GEL-PHASE COLORANT DISPERSIONS FOR COATING COMPOSITIONS

CROSS-REFERENCE TO RELATED APPLICATION

[0001] This application claims the benefit of U.S. provisional patent application number 60/692,032 filed on June 17, 2005, the entirety of which is hereby incorporated by reference.

[0002] The present invention is a gel-phase colorant comprising (a) a reaction product of: (1) a reactive material component, (2) a reactive colorant, and (3) a crosslinker having reactive groups capable of forming a bond with the reactive material component and the reactive colorant. The present invention is also a novel gel-phase colorant dispersion comprising (a) a gel-phase colorant comprising the reaction product of (1) a reactive material component, (2) a reactive colorant, and (3) a crosslinker having reactive groups capable of forming a bond with the reactive material component and the reactive colorant; and (b) a dispersion medium, wherein the dispersion medium can be an aqueous or non- aqueous-based dispersion. The gel-phase colorant dispersion of this invention can then be mixed or blended with typical coating materials. This invention is also directed to a method of preparing coating compositions comprising a binder phase of an aqueous or non-aqueous-based dispersion and a gel-phase colorant dispersion, and in particular, a method comprising the steps of (1) preparing at least one gel-phase colorant dispersion comprising a gel-phase colorant comprising a reaction product of (a) a reactive material component; (b) a reactive colorant and (c) a crosslinker; dispersed in a dispersion medium; and (2) mixing or blending the gel-phase colorant dispersion with typical coating materials. The coating composition can also comprise one or more independent gel-phase colorant dispersions. This invention is also directed to a process for achieving

a multicolor faux finish pattern on a surface utilizing a gel-phase colorant dispersion- based one-pack multiphase coating composition.

[0003] This invention is also directed to a two-layer coating system comprising a topcoat and an undercoat, wherein the topcoat is a coating composition comprising a gel- phase colorant dispersion comprising (a) a gel-phase colorant comprising (1) a reactive material component, (2) a reactive colorant, and (3) a crosslinker having reactive groups capable of forming a bond with the reactive material component and the reactive colorant; and (b) a dispersion medium; and wherein the undercoat is a waterborne coating composition comprising one or more highly water-absorbent pigments.

[0004] Figure 1 is a graphical representation showing the stages of the gel-phase colorant dispersion through the coating composition in accordance with the invention.

[0005] Figure 2 is a graphical representation showing the gel-phase colorant dispersion coating in the liquid state.

[0006] Figure 3 is a graphical representation of the gel-phase colorant dispersion coating of this invention before and after applicator imprint.

[0007] Figure 4 is a graphical representation of a cross-section of the coating on a substrate before and after an applicator imprint.

[0008] While the present invention has been illustrated by the description of embodiments thereof, and while the embodiments have been described in considerable detail, it is not the intention of the applicants to restrict or in any way limit the scope of the appended claims to such detail. Additional advantages and modifications will readily appear to those skilled in the art. Therefore, the invention, in its broader aspects, is not

limited to the specific details, the representative apparatus, and illustrative examples shown and described. Accordingly, departures may be made from such details without departing from the spirit or scope of the applicant's general inventive concept.

[0009] According to this invention, the gel-phase colorant dispersions comprises a gel-phase colorant comprising a reaction product of (1) a reactive material component, particularly those having active hydrogens such as hydroxy- or amine-functionality; (2) a reactive colorant, dispersed into a dispersion medium; and (3) a crosslinker, having reactive groups capable of forming a bond with the reactive material component and a reactive colorant. The dispersion medium can comprise aqueous or non-aqueous-based solutions or emulsions. The gel-phase colorant particles resulting from these reactions have a high affinity for the liquid medium (which can be aqueous or non-aqueous) in which they are dispersed and at all times are stable therein. The gel-phase colorant dispersion comprises discrete gel-phase colorant color particles of sufficient size to be readily visible and produce a desirable color contrast to the naked eye. The gel-phase colorant particles can be dispersed in an aqueous or non-aqueous medium of a color the same as or different from that of the gel-phase colorant. Such gel-phase colorant particles provide the desirable color contrast and are readily visible to produce a faux finish product, which is an objective of the invention. The gel-phase colorant particles are of such strength that they do not deform or change shape by the shear force imposed when the coating composition is mixed, shaken, agitated or applied to a desired substrate by a brush, roller, sprayer or other typical applicator means.

