Background of the Invention The present invention relates to solid surfaces, and more particularly, to polyester based solid surface material having translucent properties such that it may be joined with an acrylic solid surface material to achieve a visual color match between the two materials.

Solid surface materials have become one of the top choices of residential and commercial contractors for countertops and sinks and lavatory basins due to their durability and the plurality of aesthetic features that can be obtained, including variations in color and design. The term"solid surface"relates to a material that has substantially the same physical and aesthetic properties throughout its thickness.

Solid surface materials are typically molded out of various resins such as acrylic or polyester resins, depending on the intended use of the solid surface material. Particularly, it is recognized throughout the industry that the most widely used resin for horizontal surface applications or flat-sheets (collectively referred to herein as"sheets"), such as kitchen and bathroom countertops, is an acrylic based resin because of the affordability, availability, machining properties and thermoforming capabilities associated with acrylic products. Polyester or polyester- acrylate based resins (collectively referred to herein as"polyester based resins"or "polyester based materials") are best suited for sinks and lavatory basins (collectively referred to herein as"shapes") due to the thermal shock resistance properties of such resins. Once the appropriate resin is selected, it is typically combined with filler,

catalyst, and pigment (to achieve color specifications) to develop the solid surface material. For background purposes only, reference is made to US 6,554, 944 that discloses information pertaining to flat-sheets, basins, and color issues in manufacturing the combination of acrylate flat sheets and acrylate basins.

The solid surface industry desires the ability to use flat-sheet acrylic sheets in combination with polyester shapes, such as a unitary countertop with a basin, while achieving the benefit of the performance characteristics of both materials as described above. The problem with such combination, however, has been that the obvious visual differences between the two materials have made it such that a color match between the acrylic based and polyester based materials is extremely difficult. The variance in color between the acrylic based and polyester based materials is attributed to the differences in the translucency characteristics of the respective materials.

Particularly, thermal formed acrylate materials, such as those used on countertops, are much more translucent than thermal set polyester based materials, such as those used for lavatory basins and kitchen sinks as explained below.

In the case of polyester based solid surface materials, color specifications are achieved by combining promoted unsaturated polyester based resins with pigments and fillers which are then catalyzed. Particularly, during the process of creating the formulation, the combination of the promoted resin, non-color controlled alumina trihydrate filler, and catalysts contributes to color shifting within the matrix. The resulting color shifting is corrected by the induction of pigments into the material.

This heavily pigmented polyester based formulation prevents sufficient light from penetrating the matrix, thereby eliminating the appearance of depth and translucency in the material. This makes a visual color match with an acrylic sheet hard to achieve in practically all colors. As a result, solid surface manufacturers have resorted to

selling contrasting color schemes, such as a green countertop with a white basin, to customers that are willing to sacrifice a color match in favor of performance.

Accordingly, there is a need in the art for a polyester based solid surface material that has sufficient translucent properties to allow it to be joined with an acrylic solid surface material and achieve a visual color match between the two materials.

Brief Summary of the Present Invention The present invention solves this need in the art by providing a shaped basin formed of a polyester based solid surface material including a promoted polyester based resin, an unpromoted polyester based resin, a filler that is constructed of color- controlled particles of a predetermined size, pigment for coloring the solid surface material, and dye for coloring the solid surface material. The ratio of dye to pigment is such that the polyester based solid surface material can be visually color matched with an acrylic based solid surface material. In a preferred embodiment, the promoted polyester based resin and the unpromoted polyester based resin include resins such as polyester resins and polyester-acrylate resins. In an additional embodiment, the promoted polyester based resin and the unpromoted polyester based resin are unsaturated polyester based resins. The filler is preferably an alumina trihydrate filler and the polyester based solid surface material preferably has a visual translucency that is substantially similar to the visual translucency of an acrylic based solid surface material in a like color.

