Patent Application
20070033747
I. Field of the Invention
The present invention relates to the field of pigment and dye compositions. More specifically, it provides for novel compositions comprising an organic dye or pigment complexed with a support comprising a metal oxide, wherein the complex comprises a coordinate covalent bond between the dye and the support.
II. Description of Related Art
In the scientific literature, the term Maya blue refers to a “turquoise” brilliant shade of blue that is found on murals and archaeological artifacts, for example, throughout Mesoamerica. It is described in the literature as being composed of palygorskite clay and indigo, that when mixed and heated, produce the stable brilliant blue color similar to that found in Mesoamerica. Proposed methods of preparation were performed with the intent of trying to replicate the blue color found at the historical sites and to reproduce the techniques employed by the original Maya.
H. Van Olphen, Rutherford Gettens, Edwin Littman, Anna Shepard, and Luis Torres, were perhaps some of the most prominently involved scientists in the examination of organic/inorganic complex paint from the 1960's to the 1980's. In early studies, only Littman and Van Olphen published information specifically on the synthesis of the Mayan organic/inorganic complex (Olphen, 1966a; Olphen, 1966b; Littman, 1980; Littman, 1982). While their work never definitively described the technique for making the colorant, or explained the stability of the organic/inorganic complex, the results of their two decades of studies with respect to the ancient paint laid a foundation of knowledge for future investigators.
Littman has synthesized indigo-attapulgite complexes and verified that his synthetic version was indistinguishable from the original pigments found in the pre-Hispanic murals and artifacts (Littman, 1980; Littman, 1982). The prepared samples had the same physical and chemical characteristics as the authentic Maya blue examined. Littman concluded that the remarkable stability of the attapulgite was due to the heat treatment the attapulgite received during the synthesis. Others have also synthesized compounds similar to that of Maya blue by a number of routes (Torres, 1988). They employed the Gettens test to determine whether the laboratory synthesis of Maya blue was indeed authentic with the same chemical resistant properties (Gettens, 1962). The test was necessary because initial attempts of simply mixing the palygorskite clay produced the color of Maya blue but the mixture did not possess the same chemical properties as the original organic/inorganic complex samples.
Until recently, the literature for Maya paint compositions did not provide information with respect to varying the color for the paint composition based on altering the pH and particle size; nor did there appear to be mention of using alternate dye or pigment systems as described in the present invention, nor were there proposed combinations with resins or polymeric systems. The previous literature discussions of pH pertain to the alkaline pH required to reduce the indigo prior to contacting it with the clay (Littman, 1980; Littman, 1982). Moreover, there was a lack of understanding regarding the chemistry for producing stable and nontoxic paint systems by combining dyes and pigments with fibrous and layered clays.
Certain patent literature discusses organic dyes complexed in an ionic interaction with inorganic supports. U.S. Pat. No. 3,950,180 describes color compositions that involve cationic organic basic colored compounds complexed to alkali-treated inorganic substances. PCT Publication No. WO 01/04216 also describes ionic interactions in color compositions, wherein organic dyes undergo ion exchange with charged inorganic clays.
U.S. Pat. No. 7,052,541 describes color compositions comprising indigo derivatives pigments and dyes complexed to the surface of inorganic clays. These materials are useful as paints and coatings for artistic and industrial purposes, including use in cements, plastics, papers and polymers. Upon grinding and heating the organic and inorganic component as solid mixtures or in aqueous solutions, the resulting color compositions have unprecedented stability relative to the original starting material. U.S. Ser. No. 11/351,577, filed Feb. 10, 2006, further provides improved methods for making color compositions comprising organic pigments and dyes complexed to inorganic clays. Upon grinding and treating with UV light, the organic and inorganic elements combine to form a color composition having unprecedented stability relative to the original starting material alone. Using either of these method, by altering the pH during the preparation of such color compositions, control of the final color can be attained within any given set of clay/pigment materials. Additionally, by selecting a particular particle size of the clay starting material, a wide range of colors and hues can also be created.
Though of great interest and value, the use of clays suffers from various limitations that could potentially be eliminated by the use of other materials with which the Maya blue-class of pigments and dyes could be used.
Thus, in accordance with the present invention, there is provided a composition comprising an organic dye coordinately covalently bonded to a support comprising a Lewis acid metal. The color/hue of said composition can determined by the concentration of said dye and pH of said composition. The support may comprise silica, alumina, zeolite, amorphous Al(OH)3, amorphous AlO(OH), amorphous Al/SiO2, crystalline Al(OH)3, crystalline AlO(OH), gibbsite or bayerite. The organic dye may be indigo, thioindigo, dibromoindigo, Vat Orange 5 (diethoxythioindigo), oralith pink, novoperm red, Solvent Yellow 33, Maya blue, Maya purple, Maya red, Maya ultra blue, or have the formula:
wherein R1-R8 are individually H, CH3, CH2CH3, F, Cl, Br, I, CN, OH, SH, OCH3 or OCH2CH3; Y is N, O, S, or Se; and X is O or S. The Lewis acid metal may be Zr+4, Fe+3, Ti+4, Al+3, V+5, Sn+4, Nb+5 and Cr+3, or may be a Lewis acid substitute, such as one having the SiO2-XAlX, wherein 0<X<0.5, or SiO2-XMX, wherein 0<X<0.5, and M is Zr+4, Fe+3, Ti+4, Al+3, V+5, Sn+4, Nb+5 and Cr+3.