[0010] The reactive material component of this invention can include compounds having active hydrogens, epoxy compounds, carboxy compounds, and the like.

[0011] According to this invention, a desired crosslinking agent is any compound having reactive groups which will react with (1) the reactive groups of the reactive material component and (2) the reactive colorant. Since one function of the crosslinking agent is to attach the reactive colorant to the reactive material component, the crosslinking agent should have at least two distinct reactive groups - one that can react with the colorant, while the other reacts with the reactive material component. The distinct reactive groups can be either the same or different functional groups. For example, one type of functional group may react preferentially with the colorant while a different functional group may react preferentially with the reactive material component. One molecule of crosslinking agent can also include a multiplicity of reactive groups for reaction with the colorant and the reactive material component. Many useful crosslinking agents include isocyanates and polyisocyanates, which have a multiplicity of sites for reaction with the colorants or the reactive material component.

[0012] In practicing the method of the present invention, a gel-phase colorant is made by combining the reactive material component, crosslinking agent and reactive colorant together and then reacting (or allowing to react) under suitable conditions to form a gel- phase colorant. "Suitable conditions" are those conditions required to cause reaction of the crosslinking agent with the reactive material component and the reactive colorant. For example, illustrative of a aqueous gel-phase colorant suitable for this invention include the use polyester polyols (such as Piothane 70-1000 HAI or Piothane 70-500, both commercially available from Panolam Industries International, Inc., Auburn, Maine) as the reactive material component; isocyanates (such as Desmodur N3600 commercially available from Bayer Corporation, Pittsburgh, Pennsylvania) as the crosslinker. Reactive colorants contemplated by this invention include Blend-A-Color (commercially available

from Degussa Corporation of Parsippany, New Jersey), which can be used alone or in combination with other colorants. A reactive colorant component is present in a gel- phase colorant in a quantity that can vary from trace amount to about 50 weight percent or more, based on the weight of the gel-phase colorant. The above components can be heated, or merely allowed sufficient time at ambient temperature to produce the desired reaction. Suitable conditions (for reaction) and relative amounts of each chosen reactive material component, reactive colorant and crosslinking agent are dictated by the chemical character of such components and the presence or absence of catalysts, and will be apparent to those skilled in the art.

[0013] The gel-phase colorant is then dispersed in an aqueous or non-aqueous medium to produce a desired gel-phase colorant dispersion. The mode of dispersion that can include, but is not limited to, stirring, shaking, agitation with a blade, milling, and sonication, determines the size and shape of the gel-phase colorant particles. The weight of the gel-phase colorant(s) can total up to about 50 weight percent, based on the total weight of the gel-phase colorant dispersion. The coating composition of this invention can comprise one or more independent gel colorant dispersions, wherein each of the said gel colorant dispersions, either aqueous or non-aqueous, contains a different colorant so as to provide more random distribution of colorant entities.

[0014] In addition to the gel-phase colorant dispersion component, the coating composition of the invention can also comprise an aqueous or non-aqueous dispersion or emulsion. Examples of aqueous-based dispersions include, but are not limited to, water, latex emulsions, polyurethane dispersions, water-based alkyd (or alkyds modified with acrylic, urethane or styrene) emulsions, dispersions and solutions; water-based acrylic dispersions and solutions. By way of example, some latexes useful for this invention

include, but are not limited to, Joncryl SCX2577 (commercially available from S.C. Johnson, Racine, Wisconsin), UCAR 471 or UCAR 461 (both commercially available from Dow Chemical), styrene-acrylic, and SG-IO (commercially available from Rohm & Haas Company). The coating composition can be easily formulated by blending one or more gel-phase colorant dispersions with typical raw materials as needed to obtain desired application, stability, appearance, and performance properties. These include materials such as water, coalescing agents, humectants, co-binder, pigment slurries, colorants, rheology modifiers, amines, mildewcides and biocides. Desirable appearance results are obtained when the gel-phase colorant solids content in the coating formulation is above a critical value, typically of about 15% by weight. The appearance effect may become diminished as the gel-phase colorant content drops. Preferably, best patterns develop when there is a discernable difference between the gel-phase colorant and tinting colors.

[0015] The gel-phase colorant dispersion is present in the coating composition in a quantity up to 95 weight percent, and preferably in a quantity between about 65-90 weight percent, based on total coating composition weight.

