Synthetic hydrotalcites, syntheses and uses

In general, the present invention relates to novel synthetic hydrotalcites and their synthesis and use. The synthetic hydrotalcite of the present invention is C.₄Making from longer organic anions is also C₆, C₈, C₁₀, And C₁₈Functional groups containing aromatics such as linear acid saturated carboxylates, benzoates, chlorobenzoates, naphthoates, and p-hydroxybenzoates, carboxylates of acrylics and methacryl and vinylacetic acids, and mixtures of these organic anions. It can also be made from organic anions that it has. The synthetic hydrotalcites of the present invention are also C.₂It can also be made from carboxylic acid salts of higher organic acids containing heteroatoms such as nitrogen, sulfur, phosphorus and halogens.

Hydrotalcite is a derivative of bluesite, a naturally occurring, layer-forming magnesium hydroxide mineral. Synthetic hydrotalcite can be made by substituting some magnesium cations normally present in the layer with trivalent metal cations such as aluminum. The magnesium cation can also be replaced with another divalent cation. As a result of the deduction by this substitution, the charge in the layer becomes positive, so it is necessary to intercalate one anion to neutralize the charge of the molecule. The general chemical formula of synthetic hydrotalcite is described below. [M²⁺_1-xM³⁺_x(OH)₂]^{x +}[A^n-_{x / n}(mH₂O]^x-In the above chemical formula, M²⁺Is magnesium and / or other divalent cations, M³⁺Is aluminum and / or other trivalent cations, A^n-Is an anion. It should be noted that in addition to the anion, water is also part of the lattice structure.

U.S. Pat. No. 5,399,329, issued to Schutz et al. And assigned to the assignee of the invention, describes a group of hydrotalcites with unique sheet-like morphology. The full text of Schutz's '329 patent is incorporated by reference in the present invention. Schutz's '329 patent hydrotalcite is C₁From C₄Has an anion derived from the saturated carboxylic acid of. General methods of synthesis in Schutz's '329 patent include the reaction of a carboxylic acid with an alumina source in water and the resulting reaction with a magnesium source. The molar ratio of reagents is approximately Mg2: Al1: anion 1. The anion is the carboxylic acid salt of the acid used.

Hexagonal morphology is commonly observed with non-carboxylate anion hydrotalcites, but Schutz's '329 patent carboxylate anion hydrotalcites are referred to as "sheet-like" in the patent. Shows a peculiar morphology. The layer spacing of hydrotalcite as measured by the intercalation depends on the size of the intercalating anions. For example, the interplanar spacing of formate hydrotalcite made from the following anions, produced by the Schutz '329 patented method, is formate 7.64A, acetate 12.3A, propionate 13.02A, and isobutyric acid. Salt 15.15A.

In the Schutz'329 patent, alumina is reacted with a carboxylic acid at about 60 ° C for 30 minutes in an aqueous solvent, and then magnesium oxide is added at 95 ° C for about 6 hours to prepare a sheet of hydrotalcite. Drying of the reaction product gives the desired gelled hydrotalcite. The method of the Schultz '329 patent is C₁From C₄Most of the time, water-soluble carboxylic acids such as carboxylic acids are relatively successful, but water-insoluble acids are difficult. In fact, using the method of the Schutz '329 patent, C₄Butyric acid, the acid, has had some success.

Hydrotalcite has many uses, including applications such as catalysts or catalyst precursors, ion exchangers, ion absorbers, ion scavengers, and medical applications as antacids. Hydrotalcite is also used as a nanocomposite to be included in polymers to enhance various properties. There is a description in the prior art that hybrid composites combining polymers with other inorganic components such as clay and mica have improved mechanical properties. It is called a nanocomposite because the nanoscale particles of the hybrid inorganic component in the polymer matrix are dispersed.

According to Japanese patent application No. 96-189168 transferred to Mitsui Petrochemical Ind. Ltd., hydrotalcite containing carbonate anions is used in polypropylene synthesis along with other additives. It means that excellent melt flow index, flexural modulus, and isod impact force were obtained.

According to European Patent No. 0,910,131 transferred to France's AtoChem, natural hydrotalcite containing carbonate anions is used in the ethylene-vinyl acetate copolymer to produce a film with excellent adhesive strength and barrier properties. That is to say.

According to Japanese Patent Application No. 86-296799 transferred to Du-Pont Mitsui Polychemicals Co., Ltd., (Mitsui DuPont Polychemicals Co., Ltd.), natural hydrotalcite containing carbonate anion is linear. It is used for low-density polyethylene, and a film with heat insulating properties and excellent tensile strength was produced.

Strut clays and / or natural hydrotalcites are used for most nanocomposite polymer applications. The composite composition of nylon-6 and 5% clay nanocomposites has been found to exhibit 40% higher tensile strength, 68% higher tensile coefficient, 60% higher bending strength and 126% flexural modulus ( See Int'l.SAMLE Symp.Exhib. 1998, 43: 1053-1066). The nanocomposite is said to be dispersed in the polymer by one of the following two methods. 1) A chaotic method such as by intercalation, or 2) a peeling action in which nanolayers are lined up at regular intervals in the polymer. The peeling action is said to improve the properties of the polymer.

References for various clays modified by combining polar polymers such as polyamide to produce nanocomposites can be found in the patent and scientific literature.

However, introducing nanoparticles into non-polar polymers such as polyolefins to produce nanocomposites is a much more difficult task due to compatibility issues between non-polar polymers and polar nanoparticles. This incompatibility often results in uneven dispersion of inorganic components throughout the polymer, resulting in less than optimal performance. Typically, the non-polar polymer is combined with a similar but chemically modified polymer (eg, polypropylene-g-MA) that has polar functionality to act as a compatible molecule. By doing so, this problem is overcome. The polar functionality of the modified polypropylene can interact with the polarity of the nanoparticles, with non-polar moieties of the modified polypropylene interacting with the polypropylene matrix. Hypothetically, the interaction of the two polar functions provides both exfoliation and adaptation, resulting in a nanocomposite in which nanoparticles are uniformly dispersed.

U.S. Pat. No. 5,973,053 describes a layered composite clay material that introduces organic onium ions and first and second organic "guest" molecules into the space between layers to increase the inter-layer distance. .. The introduction of the organic onium ions acts to increase the compatibility of the clay with the polymer, facilitating the dispersion of the clay in the hybrid composite.

