MX2007002327A

MX2007002327A - Aluminum phosphate, polyphosphate and metaphosphate particles and their use as pigments in paints and method of making same

Info

Publication number: MX2007002327A
Application number: MXMX/A/2007/002327A
Authority: MX
Inventors: De Brito Joao; Galembeck Fernando
Original assignee: Bunge Fertilizantes Sa; Universidade Estadual De Campinasunicamp*
Priority date: 2006-02-27
Filing date: 2007-02-26
Publication date: 2008-09-26

Abstract

An aluminum phosphate composition comprising aluminum phosphate, aluminum polyphosphate, aluminum metaphosphate, or a mixture thereof. The composisition may be characterized by, when in powder form, having particles wherein some of the particles have at least one or more voids per particle. In addition, the composition is characterized by exhibiting two endothermic peaks in Differential Scanning Calorimetry between about 90 degrees to about 250 degrees Celsius. The composition is also characterized by, when in powder form, having a dispersibility of at least 0.025 grams per 1.0 gram of water. The composition is made by a process comprising contacting phosphoric acid with aluminum sulfate and an alkaline solution to produce an aluminum phosphate based product;and optionally calcining the aluminum phosphate, polyphosphate or metaphosphate based product at an elevated temperature. The composition is useful in paints and as a substitute for titanium dioxide.

