High solids color face and edge coatings for building panels

Described herein is a coated building panel having a body and a surface coating atop the body, the surface coating comprising inorganic pigment and a polymeric dispersant comprising a polymer backbone and pendant side chains extending from the polymer backbone; wherein the surface coating comprises a liquid carrier in an amount less than about 1 wt. % based on the total weight of the surface coating.

BACKGROUND

Ceiling systems are installed into room environments to help control noise as well as enhance the aesthetic appeal of those room environments. These ceiling systems may comprise one or more building panels having specific aesthetic properties that help contribute to the appeal of the room environment. Previous attempts at improving the aesthetic properties of these building panels included applying decorative coatings to the surface of the building panel. However, such decorative coatings tend to create difficulties associated with manufacturing time as well as the overall performance of the building panel at high-temperatures (i.e., increased flammability and/or blistering of the coating). Thus there exists a need for building panels comprising a decorative coating applied thereto that does not create the same difficulties with respect to manufacturing and while also not sacrificing the required aesthetic properties provided by the decorative coating

BRIEF SUMMARY

The present invention is directed to a coated building panel comprising: a body comprising an upper surface opposite a lower surface and a side surface extending between the upper surface and the lower surface; a surface coating atop the upper surface, the surface coating comprising: inorganic pigment; and a polymeric dispersant comprising a polymer backbone and pendant side chains extending from the polymer backbone; wherein the surface coating comprises a liquid carrier in an amount less than about 1 wt. % based on the total weight of the surface coating.

In other embodiments, the present invention is directed to a method of forming a building panel having a face coating, the method comprising: a) providing a body comprising an upper surface opposite a lower surface and a side surface extending between the upper surface and the lower surface; b) applying a coating composition atop the upper surface of the body, the coating composition comprising an inorganic pigment and a polymeric dispersant comprising a polymer backbone and pendant side chains extending from the polymer backbone; and c) drying the coating composition to form the face coating; wherein the coating composition has a solid's content ranging from about 45 wt. % to about 65 wt. % based on the total weight of the coating composition.

In other embodiments, the present invention is directed to a coated building panel comprising: a body comprising an upper surface opposite a lower surface and a side surface extending between the upper surface and the lower surface; a surface coating atop the upper surface, the surface coating comprising: about 70 wt. % to about 95 wt. % of a pigment based on the total weight of the surface coating, the pigment comprising an inorganic pigment having a particle size ranging from 15 nm to 500 nm; and a polymeric dispersant comprising a polymer backbone and pendant side chains extending from the polymer backbone; wherein the surface coating comprises less than 1 wt. % of a liquid carrier based on the total weight of the surface coating.

Other embodiments of the present invention include a method of forming a building panel having an edge coating, the method comprising: a) providing a body having an upper surface opposite a lower surface and a side surface extending between the upper surface and the lower surface; b) applying a thixotropic coating composition to the side surface, the thixotropic coating composition comprising a liquid carrier, a pigment, a dispersant, and a binder having a glass transition temperature less than about 20° C.; and c) drying the thixotropic coating composition for a drying period to form the edge coating, the edge coating having less than about 1 wt. % of the liquid carrier; wherein the thixotropic coating composition has a solid's content ranging from about 50 wt. % to about 80 wt. % based on the total weight of the thixotropic coating composition.

Other embodiments of the present invention provide a coated building panel comprising: a body comprising an upper surface opposite a lower surface and a side surface extending between the upper surface and the lower surface; a thixotropic surface coating applied to the side surface, the surface coating comprising: a binder having a glass transition temperature less than about 20° C.; and pigment in an amount ranging from about 25 wt. % to about 95 wt. % based on the total weight of the surface coating, the pigment comprising inorganic pigments; a ionic dispersant; wherein the surface coating is present in an amount ranging from about 7.5 g/m2to about 150 g/m2.

Other embodiments of the present invention include a coating composition comprising a liquid carrier, an inorganic pigment; and an ionic polymeric dispersant comprising a polymer backbone and pendant side chains extending from the polymer backbone, wherein the coating composition has a solid's content ranging from about 45 wt. % to about 65 wt. % based on the total weight of the coating composition.

DETAILED DESCRIPTION

(For Chemical Cases) Unless otherwise specified, all percentages and amounts expressed herein and elsewhere in the specification should be understood to refer to percentages by weight. The amounts given are based on the active weight of the material.

Terms such as “attached,” “affixed,” “connected,” “coupled,” “interconnected,” and similar refer to a relationship wherein structures are secured or attached to one another either directly or indirectly through intervening structures, as well as both movable or rigid attachments or relationships, unless expressly described otherwise. Moreover, the features and benefits of the invention are illustrated by reference to the exemplified embodiments. Accordingly, the invention expressly should not be limited to such exemplary embodiments illustrating some possible non-limiting combination of features that may exist alone or in other combinations of features; the scope of the invention being defined by the claims appended hereto.