In the Journal of Materials Sciences 35 (2000) 1045-1050, Oya et al. Fitted polypropylene, a polar monomer modified with diacetone acrylamide and maleic acid, in "Factors for Adjusting the Mechanical Properties of Clay Minerals / Polypropylene Nanocomposites" It describes intercalating into clay as an aid. Next, this organic clay is mixed with conventional polypropylene to prepare a nanocomposite. In Macromolecular Material Engineering 275,8-17 (2000), Reichert et al. Intercalated on Kay Clay, "Formation of Poly (Propene) / Organic Clay Nanocomposites: Functionality of Adaptation Aids and Effects of Organic Clay Modification" It describes the case where alkylamine is used as an engineering agent and polypropylene modified with maleic anhydride is used and the case where it is not used.

In this technical field, C₄The need for novel synthetic hydrotalcites made from longer organic anions, and C₆, C₈, C₁₀, C₁₈Functional groups containing saturated carboxylates of linear acids, benzoates, chlorobenzoates, naphthoates, aromatics such as p-hydroxybenzoates, carboxylates of acrylics and methacryl and vinylacetic acids, and mixtures of these organic anions. There is a need for new synthetic hydrotalsites to have. Since these synthetic hydrotalcites can be customized according to the properties desired for polymers made from them, examples of the above-mentioned new synthetic hydrotalcites include applications as nanocomposites in polymer applications. It also contains modified hydrotalcites that can be used in polymer nanocomposites and easily disperse in non-polar polymers without the use of compatible aids, including heteroatoms such as nitrogen, sulfur, phosphorus and halogens.₂There is also a need to make from carboxylic acid salts of organic acids and above.

<p> The present invention is described in [M.²⁺_1-xM³⁺_x(OH)₂]^{x +}[A^n-_{x / n}(mH₂O]^x-To provide a synthetic hydrotalcite having the general chemical formula of M.²⁺Is a divalent cation, M³⁺Is a trivalent cation, A^n-Is C₅~ C₁₈An organic anion selected from a linear carboxylic acid salt, an aromatic acid carboxylic acid salt, an acrylic acid carboxylic acid salt, a methacrylic acid unsaturated carboxylic acid salt, and a vinyl acetic acid unsaturated carboxylic acid salt.</p><p> The present invention also includes [M²⁺_1-xM³⁺_x(OH)₂]^{x +}[A^n-_{x / n}(mH₂O]^x-To provide a synthetic hydrotalcite having the general chemical formula of M.²⁺Is a divalent cation, M³⁺Is a trivalent cation, A^n-Is C₂~ C₄At least two of a group consisting of linear saturated carboxylic acid salts of acids, carboxylic acid carboxylates, acrylic acid carboxylic acid salts, methacrylic acid unsaturated carboxylic acid salts, and vinyl acetic acid unsaturated carboxylic acid salts. An anion with a mixture of members.</p><p> The present invention also includes [M²⁺_1-xM³⁺_x(OH)₂]^{x +}[A^n-_{x / n}(mH₂O]^x-To provide a synthetic hydrotalcite having the general chemical formula of M.²⁺Is a divalent cation, M³⁺Is a trivalent cation, A^n-Contains C containing heteroatoms such as nitrogen, sulfur, phosphorus, or halogens₂Or an organic anion having a carboxylic acid salt of an acid higher than that. According to one embodiment, the hetero atom is nitrogen in the form of an amino acid. In this embodiment, the acidic end of the amino acid is attached to the cationic site of the plate of hydrotalcite such that the amine end interacts with or reacts with the solvent or polymer molecule. Further, in an acid-modified polymer such as maleinated polypropylene, the amine is free to react with the acid moiety of the polymer to form an amide or imide. By this method, the synthetic hydrotalcite can be directly bonded to the polymer. Preferably, the amino acid is a linear alkyl. More preferably, the hydrotalcite intercalated with amino acids can be self-exfoliated and / or reversibly exfoliated. Even more preferably, the amino acid is 4-aminobutyric acid or 6-aminocaproic acid. Modified hydrotalcites or organic hydrotalcites according to the present invention can be used in polymer nanocomposites, and it is not always necessary to use a matching aid to cause dispersion of hydrotalcites throughout the polymer. In embodiments where the synthetic hydrotalcite is self-stripping in a solvent, the synthetic hydrotalcite after synthesis can be maintained as a colloidal suspension without being recovered or dried.</p><p> The present invention further states [M²⁺_1-xM³⁺_x(OH)₂]^{x +}[A^n-_{x / n}(mH₂O]^x-Provided is a method for producing a synthetic hydrotalcite having the general chemical formula of M.²⁺Is a divalent cation source, M³⁺Is a trivalent cation source, A^n-Is C₅~ C₁₈Linear carboxylic acid acidate, aromatic acid carboxylic acid salt, acrylic acid carboxylic acid salt, methacrylic acid unsaturated carboxylic acid salt, vinyl acetic acid unsaturated carboxylic acid salt, and nitrogen, phosphorus, sulfur, halogen C containing such heteroatoms₂It is an organic anion source selected from a carboxylate of an acid having or higher than that, and in the method, the trivalent cation source is reacted with the organic anion source to produce an intermediate product, and the intermediate product is produced by the above-mentioned d. It has a step of reacting with a valent cation source to produce the synthetic hydrotalcite.</p><p> The present invention also includes synthetic hydrotalcite polymer mixtures with polyadditionally polymerized polymers, [M.²⁺_1-xM³⁺_x(OH)₂]^{x +}[A^n-_{x / n}(mH₂O]^x-Provided is a synthetic hydrotalcite having the general chemical formula of M.²⁺Is a divalent cation, M³⁺Is a trivalent cation, A^n-Is C₅~ C₁₈Linear carboxylic acid acidate, aromatic acid carboxylic acid salt, acrylic acid carboxylic acid salt, methacrylic acid unsaturated carboxylic acid salt, vinyl acetic acid unsaturated carboxylic acid salt, and nitrogen, phosphorus, sulfur, halogen C containing such heteroatoms₂An organic anion selected from carboxylic acid salts of or higher acids. According to one preferred embodiment, the organic anion of the synthetic hydrotalcite is an amino acid. More preferably, the amino acid is an amino acid that promotes self-exfoliation and / or reversible exfoliation of the hydrotalcite. In addition, the polymer can be modified or functionalized with, for example, maleic acid. In an embodiment having an acid-modified or functionalized polymer, an amino acid intercalated hydrotalcite and the polymer, and an amide or imide produced by the reaction of the acid-modified polymer with the amine functional group. Can be combined through.</p><p> The present invention also provides [M] to obtain the mixture.²⁺_1-xM³⁺_x(OH)₂]^{x +}[A^n-_{x / n}(mH₂O]^x-Provided is a method for producing a synthetic hydrotalcite / polymer mixture having a step of mixing an emulsion having a polyaddition polymerization polymer having a polyaddition polymerization polymer having a synthetic hydrotalcite having a general chemical formula.²⁺Is a divalent cation source, M³⁺Is a trivalent cation source, A^n-Is C₅~ C₁₈Linear carboxylic acid acidate, aromatic acid carboxylic acid salt, acrylic acid carboxylic acid salt, methacrylic acid unsaturated carboxylic acid salt, vinyl acetic acid unsaturated carboxylic acid salt, and nitrogen, phosphorus, sulfur, halogen C containing such heteroatoms₂An organic anion source selected from carboxylic acid salts of or higher acids. According to one preferred embodiment, the organic anion of the synthetic hydrotalcite is an amino acid. More preferably, the amino acid is an amino acid that promotes self-exfoliation and / or reversible exfoliation of the synthetic hydrotalcite. In addition, the polymer can be modified or functionalized with, for example, maleic acid. In an embodiment having an acid-modified or functionalized polymer, an amino acid intercalated hydrotalcite and the polymer, and an amide or imide produced by the reaction of the acid-modified polymer with the amine functional group. Can be combined through. </p>

