of the coating on the black area divided by the reflectance of the white area. In some embodiments, the coating, when applied as a film having a film thickness of 1 mil (25 pm), exhibits a contrast ratio of 0.5 or greater, 0.6 or greater, 0.7 or greater, 0.8 or greater, or 0.9 or greater, against a black background, without a white pigment, white dye, or white additive.EXEMPLARY EMBODIMENTS

[0056] The following is a list of exemplary embodiments according to the present disclosure.

[0057] According to an embodiment, the resin composition is a liquid composition. The liquid composition may be a paint.

[0058] Embodiment Al is a resin composition comprising:a monodisperse core-shell latex comprising first core-shell particles in an aqueous solvent,the first core-shell particles comprising a film-forming shell comprising a first polymer and a rigid core comprising a second polymer,wherein upon forming a coating, the coating composition exhibits whiteness without use of a white pigment, white dye, or white additive.

[0059] Embodiment A2 is a resin composition comprising:a film-forming shell comprising a first polymer;core particles comprising a second polymer; andan aqueous solvent,the shell and the core particles forming first core-shell particles dispersed in the aqueous solvent and having a poly dispersity index in a range of about 0.1 to about 0.4,wherein upon forming a coating, the composition exhibits whiteness without use of a white pigment, white dye, or white additive.

[0060] Embodiment A3 is a resin composition comprising:a film-forming shell comprising a first polymer having a glass transition temperature (Tg) in a range of -50 °C to 30 °C;core particles comprising a second polymer having a Tg in a range of 60 °C to 115 °C; andan aqueous solvent, the shell and the core particles forming first core-shell particles dispersed in the aqueous solvent, wherein upon forming a coating, the composition exhibits whiteness without use of a white pigment, white dye, or white additive.

[0061] Embodiment A4 is a resin composition comprising:a film-forming shell comprising a first polymer;core particles comprising a second polymer; andan aqueous solvent,the shell and the core particles forming first core-shell particles dispersed in the aqueous solvent and, the first polymer and the second polymer having a difference of refractive index (RI) in a range of 0.1 to 0.35,wherein upon forming a coating, the coating composition exhibits whiteness without use of a white pigment, white dye, or white additive.

[0062] Embodiment A5 is a resin composition comprising:a film-forming shell comprising a first polymer;core particles comprising a second polymer; andan aqueous solvent,the shell and the core particles forming first core-shell particles dispersed in the aqueous solvent and having an average particle size in a range of 170 nm to 280 nm,wherein upon forming a coating, the coating composition exhibits whiteness without use of a white pigment, white dye, or white additive.

[0063] Embodiment A6 is the resin composition of embodiment Al, wherein the first coreshell particles have an average particle size in a range of 170 nm or greater, 180 nm or greater, 190 nm or greater, 200 nm or greater, or 210 nm or greater.

[0064] Embodiment A7 is the resin composition of any one of the preceding embodiments, wherein the first core-shell particles have an average particle size in a range of 310 nm or less, 300 nm or less, 290 nm or less, 280 nm or less, 270 nm or less, 260 nm or less, 250 nm or less, 230 nm or less, or 210 nm or less.

[0065] Embodiment A8 is the resin composition of any one of the preceding embodiments, wherein the first core-shell particles have an average particle size in a range of 170 nm to 310 nm, 180 nm to 280 nm, or 190 nm to 260 nm.

[0066] Embodiment A9 is the resin composition of any one of the preceding embodiments, wherein the first core-shell particles have a poly dispersity index of 0.01 or greater, 0.05 or greater, 0.1 or greater, 0.15 or greater, or 0.2 or greater.

[0067] Embodiment A10 is the resin composition of any one of the preceding embodiments, wherein the first core-shell particles have a poly dispersity index of 0.4 or lower, 0.35 or lower, or 0.3 or lower.

[0068] Embodiment Al l is the resin composition of any one of the preceding embodiments, wherein the first core-shell particles have a poly dispersity index in a range of 0.1 to 0.4, or 0.15 to 0.35.

[0069] Embodiment Al 2 is the resin composition of any one of the preceding embodiments, wherein the core particles comprise about 45 wt-% or more, 50 wt-% or more, 55 wt-% or more, 60 wt-% or more, or 65 wt-% or more of the resin composition by total weight of resins.

[0070] Embodiment Al 3 is the resin composition of any one of the preceding embodiments, wherein the core particles comprise about 80 wt% or less, 75 wt-% or less, 70 wt-% or less, 65 wt-% or less, or 60 wt-% or less of the resin composition by total weight of resins.

[0071] Embodiment A14 is the resin composition of any one of the preceding embodiments, wherein the core particles comprise about 45 wt-% to about 75 wt-%, or 50 wt-% to 70 wt-% of the resin composition by total weight of resins.