The composition may be a powder or a liquid. The composition may be resistant to decomposition by light, acids, alkalis, and solvents. The composition may further comprise a cement, polymer, plastic and/or an organic binding agent. The composition may also further comprise a gum arabic, a linseed oil, a copal, a polycarbonate, an egg tempura, or a turpentine. The composition may have a pH of between 3 and 11, or a pH of between 3 and 7.5. The composition may comprise a support selected from a group consisting of a three-dimensional support, a two-dimensional support, a one-dimensional support and an amorphous support.
In another embodiment, there is provided a method of producing a composition comprising a) combining an organic dye with a support comprising a Lewis acid metal to form a coordinate covalent bond between the dye and the Lewis acid metal; and b) heating said composition or subjecting said composition to UV radiation. The method may further comprise adjusting the pH of the organic dye. The method may further comprise applying said composition to a surface. The method may further comprise blending said composition with a polymer or organic binder. The method may further comprise homogenizing said dye by blending, grinding, milling or stirring. The method may further comprise adding a binding agent to said coating composition. The method may comprise a support is selected from a group consisting of a three-dimensional support, a two-dimensional support, a one-dimensional support and an amorphous support.
The heating may comprise heating at a temperature of between 100° C. and 300° C., or between 115° C. and 200° C. The heating may last up to four days. The composition may contain water. The composition may have a pH of between 3 and 7.5. The composition may contain the organic dye in the range of about 0.01% to about 25% by weight. The support may comprise silica, alumina, zeolite, amorphous Al(OH)3, amorphous AlO(OH), amorphous Al/SiO2, crystalline Al(OH)3, crystalline AlO(OH), gibbsite or bayerite. The organic dye may be indigo, thioindigo, dibromoindigo, Vat Orange 5 (diethoxythioindigo), oralith pink, novoperm red, Solvent Yellow 33, Maya blue, Maya purple, Maya red, Maya ultra blue, or novoperm red. The composition may contain indigo or a molecular derivative of indigo in the range of about 0.1% to 25% by weight. The composition may contain indigo or a molecular derivative of indigo at about 10% by weight at neutral or acidic pH. The Lewis acid metal may be selected from a group consisting of Zr+4, Fe+3, Ti+4, Al+3, V+5, Sn+4, Nb+5 and Cr+3. The Lewis acid metal may be a Lewis acid substitute, such as one having the formula SiO2-XAlX, wherein 0<X<0.5, or the formula SiO2-XMX, wherein 0<X<0.5, and M is Zr+4, Fe+3, Ti+4, Al+3, V+5, Sn+4, Nb+5 and Cr+3. The UV radiation may comprise ultraviolet light is in the range of about 200 to about 500 nm. The composition may be subjected to ultraviolet light for about 1 minute to about 8 hours. The composition may have a pH of between 3 to 11.
As used herein, the term “about” means within 25% of the stated value, or more preferentially within 15% of the value. As used herein the specification, “a” or “an” may mean one or more. As used herein in the claim(s), when used in conjunction with the word “comprising,” the words “a” or “an” may mean one or more than one. As used herein “another” may mean at least a second or more.
Other objects, features and advantages of the present invention will become apparent from the following detailed description. It should be understood, however, that the detailed description and the specific examples, while indicating specific embodiments of the invention, are given by way of illustration only, since various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art from this detailed description.
The following drawings form part of the present specification and are included to further demonstrate certain aspects of the present invention. The invention may be better understood by reference to one or more of these drawings in combination with the detailed description of specific embodiments presented herein.
The present invention provides a new class of materials combining organic dyes/pigments (e.g., indigo) and a support comprising a Lewis acid metal, such as Si, Al, Ti and/or Zr. The metal substitution in the support framework provides Lewis acid sites that interact with the organic dye/pigment, producing the required charge transfer complex that characteristic of the Maya Blue class of materials. The charge transfer complex comprises a coordinate covalent bond, as described below. The Lewis acid in the support matrix can be any metal that is classified as a Lewis acid—Ti+4, Al+3, V+5, etc. Further, the Lewis acid may be comprised in any type of oxide, including an oxide, a hydroxide, and/or an oxyhydroxide.
The invention has great potential in the dye and pigment industry. The extension of the original Maya Blue concept, as described in U.S. Pat. No. 7,052,541, to supports comprising solids containing Lewis acids greatly enhances the technology platform available for commercial application. There are as yet no known reports of the organic/inorganic interaction exhibited by this family of dyes/pigments in materials such as silicas, zeolites and other commonly available materials as described below. To the contrary, it has been generally believed that the “Maya Blue Family” of compounds requires the presence of the palygorskite clay as found in archeological samples. This invention extends the family of compounds to supports comprising metal oxides and greatly extends their utility, including the range of colors available and the variety of physical properties.