A unitary, visually seamless, and visually unicolor solid surface structure is also provided that includes an acrylic based solid surface sheet and a polyester based solid surface shape. The polyester based solid surface shape is formed of a polyester

based solid surface material including a promoted polyester based resin, an unpromoted polyester based resin, a filler that is constructed of color-controlled particles of a predetermined size, pigment for coloring the polyester based solid surface material, and dye for coloring the polyester based solid surface material. The ratio of dye to pigment is such that the polyester based solid surface shape can be visually color matched with the acrylic based solid surface sheet.

A process for producing a shaped basin formed of a polyester based solid surface material is further provided. The process includes the step of combining a promoted polyester based resin, an unpromoted polyester based resin, a filler that is constructed of color-controlled particles of a predetermined size, pigment for coloring the solid surface material, and dye for coloring the solid surface material. The ratio of dye to pigment is such that the polyester based solid surface material can be visually color matched with an acrylic based solid surface material.

Detailed Description of the Preferred Embodiments The present invention provides a solid surface structure and method for creating the same including an acrylic based sheet material and a polyester based shape material wherein there is a visual color match between the two materials. The term"visual"as used herein means the view from an unaided human eye and not through a microscope or the like. The term"basin"as used herein means an open, shallow container used especially for holding liquids. The visual color match between the materials is achieved by creating a polyester based material (polyester or polyester-acrylic) that is more translucent than polyester based materials used in the prior art.

As mentioned above, most prior art polyester based solid surface materials are formed of a combination of polyester resin, filler, catalyst, and pigment. Typically,

pigment content of the resin can reach as high as about 5%. The improved polyester based material of the present invention, however, includes a reduced content of pigment that is replaced with dyes in order to achieve color specifications with the depth and translucency similar to that in acrylic based solid surface products.

In the art of solid surface compositions, polyester resins, fillers, catalysts and pigments are well known ingredients and are selectively used. Polyester resins include synthetic resins which are polycondensation products of dicarboxylic acids with dihydroxy alcohols such as those prepared from polymerizable unsaturated polyesters such as those prepared from ethylenically unsaturated polycarboxcylic acids and polyhydric alcohols. Preferably the resin, when fully cured, provides desirable heat, chemical and moisture resistance. The polyester resin system will typically include various additive components for modifying a physical or chemical property of the resin system. Examples of such additive components are inhibitors, promoters, initiators, inert fillers, pigments, dyes, thixotropic additives, reinforcement materials, flame-retardants, waxes and lubricants.

An inhibitor is included in a polyester resin system to retard polymerization of the polyester material during storage of the composition or to aid in moderating the gelling or curing process. It is believed that in free-radical catalyzed addition- polymerization reactions, for example, the inhibitor compound absorbs or deactivates free radicals generated spontaneously during storage of the resin system and for a short period after the initiator is added. Examples of useful inhibitors include quaternary ammonium salts as a class, and quinones and dihydric phenols, such as para-benzoquinone, methyl para-benzoquinone, hydroquinone, 3-isopropyl catechol and 4-tertbutyl catechol. Inhibitors may be present in a polyester resin system in an amount in a range from about 0. 001 to about 0.1 weight percent of the resin system.

An initiator compound is included in a polyester resin system to catalyze polymerization. A polyester system containing ethylenically unsaturated compounds may polymerize by way of a free-radical initiated, addition-polymerization mechanism. Typical initiator compounds are organic peroxides and hydroperoxides that decompose to provide chain-initiating free radicals. Usually, room temperature initiators are added to the resin system just before intended use of the resin system, such as in a coating, casting or molding operation. Examples of suitable initiators are benzoyl peroxide, methylethylketone peroxide, tert-butyl perbenzoate, cumene hydroperoxide and dicumyl peroxide. Other initiator compounds may include azo- type compounds, such as azo-bis-isobutyronitrile. One or more initiators may be present in a polyester resin system in an amount in a range from about 0.1 to about 3 weight percent of the resin system.

One or more thixotropic materials may be added to provide thixotropic character to the resin system. Examples of such materials are fumed silica, castor oil based compositions (e. g., Thixatrol0 ST, Baker Castor Oil Company), Cab-O-Sil@, carboxymethylcellulose, modified clays, 12-hydroxystearic acid, tetrabutyl orthotitanate and microcrystalline cellulose. When used, these materials are usually present in an amount in the range of from about 0.5 percent to about 15 percent by weight of polyester present.