<p> Hereinafter, the method for synthesizing hydrotalcite of the present invention will be described in three stages. There are two alternative embodiments for the third stage. 1st step: Trivalent cation source + organic anion intermediate product 60 ° C ~ 85 ° C, 4 ~ 8 hours 2nd step: intermediate product (in water) + divalent cation source gel of synthetic hydrotalite 90 ° C ~ 95 ° C, 4 ~ 8 hours 3rd step: Drying (evaporation / vacuum drying, or filtration / vacuum drying, or spray drying) or 3rd step: Keep moist (colloidal suspension / evaporate until concentrated) Or paste)</p><p> The success of the preparation of synthetic hydrotalcites of the present invention depends largely on the first step reaction, the reaction of the trivalent cation with the particular carboxylic acid described above. By bringing the first-stage reaction closer to completion, preferably by utilizing one or more of the following methods: C₄Achieve the preparation of hydrotalcites made up of chains longer than carboxylic acids, heteroatoms containing acids, and water-insoluble aromatic acids. 1) The reaction time of the first stage can be increased from 30 minutes as shown in the Schutz '329 patent to 4-8 hours. 2) An inert organic solvent can be used as a reaction medium for the water-insoluble organic carboxylic acid together with the trivalent cation. 3) The first step can be carried out by melting the organic anion.</p><p> The following materials were used in the examples described in this document. Unless otherwise stated, Martin Magnesia Specialties Inc.'s MAGCHEM (registered trademark) 200D (high purity, high) uses CATAPAL (registered trademark) alumina, which is an aluminum oxide / monohydroxide of Vista Chemical Corporation, as a trivalent cation source. POLY EMULSION 43N40® (registered trademark) containing 39-41% non-volatile substances using reactive magnesium oxide powder as a divalent cation source and Aldrich Chemical Company's acid as an acid. CHEMCOR's trademark (used for preparing the mixture) was used as a maleated polypropylene emulsion having a nonionic emulsifier. Amino acid intercalated hydrotalcite-polypropylene mixture was prepared using Aristech maleated polypropylene, which holds the UNITE1000 (registered trademark) trademark.</p><p> RJ Lee Group, Inc., located in Monroeville, PA, USA, performed a scanning electron microscope (SEM) analysis of a sample of the synthetic hydrotalcite of the present invention. The analysis required the collection of micrographs by both secondary electron imaging (SET) and transmission electron imaging (TED) of the typical particles of the sample. Three different representative particles obtained from each sample were magnified in the range of 5,000X to 50,000X depending on the size of the particles and micrographed.</p><p><u style="single">Spray drying method</u> Preferably, the synthetic hydrotalcite of the present invention can be spray-dried using a Niro-2 fluid nozzle spray dryer with the following settings. Heated at 5.5, the nozzle pressure was set to 1 bar, and the intake port temperature was maintained at 200 to 230 ° C, which is the desired setting range, by changing the liquid supply rate (4 to 5 liters per hour). Water can be supplied to the spray dryer, preferably after the temperature has stabilized, in order to predict the required liquid supply rate and remove the residual substances used last time.</p><p><u style="single">Colloidal suspension, condensed suspension or paste</u> Instead of drying, the synthetic hydrotalcite may be kept wet or undried. Maintaining the hydrotalcite in a wet or non-dry state is particularly desirable in the embodiments of the present invention where the synthetic hydrotalcite can come into contact with a solvent and self-exfoliate. In the case of self-exfoliating synthetic hydrotalcite, the product can be isolated directly from the synthesis as a colloidal suspension of exfoliated hydrotalcite and removed without further treatment. Alternatively, the suspension may be evaporated to a concentrate of the suspension or a soft paste such as bread dough.</p><p><u style="single">Preparation of synthetic hydrotalcite</u> As described above, the preparation of the synthetic hydrotalcite of the present invention is carried out in three steps. In the first step, the organic anion source is preferably the trivalent cation source Al.³⁺As shown in US Pat. No. 5,518,704, which is incorporated herein by reference in its entirety.³⁺And another trivalent cation, Cr³⁺And Fe³⁺A mixture of at least one of them up to 50% may be used in the preparation of synthetic hydrotalcite. The second step is preferably a divalent cation source Mg with the mixture obtained in the first step.²⁺However, as shown in US Pat. No. 5,518,704, which is incorporated herein by reference in its entirety, Mg²⁺And another divalent cation, Ni²⁺, Co²⁺, Zn²⁺, Cu²⁺, And Mn²⁺A mixture of at least one of these may be used in the preparation of synthetic hydrotalcite. The third step is the drying of the resulting synthetic hydrotalcite. Alternatively, as another third step, the hydrotalcite is maintained as a wet colloidal suspension, slurry or paste. Preferably, synthetic hydrotalcite capable of self-exfoliation or reversible exfoliation is kept exfoliated as a slurry or paste. The inventors of the present invention have discovered that the first step of the preparation can be carried out in water, in an organic solvent, or in an acid melt, depending on the degree of water solubility of the organic anion used. The second step is preferably carried out in water.</p><p> The preparation of stearic acid synthetic hydrotalcite by methods using each of the above three approaches to improve the first step will be described below for illustration and non-limiting purposes.</p><p><u style="single">Example 1: First step performed using water as a medium</u> CATAPAL® alumina (0.26 mol) was suspended in 500 ml of deionized water in a 4 liter beaker, and stearic acid (0.23 mol) was added to the stirred suspension. In order to condense the volatiles in the beaker, the beaker fitted with a crystal dish filled with ice water was heated to 75 ° C to 85 ° C and kept at that temperature for 4 to 8 hours. After this, magnesium oxide (0.44 mol) was added, and then 1.5 liters of deionized water was added. The mixture was heated to 90 ° C to 95 ° C and kept at that temperature for 4 to 8 hours. The mixture was cooled to room temperature with stirring overnight. The material thus obtained is preferably dried by one of the following two methods. a) Dry in an air dryer at 130 ° C until a semi-dry solid is obtained, then dry in a vacuum oven at 80 ° C for an additional night. Alternatively, b) spray dry with the intake port temperature set to about 200 ° C and the exhaust port temperature set to about 100 ° C. The powder obtained by drying the material is the desired synthetic hydrotalcite.</p><p> In aqueous media, if less water is used than usual, the acid may float on the alumina suspension in water, slowing the reaction rate. The product of this reaction is a sticky oil with a higher density than the medium and precipitates on the bottom of the reaction vessel. In the above-mentioned medium, a part of alumina and free acid is confined, and the mixing of the reagent is very limited, so that the reaction may be very slow or may not react at all. The synthetic hydrotalcite produced by this method was not very uniform, as seen in FIG. 1, which is a scanning electron micrograph of the sample.