Description

PARTICLES OF ALUMINUM PHOSPHATE, POLYPHOSPHATE AND METAPHOSPHATE, ITS USE AS A PIGMENT IN PAINTS AND METHOD TO PRODUCE THE SAME Field of the Invention The present invention relates methods for obtaining particles of aluminum phosphate, aluminum metaphosphate, aluminum orthophosphate and aluminum polyphosphate. In addition, the present invention relates how to use such particles as pigment in paints and other applications. Background of the Invention Titanium dioxide is the most common white pigment due to its strong backscattering capability of visible light, which is dependent on its refractive index. Substitutes for titanium dioxide have been sought, but the refractive indices of the anastase and rutile forms of this oxide are much higher than any other white powder, due to structural reasons. The titanium dioxide pigments are insoluble in transport layers in which they are dispersed. The properties of the performance of such titanium dioxide pigments, including their physical and chemical characteristics, are determined by the particle size of the pigment and the chemical composition of its surface. Titanium dioxide is found commercially available under two forms of crystalline structures: anastase and rutile. Rutile pigments of titanium dioxide are preferable as they scatter light more efficiently and more stablely and durably than anastase pigments. Titanium dioxide disperses light more efficiently due to its high refractive index. The decorative and functional attributes of titanium dioxide, due to its dispersion capacity, make it a highly desired pigment. However, titanium dioxide is known to be an expensive pigment to manufacture. Accordingly, there is a need for a more affordable substitute than titanium dioxide as a pigment. As mentioned, a desired characteristic of titanium dioxide is its great ability to propagate (or disperse) visible light. This property is a result of its high refractive index, together with the absence of electronic transitions in the visible spectrum area. Many attempts have been made to replace titanium dioxide, partially or completely in its uses as a pigment. However, the refractive indices of its anastase and rutile forms are difficult to obtain by means of other white solid substances (Handbook of Chemistry and Physics, CRC Press, 57th edition, 1983). In this way, the search for new white pigments led to the search for systems with other mechanisms of light scattering. Polyphase media, which present a large variation of the index of refraction, they can function as dispersants of light. Current options for pigment or paint manufacturing processes that result in a film containing "pores" on the inside of the particles or between the particles and the resin are also quite limited. Some techniques for the preparation of particle holes have been described in the literature; however, most techniques involve the manufacture of hollow polymeric and spheroidal particles by emulsion polymerization. An example is the study by N. Kawahashi and E. Matijevic (Preparation of hollow spherical particles of Itrium compounds, Journal of Colloid and Interface Science 143 (1), 103, 1991) on the polystyrene latex layer with basic carbonate. of yttrium and subsequent calcination with high air temperatures, producing hollow particles of yttrium compounds. The preparation of hollow particles of aluminum metaphosphates by chemical reaction between sodium metaphosphate and aluminum sulfate, followed by heat treatment, was described by Galembeck et al., In patent BR 9104581. This study concerns the formation of hollow particles of sintered aluminum phosphate from sodium phosphate and aluminum nitrate. As mentioned, the two aluminum pigments, phosphate and metaphosphate can be used to largely replace Ti02 in latex-based paints PVA or acrylic emulsions. BR 9500522-6 of Galembeck et al. Describes a way of producing a white pigment from a double calcium and aluminum metaphosphate obtained from a direct chemical reaction between aluminum metaphosphate and calcium carbonate particles in a type of emulsion Polymer latex in aqueous medium. This patent extends the previous results to calcium salts that, from an environmental point of view, are advantageous due to their complete atoxicity. Many publications discuss the synthesis of aluminum phosphate materials primarily for use as a catalyst support, including crystalline and amorphous forms. Many of these methods reach high porosities and crystalline forms and few stable amorphous compositions. Examples of such materials are described in US Patents: 3,943,231; 4,289,863; 5,030,431; 5,292,701; 5,496,529; 5,552,361; 5,698,758; 5,707,442; 6,022,513; and 6,461,415. There is a need, however, for aluminum phosphate with hollow particles, particularly for producing a powder with relative ease. SUMMARY OF THE INVENTION The subject of this invention is an aluminum phosphate composition comprising aluminum phosphate, aluminum polyphosphate, aluminum metaphosphate, or a mixture thereof. The composition can be characterized because, when it is in the dust state, it has an average of one or more holes per particle. Added to this, the composition is characterized because it exhibits two endothermic peaks in Differential Scanning Calorimetry between about 90 ° C and about 250 CC. The composition is also characterized in that, when in a powder state, it has a dispersibility of at least 0.025 grams per 1.0 gram of water. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an image with energy filter of a material of the present invention seen in transmission electron microscope. Figure Ib is a clear field image of a material of the present invention seen in transmission electron microscope. Figure 2a is an image with energy filter of a material of the present invention seen in transmission electron microscope. Figure 2b is a clear field image of a material of the present invention seen in transmission electron microscope. Figure 3a is a light field image through a transmission electron microscope demonstrating a product based on aluminum phosphate that has no voids. Figure 3b is a brightfield image through a transmission electron microscope demonstrating a product based on aluminum phosphate that does not have holes. Figure 4 is a thermogram of a material of the present invention obtained by a differential scanning calorimeter. Figure 5 is a thermogram of a material of the present invention obtained by a differential scanning calorimeter. Figure 6 is a thermogram of a material of the present invention obtained by a differential scanning calorimeter. Figure 7 is a thermogram of a material of the present invention obtained by a differential scanning calorimeter. Detailed Description of the Invention In the following description, all numbers listed are approximate values, regardless of whether the words "near" and "approximately" are used in relation to them. The values can vary in 1%, 2%, 5% or sometimes 10% to 20%. Whenever a numerical range with a lower limit (R) and an upper limit (Ru) is disclosed, any number within the range is specifically described. In particular, the following numbers within the range are specifically described: R = RL + k * (RU-RL), where k is a variable in the range of 1% to 100% with an increase of 1%, for example, k is 1%, 2%, 3%, 4%, 5%, ..., 50%, 51%, 52%, ..., 95%, 96%, 97%, 98%, 99% or 100%. On the other hand, any numerical range defined by two R numbers as defined above is also specifically described. The invention described in this description relates to an aluminum phosphate composition comprising aluminum phosphate, aluminum polyphosphate, aluminum metaphosphate or a mixture thereof. The terms "aluminum phosphate" and "aluminum phosphate composition", as used herein, are intended to include aluminum phosphate as well as aluminum polyphosphate, aluminum metaphosphate and mixtures thereof. The aluminum phosphate composition is characterized in that, in the powder state, it has a dispersibility of at least 0.025 grams per 1.0 gram of water. Preferably, the composition is characterized in that, in a powder state, it has a dispersibility of at least 0.035 grams per 1.0 gram of water. Even more preferably, the composition is characterized in that, in the powder state, it has a dispersibility of at least 0.005 grams per 1.0 gram of water. The novel hollow aluminum phosphate particles can generally be characterized by several different characteristics. For example, aluminum phosphate, when prepared in the powder form, includes particles of which some of said particles have at least one void per particle, on average. Added to this, when the Aluminum phosphate, polyphosphate and / or metaphosphate are in powder form, samples subjected to a differential calorimetric scanning test will demonstrate two different endothermic peaks, said peaks generally occurring between 90 ° C and 250 ° C. Preferably, the first peak occurs approximately between the approximate temperatures of 96 ° C and 116 ° C, and the second peak occurs approximately between the temperatures of 149 ° C and 189 ° C. Even more preferably, the two peaks occur at approximately 106 ° C and approximately at 164 ° C. In addition, aluminum phosphate typically exhibits excellent dispersibility characteristics, as described. The composition of the present invention comprises non-crystalline solids, as opposed to the vast majority of inorganic industrial chemicals, including those commonly sold as crystalline aluminum phosphates or polyphosphates. The CAS number most often given to aluminum phosphate products is 7784-30-7, but this refers to a crystalline, stoichiometric solid. The invention described herein further refers to a novel aluminum phosphate, aluminum polyphosphate, aluminum metaphosphate or mixture thereof. Amorphous (ie, non-crystalline) solids exhibit differences from their crystalline counterparts under a similar composition, and such differences can achieve beneficial properties. For example, such differences may include: (i) non-crystalline solids do not diffract x-rays at sharply defined angles but instead can produce a wide dispersion halo; (ii) non-crystalline solids do not have a well-defined stoichiometry, thus they can cover a wide range of chemical compositions; (iii) the variability of chemical compositions include the possibility of incorporation of ionic constituents in addition to aluminum and phosphate ions; (iv) since amorphous solids are thermodynamically meta-stable, they can demonstrate a tendency to undergo spontaneous, morphological, chemical and structural changes; and (v) the chemical composition of the surface and volume of crystalline particles is highly uniform while the chemical composition of the surface and volume of amorphous particles may show large or small differences, either gradually or abruptly. In addition, while crystalline solids particles tend to grow by the well-known Ostwald ripening mechanism, the non-crystalline particles may expand or swell and shrink (deflate) by absorption or desorption of water, forming a plastic or gel-like material. It is easily deformed when subjected to shear, compression or capillary forces. As mentioned, in one aspect of the invention described herein, it is a synthetic process that produces non-crystalline, nano-sized aluminum phosphate particles with unique properties. When a dispersion of such particles is dried by air at an ambient temperature of more than 120 ° C, the dried particles that form have a core and shell structure. Such particles can be observed by analytical electron microscope. Moreover, these particles contain many disperse holes like closed pores in their interior. The nuclei of the particles are more plastic than the respective particle shells. This phenomenon is evidenced by the growth of the gaps by heating, while the perimeter of the peels remains essentially unchanged. Another aspect of the present invention is the development of a new product and manufacturing process for forming hollow particles of aluminum phosphate, aluminum polyphosphate and aluminum metaphosphate (and mixtures thereof) to be used as a pigment. More specifically, this aspect of the present invention relates a new pigment obtained through the reaction of phosphoric acid, in particular industrial grade phosphoric acid, with aluminum sulphate under controlled temperature and pH conditions. The reagent can be filtered, dispersed, dried, calcined, and micronized to be used as a pigment in paints, plastics, varnishes, printing paints, etc. As described, many have sought the formation of voids within particles, but it is a difficult goal to obtain because most solids form pores open to to be dried, and such open pores do not contribute to the opacity of the paint or covering power. The hollow particles formed within the aluminum phosphate, polyphosphate or metaphosphate confer beneficial characteristics, both chemical and physical, that can be used in a variety of different applications. One aspect of the present invention described herein is the production of aluminum phosphate, polyphosphate or metaphosphate (or combination thereof) with such hollow particles in order to take advantage of said beneficial characteristics. The term "hollow" used herein is generally synonymous with the term "hollow particle", and also described herein as a "closed hollow." The hollow (hollow closed or hollow particle) is part of the core and shell structure of the aluminum phosphate mixture. An example of a composition according to the present invention is seen in Figures la and 2a, in an image with energy filter in a transmission electron microscope. An example of the composition according to the present invention is seen in Figures Ib and 2b, in a clear field image in a transmission electron microscope. The samples show the voids contained in the composition of the present invention. In contrast, Figures 3a and 3b are photographic electron micrograph of brightfield transmission of an aluminum phosphate without containing voids. The ability to scatter light from samples in Figures la, Ib, 2a and 2b is superior to the ability to scatter light from the samples of Figures 3a and 3b. The gaps can be observed and / or characterized using transmission or scanning electron microscopes ("TEMs" or "SEMs"). The use of TEMs or SEMs is well known to those skilled in the art. Generally, the electron microscope is limited, by the wavelength of light, for resolutions in the range of one hundred, and usually hundreds of nanometers. TEMs and SEMs do not present this limitation and allow to obtain a considerable high resolution, in the range of a few nanometers. An optical microscope uses optical lenses to focus light waves by curving them, while an electron microscope uses electromagnetic lenses to focus electron beams curving them. The electron beams provide great advantages over the light beams, in terms of controlling the levels of magnification and in the clarity of the image that can be obtained. Scanning electron microscopes complement the transmission electron microscopes in that they provide a tool to obtain a three-dimensional image of the surface of a sample. Generally, an electron beam is produced in an electron microscope by heating a filament. The filament can be made from a variety of metallic materials, including, but not limited to, tungsten or lanthanum hexaboride. This metallic filament It works like the cathode, and when a voltage is applied, the temperature of the filament increases. An anode, which is positive with respect to the filament, forms a powerful force of attraction for the electrons. The electrons are attracted from the cathode to the anode, passing some towards the anode to form a beam of electrons that is used in the imaging of the sample. This electron beam is then condensed, and focused on the sample using electromagnetic lenses. In an SEM, scanning coils create a magnetic field that can be varied to direct the beam back and forth in a controlled manner. The same variation of voltage that creates pattern in the sample is applied in a cathode ray tube. This creates a pattern of light on the surface of the cathode ray tube that is analogous to that of the sample. As mentioned, the material of the present invention has novel features that are reflected in the tests performed on a differential scanning calorimeter. Briefly explained, a differential scanning calorimeter ("DSC") is an analytical technique in which the heat flux associated with a chemical, physical or crystallographic transformation of a material is measured as a function of temperature and time (and possibly pressure). ). Differential scanning calorimeters ("DSCs") measure the heat flow in a sample such that the temperature of the sample varies so controlled There are two basic types of DSCs, heat flux and compensated power. The heat flow DSCs include a sensor to measure the heat flow in a sample to be analyzed. The sensor has a sample position and a reference position. The sensor is installed in an oven where the temperature is dynamically modified according to a desired programmed curve. While the furnace is heating or cooling, the temperature difference between the sample and the reference positions of the sensor is measured. It is assumed that the temperature difference is to provide the heat flow of the sample. The compensated power DSC includes a reference sample holder installed in a constant temperature enclosure. Each of the supports has a heater and a temperature sensor. The average temperature between the sample and the reference is used to control the temperature, which follows a desired temperature program. In addition, the proportional power differential to the temperature difference between the supports is added to the average power of the sample holder and subtracted from the average power of the reference support in an effort to reduce to zero the temperature difference between the sample and the reference supports. The differential power is assumed to be proportional to the heat flow of the sample and is obtained by measuring the temperature difference between the sample and the reference support. In DSCs of commercially compensated power available, the difference between the temperature of the sample and the reference is generally different from zero because a proportional controller is used to control the power differential. A sample to be analyzed is loaded into a tray and placed in the sample position of the DSC. An inert reference material can be loaded into a tray and placed in the reference position of the DSC, although the reference tray is usually empty. The temperature program for conventional DSCs typically includes combinations of linear temperature ramps and constant temperature segments. The experimental result is the heat flow of the sample versus the temperature or time. The heat flow signal is the result of heat flow to or from the sample due to its specific heat and as a result of the transitions that occur in the sample. During the dynamic part of the experiment in the DSC, a temperature difference is created between the sample and the reference positions of the DSC. In heat flow DSCs, the temperature difference results from the combination of three differential heat fluxes: the difference between the sample and the reference heat flux, the difference between the sample and the heat flux of the reference sensor and the difference between the sample and the reference heat flow of the tray. In compensated power DSCs, temperature differences result from the combination of three different heat fluxes plus the power differential supplied to the sample holders: the difference between the sample and the reference heat flux, the difference between the sample and the heat flux of the support and the difference between the sample and the heat flow of the tray. The difference between the heat flux between the sample and the reference consists of the heat flux due to the difference in heat capacity between the sample and the reference or heat flux of a transition. The difference in heat flux between the sample and reference sections of the DSC is the result of the imbalance of thermal resistors and capacitors in the sensor or between the supports and the difference in the rate of heating that occurs between the sample and the reference sections of the DSC during the transition. Similarly, the difference in heat flux between the sample and the reference trays is the result of mass differences between the trays and the difference in the rate of heating that occurs during a sample transition. In conventional heat flow DSC, sensor imbalance and tray imbalance are considered negligible and the difference in the heating rate is ignored. In conventional compensated power DSCs, the unbalance of support and tray unbalance are considered negligible and the difference in the heating proportions is ignored. When the equilibrium assumptions are satisfied and the heating rate of the sample is the same as the programmed heating rate, the temperature difference is proportional to the heat flow of the sample and the differential temperature gives an accurate measurement of the heat flux of the sample. The heat flow of the sample is only proportional to the temperature difference measured between the sample and the reference when the sample heating ratio and the reference are identical, the sensor is perfectly symmetrical, and the masses of the trays are identical. The proportionality of the heat flow of the sample to the temperature difference for a sensor and balanced trays occurs only during portions of the experiment when the instrument is operating at a constant rate or rate of heating, the sample changes temperature in the same proportion as the instrument and there are no transitions that occur in the sample. During a transition, the heat flow to the sample increases or decreases from a pre-transition value depending on whether the transition is endothermic or exothermic and whether the DSC is being heated or cooled. The change in the heat flow of the sample causes the heating rate of the sample to be different from the DSC and as a consequence, the heating rate of the tray and sample sensor become different from the programmed heating rate.