[0072] Embodiment Al 5 is the resin composition of any one of the preceding embodiments, wherein the shell comprises about 20 wt-% or more, 25 wt-% or more, 30 wt-% or more, 35 wt-% or more, or 40 wt-% or more of the resin composition by total weight of resins.

[0073] Embodiment A16 is the resin composition of any one of the preceding embodiments, wherein the shell comprises about 55 wt-% or less, 50 wt-% or less, 45 wt-% or less, or 40 wt-% or less of the resin composition by total weight of resins.

[0074] Embodiment Al 7 is the resin composition of any one of the preceding embodiments, wherein the shell comprises about 25 wt-% to about 55 wt-%, or 30 wt-% to 50 wt-% of the resin composition by total weight of resins.

[0075] Embodiment Al 8 is the resin composition of any one of the preceding embodiments, wherein first polymer has a glass transition temperature (Tg) in a range of -50 °C or greater, -40 °C or greater, -30 °C or greater, -20 °C or greater, -10 °C or greater, or 0 °C or greater.

[0076] Embodiment Al 9 is the resin composition of any one of the preceding embodiments, wherein first polymer has a glass transition temperature (Tg) in a range of 30 °C or lower, 20 °C or lower, 15°C or lower, 10 °C or lower, or 0 °C or lower.

[0077] Embodiment A20 is the resin composition of any one of the preceding embodiments, wherein first polymer has a glass transition temperature (Tg) in a range of -50 °C to 30 °C, -30 °C to 20 °C, or -20 °C to 15 °C.

[0078] Embodiment A21 is the resin composition of any one of the preceding embodiments, wherein second polymer has a glass transition temperature (Tg) in a range of 60 °C or greater, 65 °C or greater, 70 °C or greater, 80 °C or greater, or 90 °C or greater.

[0079] Embodiment A22 is the resin composition of any one of the preceding embodiments, wherein second polymer has a glass transition temperature (Tg) in a range of 115 °C or lower, 110 °C or lower, 100 °C or lower, or 90 °C or lower.

[0080] Embodiment A23 is the resin composition of any one of the preceding embodiments, wherein second polymer has a glass transition temperature (Tg) in a range of 60 °C to 115 °C, 65 °C to 110 °C, or 70 °C to 100 °C.

[0081] Embodiment A24 is the resin composition of any one of the preceding embodiments, wherein the first polymer and the second polymer having a difference of refractive index (RI) in a range of 0.05 or greater, 0.08 or greater, 0.1 or greater, or 0.12 or greater.

[0082] Embodiment A25 is the resin composition of any one of the preceding embodiments, wherein the first polymer and the second polymer having a difference of refractive index (RI) in a range of 0.5 or less, 0.4 or less, 0.38 or less, 0.35 or less, 0.32 or less, 0.3 or less, or 0.28 or less.

[0083] Embodiment A26 is the resin composition of any one of the preceding embodiments, wherein the first polymer and the second polymer having a difference of refractive index (RI) in a range of 0.05 to 0.4, 0.08 to 0.38, or 0.1 to 0.35.

[0084] Embodiment A27 is the resin composition of any one of the preceding embodiments, wherein the core particles have an average particle size in a range of 150 nm or greater, 160 nm or greater, 170 nm or greater, 180 nm or greater, 190 nm or greater, or 200 nm or greater.

[0085] Embodiment A28 is the resin composition of any one of the preceding embodiments, wherein the core particles have an average particle size in a range of 250 nm or less, 230 nm or less, 210 nm or less, or 200 nm or less.

[0086] Embodiment A29 is the resin composition of any one of the preceding embodiments, wherein the core particles have an average particle size in a range of 150 nm to 250 nm, 160 nm to 230 nm, or 170 nm to 210 nm.

[0087] Embodiment A30 is the resin composition of any one of the preceding embodiments, wherein the composition is a one-component system.

[0088] Embodiment A31 is the resin composition of any one of the preceding embodiments, wherein the composition is a two-component system.

[0089] Embodiment A32 is the resin composition of any one of the preceding embodiments further comprising a secondary latex resin.

[0090] Embodiment A33 is the resin composition of any one of the preceding embodiments further comprising second core-shell particles having a different particle size than the first coreshell particles.

[0091] Embodiment A34 is the resin composition of any one of the preceding embodiments, wherein the second core-shell particles have a different chemical composition than the first coreshell particles.

[0092] Embodiment A35 is the resin composition of any one of the preceding embodiments, wherein the second core-shell particles comprise core particles having a different particle size than core particles of the first core-shell particles.