</p><p><u style="single">Example 2: First step performed with an organic solvent</u> The reaction of the trivalent cation source with a water-insoluble carboxylic acid such as stearic acid is preferably carried out in an organic solvent such as refluxed hexane. CATAPAL® alumina (0.26 mol) was suspended in 200 ml of hexane in a 4 liter beaker, and the acid (0.23 mol) was added to the stirred suspension. To condense the volatiles in the beaker, the beaker fitted with a crystal dish filled with ice water was heated to about 65 degrees and kept for 4-8 hours. Preferably, the solvent can be removed by evaporation or filtration. Water was added to the resulting residue. Next, magnesium oxide (0.44 mol) was added with vigorous stirring. The mixture was heated to about 90 ° C-95 ° C and kept at that temperature for 4-8 hours. Product separation, or drying, was performed by the method described in Example 1 above. By using this method, as can be seen from the comparison of FIGS. 1 and 2, a uniform synthetic hydrotalcite having a larger interplanar spacing value and appearing to have a smaller particle size as shown in the scanning electron micrograph. I got the site.</p><p> Performing the first step in an organic solvent results in a faster exothermic reaction, producing a soluble intermediate product in the medium. However, the disadvantage of this method is that since the second step is preferably carried out in water, it is preferable to remove the solvent before the reaction of the intermediate product with the divalent cation source.</p><p><u style="single">Example 3: First step performed with acid melt</u> A beaker containing the required amount of solid stearic acid was heated in an oil bath until the acid dissolved. To the melt, a stoichiometrically desirable amount of alumina was added little by little with stirring. The temperature was maintained for about 2 hours or longer. Water was added to the product and the mixture was stirred until uniform throughout. After adding magnesium oxide, 1.5 liters of deionized water was added. The mixture was heated to 90 ° C to 95 ° C and kept at that temperature for 4 to 8 hours. The mixture was cooled to room temperature with stirring overnight. Product separation was performed by the method described in Example 1 above.</p><p> The problem encountered with this method was that the product was sticky, as in Example 1. However, the advantage of using the acid melt method described above is that the reaction rate in the melt is much faster than the reaction rate observed in water. By stirring the melt sufficiently, a complete reaction can be expected as compared with the case of water. This can be an economical method for preparing synthetic hydrotalcites of solid fatty acids with moderate melting temperatures. The acid melt method is faster than the method using water because the reaction rate is faster, and the method using the organic solvent is not necessary to remove the organic solvent before proceeding to the second step. Faster than. Table I summarizes the interplanar spacing, layer spacing, and particle size of synthetic hydrotalcite produced by each method.</p><p><tables num="1"><img file="JP2005515230A_D0001.tif" /></tables></p><p><u style="single">Examples 4 to 20</u> Synthetic hydrotalcites made from the following organic anion sources were prepared by the methods of the invention and some of the properties of these synthetic hydrotalcites are summarized in Table II: stearic acid, glycolic acid, acetic acid, acrylic. Acid, y-butyrolactone, ethanesulfonic acid, lactic acid, hexanoic acid, octanoic acid, decanoic acid, benzoic acid, chlorobenzoic acid, cinnamic acid, naphthoic acid, methacrylic acid, acrylic acid, vinyl acetic acid, and acrylic acid and acetic acid. A mixture of stearic acid and a mixture of acetic acid, hexaneic acid and stearic acid.</p><p> The following synthetic hydrotalcites of organic anion sources, which have a long reaction time in the first step, can be prepared in water. Ethane sulfonic acid, lactic acid, benzoic acid, methacrylic acid, acrylic acid, vinyl acetate. Figures 3 to 5 are scanning electron micrographs of benzoic acid, methacrylic acid, and acrylic acid, which are the three representatives of this group, respectively.</p><p> All synthetic hydrotalcites described herein were analyzed by X-ray diffraction analysis (XRD) to determine the location, intensity and surface spacing of X-ray peaks. Since the interplanar spacing depends on the size and shape of the anions contained in the hydrotalcite, it indicates the interlayer distance of the hydrotalcite. Table II shows the interplanar spacing of each synthetic hydrotalcite. Synthetic hydrotalcites with larger interplanar spacing were synthesized with larger anions or anions with longer carbon chains, based on the assumption that they would be mixed with the polymer or exfoliated in the polymer. ..</p><p> FIG. 6 shows the increase in the interlayer distance of the hydrotalcite as the number of carbon atoms contained in the anion increases. This interlayer distance is obtained by subtracting the thickness of the brucite layer, 4.77A, from the surface spacing. In fact, the number of carbon atoms contained in the organic anion (at least the highest C)₁₀Up to) and the interlayer distance are well correlated. The maximum interlayer distance of synthetic hydrotalcite made from stearic acid is 21.6A, which is not very close to the prediction based on Figure 6. The prediction should be 26.0A, which suggests that above a certain number of carbon atoms, the carbon chain backbone may have sufficient flexibility to cause deviations from the prediction.</p><p> Synthetic hydrotalcite having an interplanar spacing of 12 A or more, which is the interplanar spacing of hydrotalcite acetate, was SEM-analyzed to measure the particle size, overall particle size, and morphology of the synthetic hydrotalcite. As in the case of Schutz '329 patent, the preferred morphology of hydrotalcite of the present invention is in the form of a sheet referred to herein as "cabbage". Synthetic hydrotalcites prepared from the following anions have been excellent examples of this morphology: acetic acid, ethanesulfonic acid, octanoic acid, benzoic acid, chlorobenzoic acid, methacrylic acid, acrylic acid, and vinylacetic acid.</p><p> In addition, synthetic hydrotalcites with morphology referred to herein as "semi-cabbets" were obtained from the following anion sources: stearic acid, decanoic acid, naphthoic acid, and stearic acid, acrylic acid and acetic acid. Mixtures and Mixtures of Acetic Acid, Caproic Acid and Stearic Acid (see Figure 7) As used herein, "semi-cabet" is one of the three representative particles selected for micrographs. Or it means that only two showed cabbage-like morphology.</p><p> Without being limited to any particular theory, the inventors of the present invention have found that the size and shape of the organic anion prevented the formation of a true cabbage shape within the crystal structure. It is considered to be one of the possible causes of cabbage-like morphology. Alternatively, it is possible that the anion having a long carbon chain of the early synthetic hydrotalcite structure and the water molecules between the layers repel each other, causing distortion in the crystal structure. In addition, a semi-cabbage-like morphology may occur due to an incomplete reaction with a trivalent cation in the first step of hydrotalcite synthesis.