Several samples of aluminum phosphate, polyphosphate and / or metaphosphate product were tested in a DSC. The results obtained from the DSC were determined using a differential scan calorimeter model "Q", 600 series, from TA Instruments, equipped with an RCS cooler and a self-sample. A nitrogen gas purge flow of 50 ml / min is used. Sample "cakes" of aluminum phosphate were dried by heating at 110 ° C to constant weight. Alternatively, the standard set forth in ASTM D-280 may be followed to achieve similar results. The resulting dry powder sample is weighed (approximately 4 grams) in an open aluminum tray (model DSC Q10). The tray is then mounted on the DSC apparatus and heated from room temperature to 420 ° C at a heating rate of 10 ° C per minute. The DSC curve is examined and the maximum heat flow rate (W / g) temperatures are recorded with respect to the sigmoid baseline drawn between room temperature and 420 ° C. The heat absorbed by the sample is measured as the area under the curve in the temperature range used. To simplify the calculations in the DSC, a sigmoidal baseline is used. Although a straight line may be adequate when the heat capacities of the solid and liquid phases do not vary dramatically, a sigmoidal baseline is typically created to define the lower limit of the area under the DSC curve. This is necessary due to the fact that the slope of the baseline, representing the heat capacity, changes with the phase transformation, and therefore, the use of a linear baseline can lead to significant errors. A sigmoidal baseline is a letter-shaped curve, which undergoes a change in level and / or slope before or after a peak. This is used as a compensation for any change in the baseline which may occur during a phase transition. The baseline undergoes adjustment for the fraction reacted with respect to time. The sigmoidal baseline is calculated, initially, as a straight line from the beginning of the initial peak to the end of the peak. It is then recalculated for each point taken as a data between peak limits as a media loaded between the horizontal projection or tangent base lines at the beginning and end of the peak. Table 1 reflects the results of several tests performed on aluminum phosphate samples, presenting data obtained from samples tested in a DSC. The first column of Table 1 is the sample number. The second column of Table 1 reflects the proportion of phosphorus mass to aluminum of the resulting mixture. The third column of Table 1 reflects the ratio of phosphorus mass to sodium of the mixtures. The fourth column of Table 1 reflects the proportion of aluminum mass to the sodium of the samples. The proportions of phosphorus, aluminum and sodium were determined by means of an emission spectrometer Atomic plasma by inductively-coupled ("ICP-OES", Optima 3000 DV model, Perkin Elmer). An approximate amount of 100 mg of a dense fluid was dissolved in 1.5 g of HCl (3 M) and 100 g of water was added. The obtained solutions were filtered and the measurement by ICP was carried out. The ICP is based on argon plasma maintained by the interaction of a radiofrequency (RF) field and ionized argon gas. In the ICP-OES, the plasma is used as a source of energy, producing a warming of 5,000, -8, 000 ° K and up to 10,000 ° K in some regions, enough to ionize and excite most of the atoms analyzed. . When the electrons decay to their natural state, the emission of light is detected. Because the excited ions emit only light at certain wavelengths, spectral lines dependent on the element in question are produced. These lines can then be used to quantitatively determine the components of the sample. A calibration curve of intensity and concentration can be used to quantitatively determine the concentration of the sample analyzed. The fifth and sect columns of Table 1 reflect the temperature at which the peaks are located with respect to the tests performed in the DSC, as described here. The seventh column reflects the integration of the curves generated by measuring the heat flow from the DSC. The remaining three columns reflect the proportions between indices of opacity, whiteness and tendency to yellow of the paintings made with a 50% replacement of the aluminum oxide with aluminum phosphate of a standard paint. The opacity index is measured according to the ASTM D 2805-96a standard, while the whiteness and yellow tendency indexes were measured according to the ASTM E 313-00 standard. The optical measurements (opacity, whiteness and tendency to yellow) were measured with a colorimeter BYK-Gardner color guide model with dial geometry d / 8 °. The Leneta schemes with reduced preparations according to ASTM D2805, using paints formulated with the described composition of the present invention and Ti02. The color guide is a portable spectrophotometer that can be used to ensure constant quality in incoming and outgoing quality control in the process of on-site controls. It is operated with batteries to respond to the demands of measurement in the field. The principle of the measurement is based on the measurement of the spectral reflection within the visible spectrum of wavelengths from 400-700 nanometers. Two measuring geometries are provided: 45/0 and d / 8 (with or without specular brightness). With 45/0, illumination occurs in a circular pattern at an angle of 45 °, while the angle of observation is 0 °. With d / 8, the light affects the sample diffusely, while the angle of observation is 8 ° "with respect to the vertical". The specular color guide of the instrument measures (d / 8) and 60 ° simultaneously. The sample is illuminated by light-emitting diodes (LEDs) with a long service life. The LEDs do not heat the sample, therefore there is no risk of causing thermal-chromic effects caused by lighting.

TABLE 1. Results of several experiments performed on aluminum phosphate samples Samples 1 to 12 were generally prepared according to the procedure set forth in Example 1. Samples 1 to 4 were aluminum phosphate "cakes" collected from the filter. Sample 3 is a mixture of the first and second "cake" type sample. Samples 5 to 12 are slurries of the aluminum phosphate mixture. Samples 13-26 are watery pastes prepared according to example 1, described herein, but reduced by the use of 1/20 of phosphoric acid provided in example 1. The process variables used were: weight ratio P / Al in the feed, pH during the addition, alkali used, sodium hydroxide, potassium or ammonium, amount of alkali added at the end of the preparation for pH adjustment. Sample 25 has no entries for the Al / Na or P / Na indices, because potassium was used as the cation in the composition. Those skilled in the art will appreciate that some cations can be exchanged in the composition depending on the circumstances and the materials available. Similarly, sample 26 uses ammonium hydroxide as a base material, and therefore does not exhibit Al / Na or P / Na index values either. The samples resulting from the DSC tests are shown in Figures 4-7. As can be seen in Figures 4-7, the total profile indicates that it is endothermic (ie, heat fluxes of the sample). Added to this, two large negative peaks can be observed, at approximately 106 ° C and approximately at 164 ° C. Of course, these two peaks can be changed up or down relative to the temperature, depending on the composition and structure of the powder. The endothermic integral, or the enthalpy of dehydration, is calculated to be approximately 490 Joules per gram. Such enthalpy of dehydration may vary, depending on factors counted. The peaks referred to here many times are overlap, so that only one peak is observed visually as a "peak-unit" in the DSC results. In some embodiments, the peak that occurs at the highest temperature ("second peak") is stronger than that which occurs at a lower temperature ("first peak"). In other embodiments, the first peak may not be well defined and is superimposed on the second peak which may be broad and well-defined. In these cases, the first peak is evidenced by a small protruding shoulder or a change in the curvature of the second peak. Additionally, the DSC results may include additional peaks outside the temperature ranges used here. Preferably, however, there are no peaks between about 300 and 400 ° C. More preferably no peaks are present between 310 ° C and 380 ° C. Even more preferably, no peaks are present between about 320 ° C and 360 ° C. Still more preferably no peaks occur between about 335 ° C and 345 ° C. Figure 4 shows two distinct peaks in the thermogram, a peak occurs at approximately 101 ° C and a peak occurs at approximately 172 ° C. The composition of the sample according to the results shown in Fig. 4 was generally prepared according to the procedure of Example 1 as provided herein. Figure 5 shows two peaks that overlap one another, such that the second peak is more visible than the first peak. The composition of the sample showing the Results of Figure 5 was generally prepared according to the procedure of Example 1 as provided herein, but reduced by the use of a 1/20 amount of phosphoric acid according to Example 1. Figure 6 also shows two overlapping peaks slightly. Figure 6 includes a sample that uses potassium as a starting or initial base material. Figure 7 also shows two peaks that overlap slightly. The sample of Figure 7 was prepared using ammonium hydroxide as an initial material. In addition to the DSC characteristics, the aluminum phosphate composition is also dispersible in water, which characterizes it then by its dispersibility in water. Dispersibility tests were performed on several samples of aluminum phosphate compositions. "Dispersibility" in water refers to the amount of aluminum phosphate dispersed or dissolved in water. It is intended to include the conditions in which the aluminum phosphate is dissolved in the form of a true solution or dispersed within an aqueous medium to obtain a stable product. Often, it is possible to have soluble and dispersible portions when the aluminum phosphate composition is mixed with the water. On the other hand, it is also possible to increase or decrease the dispersibility by adding additives to the water or by changing the pH of the solution. Therefore, the dispersibility used in the claims refers to to the amount of aluminum phosphate composition dispersed in water without the addition of other additives or reagents. The tests to determine the characteristics of the dispersion of the inventive composition were as follows: first, a measured amount of aluminum phosphate, polyphosphate or metaphosphate (or mixture thereof), typically about one gram, was added to a measured amount of dispersant. Aluminum phosphate is in the form of "cake". The water (optionally with some additives) was used as the dispersant. The resulting mixture was mixed vigorously in a vortex mixer for two minutes. The suspension was filtered by gravity through a 400 mesh stainless steel filter. The residue was washed with 2 milliliters of deionized water. The filter and the wet cake were dried in an oven at 110 ° C for twenty minutes. The mixture was then heavy. The results of the dispersion tests of the samples are shown in Table 2.