Typical fillers that may be added to the resin include aluminum trihydrate.

Pigment and/or filler may be added to mask the colorations of the surface to be sprayed, or in the case of a mold application, the coloration of the backing material in the mold.

Other pigments, fillers and/or other components for providing background colorant to the material and/or selected properties and characteristics to the resin

system both during formation and after curing may be added. For example, titanium dioxide or other pigments can be added for additional color. Materials may be added to reduce the coefficient of thermal expansion of the cured system or to provide other desired properties. One embodiment contemplates the addition of a filler such as alumina trihydrate to improve fire retardancy.

Pigments for coloring are insoluble and consist of particles that are dispersed by physical means. Examples of pigments for coloring are iron oxides, cadmium sulfide, carbon black, phthalocyanine blue, phthalocyanine green, indanthrone blue, ultramarine blue, chromium oxide, burnt umber, benzidine yellow, toluidine red and aluminum powder. When used, one or more of these additives may be present in the resin system in an amount in a range from about 1 to about 5 percent of the resin system.

In order to reduce the content of pigment in the formulation so that it can be replaced with dyes, the improved resin of the present invention is formed by combining promoted and un-promoted unsaturated polyester resins that when catalyzed, achieve cross-link with minimal color variation in the matrix. A promoter, or co-promoter, or accelerator may be included in a polyester resin system to aid in catalyzing the polymerization process. For example, in many molding or coating operations it may be desirable to initiate polymerization without the application of heat to the composition. A promoter compound typically aids in lowering the threshold temperature at which free radicals may be made available for initiating additional polymerization.

Examples of useful promoters are metal-containing compounds such as cobalt octoate, or organic compounds containing vanadium, manganese, iron or nickel, tertiary amines such as diethylaniline, or a combination of both a metal-containing

compound and a tertiary amine. Usually, a promoter compound or a combination of promoter compounds, as a promoter and co-promoter combination, may be present in a polyester resin system in an amount in a range from about 0. 01 to about 3 percent of the resin system. Unpromoted polyester based resins do not contain promoters.

The use of un-promoted polyester resin in the present invention minimizes the color shifting caused by heat induction when only promoted resins are used, as in the prior art. Therefore, the need to mask the color shifting with for non-translucent pigments is significantly reduced or eliminated.

Typically, dispersed dyes are used in polyester resins. Dispersed dyes generally contain an amino or substituted amino group but no solubilizing sulfonic groups. Dispersed dyes are water insoluble dyes introduced as dispersions or colloidal suspensions in water and are absorbed by the polyester resin. The dyes can be of various dyes, including dispersed dyes, capable of sublimation at 200°F and up, including those dyes in use on heat transfer papers for dye transfer in the textile industry. Typical disperse dyes include those of the following 3 classes of dyes (1) nitroacrylamine ; (2) azo and (3) anthraquinone.

The improved polyester based formulation also preferably includes an alumina trihydrate filler that is constructed of color-controlled particles of a specific size to ensure adequate particle packing. Use of this filler allows maximum light penetration to fill the matrix, thereby improving the material's translucency.

By using the above-mentioned compounds to control the color shift of the blended matrix, the depth and translucency of the polyester based solid surface can be retained, which ordinarily would have been lost with the introduction of a higher concentration of pigments. Accordingly, a polyester based solid surface formed in accordance with the present invention can be joined or formed with an acrylic based

solid surface and achieve an acceptable visual color match between the two surfaces.

Such a combination maximizes the advantages of the two materials; particularly, the thermoforming capabilities of acrylic based resins that are preferred for horizontal surface applications (sheets) such as countertops and the thermal shock resistance properties of polyester or polyester-acrylate based resins that are preferred for sinks and lavatory basins (shapes). Thus, an acrylic based countertop and polyester-based basin can be joined together and give the visual appearance of a seamless, one-piece structure having the same color throughout the structure.