</p><p> What was produced in water from the following anion sources did not result in synthetic hydrotalcite with the desired morphology: glycolic acid, y-butyrolactone, lactic acid. One possible reason for the failure to produce synthetic hydrotalcite with the desired morphology from these water-soluble anion sources is the presence of double anions (carboxylic acid and hydroxy acids) as shown by solid-state NMR between the layers. Cross-linking is possible.</p><p> Using the ruler shown in the SEM micrograph, the average particle size of the particles was measured in micron units. If the synthetic hydrotalcite is intended for use in nanocomposites, smaller particle sizes are preferred. The particles of the synthetic hydrotalcite of the present invention are generally in the micron range, as can be seen from the data contained in Table II. The method for drying synthetic hydrotalcite of the present invention did not seem to have any effect on the particle size.</p><p><u style="single">Comparative Examples 22 to 24</u> Synthetic hydrotalcite produced from commercially available hydrotalcite (LaRoche, acetate anion HTC-0498-10), methacrylic acid, and acrylic acid using instantly calcined alumina (FCA, available from LaRoche Industries) as a trivalent cation source. Was a morphology that could only be called semi-cabbage at best. SEM showed that FCA contained more than one aluminum compound, or that the reactivity of the acid with FCA was lower than that of CATAPAL®. As can be seen in Table II, the interplanar spacing of similar synthetic hydrotalcites produced from CATAPAL® alumina and acetic acid (Example 5) in the assignee's laboratory was 12.0 A. In comparison, the surface spacing of HTC-0498-10 (Comparative Example 22) was 9.7A.</p><p><tables num="2"><img file="JP2005515230A_D0002.tif" /></tables></p><p> Part of the hydrotalcite (Examples 1, 4, 6, 8, 12, 16, 17, 18) is solid CP-MAS C.¹³NMR analysis showed that in most cases the acid used in the preparation was actually present in the form of the carboxylate. However, in some examples (Examples 4, 6 and 8), the presence of a very small amount of free acid along with the corresponding anion showed that the reaction in the first step was incomplete.</p><p><u style="single">Example 25: Synthesis with 4-aminobutyric acid</u> Aluminum hydroxide (0.26 mol) was suspended in 50 ml of deionized water in a 500 ml flask equipped with a reflux condenser and a stirrer, and 4-aminobutyric acid (0.26 mol) was added to the stirred suspension. It was. The material was heated to 75 ° C to 85 ° C and kept at that temperature for 4 to 8 hours. After this, magnesium oxide (0.52 mol) was added, and then 150 ml of deionized water was added. The mixture was heated to 90 ° C to 95 ° C and kept at that temperature for 4 to 8 hours. The reflux condenser was removed to concentrate the material to a nominal solid concentration of 10% by weight. The mixture was then cooled to room temperature with stirring overnight. The resulting slurry was a stable viscous suspension and the solid components did not precipitate.</p><p> The aliquots of the resulting slurry were dried in an air dryer at 130 ° C. until a semi-dry solid was obtained and further dried overnight in a vacuum oven at 80 ° C. The powder obtained by drying the material is the desired synthetic hydrotalcite. 0.5 g of the dry powder was placed in a test tube and re-wetted with 4.5 ml of water. The test tube was vigorously shaken for 1 minute and the obtained slurry was allowed to rest overnight. The slurry also became a stable viscous suspension, and the solid component did not precipitate.</p><p><u style="single">Example 26: Synthesis with 6-aminocaproic acid</u> The same procedure as in Example 25 was followed, except that 6-aminocaproic acid was used instead of 4-aminobutyric acid. The resulting slurry was a stable viscous suspension and the solid components did not precipitate. The powder obtained by drying the material is the desired synthetic hydrotalcite. The re-wet powder also provided a stable suspension.</p><p><u style="single">Example 27: Synthesis with 4-aminobenzoic acid</u> The same procedure as in Examples 25 and 26 was followed, except that 4-aminobenzoic acid was used instead of 4-aminobutyric acid. The condensed slurry quickly precipitated into a powder layer, forming a clear supernatant layer. The powder obtained by drying the material is the desired synthetic hydrotalcite. The re-wet powder did not form a stable suspension and was separated into a precipitated powder layer and a clear supernatant layer.</p><p> XRDs of HT samples were taken in wet and dry conditions to see if there were any differences in the reference peaks. The results are shown in Table III. In the case of 4-aminobutyric acid, the 2-theta peak seen at 5.70 ° (corresponding to a layer spacing of 15.49A) in dry hydrotalcite was not seen in the wet sample, which means that the hydrotalcite was wet. It shows that it peels off in a state of being. Similar results were seen with 6-aminocaproic acid. This indicates that these organic hydrotalcites are added to the solvent and self-exfoliate. The data obtained with 4-aminobenzoic acid show that this organic hydrotalcite does not self-exfoliate when added to the solvent.</p><p><tables num="3"><img file="JP2005515230A_D0003.tif" /></tables></p><p><u style="single">Comparative Examples 28-32: Preparation of commercially available hydrotalcite-polypropylene mixture</u> A mixture of commercially available hydrotalcite and CHEMCOR® polypropylene emulsion was prepared by the following two methods. 1) The dried hydrotalcite was gelled again with water, mixed with the emulsion, and then spray-dried. 2) Prior to spray drying, the emulsion was added to the hydrotalcite to give the mixture.</p><p> As shown in Table IV, a mixture of 5 to 81% by weight of HTC-0498-10 (LaRoche) mixed with the solid weight of polypropylene was prepared and XRD, SEM, differential scanning calorimetry (DSC), thermogravimetric analysis. Analysis by (TGA) was performed. The regelling concentration of commercially available hydrotalcite, HTC-0498-10, is limited to about 3% in warm water. This amount is much lower than the manufacturer's claim of 8% to 10% for virgin gels before spray drying. Using this method to prepare the mixture would require a large reactor due to the low regelling concentration.</p><p><tables num="4"><img file="JP2005515230A_D0004.tif" /></tables></p><p> X-ray analysis of the mixture made from the commercial hydrotalcite, HTC-0498-10, shows a substantial reduction in interplanar spacing (from about 9.7A) as the amount of polypropylene exceeds 60%, as can be seen from Table IV. It showed 6.3A), but increased when the level was 19%. Without being limited to any particular theory, the inventors of the present invention suspect that this reduction may be due to exfoliation or dispersion of the synthetic hydrotalcite in the polymer matrix.</p><p> FIG. 8, which is a SEM micrograph of Example 32, which is a mixture containing 81% hydrotalcite, showed a clearer cabbage-like morphology than the morphology of the hydrotalcite from which the mixture was based. However, as shown in FIG. 9, the SEM of Example 28, which is a similar mixture containing 5% hydrotalcite, exhibited the morphology we call "doughnut-like" herein. Without being limited to any particular theory, the inventors of the present invention have found that the hydrophilic portion of the synthetic hydrotalcite forms a cyclic nucleus and stearate or octanoic acid mixed in the polymer matrix. It is considered that the donut-like morphology may be produced by the hydrophobic portion having an anion of the salt surrounding the nucleus. The radius of the donut-shaped particles was in the range of 2 to 3 microns. The hydrotalcite of the mixture of Example 28 is so well dispersed in the polymer matrix that it does not have a layered structure.