[0093] Embodiment A36 is the resin composition of any one of the preceding embodiments, wherein the core-shell particles make up about 25 wt-% or more, 50 wt-% or more, 60 wt-% or more, 70 wt-% or more, 80 wt-% or more, 90 wt-% or more, 95 wt-% or more, or all or substantially all of the resins in the resin composition.

[0094] Embodiment A37 is the resin composition of any one of the preceding embodiments, wherein the core-shell particles make up about 100 wt-% or less, 95 wt-% or less, 90 wt-% or less, 80 wt-% or less, or 50 wt-% or less of the resins in the resin composition.

[0095] According to an embodiment, the coating composition is a dried and / or cured coating. In some embodiments, the coating composition includes a film-forming portion and core particles having different glass transition temperatures.

[0096] Embodiment Bl is a coating comprising:a film-forming portion comprising a first polymer having a Tg in a range of -50 °C to 30 °C and a first refractive index; andcore particles dispersed throughout the film-forming portion and comprising a second polymer having a Tg in a range of 60 °C to 115 °C and a second refractive index, wherein the second refractive index is different from the first refractive index,the core particles having an average particle size in a range of 150 nm to 250 nm.

[0097] Embodiment B2 is the coating composition of embodiment Bl, wherein the core particles comprise about 45 wt-% to about 75 wt-% of the coating composition.

[0098] Embodiment B3 is the coating composition of embodiment Bl or B2, wherein the film-forming portion comprises about 25 wt-% to about 55 wt-% of the coating composition.

[0099] Embodiment B4 is a coating comprising a film comprising:a binder comprising a first polymer having a Tg of 30 °C or lower, wherein the binder makes up 25 wt-% to 55 wt-% of the film; andcore particles dispersed throughout the binder, the core particles comprising a second polymer having a Tg of 60 °C or greater, wherein the core particles make up 45 wt-% to 75 wt-% of the film.

[0100] Embodiment B5 is the coating composition of any one of the B embodiments, wherein the film exhibits an L* value of 80 or greater at a film thickness of 1 mil (25 pm) without a white pigment, white dye, or white additive.

[0101] Embodiment B6 is the coating composition of any one of the B embodiments, wherein the film exhibits a contrast ratio of 0.5 or greater against a black background at a film thickness of 1 mil (25 pm) without a white pigment, white dye, or white additive.

[0102] Embodiment B7 is the coating composition of any one of the B embodiments, wherein the resin composition or coating is a structural white paint containing less than about 10 wt-% white pigment or filler.

[0103] Embodiment B8 is the coating composition of any one of the B embodiments, wherein the resin composition or coating is a structural white paint comprising one or more ofpigments, matting agents, fillers, wetting agents, defoamers, rheological modifiers, ultraviolet (UV) light stabilizers, UV absorbers, dispersing agents, flow and leveling agents, optical brighteners, gloss additives, radical inhibitors, radical initiators, adhesion promotors, plasticizers, co-solvents, coalescing agents, reducers, reactive diluents, co-binders, photo-initiators, hardeners, catalysts, corrosion inhibitors, biocides, fungicides, surfactants, and waxes.

[0104] Embodiment B9 is the coating composition of any one of the B embodiments further comprising a secondary film-forming resin. According to an embodiment, the resin composition is applied onto a substrate to form a coating.

[0105] Embodiment Cl is a method of preparing a structural white coating, comprising: applying a film of the resin composition of any one of embodiments A to E to a substrate at a dry film thickness ranging from about 15 pm to about 200 pm; anddrying or curing or both drying and curing the film to form the structural white coating.

[0106] Embodiment C2 is the method of embodiment Cl, wherein the film is cured and wherein during curing, the first polymer self-crosslinks.

[0107] Embodiment C3 is the method of any one of the C embodiments, wherein the film is cured at ambient conditions, at an elevated temperature, by radiation, or a combination thereof.

[0108] Embodiment C4 is the method of any one of the C embodiments, wherein the coating is applied by brushing, spraying, roll coating, or a combination thereof.

[0109] Embodiment C5 is the method of any one of the C embodiments, wherein the core particles become arranged in a disordered arrangement within the film formed by the first polymer of the shell. According to an embodiment, the resin composition, the coating composition, or the method of preparing a structural white coating include various features as detailed below.

[0110] Embodiment DI is the resin composition, coating, or method of any one of the preceding embodiments, wherein the first polymer has a Tg of about 30 °C or less, 25 °C or less, 20 °C or less, or about -50 °C to about 30 °C.

[0111] Embodiment D2 is the resin composition, coating, or method of any one of the preceding embodiments, wherein the second polymer has a Tg of about 60 °C or greater, 70 °C or greater, 75 °C or greater, 90 °C or greater, or about 60 °C to about 115 °C.

[0112] Embodiment D3 is the resin composition, coating, or method of any one of the preceding embodiments, wherein the core particles comprise a polystyrene.