Table 2. Dispersibility data for aluminum phosphate particles As can be seen in table 2, the aluminum phosphate mixture, when subject to the preceding dispersibility test, exhibits a dispersibility of up to 96.3% (which is very dispersible) and as low as 65.7% (which is little dispersible). As those skilled in the art will appreciate, the dispersibility for a given composition can be adjusted depending on the final use that aluminum phosphate will have. For example, an aluminum phosphate with high dispersibility may be required for use in paint manufactures. Depending on the method used for the manufacture of paints, it may be desired to have high dispersibility or low dispersibility. The type of dispersant also has some effects on dispersibility. As seen in Table 2, when the dispersant is H20, the less dispersible sample has a dispersibility of about 81.2%, while the most dispersed sample has a dispersibility of 95.0%. In Table 2, sample A corresponds to sample 12 of Table 1. Sample C corresponds to sample 13 of Table 1. Sample D corresponds to sample 18 of table 1. Sample E corresponds to the shows 21 of Table 1, while sample F corresponds to sample 25 of Table 1. The aluminum phosphate particles described here demonstrate unique properties. For example, aluminum phosphate particles have voids, even when the particles are dried at room temperature, or at temperatures above 130 ° C. Preferably, the particles are dried between 40 ° C and 130 °. More preferably, the particles are dried between 60 ° C and 130 ° C. Even more preferably, the particles are dried between 80 ° C and 120 ° C. Added to this, the aluminum phosphate particles have a core and shell structure. In other words, these particles have chemically different shells relative to their nuclei. This property is evidenced by several observations. First, the energy-filtered inelastic electron images of the particles in the plasmon region (10-40 eV), as measured in the electron-transmission microscope, show bright lines surrounding most of the particles. The contrast observed in the plasmon micrographs depends on the local chemical composition, and in this sense, a nucleus and shell structure can be observed when examining the micrograph in Figure 1. Then, the presence of holes in the particles, as shown in Figure 1, dried at somewhat low temperatures due to the fact that the particles lose weight by deflation, while their coverages do not experience the contraction. Such holes or hollow particles are feasible if the plasticity of the core of the particle is greater than that of the shell. Additional indications of the formation of hollow particles are observed by heating the particles by concentrating electron chains in the particles. Large gaps are created within the particles, while their perimeter experiences small changes. Also in addition to the indication of the presence of closed holes, or hollow particles, is the apparent density of aluminum phosphate prepared by the process described here, which is in the range of 1.73-2., 40 g / cm3 when it is measured after drying at 110 ° C at constant weight and having a water content of approximately 15-20%, when compared to the values of 2.5-2.8 g / cm3 recorded for the dense aluminum phosphate particles. Preferably, the bulk density is less than 2.40 g / cm 3. More preferably, the bulk density is less than 2.30 g / cm 3. More preferably, the bulk density is less than 2.10 g / cm3. Even more preferably, the bulk density is less than 1.99 g / cm 3. The aluminum phosphate particles, prepared according to the process described herein, can be dispersed in latex in the presence of crystalline solid particles. If a film is deposited using this dispersion, a highly opaque film is produced. This opacity of the films occurs even in the case of using simple thin layers of particles. Experimental evidence for opaque films is obtained using aluminum phosphate, polyphosphate or metaphosphate (or mixture thereof) as a replacement for titanium dioxide (ie, Ti02). Titanium dioxide is the standard pigment commonly used as a white pigment by most manufacturers in connection with formulations of latex paints. The acrylic paints and the latex-styrene paints were prepared using a usual charge of titanium dioxide and this was compared to a paint in which fifty percent of the charged titanium dioxide was replaced by amorphous aluminum phosphate. This comparison was made in two different paint testing laboratories. Optical measurements taken from the films applied using the paints showed that aluminum phosphate replaces titanium dioxide producing white films while preserving the optical properties of the film. The results and the high effectiveness of the novel aluminum phosphate described herein are related in part to its relatively small particle size. Such small particle sizes allow the particles to be distributed extensively in the film and associate intimately with the resin and with the inorganic fillers of the paints, thereby creating clusters which are sites for the extensive formation of voids when the paint dries. The present aluminum phosphate shows this tendency to form Closed voids, or hollow particles, to a degree that has not been previously observed in polyphosphates, aluminum phosphates or any other particle. In some embodiments, the aluminum phosphate, polyphosphate or metaphosphate particles are substantially free of open pores while containing a number of closed pores. As a result, in such embodiments, the volume of "macro-pore" is substantially greater than 0.1 cm 3 / gram. The opacity of water-based paint films using aluminum phosphate in some embodiments of the present invention involves unique characteristics. The wet film is a viscous dispersion of polymer particles, aluminum phosphate, titanium dioxide and fillers. When this dispersion is applied to a film and dried, it behaves differently from a standard paint (below the critical concentration of the pigment volume, CPVC). In a standard paint, the low glass transition temperature (Tg) makes the resin plastic at room temperature and coalescent, so that the resin film fills pores and voids. A paint formulated with aluminum phosphate, however, can exhibit a different behavior. The pores in closed form, as described here, contribute to the coverage power of the film. The aluminum or polyphosphate phosphate in pigments can be prepared and used in at least one of the following forms; a dense pulp (high solids dispersion, which flows under the action of gravity or low pump pressure) with 18% or more solids; as micronized aluminum phosphate with 15-30% humidity; and also in polymeric form as micronized and calcined aluminum polyphosphate. Aluminum phosphate, aluminum polyphosphate or aluminum metaphosphate (or mixture thereof), used as a white pigment, can replace titanium dioxide in dispersions in aqueous media, such as polymer latex emulsions. The ratio or molar ratio phosphorus: aluminum of the aluminum phosphate is preferably between 0.6 and 2.5. More preferably, the phosphorus: aluminum molar ratio of aluminum phosphate is in the range of 0.8 to 2.3. Even more preferably, the phosphorus: aluminum molar ratio of aluminum phosphate is in the range of 1.1 to 1.5. As discussed, one aspect of the present invention is a novel process for producing hollow aluminum phosphate particles., aluminum polyphosphate, aluminum metaphosphate (or combination thereof) that can be used in different applications, including white pigments in the formulations of aqueous polymeric latex-based paints. The process is described in the following general steps. A person skilled in the art will recognize that certain steps can be altered or omitted altogether. These steps include: the preparation of major reagents used in the process, such as dilute solutions of phosphoric acid, dilute solutions of aluminum sulfate, and dilute solutions of sodium hydroxide sodium carbonate and dilute solutions of sodium hydroxide sodium carbonate, potassium hydroxide or ammonium hydroxide; simultaneous and controlled addition of the reagents in a reactor equipped with an agitator system to maintain the homogeneity of the mixture during the process; control of temperature and ph (acidity) of the mixture during the addition of the reactants in the reactor and, mainly the reaction time; filtration of the suspension, with approximately 8.0% solids and separation of the liquid and solid phases, in an appropriate equipment; washing impurities present in the filtered cake with a slightly alkaline aqueous solution; dispersion of the washed cake, containing about 20-30% solids, in a suitable disperser; pulp drying dispersed in a turbo-dryer; micronization of the dried product at an average particle size of 5.0 to 10 microns; and polymerization of the product dried by heat treatment of the aluminum phosphate in a calciner. There are several ways to prepare the main reagents in this process. As mentioned, a source of phosphorus for the production of aluminum phosphate and aluminum polyphosphate is phosphoric acid of fertilizing quality, of any origin, such as clarified and discolored. For example, a commercial phosphoric acid containing Approximately 54% of P205 can be chemically treated and / or diluted with process water to obtain a 20% concentration of P205. Also, as an alternative to this process (instead of phosphoric acid of fertilizer quality or purified phosphoric acid), phosphorus salts such as orthophosphates, polyphosphates or metaphosphates can be used. Another reagent for the process is commercial aluminum sulfate. Aluminum sulfate can be obtained from the reaction between alumina (aluminum oxide hydrate) with concentrated sulfuric acid (98% H2SO4), and then clarified and stored at a concentration of 28% Al203. In order for the reaction to have favorable kinetics, the aluminum sulphate is diluted with 5.0% Al203 process water. As an alternative to this process, the aluminum source can be any other aluminum salt, such as aluminum hydroxide or aluminum in its metallic form. The neutralization of the reaction is carried out with a sodium hydroxide solution, which can be obtained commercially in different concentrations. A 50% concentration of NaOH can be purchased and dissolved. For example, in the first phase of the reaction, when the initial reactants begin to be mixed, sodium hydroxide can be used in the concentration of 20% NaOH. In the second phase of the reaction, due to the need for a fine adjustment of the acidity of the product, a solution of sodium hydroxide with 5.0% NaOH Can be used. As an alternative neutralizer, ammonium hydroxide or sodium carbonate (soda solvay) can be used. In one embodiment of the present invention, a chemical reaction results in the formation of hydroxoaluminium orthophosphates, pure or mixed (ie Al (OH) 2 (H2P04) or Al (OH) (HP04) .The reaction described, is performed through of the mixture of the three reagents, ie phosphoric acid solution, aluminum sulfate solution and sodium hydroxide solution The reagents are dosed in a reactor, typically containing a stirring system, for a period of 30 minutes. the addition of reagents in the reactor, the pH of the mixture is controlled within a range of 1.4 to 4.5 and a reaction temperature between 35 ° C and 40 ° C. The reaction is completed after 15 minutes of the mixture of The reagents In this period, the pH of the mixture can be adjusted between 3.0 and 5.0, with the addition of more dilute sodium hydroxide., the temperature is preferably less than about 40 ° C. At the end of the reaction, the suspension formed may contain a molar index between the phosphorus elements: aluminum in the range of 1.1 to 1.5. After the formation of aluminum orthophosphate, the suspension is pumped to a conventional press filter containing about 6.0% to 10.0% solids, with an approximate maximum temperature of 45 ° C, a density in a range of 1.15 to 1.25 g / cm3. In the press filter, the liquid phase (sometimes referred to as the "liquor") is separated from the solid phase (often referred to as "cake"). The wet cake, containing about 18% to 45% solids, and having the possibility of still being contaminated with the sodium sulfate solution, is maintained in the filter for a wash cycle. The filtered concentrate, which is basically a concentrated solution of sodium sulfate, is extracted from the filter and stored for future use. In one embodiment of the present invention, the washing of the wet cake is performed in the same filter and in a three-stage process. The first washing ("scrubbing wash") the larger particles of the filtered substance that contaminate the cake are removed. The washing step is carried out using process water on the cake in a flow rate of 6.0 m 3 of water / dry cake ton. A second stage of washing, also using process water and with a flow of 8.0 m3 of water / ton of dry cake, can be done to further reduce, if not eliminate, the contaminants. Finally, a third washing step using a mild alkaline solution can be carried out. Said third washing step can be carried out for the neutralization of the cake and to maintain its pH in the range of 7.0. Finally, the cake can be ventilated with compressed air for a certain period of time. Preferably, the wet product has between 35% to 45% solids.