Unless otherwise specified, all percentages and amounts expressed herein and elsewhere in the specification should be understood to refer to percentages by weight. The amounts given are based on the active weight of the material. According to the present application, the term “about” means+/−5% of the reference value. According to the present application, the term “substantially free” less than about 0.1 wt. % based on the total of the referenced value.

Referring toFIGS.1and4, the present invention includes a coated building panel100(referred to herein as “building panel”) comprising a first major surface111opposite a second major surface112and a side surface113that extends between the first major surface111and the second major surface112, thereby defining a perimeter of the ceiling panel100. The side surface113may comprise an upper portion113aand a lower portion113b, wherein the upper portion113ais adjacent to the first major surface111and the lower portion113bis adjacent to the second major surface112.

Referring toFIG.3, the present invention may further include a ceiling system1comprising one or more of the building panels100installed in an interior space, whereby the interior space comprises a plenum space3and an active room environment2. The plenum space3provides space for mechanical lines within a building (e.g., HVAC, plumbing, etc.). The active space2provides room for the building occupants during normal intended use of the building (e.g., in an office building, the active space would be occupied by offices containing computers, lamps, etc.).

In the installed state, the building panels100may be supported in the interior space by one or more parallel support struts5. Each of the support struts5may comprise an inverted T-bar having a horizontal flange31and a vertical web32. The ceiling system1may further comprise a plurality of first struts that are substantially parallel to each other and a plurality of second struts that are substantially perpendicular to the first struts (not pictured). In some embodiments, the plurality of second struts intersects the plurality of first struts to create an intersecting ceiling support grid6. The plenum space3exists above the ceiling support grid6and the active room environment2exists below the ceiling support grid6.

In the installed state, the first major surface111of the building panel100may face the active room environment2and the second major surface112of the building panel100may face the plenum space3. The building panel100may be installed according to at least two variations. In a first variation, the building panel100is positioned entirely above the horizontal flange31of the support struts5. In the first variation, at least a portion of the first major surface may be concealed from the active room environment2by the horizontal flange31because the horizontal flange31contacts the first major surface111, thereby supporting it in the ceiling system1. In the first variation, the entire side surface113—including the upper portion113aand the lower portion113b—may be concealed from the active room environment2by the horizontal flange311. The second variation will be described further herein.

Referring now toFIGS.1and2, the building panel100of the present invention may have a panel thickness t0as measured from the first major surface111to the second major surface112. The panel thickness t0may range from about 12 mm to about 40 mm—including all values and sub-ranges there-between. The building panel100may have a length LPranging from about 30 cm to about 310 cm—including all values and sub-ranges there-between. The building panel100may have a width WPranging from about 10 cm to about 125 cm—including all values and sub-ranges there-between.

The building panel100may comprise a body120and a surface coating200applied thereto—as discussed further herein. The body120comprises an upper surface121opposite a lower surface122and a body side surface123that extends between the upper surface121and the lower surface122, thereby defining a perimeter of the body120. The body120may have a body thickness t1that extends from the upper surface121to the lower surface122. The body thickness t1may range from about 12 mm to about 40 mm—including all values and sub-ranges there-between.

The body120may be porous, thereby allowing airflow through the body120between the upper surface121and the lower surface122—as discussed further herein. The body120may be comprised of a binder and fibers. In some embodiments, the body120may further comprise a filler and/or additive.

The fibers may be organic fibers, inorganic fibers, or a blend thereof. Non-limiting examples of inorganic fibers mineral wool (also referred to as slag wool), rock wool, stone wool, and glass fibers. Non-limiting examples of organic fiber include fiberglass, cellulosic fibers (e.g. paper fiber—such as newspaper, hemp fiber, jute fiber, flax fiber, wood fiber, or other natural fibers), polymer fibers (including polyester, polyethylene, aramid—i.e., aromatic polyamide, and/or polypropylene), protein fibers (e.g., sheep wool), and combinations thereof.

Referring now toFIG.2, the building panel100may further comprise the surface coating200applied to at least one of the first major surface121and/or the side surface123of the body120. The surface coating200may be a color surface coating200. According to the present invention the terms “color surface coating” and “surface coating” may be used interchangeably. The term “color surface coating”200refers to a surface coating200comprising a color pigment and the resulting surface coating200exhibits a color on the visible color spectrum—i.e., violet, blue, green, yellow, orange, or red. The color surface coating200may also have a color of white, black, or grey. The color surface coating200may further comprise combinations of two or more colors—such a primary color (i.e., red, yellow, blue) as well as an achromatic color (i.e., white, grey).

A non-limiting example of a color surface coating200may be pink and produced from a combination of red and white pigments. Another non-limiting example of a color surface coating200may be green and produced from a combination of blue and yellow pigments. Another non-limiting example of a color surface coating200may be brown and produced from a combination of red, yellow, and black pigments.