[0113] Embodiment D4 is the resin composition, coating, or method of any one of the preceding embodiments, wherein the core particles comprise polymer or copolymer derived from reactants including (a) at least one aromatic reactant comprising pendant free-radically-polymerizable functionality; optionally (b) at least one free-radically-polymerizable reactant having pendant acid functionality (or a salt or ester thereof); and optionally (c) at least one other copolymerizable reactant with free-radically-polymerizable functionality.

[0114] Embodiment D5 is the resin composition, coating, or method of any one of the preceding embodiments, wherein the core particles comprise polymer or copolymer derived from monomers selected from styrene, alpha-methyl styrene, t-butyl styrene, 1,3-diisopropenylbenzene, 2,4,6-trimethylstyrene, 2,4-dimethylstyrene, 2,4-diphenyl-4-methyl-l-pentene, 2, 5 -dimethyl styrene, 2-vinylnaphthalene, 3 -methyl styrene, 4-benzyloxy-3-methoxystyrene, 9-vinylanthracene, a,2-dimethylstyrene, benzyl (meth)acrylate, phenoxy ethyl (meth)acrylate, phenoxy ethylene glycol (meth)arylate, phenoxy diethylene glycol (meth)acrylate, 2-hydroxy 3-phexoxy propyl (meth)acrylate, 2-hydroxy o-phenylphenol propyl (meth)acrylate, ethoxylated o-phenylphenol (meth)acrylate, combinations of these, and mixtures or combinations thereof.

[0115] Embodiment D6 is the resin composition, coating, or method of any one of the preceding embodiments, wherein the first polymer comprises a latex polymer derived from monomers selected from N-substituted (meth)acrylamide, octyl (meth)acrylate, nonylphenol ethoxylate (meth)acrylate, isononyl (meth)acrylate, 1,6-hexanediol (meth)acrylate, isobornyl (meth)acrylate, 2-(2-ethoxyethoxy)ethyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, lauryl (meth)acrylate, beta-carboxyethyl (meth)acrylate, butyl (meth)acrylate; isobutyl (meth)acrylate, cycloaliphatic epoxide, alpha-epoxide, 2-hydroxyethyl (meth)acrylate, (meth)acrylonitrile, maleic anhydride, itaconic acid, isodecyl (meth)acrylate, dodecyl (meth)acrylate, n-butyl (meth)acrylate, methyl (meth)acrylate, hexyl (meth)acrylate, (meth)acrylic acid, N-vinyl caprolactam, stearyl (meth)acrylate, hydroxy functional caprolactone ester (meth)acrylate, octadecyl (meth)acrylate, isooctyl (meth)acrylate, hydroxyethyl (meth)acrylate, hydroxymethyl (meth)acrylate, hydroxypropyl (meth)acrylate, hydroxyisopropyl (meth)acrylate, hydroxybutyl (meth)acrylate, hydroxyisobutyl (meth)acrylate, tetrahydrofurfuryl (meth)acrylate, and mixtures or combinations thereof.

[0116] Embodiment D7 is the resin composition, coating, or method of any one of the preceding embodiments, wherein the first polymer comprises a polymer derived from monomers selected from (meth)acrylic acid, sorbic acid, maleic anhydride, maleic acid, crotonic acid, itaconic acid, cinnamic acid, palmitoleic acid, oleic acid, linoleic acid, arachidonic acid, benzoic acid, fumaric acid, and mixtures or combinations thereof.

[0117] Embodiment D8 is the resin composition, coating, or method of embodiment D7, wherein the first polymer comprises a copolymer derived from the reaction of at least one vinyl ester monomer with at least one ethylenically unsaturated or free radically polymerizable monomer.

[0118] Embodiment D9 is the resin composition, coating, or method of any one of the preceding embodiments, wherein the first polymer comprises a copolymer of two or more of butyl (meth)acrylate, methacrylic acid, methyl methacrylate, hydroxy ethyl methacrylate, and 2-ethylhexyl acrylate.

[0119] Embodiment DIO is the resin composition, coating, or method of any one of the preceding embodiments, wherein the first polymer comprises a copolymer that is functionalized.

[0120] Embodiment DI 1 is the resin composition, coating, or method of any one of the preceding embodiments, wherein the first polymer comprises a chain transfer agent, optionally wherein the chain transfer agent comprises N-dodecyl mercaptan, T-dodecyl mercaptan, 2-mercaptoethanol, 1 -propanethiol, 2-mercaptopropionic acid, 3 -mercaptopropionic acid, 2-methyl2propanethiol, 2-mercaptobutyric acid, 3-mercaptobutyric acid, 4-mercaptobutyric acid, or a combination of two or more thereof.