</p><p> Thermogravimetric analysis of a mixture made from the commercially available hydrotalcite HTC-0498-10 and polypropylene shows the percentage of residue that indicates the amount of hydrotalcite contained in the material. As Table V shows, the percentage of the residue increases with the percentage of hydrotalcite in the material, which is the non-volatile material that remains after heating the sample to raise the temperature. Is shown.</p><p> The DSC transition temperature represents the temperature at which the phase change occurs in the mixture and represents the minimum temperature required to process these materials in polymer applications. The first phase transition temperature occurred at about 150 ° C for the mixture. Some of these materials showed lower transition temperatures, which may be due to water loss.</p><p><u style="single">Examples 33-38: Preparation of Synthetic Hydrotalcite-Polymer Mixture</u> A part of the synthetic hydro of the present invention using the above-mentioned preparation method 1 used in Comparative Examples 28 to 32 and using stearic acid, octanoic acid, vinyl acetate, and a mixture of acetic acid, caproic acid, and stearic acid as raw materials. A mixture made from tarcite was prepared. These synthetic hydrotalcites did not show the problem of regelation, which was very difficult to stir when the concentration exceeded 3% using the commercially available hydrotalcite HTC-0498-10. A second method of adding the polypropylene emulsion as the final step of hydrotalcite preparation before spray drying was also attempted with synthetic hydrotalcite prepared from methacrylic acid and acrylic acid.</p><p> The synthetic hydrotalcite was added to water to make up about 3% by weight. The temperature of this mixture was raised to about 40 ° C to 60 ° C and the required amount of polypropylene emulsion was slowly added to the gel with vigorous stirring according to the desired composition of the mixture. Sufficient water was added to keep the mixture as a fluid. The mixture was heated to about 80 ° C., maintained at that temperature for about 1 hour and then cooled to room temperature with continuous stirring overnight. The mixture was spray-dried at an intake port temperature of 230 ° C. and an exhaust port temperature of 90 ° C. to 105 ° C. Each mixture was analyzed by XRD, SEM, TGA and DSC. The results of Examples 30 to 35 are summarized in Table V.</p><p> A mixture of synthetic hydrotalcite and polypropylene using stearic acid, octanoic acid, methyl methacrylate and acrylic acid was also prepared by a method requiring the addition of the polypropylene emulsion to the synthetic hydrotalcite before separation. The resulting mixture was spray dried and separated by the method described above.</p><p><tables num="5"><img file="JP2005515230A_D0005.tif" /></tables></p><p> Mixture compositions with longer carbon chain synthetic hydrotalcite had varying effects on surface spacing. As can be seen from Table V, when a mixture of synthetic hydrotalcites of stearic acid, vinyl acetate and acrylic acid is used, the interplanar spacing is 35.2%, respectively, even if the hydrotalcite composition is in the range of 38% to 57%. It decreased by 12.4% and 17.5%. The interplanar spacing of the mixture using octanoic acid, mixed acid (acetic acid, caproic acid, stearic acid) and methacrylic acid increased by 16.3%, 3.7% and 17.4%, respectively, as compared with the synthetic hydrotalcite used as the raw material of the mixture. .. Without being limited to any particular theory, the inventors of the present invention find it difficult to uniformly mix synthetic hydrotalcite with the prepylene, or the structure of the organic anion is the interplanar spacing of the mixture. We believe that these results may suggest that they have different effects on. SEM micrographs of a mixture of synthetic hydrotalcite and polypropylene from octanoic acid and mixed acids (acetic acid, caproic acid, stearic acid) showed donut-like morphology.</p><p> FIG. 10, which is an SEM micrograph of Example 34, which is a mixture of synthetic hydrotalcite and polypropylene made from methacrylic acid, did not show the above-mentioned donut-like morphology, nor was it called semi-cabbage. The particle size of the mixture of synthetic hydrotalcite and polypropylene made from methacrylic acid averaged 5X3 angstroms.</p><p> As shown in Table V, the residue obtained from TGA of synthetic hydrotalcite made from anions other than acetate correlates with the residue of the hydrotalcite when correlated based on the weight contribution of the anion. .. The DSC transition temperature of these materials was similar to that of materials made from HTC-0498-10, and the first transition temperature was in the range of 148 ° C to 152 ° C. Therefore, these materials can be processed with polymers at normal temperatures.</p><p> The method of mixing the hydrotalcite and the polyaddition polymerization polymer of the present invention is shown in the drawing by giving an example using polypropylene, but those skilled in the art have shown polyethylene, polybutene-1, poly-4-methyl-penten-1. , Polystyrene, polyvinyl chloride, etc. It will be readily appreciated that other heavy addition polymerization polymers can be used in the present invention.</p><p><u style="single">Examples 39-41: Polymerization of methyl methacrylate using hydrotalcite produced from synthetic methacrylic acid</u> The reaction was carried out in a 1 liter CHEMCO® reactor under 20 psig of nitrogen at a stirring rate of 400 rpm. Table VI shows the amount of hydrotalcite produced from methyl methacrylate and methacrylic acid, and the reaction temperature. In each example, an appropriate amount of hydrotalcite produced from 460 ml of water, 100 g of methyl methacrylate and methacrylic acid was placed in the reactor. The reactor was first purged with nitrogen and then pressurized. 470 g of methyl methacrylate, 0.5 g of initiator AIBN (2,2-azobisisobutynitrile) and surfactant (Aerosol OT available from Cytec Industries) A solution in which 75% (2.5 g) was dissolved was pumped to the reactor heated to 70 ° C. at 88 ml / h. The reaction was continued until agitation became difficult due to the formation of lumps of solid product. At that point, the above-mentioned methyl methacrylate feeding was stopped and the temperature was maintained for about 30 minutes to allow all residual methyl methacrylate to react. After cooling the reactor to room temperature, the polymer pieces were removed and air dried at room temperature (preferably under draft). The amount of polymer obtained as a result is shown in Table VI.</p><p><tables num="6"><img file="JP2005515230A_D0006.tif" /></tables></p><p> Copolymerization of synthetic hydrotalcites produced from methacrylic acid with methyl methacrylate has been shown to have the potential to produce masterbatch materials. By doing so, a mixture with a polyadditionally polymerized polymer such as polypropylene can be prepared from these master batches. By using the Aerosol OT surfactant, it was expected that the copolymer would be uniformly agitated in the water in which the reaction was carried out. In all examples, slurry formation occurred only at the beginning of the polymerization. As the amount of the polymer increased, the suspended particles became spherical or agglomerated, and stirring became difficult, so that the polymerization had to be stopped early. The resulting product was a yellowish brown, hard polymer.