The color for the color composition comes from an organic dye or pigment. The dyes and/or pigments are typically commercially available (e.g., Clariant Co.). This chromophore may be indigo or a molecular derivative of indigo such as thioindigo, dibromoindigo, Vat Orange 5 (diethoxythioindigo), oralith pink, novoperm red, or Solvent Yellow 33. Other derivatives of indigo are shown in Schemes 1 and 2. The chromophore may also be a different derivative, such as one containing an additional conjugated ring or ligand.
Wherein, in Scheme 1, R1-R8 are individually H, CH3, CH2CH3, F, Cl, Br, I, CN, OH, SH, OCH3 or OCH2CH3; Y is N, O, S, or Se; X is O or S;
Wherein, in Scheme 2, R1-R8 are individually H, CH3, CH2CH3, F, Cl, Br, I, CN, OH, SH, OCH3 or OCH2CH3; R9-R11 are individually SiO3, SiOH or H2O; Y is NH, O, S, or Se; X is O or S; M(n+) is Al, Sn, Nb, Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Pt, Pd or Zn; and n is 1, 2, 3, or 4.
The compositions of the present invention will comprise a support comprising a metal oxide, such as those containing, Si, Al, Ti and Zr. Metal oxides comprise metal oxides (e.g., Al2O3), metal hydroxides (e.g., Al(OH)3), or metal oxyhydroxides (e.g., AlO(OH)3). In particular, high surface area silica and alumina oxide powders are contemplated for their use. One or more metal oxides may comprise compositions of the present invention. The supports may be of any structure including, in non-limiting examples, amorphous, polymorphic, one-dimensional, two-dimensional, three-dimensional, non-crystalline, crystalline, micro-crystalline, quasi-crystalline, or any combination of these types. Non-limiting examples of three-dimensional supports include zeolites and alumina (Al2O3). Non-limiting examples of two-dimensional supports include crystalline Al(OH)3 and crystalline AlO(OH). Non-limiting examples of amorphous supports include amorphous Al/SiO2, amorphous Al(OH)3 and amorphous AlO(OH). Further, hydrates of any of the supports are also contemplated by the present invention.
Silica-based supports. The chemical compound silicon dioxide, also known as silica, is the oxide of silicon, with the chemical formula of SiO2.
Hi-Sil silicas (PPG Industries) offer consistent and high loadings of active ingredients in agricultural products such as pesticides, insecticides, and herbicides, and are effective in vitamin premixes for animal feed. Hi-Sil silicas used as free flow agents are excellent grinding and suspension aids in animal feed supplements. Hi-Sil silicas are also used as carriers in the rubber industry for dry liquid powder blends of rubber compounding additives, such as plasticizers, bonding agents and antioxidants. Hi-Sil ABS silica is a synthetic amorphous silicon dioxide designed as a carrier to convert liquid plasticizers, process oils and other rubber compounding ingredients to free-flowing powders for introduction into rubber compounds. Hi-Sil ABS silica is a white precipitated silica powder with a uniform spherical shape and a median agglomerate diameter of 20 micrometers. It is amorphous in structure and highly porous with a surface area of 150 m2/g. Hi-Sil ABS silica is pure white in color, has a neutral pH and is chemically inert.
SUNSIL-130 (Sunjin Chemicals) is spherical porous silica powders and its mean particle size is about 6-9 μm. SUNSIL-130SC series are silicone oil coated silica. This silicone oil coating gives silica excellent water-repellant property, better smoothness, softer feeling, improved affinity and spread when applied to the skin. SUNSIL-130SC series are produced through slurry process (wet process) so its silicone coating is more durable and tight compared to the products produced through dry process. Compared to its competitive products, SUNSIL-130 has better smoothness, adhesiveness and smoothness to the skin due to its much sharper particle size distribution. There is almost no >15 μm particle which causes several disadvantages to cosmetic formulation including coarse feeling, loose touch, and diminished adhesiveness to the skin due to its much bigger size and heavier weight.
AB 762M (International Resources) white precipitated silica powder has a median agglomerate size of seven micrometers and a neutral pH. Efficiency AB 762M silica is a premium grade antiblock which provides efficient antiblock at an equivalent silica loading, resulting in a very cost effective formulating alternative.
SinoSi's Nano-Meter Silicon Materials (Sino Surplus) is a powder which main includes SiPowder, SiC Powder, Si2N4 Powder, Si/N/C Powder and C Powder and so on. The primary principle of laser synthesis Nano powder is that the gas phase synthesis reaction induced by the laser takes place as gas reactants coming into the laser beam to form the reaction zone, making use of the property of some gas reactants strongly absorbing the power of the energy of the laser due to their absorbing line nearly according with the wave line of the laser, and Nan powders are finally formed by a rapid condensing course. Because of high purity of reactants controlled by the quality flow meters, a very small reaction zone, and reaction under the cool wall condition and all powders passing through nearly the same Temperature? Time course which make the nucleus forming, particles growing up and terminating completed within 10−3 second and particles being cooled within 103-106/s, the powders present very small size, high purity and high uniformity. In order to control the oxygen and purity of products, the reacting system is pumped into vacuum and filled with high pure protected gas before the production, the oxygen content is controlled with the oxygen analytic apparatus during the production. Finally, keeping from oxygen, the products are gathered and parked at nitride gas condition.