In some embodiments, the surface coating200may include a face coating210that is applied to the first major surface121of the body120. In other embodiments, the surface coating200may include an edge coating230that is applied to the side surface123of the body120. In other embodiments, the building panel100may comprise both the face coating210applied to the first major surface121of the body120as well as the edge coating230applied to the side surface123of the body120.

The face coating210may comprise an upper surface211opposite a lower surface212. The face coating210has a face coating thickness t2—as measured from the upper surface211to the lower surface212of the face coating210. The face coating thickness t2may range from about 200 μm (micron) to about 500 μm—including all thicknesses and sub-ranges there-between. The lower surface212of the face coating210may be in direct contact with the upper surface121of the body120. The upper surface211of the face coating210may form at least a portion of the first major surface111of the building panel100—as discussed further herein.

Although not shown, the building panel100of the present invention may further comprise a non-woven scrim. The non-woven scrim may comprise an upper surface opposite a lower surface. The lower surface of the non-woven scrim may be positioned immediately adjacent to and in direct contact with the upper surface121of the body120. The face coating210may be applied to the non-woven scrim such that the lower surface212of the face coating210is in direct contact with the upper surface of the non-woven scrim.

The face coating210may comprise a first binder, a first pigment, and a first dispersant. The face coating210, in the dry-state, may be present on the upper surface121of the body120in an amount ranging from about 26 g/m2to about 220 g/m2—including all amounts and sub-ranges there-between. According to the present invention, the phrase “dry-state” indicates a composition that is substantially free of a liquid carrier (e.g., liquid water). Thus, the face coating210in the dry-state may comprise the first pigment, the first dispersant, the first binder, and less than about 0.1 wt. % of liquid carrier based on the total weight of the face coating210. In a preferred embodiment, the fact coating210in the dry-state has a solid's content of about 100 wt. % based on the total weight of the face coating210. Conversely, a composition that is in a “wet-state,” which refers to a composition containing various amounts of liquid carrier—as discussed further herein.

The first binder may be present in the face coating210in an amount ranging from about 5 wt. % to about 20 wt. % based on the total dry-weight of the face coating210—including all wt. % and sub-ranges there-between. The first binder may be polymeric. The first binder may have a glass transition temperature (“Tg”) that is greater than room temperature (“Tm”)—wherein room temperature ranges from about 21° C. to about 40° C. including all temperatures and sub-ranges there-between. In some embodiments, the first binder may have an overall charge that is anionic.

Non-limiting examples of the first binder include polymers selected from polyvinyl alcohol (PVOH), latex, an acrylic polymer, polymaleic anhydride, or a combination of two or more thereof. Non-limiting examples of latex binder may include a homopolymer or copolymer formed from the following monomers: vinyl acetate (i.e., polyvinyl acetate), vinyl propinoate, vinyl butyrate, ethylene, vinyl chloride, vinylidene chloride, vinyl fluoride, vinylidene fluoride, ethyl acrylate, methyl acrylate, propyl acrylate, butyl acrylate, ethyl methacrylate, methyl methacrylate, butyl methacrylate, hydroxyethyl methacrylate, hydroxyethyl acrylate, styrene, butadiene, urethane, epoxy, melamine, and an ester. Preferably the binder is selected from the group consisting of aqueous lattices of polyvinyl acetate, polyvinyl acrylic, polyurethane, polyurethane acrylic, polystyrene acrylic, epoxy, polyethylene vinyl chloride, polyvinylidene chloride, and polyvinyl chloride.

The first dispersant may be present in the face coating210in an amount ranging from about 0.05 wt. % to about 2.0 wt. % based on the total dry-weight of the face coating210—including all wt. % and sub-ranges there-between. The first dispersant may be ionic in nature—i.e., comprise one or more ionic groups such as anionic group or cationic group. In a preferred embodiment, the ionic group is anionic. The first dispersant may be polymeric having a molecular weight of at least 1,000 Mn. The first dispersant may comprise a hydrophilic portion and a hydrophobic portion—wherein the hydrophobic portion is used to attract to the first pigment while the first hydrophilic portion is used to disperse the attached pigment into the liquid carrier—i.e., water.

Referring now toFIG.7, the present invention may comprise the first pigment60treated with the first dispersant70, thereby forming a first dispersible pigment50. As demonstrated byFIG.7, the first dispersant70comprises a polymer backbone73and at least one pendant side-chain74that extends from the polymer backbone73. The ionic group72of the first dispersant70may be located at the tip of the pendant side-chain74. In a preferred embodiment, the first dispersant70comprises multiple pendant side-chains74—each of which have an ionic group72located at the tip of the pendant side-chain74.

The ionic group72is distanced from the polymer backbone73by a side-chain length as measured from the polymer backbone73to the tip or end of the pendant side-chain74. The separation of the ionic group72from the polymer backbone73via the pendant side-chain74allows for a greater number of ionic groups72to be attached to a single dispersant (i.e., the first dispersant70) because the ionic groups72are not forced apart by the steric hindrance of the polymer backbone73that normally results when ionic groups are located directly on the backbone of the polymer dispersant (for example, seeFIG.6as discussed further herein). Less separation between ionic groups72on the first dispersant70results in a greater number of attachment points of the first dispersant70to the pigment60, thereby provides a stronger attachment of the first dispersant70to the first pigment60, thereby ensuring that the pigment is provided with the desired hydrophilicity imparted by the hydrophilic portion of the first dispersant70.