[0121] Embodiment D12 is the resin composition, coating, or method of any one of the preceding embodiments, wherein the first polymer is a self-crosslinking polymer.

[0122] Embodiment A38 is the resin composition, coating, or method of any one of the preceding embodiments, wherein the core-shell particles make up about 10 wt-% or more, 20 wt-% or more, 25 wt-% or more, 30 wt-% or more, 35 wt-% or more, or 40 wt-% or more of the total weight of the resin composition.

[0123] Embodiment A39 is the resin composition, coating, or method of any one of the preceding embodiments, wherein the core-shell particles make up about 95 wt-% or less, 90 wt-% or less, 80 wt-% or less, 70 wt-% or less, 60 wt-% or less, 50 wt-% or less, 45 wt-% or less, or 40 wt-% or less of the total weight of the resin composition.

[0124] Embodiment A40 is the resin composition, coating, or method of any one of the preceding embodiments, wherein the core-shell particles make up about 25 wt-% to about 55 wt-%, or 30 wt-% to 50 wt-% of the total weight of the resin composition.EXAMPLESVarious structural white paint samples were prepared and compared to a conventional latex paint with and without white pigment (TiCh). The paints were applied onto test sheets including a white and black background, dried / cured, and evaluated for contrast ratio, L* value (whiteness), and film formation. The contrast between the paint applied over the black background and the white background was determined by a spectrophotometer. The contrast values range from 0 to 1. A low contrast value indicates low opacity, while a high contrast value indicates high opacity. L* values were measured using a spectrophotometer. Film formation was evaluated visually by observing the presence or absence of cracks and flakiness.PREPARATION OF CORE-SHELL LATEX

[0125] An exemplary embodiment of a core-shell latex preparation is described.

[0126] A first pre-emulsion was prepared by adding 320 grams of deionized water, 0.38 grams of surfactant RHODAPEX LA 40SZ (available from Syensqo in Brussels, Belgium), and 118 grams of styrene seed latex in a clean four-neck 3-liter reactor equipped with mechanic agitator, nitrogen inlet, thermometer, and condenser. The reactor was heated to 85 °C. The preemulsion was prepared by adding the ingredients in TABLE 1 below in a suitable size beaker and agitated at high speed for at least 30 minutes. The initial initiator solution (0.72 grams ofammonium persulfate dissolved in 20 grams of DI water) was added to the reactor at 85 °C in one shot just before pre-emulsion feeding. The first stage pre-emulsion and initiator solution (2.52 grams of ammonium persulfate dissolved in 55 grams of DI water) were fed within 150 minutes. The reaction was held at 85 °C for 40 minutes.

[0127] After holding, the pre-emulsion #2 and initiator solution #2 (1.35 grams ammonium persulfate dissolved in 40 grams of DI water) were fed into the reactor over 60 minutes. After holding for 60 minutes, the reaction was cooled down to 45 °C and the pH of the latex was adjusted with 28 % aqueous ammonium to above 9.0. Then, 4.17 grams of adipic dihydrazide was added to the reactor under agitation. The agitation was kept on for at least 30 minutes before the latex was discharged through a 100 mesh filter. The typical NVM (non-volatile matter) of the latex was around 46 % with volume average particle size of 253 nm and poly dispersity index of 0.28 measured by dynamic light scattering method.TABLE 1. Pre-emulsion compositionsEXAMPLE 1

[0128] A core-shell latex sample with 200 nm particle size was prepared and applied onto a test substrate with a drawdown application (wire-wound Mayer rod), and dried at 20 to 25 °C. The core particles were composed of styrene and acrylic acid and had a particle size of about 150nm. The shell polymer was composed of methacrylic acid, 2-hydroxyl ethyl methacrylate, and butyl acrylate. The core-shell particles had a concentration of 46.7 wt-% in water. A photograph and a scanning electron microscope (SEM) image are shown in FIGS. 3A and 3B, respectively. The dried fdm was observed to exhibit a disordered nanostructure of polymer particles within the film.EXAMPLE 2

[0129] Three samples of core-shell latex were prepared with different particle sizes. One sample with a blend of two particle sizes was also prepared. The samples were applied at a wet film thickness of 2.5 mil (62.5 pm) onto a black background and allowed to dry at ambient conditions, the contrast ratio, and L* value (whiteness) of the dried samples were measured. The samples and the results are shown below in TABLE 2.TABLE 2.

[0130] It was observed that each sample exhibited a high contrast ratio and L* value without the use of any white pigment, dye, or filler. The blended sample was observed to exhibit a higher contrast ratio, and L* value than either of the individual samples on their own.EXAMPLE 3

[0131] Sample 1 A from EXAMPLE 2 was mixed with common paint additives to test the feasibility of using common coating application methods. The composition is shown below in TABLE 3.TABLE 3.