U.S. Pat. Nos. 6,855,751, 6,849,242, 6,749,823, 6,696,034, 6,569,922, 6,387,302, 6,386,373, 6,333,013, 6,235,270, 6,225,245, 6,071,838, 6,071,487, 6,047,568, 6,007,786, RE36,396, 5,897,888, 5,888,587, 5,720,909, 5,604,163, 5,486,420, 5,480,755, 5,480,696, 5,395,604, 5,376,449, 5,307,122, 5,306,588, 5,211,733, 5,156,498, 5,145,510, 5,083,713, 5,049,596, 4,837,011, 4,804,532, 4,767,433, 4,755,368, 4,678,652, 4,593,007, 4,375,373 and 4,345,015 describe silica powders and methods for their production.
Zeolites. Zeolite is an inorganic porous material having a highly regular structure of pores and chambers that allows some molecules to pass through, and causes others to be either excluded, or broken down. What a zeolite does, and how it does it, depends upon the exact shape, size, and charge distribution of the lattice structure of the zeolite. There are hundreds of different zeolites found in nature and made by man.
In nature, zeolites are often formed where volcanic rock of specific chemical composition is immersed in water so as to leach away some of the components. Composition and pore size, of course, depend upon what kind of rock minerals are involved. Industry has mimicked some of the natural zeolites, and formed many new ones targeted towards very specific purposes. Many of these are used in the petrochemical industry to “crack,” or break down various raw materials to form specific chemicals like gasoline. Other zeolites of this kind are used to break down odors at home and at work. Others are used as simple molecular sieves, separating oxygen, argon, nitrogen, and other components of air.
Zeolyst International provides a variety of zeolite products. Five general groups are provided: Zeolite Y products, Beta type Zeolite products, Mordenite type Zeolite products, ZSM-5 Zeolite type products and Ferrierite type Zeolite products. The characteristics of the groups are set out below:
*m2/g
Additionally, U.S. Pat. Nos. 6,357,678, 5,387,564, 4,594,332, 4,551,322, 4,405,484, 4,339,419, 4,305,916, 4,303,629, 4,303,628, 4,303,627 and 4,303,626 provide zeolite compositions and methods of making them.
Aluminum-containing supports. A wide variety of supports containing aluminum exist are well-known to those of skill in the art. Non-limiting examples of aluminum-containing supports include alumina, amorphous Al(OH)3, amorphous AlO(OH), amorphous Al/SiO2 (Al substituted SiO2), crystalline Al(OH)3, crystalline AlO(OH), gibbsite and bayerite. Minerals such as boehmite and diaspore comprise the chemical formula AlO(OH). Minerals such as gibbsite, bayerite, doyleite and nordstrandite comprise the chemical formula Al(OH)3. Any support, amorphous, non-crystalline or crystalline, comprising Al(OH)x, AlO(OH)x, and Al((OH)3)x is contemplated by the present invention.
Alumina, also known as aluminum oxide, is a chemical compound of aluminum and oxygen with the chemical formula Al2O3. It is also commonly referred to as alumina in, for example, the mining, ceramic, and materials science communities.
Gibbsite is also known as hydrargyllite and comprises the chemical formula Al(OH)3. Gibbsite is an important ore of aluminium and is one of three minerals that make up the rock bauxite. Bauxite is often thought of as a mineral but is really a rock composed of aluminium oxide and hydroxide minerals such as gibbsite, boehmite, and diaspore (HAlO2), as well as clays, silt, and iron oxides and hydroxides. Bauxite is a laterite, a rock formed from intense weathering environments such as found in richly forested, humid, tropical climates.
Gibbsite has three named structural polymorphs or polytypes: bayerite, doyleite, and nordstrandite. Gibbsite and bayerite are monoclinic, whereas doyleite and nordstrandite are triclinic forms.
The structure of gibbsite is interesting and analogous to the basic structure of the micas. The basic structure forms stacked sheets of linked octahedrons of aluminium hydroxide. The octahedrons are composed of aluminium ions with a +3 charge bonded to six octahedrally coordinated hydroxides with a −1 charge. Each of the hydroxides is bonded to only two aluminiums because one third of the octahedrons are vacant a central aluminium. The result is a neutral sheet since + 3/6=+½ (+3 charge on the aluminiums divided by six hydroxide bonds times the number of aluminiums) and −½=−½ (−1 charge on the hydroxides divided between only two aluminiums); thus the charges cancel. The lack of a charge on the gibbsite sheets means that there is no charge to retain ions between the sheets and act as a “glue” to keep the sheets together. The sheets are only held together by weak residual bonds and this results in a very soft easily cleaved mineral.
Gibbsite's structure is closely related to the structure of brucite, Mg(OH)2. However the lower charge in brucite's magnesium (+2) as opposed to gibbsite's aluminium (+3) does not require that one third of the octahedrons be vacant of a central ion in order to maintain a neutral sheet. The different symmetry of gibbsite and brucite is due to the different way that the layers are stacked.
It is the gibbsite layer that in a way forms the “floor plan” for the mineral corundum, Al2O3. The basic structure of corundum is identical to gibbsite except the hydroxides are replaced by oxygen. Since oxygen has a charge of −2 the layers are not neutral and require that they must be bonded to other aluminiums above and below the initial layer producing the framework structure that is the structure of corundum.