Then, in this particular embodiment of the invention, it is possible to proceed to the dispersion of the cake in such a way that the filtered cake, wet and washed, and containing approximately 35% solids, is extracted from the filter press by a conveyor belt and transferred to a reactor / disperser. The dispersion of the cake is aided by the addition of a dilute solution of tetra-sodium pyrophosphate. After the dispersion stage, the product is then dried, when the aluminum phosphate "pastes" or becomes denser, with a percentage of solids within the range of 18% to 50%, it is pumped to the drying unit. In one embodiment, the removal of water from the material can be done with the drying equipment, such as a "turbo dryer" through the injection of a stream of hot air, at a temperature between 135 ° C to 140 ° C , through the sample. The final moisture of the product may preferably be maintained in the range of 10% to 20% water content. In certain embodiments of the present invention, the next step of the process may include the calcination of the product. In this stage, the orthophosphate of the dried aluminum, such as Al (H2P04) 3, is condensed by a heat treatment to form a hollow aluminum polyphosphate, where (Al (n + 2) / 3 (PnO (3n + 1)), where "n" can be any integer greater than 1, preferably, n is greater than or equal to 4. More preferably, n is greater than or equal to 10. Even more preferably, n is greater or equal to 20. Preferably n is less than 100. Even more preferably, n is less than 50. This process step is performed by heating the aluminum phosphate, in a dry pulverized type calciner, at a temperature in the range of 500 ° C to 600 ° C. After polymerization, the product can be cooled quickly and sent to the micronization unit. At this time, the micronization stage can be performed. Finally, the resulting product that comes out of the dryer (or the calciner) is transferred to the crusher and finishing unit, falling into a micronizer / classifier, and maintaining the granulometry between the range of 99.5% and less than a 400 mesh. Aluminum phosphate or aluminum polyphosphate, after heat treatment, can be applied as a white pigment in the formulation of water-based paints for the home, due to its self-opacity properties in latex, PVA, and acrylic films , thanks to the formation of particles with hollow structures with high light scattering capacity, during the painting drying process. A variety of paints can be formulated using the aluminum phosphate or polyphosphate made in accordance with various embodiments of the present invention as a pigment, either alone or in combination with another pigment such as titanium dioxide. A paint comprises one or more pigments and one or more polymers as a binder (sometimes referred to as "polymer binder "), and optionally several additives.There are water-based paints and non-water based paints.A water-based paint is generally composed of four basic components: binder, aqueous support, pigment (s) and additive (s). Binder is a non-volatile resinous material that is dispersed in an aqueous support to form a latex When the aqueous support evaporates, the binder forms a paint film that binds the pigment particles and other non-volatile components of the composition to water. Water-based paint compositions can be formulated in accordance with the methods and components disclosed in US Pat. No. 6,646,058, with or without modifications.The citation of said patent is hereby incorporated by reference.Polyphosphate of aluminum or polyphosphate produced from According to various embodiments of the present invention it can be used to formulate water-based paints as a pigment, either alone or in combination with the titanium dioxide. A common type of paint is latex paints which comprise a binder polymer, a cover pigment and optionally a thickener and other additives. Once again, the aluminum phosphate or polyphosphate made according to various embodiments of the present invention can be used to formulate a pigment for latex paints, alone or in combination with titanium dioxide. Other components for making a latex paint are described in US patents 6,881,782 and 4,782,109, which are incorporated in the present by reference in its entirety. Illustratively, the available components and methods for making latex paints are briefly explained below. In some embodiments, the available binder polymers include emulsions of unsaturated monomers copolymerized, ethylenically including 0.8% to 6% fatty acid, acrylate or methacrylate such as lauryl methacrylate and / or stearyl methacrylate. Based on the weight of the ethylenically copolymerized monomers, the binder polymer comprises 0.8% to 6% fatty acid methacrylate or acrylate wherein the preferred compositions contain between 1% to 5% fatty acid acrylate or methacrylate having an aliphatic fatty acid chain with 10 to 22 carbon atoms. Preferred copolymer compositions are based on copolymerized methacrylate fatty acid. Preferred are lauryl methacrylate and / or stearyl methacrylate, lauryl methacrylate being the most preferred monomer. Other useful fatty acid methacrylates include myristyl methacrylate, decyl methacrylate, palmitic methacrylate, oleic methacrylate, hexadecyl methacrylate, cetyl methacrylate and eicosyl methacrylate and similar linear chains of aliphatic methacrylates. Methacrylates or fatty acid acrylates typically comprise commercial fatty oils having reacted with methacrylic acid or acrylic acid to provide primarily a portion of the fatty acid methacrylate with a lower amount of other acid acrylates or methacrylates.