Additionally, less separation of ionic groups72on the first dispersant70allows for better attachment of the first dispersant70to pigments having a smaller particle size—i.e., pigments having a particle size less than about 1 μm, preferably less than about 500 nm. The first pigment having smaller particles may have a particle size ranging from about 15 nm (nanometer) to about 400 nm (including all sizes and sub-ranges there-between)—because the greater density of ionic groups72on the first dispersant70can better accommodate the smaller volume occupied by each of the first pigments that would other not be possible with pigments having ionic groups attached directly to the polymer backbone of a dispersant because of the steric hindrance of the polymer backbone.

According to some embodiments, the dispersant may comprise an anionic polyacrylic polymer having a salt group formed from a neutralization of an acid group with a compound forming a cation. For examples, the polymer may comprise one or more pendant side chains comprising a terminal carboxylic acid group that is neutralized with sodium or ammonia to form a carboxylate anion and a sodium cation and/or ammonium cation. Alternatively, the polymer may comprise one or more pendant side chains comprising a terminal sulfonic acid group that is neutralized with the aforementioned sodium or ammonia compounds to form a salt group.

The first dispersant of the present invention may have a pH ranging from about 7.0 to about 8.0—including all pHs and sub-ranges there-between. In a preferred embodiment, the dispersant is an anionic polymer having a pH ranging from about 7 to about 8—including all pHs and sub-ranges there-between. The first dispersant may have a specific gravity (relative to water) that is less than 1. Specifically, the first dispersant may have a specific gravity (relative to water) ranging from about 0.8 to about 0.95—including all specific gravities and sub-ranges there-between. In a preferred embodiment, the first dispersant may have a specific gravity (relative to water) of about 0.95. The first dispersant may be commercially available as Zephrym™ PD 4974.

The first pigment may be present in the face coating210in an amount ranging from about 70 wt. % to about 95 wt. %—including all wt. % and sub-ranges there-between—based on the total dry-weight of the face coating210. Similar to the phrase “dry-state”—the phrase “dry-weight” refers to the weight of a component or composition without including any additional weight of liquid carrier. Thus, when calculating the dry weight of a component or composition, the calculation should be based solely on the weight of the solid components (e.g., dispersant, pigment, binder, etc.), and should exclude any amount of residual liquid carrier that may still be present from the wet-state.

The first pigment may be an inorganic pigment. The first pigment may be a particle exhibiting one of the previously discussed colors with respect to the color surface coating200. Thus, the face coating210may also be referred to herein as a “color face coating”210. Non-limiting examples of inorganic pigment include particles of carbon black, graphite, graphene, copper oxide, iron oxide, zinc oxide, calcium carbonate, manganese oxide, titanium dioxide and combinations thereof. The inorganic pigments may include individual particles having colors selected from, but not limited to, red, blue, yellow, black, green, brown, violet, white, grey and combinations thereof. The particles that make up the first pigment may have a particle size ranging from about 15 nm to about 1000 μm—including all sizes and sub-ranges there-between.

Previously, using such pigments to create face coatings required the face coatings to be applied using large amounts of carrier (i.e., low solids content during application of the coatings) and/or large amounts of other additives because such pigments will easily aggregate, thereby forming clumps that result in undesirable aesthetic properties in the resulting face coating. According to the present invention, however, face coatings using such pigments may be formed using high-solid's contents without risk of aggregating—as described further herein.

Creating the face coating210on the building panel100that exhibits the desired aesthetic qualities—i.e., a superior colored face on the building panel100—is achieved by homogeneous distribution of the pigment within the face coating210. When using the first pigment, which has a maximum particle size of about 1,000 μm, ensuring proper distribution of the pigment may be obtained by adding the first dispersant to the face coating210. The dispersant may be polymeric and have an ionic charge.

According to some embodiments of the present invention, the first pigment may comprise carbon black, which exhibits a cationic charge, and the first dispersant may comprise anionic polyacrylic dispersant having a pH of about 7.5.

The face coating210may be formed by applying a face coating composition n the wet-state. The face coating composition may comprise the first pigment, the first dispersant, and the first binder, as well as a liquid carrier. The liquid carrier may be selected from water, VOC solvent—such as acetone, toluene, methyl acetate—or combinations thereof. In a preferred embodiment, the liquid carrier is water and comprises less than 1 wt. % of VOC solvent based on the total weight of the liquid carrier.

The face coating composition has a high-solid's content. According to the present invention, the term “high solids content” refers to a solids content of at least 45 wt. % based on the total weight of the face coating composition. Stated otherwise, the liquid carrier is present in a maximum amount of about 55 wt. % based on the total weight of the face coating composition.