Gibbsite is often found as a part of the structure of other minerals. The neutral aluminium hydroxide sheets are found sandwiched between silicate sheets in important clay groups: the illite, kaolinite, and montmorillonite/smectite groups. The individual aluminium hydroxide layers are identical to the individual layers of gibbsite and are referred to as “gibbsite layers.”
Additionally, U.S. Pat. Nos. 5,514,316, 5,880,196, 6,555,496, 6,593,265, 6,689,333, 6,710,004 and 7,022,304 provide aluminum-containing compositions and methods of making them.
A Lewis acid is an electron pair acceptor. A Lewis base is an electron pair donor. This definition is quite general—any Arrhenius acid or base, or any Brønsted-Lowry acid or base can also be viewed as a Lewis acid or base. The reaction of H1+ with OH1−, for instance, involves donation and acceptance of a proton, so it is certainly legitimate to call it a Brønsted-Lowry acid-base reaction. But if one looks at the Lewis structures for the reactants and products, one sees that it is also legitimate to call this a Lewis acid-base reaction.
The hydroxide ion donates a pair of electrons for bond formation, thus OH1− is a Lewis base in this reaction. The hydrogen ion accepts the pair of electrons so it is acting as a Lewis acid. Shown below is an example of a Lewis acid-base reaction that cannot be viewed as a Brønsted-Lowry acid-base reaction.
The BF3 is the Lewis acid and the N(CH3)3 is the Lewis base. Both of the electrons in the bond formed by a Lewis acid-base reaction come from the same atom (in the above example, the nitrogen donates both electrons). Such bonds are called coordinate covalent bonds. In preferred embodiments, compounds of the present invention feature such coordinate covalent bonds. A coordinate covalent bond is represented by an arrow pointing from the donor of the electron pair to the acceptor of the electron pair:
Accordingly, a coordinate covalent bond (also known as dative covalent bond) is a special type of covalent bond in which the shared electrons come from one of the atoms only. Coordinate covalent bonds are formed when a Lewis base (an electron donor) donates a pair of electrons to a Lewis acid (an electron accepter). The resultant compound may then be called an adduct (a compound formed by the addition reaction between two molecules). The process of forming a dative bond is typically called coordination. Once the bond has been formed, its strength is no different from that of a covalent bond.
A compound that contains a lone pair of electrons is capable of forming a coordinate covalent bond. Coordinate covalent bonds can be found in many different substances, such as in simple molecules like carbon monoxide (CO), which contains one coordinate covalent bond and two normal covalent bonds between the carbon atom and the oxygen atom, or the ammonium ion (NH4+), where a coordinate covalent bond is formed between a proton (a H+ ion) and the nitrogen atom. Coordinate covalent bonds are also formed in electron deficient compounds, such as in solid beryllium chloride (BeCl42−), in which every beryllium atom is bonded to four chlorine atoms, two with normal covalent bonding, and the other two with coordinate covalent bonds, which will give it a stable octet of electrons.
Coordinate covalent bonding can also be found in coordination complexes involving metal ions, as in certain embodiments of the present invention, especially if they are transition metal ions. In such complexes, substances in a solution act as Lewis bases and donate their free pairs of electrons to the metal ion, which acts as a Lewis acid and accepts the electrons. The resulting compound may be called a coordination complex, while the electron donors are often called ligands. There are many chemicals with atoms that have lone pairs of electrons, such as oxygen, sulfur, nitrogen, halogens or halide ions, which, in solution, can donate their electron pairs to become ligands. A common ligand is water (H2O), which will form coordination complexes with metal ions, like Cu2+, which will form [Cu(H2O)6]2+ in aqueous solution. Other common simple ligands are ammonia (NH3), fluoride ions (F−), chloride ions (Cl−) and cyanide ions (CN−).
There are six classes of Lewis acids: (heavy) metal Lewis acids, pi-LUMO Lewis acids, Lobe-LUMO Lewis acids, onium ion Lewis acids, s-LUMO Lewis acids and the proton Lewis acid. Of particular interest in the present invention are (heavy) metal Lewis acids. Heavy metal Lewis acids may be categorized as hard, borderline or soft (correlating with high-to-low oxidation states). Examples of heavy metal Lewis acids include Sc3+, Ti2+, Ti3+, Ti4+, V2+, V3+, V4+, V5+, Cr2+, Cr3+, Cr6+, Mn2+, Mn3+, Fe2+, Fe3+, Co2+, Co3+, Ni2+, Ni3+, Cu+, Cu2+, Zn2+, Y3+, Zr2+, Zr4+, Nb3+, Nb5+, Mo2+, Mo3+, Mo4+, Mo5+, Ru2+, Ru3+, Ru4+, Ru8+, Rh2+, Rh3+, Pd2+, Pd4+, Ag+, Cd2+, In+, In3+, Sn2+, Sn4+, La3+, Ce3+, Ce4+, Pr3+, Nd3+, Pm3+, Sm2+, Sm3+, Eu2+, Eu3+, Gd3+, Tb3+, Dy3+, Ho3+, Er3+, Tm3+, Yb2+, Yb3+, Lu3+, Hf4+, Ta5+, W2+, W3+, W4+, W5+, Re3+, Re4+, Os2+, Os6+, Os8+, Ir3+, Ir4+, Pt2+, Pt4+, Au+, Au3+, Hg2+, Hg22+, Tl+, Pb2+, Pb4+, Bi3+, and Bi5+.