[0132] The composition was applied onto substrates by brushing and by spraying. It was observed that both application methods could be used to apply the composition with good results.EXAMPLE 4

[0133] Two samples of core-shell latex (Samples 4A and 4B) were prepared with a selfcrosslinking shell polymer (methacrylic acid, 2-hydroxylethyl methacrylate, butyl acrylate, diacetone acrylamide, and dihydrazide). The core particles were composed of styrene and methacrylic acid and had a particle size of about 150 and 220 nm. The core-shell particles had a concentration of around 45 wt-% in water. The samples were applied at different thicknesses applied onto a test substrate and dried at ambient conditions to evaluate film forming, contrast ratio, and L* value (whiteness) of the dried samples. The samples and the results are shown below in TABLE 4.TABLE 4.

[0134] It was observed that the samples with 205 particle size had a slightly lower contrast ratio and L* value than the samples with 246 nm particle size. It was further observed that the coatings had improved film formation as compared to non-self-crosslinking compositions. The non-self-crosslinked samples started to show cracks and flakiness at high film thicknesses (4 mils wet film thickness), while no cracks or flakiness were observed at 4 mils wet film thickness with the self-crosslinked samples.EXAMPLE 5

[0135] A comparative sample of conventional latex paint Bayhydrol A-2846 (available from Covestro AG in Leverkusen, Germany) was also applied onto a test substrate. The contrast ratio of the sample was determined and compared to the core-shell latex Sample 4B.

[0136] Without any white pigment, A-2846 had a contrast ratio of 0.008. Sample 4 had a contrast ratio of 0.78.EXAMPLE 6

[0137] The ability of a core-shell latex to replace at least some of TiCh in a latex paint was evaluated. A comparative sample of conventional latex paint Bayhydrol A-2846 was prepared with 0.273 kg / L (2.28 Ib / gal) of TiCh to achieve a 0.936 contrast ratio on a test substrate. Sample 4B from Example 4 was mixed with varying amounts of TiChto prepare Samples 5A-5C, reducing the amount of TiCh until a similar contrast ratio was achieved as in the comparative sample. The samples were applied onto test substrates and dried at ambient conditions. The contrast ratio of each sample was determined. The samples and the results are shown below in TABLE 5.TABLE 5.

[0138] It was observed that the amount of TiCh could be lowered by 26 % (from 0.273 kg / L to 0.203 kg / L) by using the core-shell latex, while maintaining a similar contrast ratio (0.936 for the comparative sample vs. 0.938 for Sample 5C).

[0139] All references and publications cited herein are expressly incorporated herein by reference in their entirety into this disclosure, except to the extent they may directly contradict this disclosure. Although specific embodiments have been illustrated and described herein, it will be appreciated by those of ordinary skill in the art that a variety of alternate and / or equivalent implementations can be substituted for the specific embodiments shown and described without departing from the scope of the present disclosure. It should be understood that this disclosure is not intended to be unduly limited by the illustrative embodiments and examples set forth herein and that such examples and embodiments are presented by way of example only with the scope of the disclosure intended to be limited only by the claims set forth here.

Claims

CLAIMSWhat is claimed is:

1. A resin composition comprising:a monodisperse core-shell latex comprising first core-shell particles in an aqueous solvent,the first core-shell particles comprising a film-forming shell comprising a first polymer and a rigid core comprising a second polymer,wherein upon forming a coating, the coating composition exhibits whiteness without use of a white pigment, white dye, or white additive.

2. A resin composition comprising:a film-forming shell comprising a first polymer;core particles comprising a second polymer; andan aqueous solvent,the shell and the core particles forming first core-shell particles dispersed in the aqueous solvent and having a poly dispersity index in a range of about 0.1 to about 0.4,wherein upon forming a coating, the composition exhibits whiteness without use of a white pigment, white dye, or white additive.

3. A resin composition comprising:a film-forming shell comprising a first polymer having a glass transition temperature (Tg) in a range of -50 °C to 30 °C;core particles comprising a second polymer having a Tg in a range of 60 °C to 115 °C; andan aqueous solvent,the shell and the core particles forming first core-shell particles dispersed in the aqueous solvent,wherein upon forming a coating, the composition exhibits whiteness without use of a white pigment, white dye, or white additive.

4. A resin composition comprising:a film-forming shell comprising a first polymer;core particles comprising a second polymer; andan aqueous solvent,the shell and the core particles forming first core-shell particles dispersed in the aqueous solvent and, the first polymer and the second polymer having a difference of refractive index (RI) in a range of 0.1 to 0.35,wherein upon forming a coating, the coating composition exhibits whiteness without use of a white pigment, white dye, or white additive.