The solids content of the face coating composition may range from about 45 wt. % to about 70 wt. %—including all wt. % and sub-ranges there-between. In a preferred embodiment, the solids content of the face coating composition may range from about 45 wt. % to about 65 wt. % based on the total weight of the face coating composition—including all wt. % and sub-ranges there-between. In some embodiments, the face coating composition may have a solids content of at least 50 wt. % based on the total weight of the face coating composition. In some embodiments, the face coating composition may have a solids content of at least 60 wt. % based on the total weight of the face coating composition.

The solid's content is calculated as the fraction of materials present in the face coating composition that are not the liquid carrier. Specifically, the solid's content of the face coating composition may be calculated as the amount of dispersant, pigment, and binder in the face coating composition and dividing it by the total weight of the face coating composition (including liquid carrier).

Therefore, the amount of each component in the face coating composition may be calculated by multiplying the desired amount of each of the first dispersant, the first pigment, and the first binder present in the face coating210in the dry-state by the total solids content of the face coating composition. For example, for a face coating210in the dry-state comprising about 60 wt. % of pigment, whereby that face coating210is formed from a face coating composition having a solids content of 70 wt. %—the amount of the first pigment in the face coating composition would be 42 wt. % based on the total weight of the face coating composition in the wet-state—i.e., 60 wt. %×0.7=42 wt. % of pigment in the face coating composition.

The face coating composition may have a viscosity ranging from about 250 cps to about 2,500 cps as measured by a Brookfield viscometer at 10 RPM using a #4 spindle at room temperature—including all viscosities and sub-ranges there-between. In a preferred embodiment, the face coating composition may have a viscosity ranging from about 350 cps to about 1,500 cps as measured by a Brookfield viscometer at 10 RPM using a #4 spindle at room temperature—including all viscosities and sub-ranges there-between. The face coating composition may have a viscosity ranging from about 350 cps to about 750 cps as measured by a Brookfield viscometer at 10 RPM using a #4 spindle at room temperature—including all viscosities and sub-ranges there-between. The face coating composition may exhibit a cationic charge.

The face coating composition (i.e., in the wet-state) may be applied to the upper surface121of the body120in an amount ranging from about 26 g/m2to about 220 g/m2—including all sub-ranges and values there-between. The face coating composition may be applied to the upper surface121by roll coating, brush coating, and spray coating, and/or curtain blade.

Adding the first dispersant to the first coating composition of the present invention allows for not only the first pigment to have a maximum particle size of about 1000 μm, but also allows for the first coating composition to have the aforementioned high solid's content without risk of causing the first pigment to aggregate. The high solid's content provides for faster application and drying of face coating composition into the face coating210. Specifically, after application to the body120, the face coating composition is dried, thereby driving off the liquid carrier thereby creating the face coating210, which as previously discussed is in the dry-state.

Specifically, the face liquid-based coating composition may be dried in a conventional oven at a first elevated temperature for a first drying period. The first elevated temperature may range from about 67° C. to about 232° C.—including all sub-ranges and temperature there-between. In some embodiments, the first elevated temperature may range from about 67° C. to about 190° C.—including all sub-ranges and temperature there-between. In some embodiments, the first elevated temperature may range from about 93° C. to about 232° C.—including all sub-ranges and temperature there-between.

The first drying period may range from about 10 seconds to about 120 seconds—including all sub-ranges and temperature there-between. The resulting face coating210may be present on the upper surface121of the body120in an amount ranging from about 10 g/m2to about 132 g/m2—including all amounts and sub-ranges there-between.

Referring now toFIGS.1-4concurrently, the resulting building panel100may comprise the face coating210—whereby the first major surface111of the building panel.100comprises the upper surface211of the face coating210. Thus, in the installed state, at least a portion of the upper surface211of the face coating210faces the active room environment2. The face coating210may be substantially continuous. The term “substantially continuous” means less than 5% of the available surface area on the referenced surface contains pin-holing or blistering.

According to other embodiments, the building panel100may comprise a surface coating200applied to the side surface123of the body120to form an edge coating230. The edge coating230may be substantially continuous. The edge coating230may comprise one or more of the previously discussed color pigments. Thus, the edge coating230may also be referred to herein as a color edge coating230.

The edge coating230may comprise an outer surface231opposite an inner surface232. The edge coating230has an edge coating thickness t3was measured from the outer surface231to the inner surface232of the edge coating210. The edge coating thickness t3may range from about 100 μm to about 600 μm—including all thicknesses and sub-ranges there-between. In a preferred embodiment, the edge coating thickness t3may range from about 200 μm to about 500 μm—including all thicknesses and sub-ranges there-between. The edge coating230(i.e., in the dry-state) may be present in an amount ranging from about 7.5 g/m2to about 150 g/m2—including all amounts and sub-ranges there-between.