One or more binding agent or modifiers may be added to the paint composition to increase stability, uniformity, spreadability, adhesion, coating thickness, etc. Binding agents and modifiers are well known in the art of paint formulation and may be included in the current coating composition. Binding agents such as solvent-containing binding agents (acryl, cyclized rubber, butyl rubber, hydrocarbon resin, α-methylstyrene-acrylonitrile copolymers, polyester imide, acryl acid butyl esters, polyacrylic acid esters, polyurethanes, aliphatic polyurethanes and chloro sulphonated polyethylene), and thermoplastic materials (polyolefins, α-ethylstyrene-acrylonitrile copolymers, polyester imide and polyamide) may be added to the paint composition. Similarly, polymers such as acrylate, styrene acrylate, acrylonitrile copolymer, polyethylene, polyethylene oxidate, chlorosulfonated polyethylene, ethylene-acrylic acid copolymer, methacrylate, vinylpyrrolidone-vinyl acetate copolymer, vinylidene chloride copolymer, polyvinylpyrrolidone, polyisopropyl acrylate, polyurethane, cyclized rubber, butyl rubber, hydrocarbon resin, α-methylstyrene-acrylonitrile copolymer, polyester imide, acryl acid butyl esters, or polyacrylic acid esters may be added.
The paint composition can be blended with a variety of other medium including gum arabic, linseed oil, copal, polycarbonate, egg tempura, and turpentine to create blended systems. The blended paint color can be altered depending on the medium in which it is blended. Grinding the initial powder to various particle sizes prior to or during blending with a medium can result in color control.
A series of experiments were developed to optimize the properties and hues of the synthetic versions of organic/inorganic complex. The synthetic versions of organic/inorganic complex were tested for stability using the Gettens test; however, the inventors have found that the Gettens test is limited and alternative methods such as IR have also been employed in these studies. Specifically, by examining the effects of dye or pigment, such as dibromoindigo, concentration, pH, and particle size, a paint possessing a color remarkably similar and stable to that of a known organic/inorganic complex was developed. The stability of the complex can be seen by its resistance to decomposition when exposed to light. Since the complex is formed with both organic and inorganic components, the stability is much higher than if only organic components were used. Based on these studies, a wide range of blues and green hues were developed as well. The present invention has established a synthetic route that can be reproduced based on the instrumental analysis that have established the chemical interactions necessary for a stable reproducible paint.
If one wishes to reproduce a “color” that resembles another color, there are many limitations on how the two could be compared. The concept of color is only accurate if one considers that color does not exist independently of normal color vision. Spectroscopic analyses such as UV/Visible are unavailing considering that certain indigo derivatives are practically insoluble in aqueous acids and aqueous alkaline solutions. Indigo derivatives are soluble in some non-polar solvents but only in the concentration range of 10−5-10−6 mol/L. Heating a mixture of an indigo derivative may indeed produce a color that ‘looks’ like the organic/inorganic complex seen at so many archaeological sites. But in the absence of knowing the precise quantity, conditions, and binding agents that the Mayans used, the reproductions described in the literature could only be analyzed by an aesthetic visual comparison and represent different chemical techniques for producing a Maya Blue “type” organic/inorganic paint powder.
Early attempts at recreating Maya blue were made by first reducing indigo with sodium hydrosulfite, then contacting it with clay and exposing the mixture to air (Olphen, 1966b). It was also found that heating the paint pigments at moderate temperatures caused the treated pigments to become stable to hot concentrated mineral acids, stable to acetone extraction, and stable to color change when exposed to heat (250° C.) (Olphen, 1966a; Olphen, 1966b). The paint compositions produced in this manner are resistant to decomposition by light. This means that, when exposed to strong sunlight or other light sources as is common for painted surfaces, the composition will not noticeably change in color and the intensity, as measured by IR spectroscopy or x-ray diffraction, and will not decrease more than 10% over a 1 year period. The composition is also resistant to decomposition by acids, alkalis, and solvents. When exposed to acidic or basic solutions, the composition will not noticeably change in color and the intensity, as measured by IR spectroscopy or x-ray diffraction, will not decrease more than 10% over a 1 year period.
The general method for producing a color composition comprises providing a molecular derivative of indigo, indigo derivative or any cationic organic dye or cationic pigment. The derivative of indigo can be selected from any indigo derivative shown in Scheme 1. The amount of dye or pigment used can be in the range of 0.01%, 0.02%, 0.03%, 0.04%, 0.05%, 0.06%, 0.07%, 0.08%, 0.09%, 0.1%, 0.2%, 0.3%, 0.4%, 0.5%, 0.6%, 0.7%, 0.8%, 0.9%, 1.0%, 2.0%, 3.0%, 4.0%, 5.0%, 6.0%, 7.0%, 8.0%, 9.0%, 10.0%, 11.0%, 12.0%, 13.0%, 14.0%, 15.0%, 16.0%, 17.0%, 18.0%, 19.0%, 20.0%, 21%, 22%, 23%, 24% or 25% by weight or more preferably 0.1% to 25% by weight or ideally at about 6% by weight.