5. A resin composition comprising:a film-forming shell comprising a first polymer;core particles comprising a second polymer; andan aqueous solvent,the shell and the core particles forming first core-shell particles dispersed in the aqueous solvent and having an average particle size in a range of 170 nm to 310 nm,wherein upon forming a coating, the coating composition exhibits whiteness without use of a white pigment, white dye, or white additive.

6. The resin composition of any one of claims 1 to 5, wherein the first core-shell particles have an average particle size in a range of 170 nm to 310 nm.

7. The resin composition of any one of claims 1 to 6, wherein the core particles comprise about 45 wt-% to about 75 wt-% of the composition by total weight of resins.

8. The resin composition of any one of claims 1 to 7, wherein the shell comprises about 25 wt-% to about 55 wt-% of the coating composition by total weight of resins.

9. The resin composition of any one of claims 1 to 8, wherein the composition is a one-component system.

10. The resin composition of any one of claims 1 to 9, wherein the composition is a two-component system.

11. The resin composition of any one of claims 1 to 10 further comprising a secondary latex resin.

12. The resin composition of any one of claims 1 to 11 further comprising second core-shell particles having a different particle size than the first core-shell particles.

13. The resin composition of any one of claims 1 to 12, wherein the second core-shell particles have a different chemical composition than the first core-shell particles.

14. The resin composition of any one of claims 1 to 13, wherein the second core-shell particles comprise core particles having a different particle size than core particles of the first core-shell particles.

15. A coating compri sing :a film-forming portion comprising a first polymer having a Tg in a range of -50 °C to 30 °C and a first refractive index; andcore particles dispersed throughout the film-forming portion and comprising a second polymer having a Tg in a range of 60 °C to 115 °C and a second refractive index, wherein the second refractive index is different from the first refractive index,the core particles having an average particle size in a range of 150 nm to 250 nm.

16. The coating of claim 15, wherein the core particles comprise about 45 wt-% to about 75 wt-% of the coating composition.

17. The coating of claim 15 or 16, wherein the film-forming portion comprises about 25 wt-% to about 55 wt-% of the coating composition.

18. A coating comprising a film comprising:a binder comprising a first polymer having a Tg of 30 °C or lower, wherein the binder makes up 25 wt-% to 55 wt-% of the film; andcore particles dispersed throughout the binder, the core particles comprising a second polymer having a Tg of 60 °C or greater, wherein the core particles make up 45 wt-% to 75 wt-% of the film.

19. The coating of claim 18, wherein the film exhibits an L* value of 80 or greater at a film thickness of 1 mil (25 gm) without a white pigment, white dye, or white additive.

20. The coating of claim 18 or 19, wherein the film exhibits a contrast ratio of 0.5 or greater against a black background at a film thickness of 1 mil (25 pm) without a white pigment, white dye, or white additive.

21. The resin composition or coating of any one of claims 1 to 20, wherein the resin composition or coating is a structural white paint containing less than about 10 wt-% white pigment or filler.

22. The resin composition or coating of any one of claims 1 to 21, wherein the resin composition or coating is a structural white paint comprising one or more of pigments, matting agents, fillers, wetting agents, defoamers, rheological modifiers, ultraviolet (UV) light stabilizers, UV absorbers, dispersing agents, flow and leveling agents, optical brighteners, gloss additives, radical inhibitors, radical initiators, adhesion promotors, plasticizers, co-solvents, coalescing agents, reducers, reactive diluents, co-binders, photo-initiators, hardeners, catalysts, corrosion inhibitors, biocides, fungicides, surfactants, and waxes.

23. The resin composition or coating of any one of claims 1 to 22 further comprising a secondary film-forming resin.

24. A method of preparing a structural white coating, comprising:applying a film of the resin composition of any one of claims 1 to 14 to a substrate at a dry film thickness ranging from about 15 pm to about 200 pm; anddrying or curing or both drying and curing the film to form the structural white coating.

25. The method of claim 24, wherein the film is cured and wherein during curing, the first polymer self-crosslinks.

26. The method of claim 24 or 25, wherein the film is cured at ambient conditions, at an elevated temperature, by radiation, or a combination thereof.

27. The method of any one of claims 24 to 26, wherein the coating is applied by brushing, spraying, roll coating, or a combination thereof.

28. The method of any one of claims 24 to 27, wherein the core particles become arranged in a disordered arrangement within the fdm formed by the first polymer of the shell.

29. The resin composition, coating, or method of any one of claims 1 to 28, wherein the first polymer has a Tg of about 30 °C or less, 25 °C or less, 20 °C or less, or about -50 °C to about 30 °C.

30. The resin composition, coating, or method of any one of claims 1 to 29, wherein the second polymer has a Tg of about 60 °C or greater, 70 °C or greater, 75 °C or greater, 90 °C or greater, or about 60 °C to about 115 °C.