The edge coating230may comprise a second pigment, a second dispersant, and a second binder. The second binder may be present in an amount ranging from about 1 wt. % to about 50 wt. % based on the total dry-weight of the edge coating230—including all amounts and sub-ranges there-between. The second binder may be thixotropic. The term “thixotropic” refers to a composition that has a high viscosity (e.g., 40,000 cps) at low-shear and a low viscosity (e.g., 800 cps) at high-shear. Non-limiting examples of thixotropic binder include polymers selected from polyvinyl alcohol (PVOH), aforementioned latex, acrylic polymer, polymaleic anhydride, or a combination of two or more thereof.

The second binder may be a thixotropic polymeric having a Tg that is less than room temperature (“Tm”). In a preferred embodiment, the second binder is a thixotropic polymeric binder having a Tg less than 20° C.—preferably less than 19° C. The binder may be film-forming and having a minimum film-forming temperature of about 12° C. The term “film-forming temperature” refers to the temperature at which a composition forms a film.

The second pigment may be present in an amount ranging from about 1 wt. % to about 95% based on the total dry-weight of the edge coating230—including all wt. % and sub-ranges there-between. The second pigment may be present in an amount ranging from about 1 wt. % to about 80 wt. % based on the total dry-weight of the edge coating230—including all wt. % and sub-ranges there-between. The second pigment may be present in an amount ranging from about 30 wt. % to about 80 wt. % based on the total dry-weight of the edge coating230—including all wt. % and sub-ranges there-between.

The second pigment may comprise one of the pigments previously listed as being suitable for the first pigment. In other embodiments, the second pigment may comprise one or more white pigments having a particle size ranging from about 0.1 μm to about 1000 μm—including all sizes and sub-ranges there-between. In some embodiments, the second pigment may comprise one or more white pigments having a particle size ranging from about 0.1 μm to about 250 μm—including all sizes and sub-ranges there-between.

The second dispersant may be present in an amount ranging from about 0.01 wt. % to about 2.0 wt. % based on the total dry-weight of the edge coating230—including all wt. % and sub-ranges there-between. Like the first dispersant, the second dispersant may comprise a hydrophilic portion and a hydrophobic portion.

When the second pigment has a particle size in the same range as disclosed for the smaller first pigment, the second dispersant may comprise one or more compounds listed as being suitable for the first dispersant.

Referring now toFIG.6, when the second pigment20has a particle size ranging from about 0.1 μm to about 250 μm, the second dispersant40may comprise anionic polyacrylic dispersants wherein the ionic group41is located directly on the polymer backbone41of the second dispersant40. Together, the second pigment20and the second dispersant40form a second dispersible pigment10.

The edge coating230may be formed by applying an edge coating composition having a solids content ranging from about 65 wt. % to about 80 wt. %—including all amounts and sub-ranges there-between. The edge coating composition may be thixotropic. The edge coating composition may be thixotropic. The edge coating composition may have a viscosity ranging from about 6,000 cps to about 10,000 cps as measured by a Brookfield viscometer at 10 RPM using a #4 spindle at room temperature—including all viscosities and sub-ranges there-between. The edge liquid-based coating composition may comprise water as the liquid carrier, wherein the liquid carrier comprises less than 1 wt. % of VOC solvent.

The edge coating composition may be applied to the body side surface123in an amount ranging from about 10 g/m2to about 200 g/m2including all sub-ranges and values there-between. The edge coating composition may be applied to the side surface123of the body120by spray, roll, wheel coater, and vacuum coating.

The edge coating composition may be dried at an elevated temperature for a drying period—wherein the elevated temperature ranges from about 120° C. to about 240° C.—including all sub-ranges and temperature there-between. The drying period may range from about 10 seconds to about 120 seconds—including all sub-ranges and temperature there-between. The resulting edge coating230(i.e., in the dry-state) may be present in an amount ranging from about 7.5 g/m2to about 150 g/m2—including all amounts and sub-ranges there-between.

According to the embodiments where the building panel100comprises the edge coating230, the side surface113of the building panel100may comprise the edge coating230. Specifically, the side surface113of the building panel100may comprise the outer surface231of the edge coating230. Thus, the outer surface231of the edge coating230may for the upper portion113aand the lower portion113bof the side surface113of the building panel100. Specifically, the upper portion113aof the side surface113may comprise an upper edge coating portion231aand the lower portion113bof the side surface113may comprise a lower edge coating portion231b.

Although not pictured, some embodiments of the present invention include a building panel comprising a surface coating200comprising only the edge coating230. Specifically, the building panel100may comprise a first major surface opposite a second major surface and a side surface extending there-between. The side surface113of the building panel100may comprise the edge coating230, the first major surface111of the building panel100may comprise the upper surface121of the body120and the second major surface112of the building panel100may comprise the lower surface122of the body120.