Unsaturated ethylenically polymerizable monomers contain unsaturated carbon-carbon and include vinyl monomers, acrylic monomers, allylic monomers, acrylamide monomers, and unsaturated mono and di-carboxylic acids. Vinyl esters include vinyl acetate, vinyl propionate, vinyl butyrates, vinyl benzoates, isopropyl vinyl acetates and similar esters; vinyl halides including vinyl chloride, vinyl fluoride and vinylidene chloride, vinyl aromatic hydrocarbons including styrene, methyl styrene and the like alkyl styrene, chlorostyrene, vinyl toluene, vinyl naphthalene and divinyl benzene; aliphatic vinyl hydrocarbon monomers including alpha olefins such as ethylene, propylene, isobutylene, and cyclohexene as well as conjugated dienes such as 1,3-butadiene, methyl-1,2-butadiene, 1,3-pentadiene, 2,3-dimethyl-butadiene, isoprene, cyclohexane, cyclopentadiene and dicyclopentadiene. Vinyl alkyl ethers include methyl vinyl ether, vinyl isopropyl ether, vinyl n-butyl ether and vinyl isopropyl ether. The acrylic monomers include monomers such as low alkyl esters of methacrylic or acrylic acid having an alkyl ester portion containing from 1 to 12 carbon atoms such as aromatic derivatives of acrylic and methacrylic acid. Useful acrylic monomers include, for example, methacrylic and acrylic acids, methyl acrylate and methacrylate, ethyl acrylate and methacrylate, butyl acrylate and methacrylate, propyl acrylate and methacrylate, 2-ethyl hexyl acrylate and methacrylate, cyclohexyl acrylate and methacrylate, decyl acrylate and methacrylate, isodecyl acrylate and methacrylate, benzyl acrylate and methacrylate and various reaction products such as butyl phenyl, and cresyl glycidyl ethers reacted with methacrylic and acrylic acids, hydroxy alkyl acrylates and methacrylates such as hydroxyethyl and hydroxypropyl acrylates and methacrylates, such as amino acrylates and methacrylates. The acrylic monomers may include much less acrylic acids including methacrylic and acrylic acids, ethacrylic acid, alpha-chloroacrylic acid, alpha-cyanoacrylic acid, crotonic acid, beta-acryloxy propionic acid and beta-styryl acrylic acid. In other embodiments, the polymers useful as component (a), the "binder polymer", of the latex paints are copolymerization products of a mixture of co-monomers which comprise monomers selected from styrene, methyl styrene, vinyl, or combinations of the same. Preferably the co-monomers comprise (more preferably consist essentially of) at least 40 mole percent of monomers selected from styrene, methyl styrene, or combination thereof and at least 10 mole percent of one or more monomers selected from acrylates, methacrylates and Acrylonitrile Preferably, the acrylates and methacrylates contain from 4 to 16 carbon atoms such as, for example, 2-ethylhexyl acrylate and methyl methacrylate. It is also preferable that the monomers be used in a proportion such that the final polymer has a glass transition temperature (Tg) greater than 21 ° C and lower than 95 ° C. The polymers preferably have an average molecular weight of at least 100,000. Preferably, the binder polymer comprises interpolymerized units derived from 2-ethylhexyl acrylate. More preferably, the binder polymers comprise polymerized units comprising from 50 to 70 mole percent of units derived from styrene, methyl styrene or combinations thereof; from 10 to 30 percent in moles of units derived from the methyl acrylate, acrylonitrile or combination thereof. Illustrative examples of available binder polymers include copolymers whose interpolymerized units are derived from about 49 mole percent styrene, 11 mole percent alpha-methylstyrene, 22 mole percent 2-ethylhexyl acrylate, and 18 mole percent methyl methacrylate with a Tg of about 45 ° C (available as Neocryl XA-6037 polymer emulsion from ICI Americas, Inc. Bridgewater, NJ, United States); a copolymer whose units are derived from about 51 weight percent styrene, 12 weight percent a-methylstyrene, 17 weight percent 2-ethylhexyl acrylate, and 19 weight percent methyl methacrylates with a Tg of about 44 ° C (available as Joncryl 537 polymer emulsion of S.C. Johnson & Sons, from Racine, Wisconsin, United States); and a terpolymer whose interpolymerized units are derived from about 54 percent by moles of styrene, 23 percent by moles of 2-ethylhexyl acrylate, and 23 percent by moles of acrylonitrile with a Tg of about 44 ° C (available as a Carboset XPD polymer emulsion) -1468 from Goodrich Co.). Preferably the binder polymer is Joncryl 537. As described below, the aluminum phosphate, polyphosphate and metaphosphate produced according to various embodiments of the present invention can be used to formulate a latex paint pigment, alone or in combination with other pigments. . Other additional coating pigments include opacifying white coating pigments and colored organic and inorganic pigments. Representative examples of available opacifying white copper pigments include rutile titanium dioxide and anastase, lithopon, zinc sulphide, lead titanate, antimony oxide, zirconium oxide, barium sulphide, white lead, zinc oxide, pigment oxide compound of zinc and basic lead sulfate and the like, as well as mixtures thereof. A preferred organic white pigment is rutile titanium dioxide. More preferably rutile titanium dioxide having an average particle size between about 0.2 to 0.4 microns. Examples of colored organic pigments are phthalo blue and yellow hansa. As an example of colored inorganic pigments are red iron oxide, brown oxide, ocher, and dark ocher. The most known latex paints contain thickeners to modify the rheological properties of paints and ensure good dispersion, application and handling characteristics. Available thickeners include a non-cellulosic thickener (preferably, an associative thickener, more preferably, an associative urethane thickener). Associative thickeners such as, for example, hydrophobically modified acrylic alkali swellable copolymers, and hydrophobically modified urethane copolymers generally impart greater Newtonian rheology to emulsified paints compared to conventional thickeners such as, for example, cellulosic thickeners. Representative examples of available associative thickeners include polyacrylic acids (available for example from Rohm &Hass Co., Philadelphia, Pennsylvania, United States, such as Acrysol 825 and rheologically modified QR-708) and activated attapulgite (available from Engelhard, Iselin, NJ, United States as Attagel 40). Latex-paint films are formed by the coalescence of the binder polymer to form a bonded matrix at an ambient temperature of paint application forming a hard film and free of stickiness. The coalescing solvents help the coalescence of the binder film formation by lowering the film forming temperature. Latex paints preferably contain coalescing solvents. Some representative examples of available coalescent solvents include 2-phenoxyethanol, diethylene glycol butyl ether, dibutyl phthalate, diethylene glycol, 2,2,4-trimethyl-1,3-pentanediol monoisobutyrate and combinations thereof. Preferably, the coalescing solvent is diethylene glycol butyl ether (butyl carbitol) (available from Sigma-Aldrich, Milwaukee, Wisconsin, United States) or 2,4,4-trimethyl-1,3-pentanediol monoisobutyrate (available from Eastman Chemical Co. , Kingsport, Tennessee, United States, like Texanol), or combinations thereof. The coalescing solvents are preferably used at levels of between 12 to 60 grams (preferably 40 grams) of coalescing solvent per liter of latex paint or about 20 to 30 weight percent based on the weight of solid polymers in the paint. Paints formulated in accordance with various embodiments of the present invention may further comprise conventional materials used in paints such as, for example, plasticizers, anti-foaming agents, pigment extenders, pH correctors, dye inks, and biocides. These typical ingredients are listed, for example, in the document "TECHNOLOGY OF PAINTS, VARNISHES AND LACQUERS, edited by C. R.