The present invention can be viewed as a process for producing a three- dimensional basin shaped item or product comprising polyester based material including a promoted polyester based resin, an unpromoted polyester based resin, a filler that is constructed of color-controlled particles of a predetermined size, a pigment for coloring the solid surface material; and dye for coloring the solid surface material, wherein the ratio of dye to pigment is such that the polyester based solid surface material can be visually color matched with an acrylic based solid surface material, with the process, for example, including cutting or otherwise defining a flat blank such as from a rigid flat sheet comprising acrylic based solid surface sheet including colorants, with the blank cut or otherwise defined to have an outline generally commensurate with the desired top outline shape of the basin shaped item to be produced; and the blank including preferably at least one wide side smooth or finished in smoothness and appearance, and including heating the blank to flexible softness; if the heating of the blank is not performed in the molding tool, then locating and indexing the heated blank within a molding tool including a bowl-shaped tool portion; maintaining the peripheral side edges of the heated blank unrestrained and free to be moved inward when indexed to the basin-shaped tool portion or the

molding tool in general; applying force to the heated blank with the molding tool and forcing the heated blank toward the basin-shaped tool portion sufficiently to force the heated blank into a basin shaped item; cooling the basin shaped item to a greater stiffness; removing the basin shaped item from the molding tool; and if desired to make the basin a sink or lavatory having drain openings, trimming a top edge of the basin shaped item to greater evenness or whatever shape is needed; cutting a drain opening through a bottom of the basin shaped item; cutting an overflow opening near the top edge and through a side of the basin, and re-facing by sanding and polishing with progressively finer abrasives the interior or exposed in-use surfaces of the basin to greater smoothness or uniform appearance. It should be noted that not all sinks, particularly kitchen style sinks for example, include overflow drain holes.

In another embodiment, the present invention can be viewed as a process of producing a countertop with attached basin shaped sink such as a lavatory or bar sink or the like of the type wherein both the countertop and sink comprise polyester based material as defined herein and the countertop includes a sink cut-out opening, with the improvements comprising thermofbrming of the sink into as basin shaped form, attaching the basin shaped sink to the underside of the acrylic based countertop and surrounding the sink cut-out, and more specifically using a rigid flat blank comprising plastics preferably acrylics; heating the blank to flexible softness; locating the heated blank within a thermoform molding tool; maintaining peripheral side edges of the heated blank unrestrained in the thermoform molding tool so that the side edges are free to be moved inward; actuating the thermoformed molding tool sufficiently to form the heated blank into a basin shaped sink wherein the smooth side of the blank is the interior or concave surface of the basin shaped sink; cooling the basin shaped sink to a greater stiffness ; removing the basin shaped sink from the molding tool;

machining a top edge of the basin shaped sink to greater evenness; defining a drain opening through a bottom of the basin shaped sink such as by machining; sanding and polishing in the interior surface of the basin if needed, adhering the top edge of the basin shaped sink to an underside of the countertop and surrounding the sink cut-out opening in the countertop, the adhering being through the use of adhesives.

Clearly some of the herein provided steps can be re-arranged in order or in some cases completely eliminated or defined more narrowly within the scope of the present invention.

In one embodiment of the present invention, to manufacture a translucent almond color solid surface structure would include an acrylic based solid surface sheet having a particular almond color and a polyester based solid surface shape formed of a polyester based material based solid surface material including about 28. 94 weight % of a liquid unsaturated unpromoted polyester resin, about 10.0 weight % of a liquid unsaturated promoted polyester resin, about 58.54 weight % of alumina trihydrate filler, about 0. 58 weight % of yellow Rls dye (powder), about 0.16 weight % of scarlet Rls dye (powder), about 0.19 weight % of blue Rls dye (powder) and about 1.59 weight % of W1072-Czz pigment. The polyester based solid surface material of the almond color solid surface structure had a visual translucency that is substantially similar to the visual translucency of an acrylic based solid surface material in the structure.

Certain modifications and improvements will occur to those skilled in the art upon a reading of the forgoing description of the present invention. All such modifications and improvements of the present invention have been deleted herein for the sake of conciseness and readability but are properly within the scope of the following claims.