Although not pictured, some embodiments of the present invention include a building panel comprising a surface coating200, wherein the surface coating200comprises only the face coating210. Specifically, the building panel100may comprise a first major surface111opposite a second major surface112and a side surface113extending there-between. The first major surface111of the building panel100may comprise the upper surface211of the face coating210, the second major surface112of the building panel100may comprise the lower surface122of the body120, and the side surface113of the building panel100may comprise the body side surface123.

Referring now toFIG.4, building panels300,400,500are illustrated in accordance with other embodiments of the present invention. The building panels300,400, and500are similar to building panel100except as described herein below. The description of building panel100above generally applies to building panels300,400, and500described below except with regard to the differences specifically noted below. A similar numbering scheme will be used for the building panels300,400, and500as with building panel100except that the 300-, 400-, and 500-series of numbers will be used.

Referring now toFIG.5, the building panel500may be installed according to the second variation, as described herein. The building panel500may be positioned such that the upper portion513aof the side surface513is below the horizontal flange31, thereby extending into the active room environment2. In the second variation, the lower portion513bof the side surface513is above the horizontal flange31extending into the plenum space3. In the second variation, the first major surface511and the upper portion513aof the side surface513of the building panel500is exposed to the active room environment2. In the second variation, the lower portion513bof the side surface513may be concealed from the active room environment2. The lower portion513bof the side surface513may be adjacent to at least a portion of the vertical web32as viewed along a horizontal direction. The lower portion513bof the side surface513as well as the second major surface512may be exposed to the plenum space3.

According to these embodiments, the upper portion513aand the lower portion513bmay comprise the surface coating200—specifically, the first face coating210. According to these embodiments, the first major surface511may comprise the surface coating200—specifically, the edge coating230. Therefore, the surface coating200may be exposed to the active room environment on the first major surface511and the upper portion513aof the side surface513of the building panel500in the installed state.

The invention will be described in greater detail by way of specific examples. The following examples are offered for illustrative purposes and are not intended to limit the invention in any manner.

EXAMPLES

The following experiment is directed to a high solids color coating composition of the present invention that may be used to form a coating with superior aesthetic properties. Coating compositions were prepared according to the following formulations set forth in Table 1:

The binder is carboxylated polyvinyl acetate homopolymer. Pigment 1 is calcium carbonate having a particle size of about 12 μm. Pigment 2 is kaolin having a particle size of about 2 μm. Pigment 3 is calcined diatomaceous earth having a particle size of about 18 μm.

The first dispersant is an anionic polymer dispersant having pendant side-chains extending from a polymer backbone wherein the anionic groups are located on the terminal ends of the pendant side-chains. The first dispersant comprises the anionic polymer dispersed in water at a solids content ranging from about 30 wt. % to about 34 wt. %. The additive includes a mixture of defoamer and biocide. The thickener includes hydroxyethylcellulose.

Each component (e.g., Pigments 1-3, first dispersant, binder, etc.) may be provided as a solid or as a pre-made mixture with water in various solids content. Thus, to account for some of the coating composition components being pre-mixed with water, the total solids content of the overall coating composition in water is provided.

The viscosity of each of the coating compositions of Examples 1-4 as well as Comparative Example 1 were then measured using a Brookfield viscometer as various RPMs. The composition of each example was also allowed to sit for various periods of time—after which the stability of each composition was observed in the form of hard-packing, which refers to the presence of agglomeration of the pigments into hard packs (as compared to a uniform dispersion of the individual pigments throughout the carrier). The results are set forth in Table 2.

As demonstrated by Table 2, the coating composition of the present invention provides the desired viscosity while also providing superior stability of the pigments within the coating composition over time. Superior stability of the pigment in the coating composition translates to better color distribution in the resulting coating formed from the coating composition. As a result, coating compositions having higher solids contents can be achieved without sacrificing the desired aesthetic properties of the resulting coating.

The following experiment is directed to a high solids coating composition of the present invention that may be used to form a coating with superior aesthetic properties when using pigments having a particle size ranging from about 15 nm to about 1,000 μm. Coating compositions were prepared according to the following formulations set forth in Table 3:

The binder is carboxylated polyvinyl acetate homopolymer. Pigment 1 is calcium carbonate having a particle size of about 12 μm. Pigment 2 is kaolin having a particle size of about 2 μm. Pigment 3 is calcined diatomaceous earth having a particle size of about 18 μm.

The first dispersant is an anionic polymer dispersant having pendant side-chains extending from a polymer backbone wherein the anionic groups are located on the terminal ends of the pendant side-chains. The first dispersant liquid has a solids content ranging from about 30 wt. % to about 34 wt. % and comprises water as a carrier. The second dispersant is an anionic dispersant having anionic groups attached directly to the polymeric backbone and no pendant side-chains. The second dispersant liquid has a solids content of about 45 wt. % and comprises water as a carrier. The additive includes a mixture of defoamer, wetting agent, and biocide/antimicrobial agents. The thickener includes hydroxyethylcellulose.

Each component (e.g., Pigments 1-3, first dispersant, second dispersant, etc.) may be provided as a solid or as a pre-made mixture with water in various solids content. Thus, to account for some of the coating composition components being pre-mixed with water, the total solids content of the overall coating composition in water is provided.