Martens, R.E. Kreiger Publishing Co. , p. 515 (1974). Paints are commonly formulated with "functional extenders" to increase coverage, reduce cost, allow durability, alter appearance, control rheology and influence other desirable properties. Examples of functional extenders include, for example, barium sulfate, calcium carbonate, clay, gypsum, silica, and talc. The most common functional extenders for interior paints are clays. Clays have a number of properties that make them desirable. Cheap calcined clays, for example, are useful in controlling low viscosity indexes and have a large surface area, which contributes to "dry skin". But, the surface area is also tending to catch spots. Because this tendency to absorb dirt or stains, it is preferable that the calcined clays be used in the paints of the present invention only in small quantities required for rheological control, for example, typically less than half of the total of the extender pigments, they are not used at all. Preferred extenders for use in the paints of the present invention are calcium carbonates; more preferably they are ultra fine milled calcium carbonates such as, for example, Opacimite (available by ECC International, Sylacauga, Alabama, United States), Supermite (available from Imerys, Roswell, Georgia, United States), or others with a particle size of approximately 1.0 to 1.2 microns. The ultra-fine calcium carbonate helps to space the titanium dioxide optimally to cover (see, for example, KA Haagenson, "The effect of extending particles size on the hiding properties of an interior latex fíat paint," American Paint &Coatings Journal, Apr. 4, 1988, pp. 89-94). Latex paints formulated according to a variety of embodiments of the present invention can be prepared for use with conventional techniques. For example, some of the ingredients in the paints are usually mixed under high stresses to form a mixture commonly referred to by the paint formulators as "the grind." The consistency of this mixture is comparable to that of an aqueous paste, which is desirable in terms of efficiently dispersing the ingredients with a high-shear agitator. During the preparation of the grind, energy of shear stresses is used to break up agglomerated pigment particles. The ingredients not included in the grind are commonly referred to as "the rest". This remainder is usually much less viscous than the grind, and is usually used to dilute the grind to obtain a final paint with the proper consistency. The final mix of the grind with the rest it is typically a mixer with low cutting voltages. Most polymer latexes are not stable at shear stresses, and therefore are not used as a component in grinding. The incorporation of unstable latexes to shear stresses in the milling can result in the coagulation of the latex, forming a lumpy paint with little or no capacity to form film. Consequently, the paints are usually prepared by adding latex polymer in the rest. However, the same paints formulated according to various embodiments of the invention contain latex polymers that are generally stable to shear stresses. Therefore, latex paints can be prepared by incorporating some or all of the latex polymer into the grind. Preferably, at least some of the latex polymer is placed in the mill. Two examples of possible ways that the process can take are described below. Once again, it is emphasized that a person skilled in the art will be able to recognize variants that can be used to carry out the novel process described here. The following examples are presented to exemplify embodiments of the invention. All numerical values are approximate. When some numerical ranges are given, it should be understood that while embodiments may be outside these ranges they may be kept within the scope of the present invention. The specific details described in each example should not necessarily be interpreted as necessary features of the invention. Example 1 In this example, 535.0 Kg of aluminum phosphate were prepared. The product was dried in a "tube-dryer" and having characteristics of hollow particles with 15% humidity and an index of P: A1 (phosphorus: aluminum) of 1: 1.50. 940.0 kg of fertilizer containing 55.0% of P205 were prepared. In the initial preparation phase, an acid discoloration was carried out, which lasted approximately thirty minutes, at a temperature of 85 ° C. For this phase, a solution with 8.7 kg of hydrogen peroxide containing about 50% H202 was added to the acid. Then, the acid was diluted with 975.0 Kg of process water, cooled to a temperature of 40 ° C and then stored at a concentration of 27.0% of P202. The aluminum source used in this application was a commercial aluminum sulfate solution containing 28% Al203. The solution was filtered and diluted with process water. Specifically, 884.30 kg of an aluminum sulfate solution and 1776.31 Kg of process water was combined to create a solution of approximately 9.30% Al203. This particular experiment uses as a neutralizing reagent a diluted commercial sodium hydroxide solution, containing 20.0% NaOH. Specifically, 974.0 Kg of sodium hydroxide solution were mixed with 50% of NaOH and 1,461.0 kg of process water. The final mixture was cooled to 40 ° C. The three reagents were mixed simultaneously, for approximately 30 minutes, in a 7,500 liter reactor. During the addition of reagents in the reactor, the temperature mixture was maintained in the range of 40 ° C to 45 ° C, the pH was controlled to stay in the range of 4.0 to 4.5. At the end of the addition of the reagents, the mixture was kept stirring for approximately 15 minutes. The pH at that time was controlled to approximately 5.0 with the addition of a sodium hydroxide solution containing 5.0% NaOH. The suspension was approximately 7,000 kg with a density of 1.15 g / cm3, presenting 6.5% solids, which represents about 455.0 kg of precipitates. Then, the suspension was filtered on a filter press resulting in 1,300 kg of wet cake and 5,700 kg of filtered liquid. The filtered liquid consists primarily of a solution of sodium sulfate (Na2SO4). The cake consists of approximately 35% solids. The cake was washed, directly on the filter press, with 3.860 liters of process water, at room temperature, beginning to be maintained at a washing rate of about 8.5 cm3 of washing solution per ton of dry cake. The filtrate generated in the cake washer was stored for an optional future use or for effluent treatment. The cake extracted from the filter, near 1,300 kg, was then transferred to a distributor (approximately 1,000 liters) through a conveyor belt. The dispersion, containing approximately 35% solids, having a density of 1.33 g / cm3 and a viscosity of 17.400 cP and can be used as a gouache to make paint. The dispersed suspension of aluminum phosphate, with approximately 35% solids, was then pumped into a turbo-dryer. The product was heated, through a stream of hot air, to a temperature of 135 ° C. About 535.0 kg of aluminum orthophosphate with a moisture content of 15% were produced. The final product was micronized and its granulometry was maintained below a 400 mesh. The final analysis of the dried product presented the following results: the phosphorus content in the product was approximately 20.2%; the aluminum content was approximately 13.9%; the sodium content was approximately 6.9% and the mp of the aqueous dispersion was approximately 7.0; the water content was approximately 15%; the bulk density was 2.20 g / cm3, and the average diameter of the powder particles was between 5 to 10 μm. Example 2 From the results of Example 1, about 200 kg of micronized aluminum phosphate were used. The sample It was used for the production of a sample of paint for the home. Initially, 900 liters of white opaque acrylic paint were prepared. Such painting was applied and its performance was evaluated in comparison with one of the commercially available paints. The basic composition of the paint based on the original formulation with a content of about 18% titanium dioxide was as follows: approximately 14.20% aluminum phosphate; approximately 8.34% titanium oxide; approximately 7.10% kaolin; about 10.36% agalmatolite, about 0.84% diatomite; approximately 12.25% acrylic resin and approximately 47.45% PVC. The characteristics of the paint prepared with aluminum phosphate, after the application of the same in the painting, was as follows: a) wet coverage similar to the coverage of the reference paint; b) dry coverage better than coverage with the reference paint; and c) the resistance tests after six months as home paint showed excellent results. Finally, it was observed that the water-soluble opaque acrylic paint with aluminum phosphate, prepared in Example 2, retained all the characteristics of the commercially available paints with a yield of 50 m2 / 3.6 liters on surfaces prepared with filling. The X-ray images together with the TEM images showed that the invention described here is a hydrated phosphate of neutral and non-crystalline aluminum made freely of aggregate particles of nanometric size. In addition, the average aggregate size of swollen particles (in the aqueous slurry) is in the range of 200-1500 nm, as determined by dynamic light scattering. More preferably, the average aggregate size of swollen particles (in the slurry) is in the range of 400-700 nm. The particle size can individually have a radius as small as 5 to 80 nm, as determined by the electron microscope. More preferably, the particle size individually can have a radius as small as 10 to 40 nm. As will be mentioned, a basic water-based paint with titanium dioxide is made of a convenient latex dispersion and pigment particles. The latex particles are responsible for carrying out the bonding of the coalescing film with the pigment particles, and are responsible for the covering power of the film. A variety of additives are also used, such as: inorganic fillers, which decrease resin and pigment requirements; coalescing agents, which improve the formation of resin film, dispersants and rheological modifiers, which prevent the caking of the pigment and fillers and improve the storage time together with the rheological properties. In a typical dry film paint, the pigment and cargo particles are dispersed in a resin film. The power of coverage is largely dependent on the refractive indices of and particle sizes. As mentioned, titanium dioxide is the most commonly used white pigment due to its high refractive index and the absence of light absorption in the visible region. A dry film of paint formulated with the novel aluminum phosphate in some embodiments has marked differences from a dry film of traditional paint. First, the film with aluminum phosphate is not exactly a resinous film. This, in general, is formed by a mesh of resin and aluminum phosphate. It is thus a nanocomposite film that combines two inter-penetrating phases with different properties to achieve synergistic advantages, with respect to mechanical properties of the film and resistance to water or other aggressions. Second, the good coverage power of the film is obtained with low titanium dioxide contents, because the film contains a large number of closed pores that scatter light. On the other hand, if a particle of titanium dioxide is adjacent to one of these holes, it will disperse much more than if it is completely surrounded by the resin, due to the larger gradient of the refractive index. This creates a synergy between the novel aluminum phosphate and titanium dioxide, so much that concerns the power of coverage. In comparative tests a standard paint of dried film with respect to a film with phosphate of Aluminum, a standard market formulation of a semi-matt acrylic paint was selected and the titanium dioxide was progressively replaced by the novel aluminum phosphate product described herein. The water content and other paint components were adjusted as necessary. Many of the modifications in the formula in this embodiment relate to a decrease in the use of thickener / rheology modifiers, dispersants, acrylic resins and coalescing agents. Table 3 describes an example of one of the formulas used in this experiment, together with the corresponding formulas for the novel aluminum phosphate.