</p><p> TGA analysis of the products showed varying levels (1.6% -8%) of hydrotalcite produced from methyl methacrylate based on the percentage of residue, as shown in Table VI. This percentage indicates the amount of alumina and magnesium left after all carbon sources in the sample have volatilized. The example with the highest percentage of hydrotalcite weight at the start resulted in the highest residue. The first DSC transition temperature (114 ° C to 122 ° C) showed only a small diffusion peak and may not indicate a true polymer transition temperature. Higher processing temperatures may be required for polymer applications, as the second transition at 370 ° C is expected to be due to the phase change of the copolymer. In toluene and ethyl acetate, and to some extent in methylene chloride, these polymers dissolve or become clear gels. The copolymer with the smallest amount of synthetic hydrotalcite (1.6% TGA residue) produced from methacrylic acid was the most soluble in toluene. The solution containing this copolymer was dried to obtain a transparent film having excellent adhesiveness.</p><p><u style="single">Example 42: Compounding of hydrotalcite intercalated with amino acids using polypropylene maleated</u> Synthetic hydrotalcites intercalated with amino acids according to the present invention are particularly useful for the production of inorganic polymers / mixtures according to the present invention. In a preferred embodiment, the amino acid intercalated synthetic hydrotalcite can be self-exfoliated in a solvent. Preferably, according to this embodiment, the amino acid intercalation synthetic hydrotalcite is isolated from the synthesis and maintained as a slurry, suspension or paste. In this embodiment, the amino acid intercalated hydrotalcite is isolated from the synthesis and maintained in an exfoliated state. Alternatively, the amino acid intercalated hydrotalcite may be isolated, dried, and later added to a solvent to induce self-exfoliation. In either embodiment, the hydrotalcite is added to the molten polymer as a slurry, suspension or paste. Since the amino acid intercalated hydrotalcite can undergo self-exfoliation, it can be more easily dispersed in the polymer mixture without the use of a matching aid. No compatible aid is required, but molecules that serve as compatible aids may be used in the amino acid intercalation synthetic hydrotalcite according to this embodiment of the present invention.</p><p> In one embodiment, the modified polyaddition polymerization polymer is used to combine the amino acid intercalation synthetic hydrotalcite. Preferably, the modified polyaddition polymerization polymer is an acid modified polyolefin, such as polypropylene maleated. The hydrotalcite can be combined by using the acid-modified polymer alone or by using a mixture of the modified polymer and the non-modified polymer. According to one preferred embodiment, the amino acid intercalation synthetic hydrotalcite is combined with the amino acid intercalation synthetic hydrotalcite using a polyolefin modified with a molten acid, such as polypropylene maleated, and acid modified with the amino acid intercalation synthetic hydrotalcite. Produce a "master batch" of quality polyolefin. The unmodified polyaddition polymerization polymer can then be combined to form the final nanocomposite.</p><p> Without being limited by theory, it is considered that the amine group of the amino acid intercalated hydrotalcite reacts with the acid moiety of the modified polyolefin to form an amide or imide. By this method, the hydrotalcite actually binds to the polymer and improves the dispersion of the hydrotalcite in the nanocomposite.</p><p> In a 600 ml metal beaker in a heating jacket, 166.7 g of nominally 6 wt% (10.0 g) 6-aminocaproic acid-based hydrotalcite slurry with 10 g of UNITE1000® maleinated polypropylene added. Mixing was performed using a high speed (up to 8000 rpm) Giftord-Wood homomixer plugged into various transformers so that the mixing rate could be adjusted. The mixture is then heated with stirring. Continue mixing and heating until the mixture becomes a sticky paste. The material is then removed from the beaker and air dried. A part of the material after air drying was ground and XRD analyzed.</p><p> Air-dried hydrotalcite obtained from samples obtained by grinding UNITE 1000® and UNITE and hydrotalcite at 50/50, and batches of hydrotalcite produced in 8% by weight slurry. XRD analysis of the site. Since the stickiness of the 6% by weight slurry was insufficient for XRD in the wet state, an 8% by weight preparation was used for this comparison. Since the 6% by weight and 8% by weight hydrotalcite slurries mentioned above were prepared in the same way, it is unlikely that there is a real difference between the two slurries.</p><p> Figure 11 shows the 8% by weight slurry of undried hydrotalcite, the air-dried sample of hydrotalcite made from 8% by weight slurry, the sample of UNITE 1000 (registered trademark), and the sample of UNITE and hydrotalcite from the bottom. XRD scan of a sample of 50/50 mixture. Looking at Figure 11, what is interesting in each scan is about 6 °. A scan of the air-dried sample of hydrotalcite (second from the bottom) showed a strong base peak in this part, which may indicate a state in which it was not exfoliated. This peak is not present in the 8 wt% slurry scan (bottom), indicating hydrotalcite in a stripped state. A scan of the 50/50 mixture of UNITE and hydrotalcite (top) shows no of the aforementioned base peaks. Small peaks are seen, due to UNITE1000® resin.</p><p> For comparison, FIG. 12 shows the evolution of the hydrotalcite by heating. FIG. 12 shows, in order from the bottom, a 10% by weight slurry of the undried hydrotalcite, an air-dried sample of hydrotalcite made from the 10% by weight slurry, and a sample of the 10% by weight slurry dried at 100 ° C. XRD scan of a sample of 10 wt% slurry dried at 150 ° C. In the air-dried sample (second from the bottom), the peak due to 6-aminocaproic acid appears in the range of about 12 ° to about 37 °. In scans of samples dried at 100 ° C (second from the top) and 150 ° C (top), the peaks due to 6-aminocaproic acid gradually disappeared as the heat treatment increased, and the structure of the hydrotalcite (the structure of the hydrotalcite (top)). It can be seen that only the peak of the brucite layer + layer spacing) is left behind. As it heats, it can be seen that the base peak at about 6 ° becomes steeper until the hydrotalcite structure is destroyed.</p><p> Going back to Figure 11 and looking at the scan of the 50/50 mixture of UNITE and hydrotalcite (top), there is still a peak showing 6-aminocaproic acid. This indicates that the hydrotalcite structure was not disrupted in the preparation of the 50/50 mixture. Furthermore, the absence of a strong base peak at about 6 ° indicates that the hydrotalcite is completely exfoliated. If the 50/50 mixture of UNITE and hydrotalcite was just a physical mixture of unexfoliated hydrotalcite and the polymer, a peak of about 6 ° would still remain. Thus, the 50/50 mixture of UNITE and hydrotalcite is a true nanocomposite.</p><p> The above-mentioned drawings showing the embodiments of the present invention are presented for the purpose of explanation without limitation. Those skilled in the art will readily appreciate that the embodiments described herein can be modified or modified in a variety of ways without departing from the intent and scope of the invention. The scope of the present invention is defined by the claims attached herein.</p>