The viscosity of each of the coating compositions of Example 5 and Comparative Example 2 were then measured using a Brookfield viscometer as various RPMs. The results are set forth in Table 4.

As demonstrated by Table 4, the coating composition of the present invention provides the desired viscosity at much higher solids contends as compared to other anionic dispersants having the ionic group present directly on the polymer backbone.

Additionally, the enhanced dispersion of the pigments using the dispersant of the present invention is reflected in the superior drawdown color values. The drawdown color evaluations of each sample were measured and compared against each other. The color evaluations were performed by measured for a change in color value—i.e. “Delta E” (Δ E). Delta E value is measured by the following calculation:
ΔE=[(L2−L1)2+(a2−a1)2+(b2−b1)2]1/2

wherein L1, a1, and b1are color values of Comp. Ex. 2, measured using a Minolta Chroma Meter CR 410 from Minolta Corporation. The L2, a2, and b2values are the color values of Ex. 5 as measured by the Minolta Chroma Meter CR 410. The color values are shown in Table 5.

As demonstrated by Table 5, the coating formed from the coating of Example 5 exhibits superior color values demonstrated by the ΔE being greater than 0. Additionally, the enhanced dispersion of the pigments using the dispersant of the present invention is reflected in the superior gloss values. The gloss values are shown in Table 6.

As demonstrated by Table 6, the enhanced pigment dispersion of Example 5 (as compared to Comparative Example 2) creates a better colored face coating that absorbs more incident light, thereby providing a less gloss surface and providing superior color appearance.

The following experiment is directed to a high solids coating composition of the present invention that may be used to form a coating with superior aesthetic properties when using pigments having a particle size ranging from about 15 nm to about 1000 μm. Coating compositions were prepared according to the following formulations set forth in Table 7:

The binder is carboxylated polyvinyl acetate homopolymer. Pigment 1 includes calcium carbonate having a particle size of about 12 μm. Pigment 2 includes kaolin having a particle size of about 2 μm. Pigment 3 includes calcined diatomaceous earth having a particle size of about 18 μm. Pigment 4 includes carbon black having a particle size less than about 1 μm.

The first dispersant is an anionic polymer dispersant having pendant side-chains extending from a polymer backbone wherein the anionic groups are located on the terminal ends of the pendant side-chains. The first dispersant liquid has a solids content ranging from about 30 wt. % to about 34 wt. % and comprises water as a carrier. The second dispersant is an anionic dispersant having anionic groups attached directly to the polymeric backbone and no pendant side-chains. The second dispersant liquid has a solids content of about 45 wt. % and comprises water as a carrier. The additive includes a mixture of defoamer, wetting agent, and biocide/antimicrobial agents. The thickener includes hydroxyethylcellulose.

Each component (e.g., Pigments 1-4, first dispersant, second dispersant, etc.) may be provided as a solid or as a pre-made mixture with water in various solids content. Thus, to account for some of the coating composition components being pre-mixed with water, the total solids content of the overall coating composition in water is provided.

Two sets of viscosity measurements were performed on the compositions of Example 6 and Comparative Example 3. The first set of viscosity measurements were performed immediately after the respective compositions were formed. Each sample was then allowed to sit undisturbed for a period of 24 hours, whereby the viscosity of each sample was then subjected to another viscosity test using a Brookfield viscometer as various RPMs. The drawdown color evaluations of each sample were also measured and compared against each other. The results are set forth in Table 8.

As demonstrated by Table 8, the coating composition of the present invention provides the desired viscosity stability over time at much higher solids contends as compared to other anionic dispersants having the ionic group present directly on the polymer backbone.

Additionally, the enhanced dispersion of the pigments using the dispersant of the present invention is reflected in the superior drawdown color values. The drawdown color evaluations of each sample were measured and compared against each other. The color evaluations were performed by measured for a change in color value—i.e. “Delta E” (ΔE)—wherein L1, a1, and b1are color values of Comp. Ex. 2, measured using a Minolta Chroma Meter CR 410 from Minolta Corporation. The L2, a2, and b2values are the color values of Ex. 5 as measured by the Minolta Chroma Meter CR 410. The color values are shown in Table 9.

As demonstrated by Table 9, the coating formed from the coating of Example 6 exhibits a change in color values demonstrated by the ΔE being greater than 0. Additionally, the enhanced dispersion of the pigments using the dispersant of the present invention is reflected in the superior gloss values. The gloss values are shown in Table 10.

As demonstrated by Table 10, the enhanced pigment dispersion of Example 6 (as compared to Comparative Example 3) creates a better colored face coating that absorbs more incident light, thereby providing a less gloss surface and providing superior color appearance.

As those skilled in the art will appreciate, numerous changes and modifications may be made to the embodiments described herein, without departing from the spirit of the invention. It is intended that all such variations fall within the scope of the invention.