The next step comprises combining the dye/pigment with a support. This step may further comprise the grinding of the dye or pigment with the support, for example, in a blender, industrial blender, industrial mixer, shear blender, or a precise solid state blender. The support and the dye/pigment may be ground separately and then ground together or they may be combined and ground to both mix the two components in order to obtain the preferred ratio. Techniques for grinding and blending the dye/pigment and support compositions are found in Mixing of Solids (Weinekotter and Gericke, 2000), Powder and Bulk Solids Handling Processes (Iinoya et al., 1988), or Bulk Solids Mixing (Gyenis and Gyenis, 1999). De-ionized water may be added during blending to attain a homogenized mixture.
The next step comprises heating the color composition. The heating may comprise heating at a temperature of 100° C., 110° C., 115° C., 120° C., 125° C., 130° C., 135° C., 140° C., 145° C., 150° C., 155° C., 160° C., 165° C., 170° C., 175° C., 180° C., 185° C., 190° C., 195° C., 200° C., 205° C., 210° C., 215° C., 220° C., 225° C., 230° C., 235° C., 240° C., 245° C., 250° C., 255° C., 260° C., 265° C., 270° C., 275° C., 280° C., 285° C., 290° C., 295° C. or 300° C., or more particularly between 115° C. and 200° C. The heating may be for several hours, 1 day, 2 days, 3 days, or may last up to four days. The heating can be carried out in, but not limited to, a batch oven, a drying oven, an infrared oven, or a powder coating oven.
An alternative to heating comprises treating the color composition with radiation, including ultraviolet. Light radiation in the range from 10 nm to 500 nm will be used in accordance with the present invention, particularly 200-400 nm (i.e., near UV). Treatment times will vary from very brief—as short as one minute—to several hours (1, 2, 3, 4, 5, 7, 8, 9, 10, 11, 12, 18, 24, 36, 48 or more hours). Suitable devices for providing UV exposure exist including chambers and reactor vessels.
Next the pH of the color composition may be adjusted to an acidic or neutral pH, depending on the final color desired. Exemplary examples of the acid used to adjust the pH comprise: any protonic acid, H2SO4, HClO4, HClO3, H3PO4, HNO3, HCN, HF, HBr, H1, H3O+, or CH3COOH, or more preferably HCl. Exemplary examples of the base used to adjust the pH comprise: LiOH, NaOH, KOH, RbOH, CsOH, Ca(OH)2, Sr(OH)2, Ba(OH)2 or more preferably NaOH. The pH of the color composition can be 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, or 12. The pH of the system can be monitored with a pH meter that is calibrated with buffers of pH 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, or 12.
Additional steps in making the color composition may comprise: treating the color composition with acid such as but not limited to any protonic acid, H2SO4, HClO4, HClO3, H3PO4, HNO3, HCN, HF, HBr, H1, H3O+, or CH3COOH, or more preferably HCl, to remove impurities from the clay; applying the color composition to a surface; blending the color composition with a polymer, plastic or organic binder as discussed in Encyclopedia of Polymer Science and Engineering, 2nd ed. (Herman, 1990) and Paint and Surface Coatings: Theory and Practice, 2nd ed. (Lambourne and Strivens, 1999).
The following patents are included as examples to demonstrate certain embodiments of the invention. However, those of skill in the art should, in light of the present disclosure, appreciate that many changes can be made in the specific embodiments which are disclosed and still obtain a like or similar result without departing from the spirit and scope of the invention. U.S. Pat. No. 3,950,180 covers the method of manufacturing color compositions that include zeolite and montmorillonite. U.S. Pat. No. 5,061,290 covers the method of using indigo derivatives as a dyeing agent. U.S. Pat. No. 4,246,036 covers the method of manufacturing color compositions that are comprised of asbestos-cement. U.S. Pat. No. 4,640,862 covers color compositions that are used for coating an expanded polystyrene “drop-out” ceiling tile. U.S. Pat. No. 4,868,018 covers color compositions that are used with a mixture of epoxy resin, epoxy resin hardener, and Portland cement to form a coating which can be applied to a surface to form simulated marble products. U.S. Pat. No. 4,874,433 covers a method for encapsulating color compositions in and/or to a zeolite. U.S. Pat. No. 5,574,081 covers a method of manufacturing waterborne clay-containing emulsion paints with improved application performance using color compositions. U.S. Pat. No. 5,972,049 covers the method of manufacturing and using color compositions to form dye carriers used in the dyeing process for hydrophobic textiles. U.S. Pat. No. 5,993,920 covers the method of manufacturing and using color compositions with stone powder and/or cement powder, fine sawdust and/or the heart of a kaoliang stalk and other materials to form an incombustible artificial marble. U.S. Pat. No. 6,339,084 covers the method of manufacturing thiazine-indigo pigments. U.S. Pat. No. 6,402,826 covers the method and manufacturing of color compositions for paper coating.