[0016] The shape, size and color of the gel-phase colorant particles, and hence the dispersion and aesthetic appearance and integrity of the final coating film may depend on the following variables:

a) composition of the gel-phase colorant (type and ratios of reactants);

b) extent of the crosslinking reaction prior to dispersion; c) amount of mechanical dispersion energy; d) composition, color, and opacity of the dispersion medium; and

e) ratio of the gel-phase colorant to the dispersion medium. Thus, such variables can be varied accordingly to achieve a desired effect.

[0017] Another embodiment of this invention is a two-layer coating system comprising a topcoat, wherein the topcoat is a waterborne dispersion comprising the gel- phase colorant dispersion, and an undercoat, wherein the undercoat comprises a highly water absorbing pigment. The undercoat of this invention should have a pigment volume concentration of at least 55, and can be between 55 and 80 or between 65 to 75. The pigment utilized in the undercoat can be any highly water absorbent pigment that is water insoluble, including by way of nonlimiting example, aluminum silicate and calcium carbonate. The undercoat can be formulated by adding the following ingredients under mild agitation.

[0018] The two-layer coating system is applied to obtain a multi-tone coating on a surface of a substrate by:

a. applying an undercoat, wherein the undercoat is a waterborne coating comprising one or more highly water absorbent pigments; b. applying a topcoat over the undercoat wherein the topcoat comprises a gel- phase colorant dispersion comprising a gel-phase colorant comprising (a) a reaction product of: (1) a reactive material component, (2) a reactive colorant, and (3) a crosslinker having reactive groups capable of forming a bond with the reactive material component and the reactive colorant; and (b) a dispersion medium.

The undercoat and/or topcoat can be applied to the surface using brush, drawdown, roller, spray application, or any other method of the art, and allowed to dry .

[0019] The present invention has the special advantage of achieving different multicolor desirable effects and patterns. The coating compositions of this invention can be applied to essentially any surface that is amenable to conventional coating techniques, by spray, roller, brush, or other applicators. Striking patterns can be made utilizing a variety of applicators. When the tinted coating composition is applied multi-directionally using an applicator providing a textured result, the coating develops a random pattern in which areas of varying film thickness display shades of varying color and sheen. As the coating is applied, the gel-phase colorant is preferentially stamp-deposited onto the substrate surface, resulting in layering or stratification of the gel-phase color and the tinting color of the emulsion phase. As a consequence, in a textured coating, the thinner regions of the coating display more of the gel phase color, while the thicker areas exhibit more of the tinting color. Thus, faux patterns comprising randomly distributed domains of two or more colors and any color combinations of these colors can be made.

EXAMPLE 1

[0020] The following example illustrates the preparation of a gel-phase colorant dispersion of this invention. A homogeneous mixture of Piothane 70-1000 HAI, Colortrend 802/803 green colorant, and Desmodur N 3600 is prepared and allowed to equilibrate to a temperature of 7O ⁰ F before the dibutyl tin dilaurate catalyst is added and allowed to mix in at 100 rpm using a mixing blade. After 5 minutes, agitation is stopped and the latex is added on top of the reaction mixture. After 40 minutes of adding the dibutyl tin dilaurate catalyst, mixing is restarted at 400 rpm and allowed to continue for another 1 hour resulting in a green gel-phase colorant dispersion product.

US2006/023687

Gel-Phase Colorant Composition

To form the gel-phase colorant dispersion, the above gel-phase colorant can be dispersed in 630 parts of SC Johnson Joncryl SCX-2577 styrene- acrylic latex emulsion.

EXAMPLES 2 and 3

The following examples illustrate a topcoat formulation utilizing two different colored gel-phase colorant dispersions.

% non- volatile by weight 46 weight per gallon (#/gal) 8.8

EXAMPLE 3

% non-volatile by weight 46 weight per gallon (#/gal) 8.8

The above formulations are tinted with colorants in the range of 2-4 ounces of colorant per gallon, providing a contrasting color to the bead in the formulation. When these formulations are applied separately to the undercoater described in the invention using a variety of application techniques, a multi-tone film appearance results which is both unique and pleasing as an aesthetic coating.

EXAMPLE 4

The following example illustrates an undercoat formulation that can be made in accordance with this invention.

PVC 73.70 non-volatile by weight 61.80 weight (pounds) per gallon 12.6