Table 3. A standard formula for paint commonly used in the market and the corresponding formula using aluminum phosphate. The quantities are given in grams In the previous formula, a 50% replacement of Ti02 (based on weight) was performed, maintaining the conditions of opacity and whiteness of the dry film. Added to this, the other properties of the novel product such as a rheological modifier and also as a film structuring agent were experienced. The comparison between the two formulas above shows that the pigments made with the embodiments of the present invention also accompanied with a reduction of the Additional cost that resulted from the replacement of the titanium dioxide pigment, on the other hand, such gains can be obtained during the production of a better performance in the applied paint film. The invention described herein may also be used for the replacement of up to, and including, 100% Ti02 by aluminum phosphate, aluminum polyphosphate, aluminum metaphosphate (or mixture thereof). It can be observed from the preceding description of the different embodiments of the present invention that the process and the product, both novel, differ from the existing aluminum phosphates, polyphosphates or metaphosphates in many aspects. For example, since the stoichiometry is not defined, various formulations of the invention can be prepared by changes in the manufacturing process and thus the final composition. Because the invention is carried out under controlled levels of pH, this is close to neutral and thus avoiding environmental and toxicological problems. Additionally, the invention may also be free of corrosion problems associated with some aluminum phosphates found on the market and used in the transformation of iron oxides into iron phosphates. In addition, the need for no stoichiometric ratio together with the relative non-crystallinity (both in the state or form of wet paste and powder) and the carefully controlled water content of the dry powder allow easy control of swelling which is beneficial for its performance. The particles carried to nanometric size are easily dispersed and stable before decantation, which allows a uniform dispersion in the paint. In addition, nanoparticles can be highly compatible with latex particles, by means of capillary adhesion mechanisms (in the dry dispersion state) followed by ion clustering by electrostatic adhesion (in dry films), in many cases, bicontinuous networks can be formed. Finally, the novel product is also highly compatible with any other particulate solids commonly used as paint fillers, such as various silicates, carbonates and oxides found in water-based dispersions, which may contribute to the cohesion and strength of the dry paint film. In this way, the invention described here uses a different raw material that offers alternative benefits, making the process more economical and offering surprising results. Described here is the purification, decolorization and purification of a phosphoric acid, widely available in the fertilizer industry. Phosphoric acid is generally available at a price that results in a fraction of the price of the phosphates or metaphosphates previously used. While phosphoric is the raw material that typically presents the high price used in the manufacture of manufactured aluminum phosphate pigments, the use of an acid grade allows a significant reduction in the manufacturing costs of aluminum phosphates. This process makes the wide adoption of these pigments feasible. Added to this, certain features of the invention described herein present new ways to use aluminum phosphates, either in the form of a dispersion or in the form of a wet powder. These new methods allow important technological advances. For example, novel methods and products prevent problems of particle aggregation, which impairs performance and reduces its coverage power. In addition, the novel method and product eliminates problems of particle dispersion in latex particles used in the manufacture of water paints, facilitating the processed use of aluminum phosphate in household paints. In addition, novel processes and products do not require excessive steps or stages of phosphate drying, which would increase the complexity and cost of manufacturing. Another beneficial aspect of the novel process described here is that it can be considered "chemically ecological" or product of zero effluents, because it is carried out under conditions of mild temperatures and pressures that do not create environmental problems during the manufacturing process. Due to its chemical nature, the waste created by the novel process described can be disposed of safely in the environment as a component of the fertilizer. This is produced as a wet paste as well as a dry powder. In both cases it disperses easily in water, forming stable dispersions that have stable rheological characteristics. As demonstrated above, embodiments of the invention provide a novel method of making amorphous aluminum phosphate. While the invention has been described with respect to a limited number of embodiments, the specific features of one embodiment should not be attributed to other embodiments of the present invention. None of the embodiments is entirely representative of the present invention. In some embodiments, the compositions or methods may include numerous components or steps not mentioned herein. In other embodiments, the compositions or methods do not include, or are substantially free of, any components or steps not listed herein. There are variations and modifications of the realizations. The method of producing the resins is described as covering a number of acts or stages. These stages or acts can be performed in any sequence or order unless otherwise indicated. Finally, any number disclosed here should be interpreted as approximate, beyond the terms "near" and "approximately" are used in the description of the numbers. The appended claims seek to cover all modifications and variations within the scope of the present invention.

Claims

CLAIMS 1. An aluminum phosphate composition comprising aluminum phosphate, aluminum polyphosphate, aluminum metaphosphate or a mixture thereof, wherein the composition includes particles, and at least some of the particles, when in a powder state. , have an average of one or more gaps closed per particle, and the composition is further characterized because: (a) in powder state, exhibits two endothermic peaks in differential scanning calorimetry between about 90 ° C and about 250 ° C; and (b) in a powder state, has a water dispersibility of at least 0.025 grams per 1.0 gram of water. The composition according to claim 1, wherein said first endothermic peak in differential scanning calorimetry occurs between 90 ° C and 120 ° C, and said second endothermic peak occurs between 150 ° C and 180 ° C. 3. The composition according to claim 1 wherein no peak is exhibited between about 335 ° C and 345 ° C in differential scanning calorimetry. 4. The composition according to claim 1, further comprising an ion. 5. The composition according to claim 1, further comprising sodium. 6. The composition according to claim 1, which also includes potassium. The composition according to claim 1, further comprising ammonium. 8. A paint, varnish, lacquer, printing ink or plastic, containing the composition of claim 1 as an ingredient. 9. The composition according to claim 1, wherein the composition, in fluid form, has a pH in the range of about 3.0 and about 7.5. 10. The composition according to claim 1 wherein the composition is obtained by contacting a combination of materials containing phosphoric acid, aluminum sulfate and alkaline solution. The composition according to claim 1 wherein the composition is characterized by a bulk density less than 2.40 grams per cubic centimeter, and wherein the average particle radius of the individual particles of dry powder is between 10 to 100 nanometers . 12. A paint comprising a solvent and an aluminum phosphate composition, comprising: aluminum phosphate, aluminum metaphosphate or a mixture thereof, wherein the composition includes particles and at least some of the particles, when in the form of powder, present an average of one or more gaps closed per particle, and the composition is also characterized because: (a) in powder state, exhibits two endothermic peaks in Differential Scanning Calorimetry between about 90 ° C and about 250 ° C; and (b) in a powder state, has a water dispersibility of at least 0.025 grams per 1.0 gram of water. The paint according to claim 12, wherein said paint also comprises titanium dioxide in a reduced amount. 14. The paint according to claim 12, wherein said composition does not exhibit peaks between about 335 ° C and 345 ° C in differential scanning calorimetry. 15. The paint according to claim 12, wherein said paint is substantially free of titanium dioxide. 16. The paint according to claim 12, wherein said solvent comprises water. 17. The paint according to claim 12, wherein said solvent comprises a polar solvent. 18. The paint according to claim 12, wherein said solvent comprises a non-polar solvent. 19. The paint according to claim 12, wherein said solvent comprises an organic solvent. 20. A method for producing a paint, comprising the following steps: combining a solvent and a composition, wherein said composition comprises: a phosphate composition of aluminum comprising: aluminum phosphate, aluminum polyphosphate, aluminum metaphosphate or mixture thereof, wherein the composition includes particles and at least some of the particles, being in powder form, have an average of one or more voids closed by particle, and the composition is further characterized because: (a) in powder state, exhibits two endothermic peaks in differential scanning calorimetry between about 90 ° C and about 250 ° C; and (b) in a powder state, has a water dispersibility of at least 0.025 grams per

1.0 gram of water.