As used herein, the term “organic/inorganic complex” refers to a complex featuring a coordinate covalent bond among one or more organic molecules and one or more inorganic molecules. As used herein the term “color composition” refers to a pigment or dye complexed to a support material comprising a Lewis acid metal as described herein. As used herein, the term “coating composition” is synonymous with “color composition” and “paint powder.” As used herein, the term “cement” refers to Portland cement types I, II, III, IV, IA, IIA, IIIA or as covered in The Chemistry of Portland Cement, 2nd ed. (Bogue, 1955); or any cement type discussed in the Dictionary of Cement Manufacture & Technology Zement Woerterbuch (Amerongen, 1986). The chemistry of cements use in the present invention is covered in The Chemistry of Cements, 2nd volume (Taylor, 1964).
The Maya/Blue concept is based on the electronic interaction between the organic molecule (indigo) and the clay (palygorskite). Though we and others have studied authentic Maya Blue pigments and many theories as to the origin of the Maya Blue color were described, it was not until we began to produce synthetic samples with molecules unknown to the Maya that the real chemical nature of the complexes were revealed. The basic concept was that the organic compound interacted with “sites” at the surface of the clay through gentle heating of the two starting phases. Electron density was exchanged, stabilizing the complex and leading to a change in the color.
The organic/inorganic complexes (OICs) described above use common clays as the inorganic portion. These clays, though inexpensive and abundant, contain variable amounts of metals such as Al and Fe. This variation is not a problem for quality control if the clay is obtained from a common source. However, because the clays are difficult to synthesize in the laboratory, it is difficult to distinguish between the role played by Fe and Al in developing the final properties of the OIC. Further, the ability to form OICs using other inorganic materials that are inexpensive and readily available would be very advantageous.
The following examples are included to demonstrate preferred embodiments of the invention. It should be appreciated by those of skill in the art that the techniques disclosed in the examples which follow represent techniques discovered by the inventor to function well in the practice of the invention, and thus can be considered to constitute preferred modes for its practice. However, those of skill in the art should, in light of the present disclosure, appreciate that many changes can be made in the specific embodiments which are disclosed and still obtain a like or similar result without departing from the spirit and scope of the invention.
Materials & Methods
SiAl-Novaperm Red complex preparation. SiAl (3111) (Silica Alumina, a white zeolite powder) purchased from Davidson Catalysts was mixed with Novoperm Thi red 4G-70 purchased from Clariant corporation 95:5% by weight and mixed in a blender for 5 min. The mixture was then ball milled in a ball mill for 18 hrs and subsequently heated in an oven at 125° C. for 24 hrs. The color change of the ball milled composition changed to a light orange color as shown in
Paint Preparation. The above material was used as a pigment in paint at a pigment content of 11.78% and percentage non volatile matter of 38.60%. The formulation is listed in Table 2. The paint was applied on a pre-printed Al panel with a 10 mil wet film applicator and allowed to mature for 7 days.
Results
Accelerated weather results. The paints were exposed to accelerated UV and condensation weathering chamber (QUV Basic obtained from Q panel instruments) for a period of 146 hours with the QUV cycle set to 8 hrs of UF at 60° C. followed by 4 hours of condensation at 40° C. The color readings were recorded after 146 hrs and found to be 1.54 for the heated mixture and 3.57 for the non heated mixture. The color readings (ΔE) for both heated and non heated mixture of SiAl-Novoperm red is listed in Tables 3 and 4.
Similar paint was made with non heated mixture of SiAl and Novoperm red and draw down made with a 10 mil applicator and allowed to mature for 7 days.
It can be observed from Tables 3 and 4 that the heated SiAl-Novoperm red (ΔE 1.54) mixture is more resistant to the effects of UV and moisture condensation than the non heated mixture of SiAl and Novoperm Red (ΔE 3.57).
TGA and DTA Analysis. TGA and DTA analysis was done for the dye Novoperm Red and the heated SiAl-Novoperm Red mixture. The results are as shown in the
Si/Al and zeolites, materials commonly used as chemical and petroleum refining catalysts, have the advantage of being synthesized with known controllable compositions. Cracking catalysts, for example, are made with varying amounts of Al replacing Si in the amorphous SiO2 lattice (i.e., Al substituted SiO2). The amount of Al is adjusted to create Lewis acid sites for various applications. An example of a thioindigo complex with a 10% Al doped amorphous SiO2 is shown in
All of the methods disclosed and claimed herein can be made and executed without undue experimentation in light of the present disclosure. While the compositions and methods of this invention have been described in terms of preferred embodiments, it will be apparent to those of skill in the art that variations may be applied to the methods and in the steps or in the sequence of steps of the method described herein without departing from the concept, spirit and scope of the invention. More specifically, it will be apparent that certain agents which are both chemically and physiologically related may be substituted for the agents described herein while the same or similar results would be achieved. All such similar substitutes and modifications apparent to those skilled in the art are deemed to be within the spirit, scope and concept of the invention as defined by the appended claims.
The following references, to the extent that they provide exemplary procedural or other details supplementary to those set forth herein, are specifically incorporated herein by reference:
This application claims the benefit of U.S. Provisional Application No. 60/691,683 filed Jun. 17, 2005, which is incorporated by reference in its entirety.
The government may own rights in the present invention pursuant to Grant No. 26-3000-20 from the Department of Energy.
| Number | Date | Country | |
|---|---|---|---|
| 60691683 | Jun 2005 | US |