31. The resin composition, coating, or method of any one of claims 1 to 30, wherein the core particles comprise a polystyrene.

32. The resin composition, coating, or method of any one of claims 1 to 31, wherein the core particles comprise polymer or copolymer derived from reactants including (a) at least one aromatic reactant comprising pendant free-radically-polymerizable functionality; optionally (b) at least one free-radically-polymerizable reactant having pendant acid functionality (or a salt or ester thereof); and optionally (c) at least one other copolymerizable reactant with free-radically-polymerizable functionality.

33. The resin composition, coating, or method of any one of claims 1 to 32, wherein the core particles comprise polymer or copolymer derived from monomers selected from styrene, alphamethyl styrene, t-butyl styrene, 1,3-diisopropenylbenzene, 2,4, 6-trimethyl styrene, 2,4-dimethylstyrene, 2,4-diphenyl-4-methyl-l -pentene, 2,5-dimethylstyrene, 2-vinylnaphthalene, 3-m ethyl styrene, 4-benzyloxy-3 -methoxy styrene, 9-vinylanthracene, a,2-dimethylstyrene, benzyl (meth)acrylate, phenoxy ethyl (meth)acrylate, phenoxy ethylene glycol (meth)arylate, phenoxy diethylene glycol (meth)acrylate, 2-hydroxy 3-phexoxy propyl (meth)acrylate, 2-hydroxy o-phenylphenol propyl (meth)acrylate, ethoxylated o-phenylphenol (meth)acrylate, combinations of these, and mixtures or combinations thereof.

34. The resin composition, coating, or method of any one of claims 1 to 33, wherein the first polymer comprises a latex polymer derived from monomers selected from N-substituted (meth)acrylamide, octyl (meth)acrylate, nonylphenol ethoxylate (meth)acrylate, isononyl(meth)acrylate, 1,6-hexanediol (meth)acrylate, isobornyl (meth)acrylate, 2-(2-ethoxyethoxy)ethyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, lauryl (meth)acrylate, betacarboxyethyl (meth)acrylate, butyl (meth)acrylate; isobutyl (meth)acrylate, cycloaliphatic epoxide, alpha-epoxide, 2-hydroxyethyl (meth)acrylate, (meth)acrylonitrile, maleic anhydride, itaconic acid, isodecyl (meth)acrylate, dodecyl (meth)acrylate, n-butyl (meth)acrylate, methyl (meth)acrylate, hexyl (meth)acrylate, (meth)acrylic acid, N-vinylcaprolactam, stearyl (meth)acrylate, hydroxy functional caprolactone ester (meth)acrylate, octadecyl (meth)acrylate, isooctyl (meth)acrylate, hydroxyethyl (meth)acrylate, hydroxymethyl (meth)acrylate, hydroxypropyl (meth)acrylate, hydroxyisopropyl (meth)acrylate, hydroxybutyl (meth)acrylate, hydroxyisobutyl (meth)acrylate, tetrahydrofurfuryl (meth)acrylate, and mixtures or combinations thereof.

35. The resin composition, coating, or method of any one of claims 1 to 34, wherein the first polymer comprises a polymer derived from monomers selected from (meth)acrylic acid, sorbic acid, maleic anhydride, maleic acid, crotonic acid, itaconic acid, cinnamic acid, palmitoleic acid, oleic acid, linoleic acid, arachidonic acid, benzoic acid, fumaric acid, and mixtures or combinations thereof.

36. The composition of claim 35, wherein the first polymer comprises a copolymer derived from the reaction of at least one vinyl ester monomer with at least one ethylenically unsaturated or free radically polymerizable monomer.

37. The resin composition, coating, or method of any one of claims 1 to 36, wherein the first polymer comprises a copolymer of two or more of butyl (meth)acrylate, methacrylic acid, methyl methacrylate, hydroxyethyl methacrylate, and 2-ethylhexyl acrylate.

38. The resin composition, coating, or method of any one of claims 1 to 37, wherein the first polymer comprises a copolymer that is functionalized.

39. The resin composition, coating, or method of any one of claims 1 to 38, wherein the first polymer comprises a chain transfer agent, optionally wherein the chain transfer agent comprises N-dodecyl mercaptan, T-dodecyl mercaptan, 2-mercaptoethanol, 1 -propanethiol, 2-mercaptopropionic acid, 3 -mercaptopropionic acid, 2-methyl2propanethiol, 2-mercaptobutyric acid, 3 -mercaptobutyric acid, 4-mercaptobutyric acid, or a combination of two or more thereof.

40. The resin composition, coating, or method of any one of claims 1 to 39, wherein the first polymer is a self-crosslinking polymer.

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