Hereinafter, the present invention will be described for the purpose of illustration, but the present invention is not limited by the following figures.<figref num="1">FIG. 1 is a photomicrograph of the synthetic hydrotalcite produced in Example 1.</figref><figref num="2">FIG. 2 is a photomicrograph of the synthetic hydrotalcite produced in Example 2.</figref><figref num="3">FIG. 3 is a photomicrograph of benzoic acid-induced synthetic hydrotalcite.</figref><figref num="4">FIG. 4 is a photomicrograph of synthetic hydrotalcite induced by methacrylic acid.</figref><figref num="5">FIG. 5 is a photomicrograph of synthetic hydrotalcite induced by acrylic acid.</figref><figref num="6">Figure 6 predicts the relationship between the interlayer distance and the number of carbon atoms in the anion and shows it in the figure.</figref><figref num="7">FIG. 7 is a photomicrograph of synthetic hydrotalcite induced by aspirin, caproic acid, and stearic acid, showing a "semi-cabbage" -like morphology.</figref><figref num="8">FIG. 8 is a photomicrograph of a mixture of about 81% hydrotalcite and polypropylene, showing a preferred "cabbage-like morphology".</figref><figref num="9">FIG. 9 is a photomicrograph of a mixture of about 5% hydrotalcite and polypropylene, showing a "doughnut" -like morphology.</figref><figref num="10">FIG. 10 is a photomicrograph of a mixture of synthetic hydrotalcite and polypropylene induced by methacrylic acid.</figref><figref num="11">FIG. 11 shows the 8% by weight slurry of the above-mentioned undried hydrotalcite, an air-dried sample of hydrotalcite taken from the 8% by weight slurry, a sample of UNITE 1000 (registered trademark), and 50 of UNITE and hydrotalcite. / 50 XRD scan of the mixture sample.</figref><figref num="12">FIG. 12 shows a 10 wt% slurry of undried hydrotalcite, an air-dried sample of hydrotalcite taken from the 10 wt% slurry, a sample of 10 wt% slurry dried at 100 ° C, and 150 ° C. XRD scan of a sample of 10 wt% slurry dried in.</figref>