USOO732675OB1 (12) United States Patent (10) Patent No.: US 7,326,750 B1 Isik et al. (45) Date of Patent: Feb. 5, 2008 (54) EXPANDED NANOCLAYS AND METHOD OF OTHER PUBLICATIONS PRODUCING SUCH EXPANDED NANOCLAYS Abstract Only—Sidheswaran et al., “Intercalation of Salts of Fatty Acids into Kaolinite” Clays and Clay Minerals; vol. 38 (1); Feb. (76) Inventors: Kivanc Isik, Kurtulus 2014, Sok. Ulker 1990; pp. 29-32. Apt. No:1/9, Aydin (TR) 09020; Abstract Only—Grigor'eva et al.; “Mechanochemical Synthesis Gokhan Andi, 1722 Cambridge Rd., of Dispersed Composites with Layer Structure from Kaolinite and Ann Arbor, MI (US) 48104 Some Organic and Inorganic Acids:IR Study Inorganic Materials; vol. 32 (2): 1996; pp. 194-199. (*) Notice: Subject to any disclaimer, the term of this Chou et al.: “Unusual Intercalation of Cationic Smectite Clays with patent is extended or adjusted under 35 Detergent-Ranged Carboxylic Ions' Macromolecular Rapid Com U.S.C. 154(b) by 0 days. munications; vol. 26 (23); Dec. 2, 2005; pp. 1841-1845. (21) Appl. No.: 11/548,748 * cited by examiner (22) Filed: Oct. 12, 2006 Primary Examiner Jerry A. Lorengo Assistant Examiner Shuangyi Abu-Ali (51) Int. Cl. (74) Attorney, Agent, or Firm—IP Authority, LLC; Ramraj C08 3/34 (2006.01) Soundararajan B32B5/16 (2006.01) C09K 3/00 (2006.01) (57) ABSTRACT (52) U.S. Cl. ...................... 524/445; 524/446; 428/328; 51.6/101 (58) Field of Classification Search ............ 106/287.17 A method of producing nanoclays comprising the steps of See application file for complete search history. preparing a first intercalant alkali Salt of a carboxylic acid, (56) References Cited adding the first intercalant to a Swelled clay at a temperature of at least 50° C. so that the metal ions on the clay surface U.S. PATENT DOCUMENTS forms a complex with the carboxyl group that enlarges the 5,760,121 A 6, 1998 Beall et al. space between the two galleries of clay. The method further 5,844,032 A * 12/1998 Serrano et al. ............. 524,445 comprises the step of adding an organic acid as a second 6.242,500 B1 6/2001 Lan et al. ................... 516. 101 intercalant to the clay modified by the first intercalant to 2001/0025076 A1* 9, 2001 Lan et al. ................... 524,445 form a clay/organic salt?organic acid complex. The clay/ 2002/0022678 A1 2/2002 Lan et al. ................... 523,202 organic salt?organic acid complex may be post processed by 2002/005874.0 A1* 5, 2002 Lorah et al. ................ 524,445 precipitating, homogenizing with a solution comprising of 2004/0183051 A1* 9, 2004 Wenzel et al. .......... 252/.378 R water and alcohol, filtering, drying, milling, and sieving to 2004/0241427 A1* 12/2004 Zhu et al. ................... 428,328 produce the desired nanoclay. FOREIGN PATENT DOCUMENTS WO 2004/063264 A1 T 2004 28 Claims, 7 Drawing Sheets occo to Exchangabe Cations -- Na Ca Tetrahedra Octahedral Tetrahedral U.S. Patent Feb. 5, 2008 Sheet 1 of 7 US 7,326,750 B1 Exchangable Cations --> Na' | Ca" Tetrahedral Octahedral Tetrahedral Figure 1 U.S. Patent Feb. 5, 2008 Sheet 2 of 7 US 7,326,750 B1 Reacting Swelling Carboxic acids with alkali MMT-clay base to produce first intercalant produced S101 S102 Mixing first intercalant with 100 Swelled clay to produce a first mixture SO3 Adding second intercalant to the first mixture tO produce a second mixture S104 Percipating the second mixture to produce expanded nanoclay S105 Post-processing expanded nanoclay S106 v Nanoclays Figure 2 U.S. Patent Feb. 5, 2008 Sheet 3 of 7 US 7,326,750 B1 „v _O HAI O O \/OO IAI CD\/ U.S. Patent US 7,326,750 B1 H--O- | H-O | Y?H0--H | |D --OH |UI|| O U.S. Patent Feb. 5, 2008 Sheet 5 of 7 US 7,326,750 B1 14.3 A A-1 C 9 S GD 2 wim C) n1 2 4 6 8 10 12 2 Theta Figure 5 U.S. Patent Feb. 5, 2008 Sheet 6 of 7 US 7,326,750 B1 2 4 6 8 10 12 2Theta Figure 6 U.S. Patent Feb. 5, 2008 Sheet 7 of 7 US 7,326,750 B1 -Akali Salt/Organic Acid Modified MMT Y-N 41.10 A 2 4. 6 8 1O 12 2 Theta Figure 7 US 7,326,750 B1 1. 2 EXPANDED NANOCLAYS AND METHOD OF Conventional intercalating agents like 12-aminolauric PRODUCING SUCH EXPANDED acid, hexadecylamine, fatty amine, bis (2-hydroxy ethyl) NANOCLAYS methyl tallow alkyl amine and stearyl amine have low molecular weights and can be converted to the correspond BACKGROUND OF THE INVENTION ing ammonium salts such as quaternary ammonium chloride or bromide salts. Through ionic exchange reactions, the 1. Field of Invention counter ions in the interlayers of the clay can be ionically The present invention relates generally to nanoclays. exchanged and the basal spacing is extended to an amount More specifically, the present invention relates to a method between 13.2 and 22.7° A. of producing expanded clays using carboxylic acid salts and 10 U.S. Pat. No. 6,414,069 to Pinnavaia uses an intercalating soluble organic acids. agent CH-(CH2)NH in the exchange reaction with metal 2. Discussion of Prior Art ion salts in the layered structure of montmorillonite clay (MMT) and organically modified MMT is then dispersed in Nanocomposites are a new class of composite materials diglycidyl ether of bisphenol-A to form epoxy/layered clay that contain nano-level inorganic particulates such as silica 15 nanocomposite. By using Such intercalating agents, the basal (as described in the paper to Motomatsu, et al. titled “Micro spacing of MMT is increased to 18A. The mixture of MMT structure of acrylic polymer-silica nanocomposite Surface by with epoxy resin forces the polymeric molecules into the scanning force microscopy') and clay (as described in the clay layers and a nanocomposite structure is formed after paper to Kawasumi, et al. titled "Preparation and mechanical curing at 75° C. The interlayer distance (basal spacing) of properties of Polypropylene-clay hybrids’) in polymer clay is between 13-18 A, which allows the epoxy to structures. The first clay/polymer nanocomposites based on polymerize within and further exfoliate the layered structure Nylon-6 (as described in the publication to Okada, et al. of the clay. titled “Synthesis and properties of nylon 6/clay hybrids, Japanese Patent No. 8-22946 (Toyota Company) discloses Polymer based molecular composites”) were produced on commercial inorganic/organic polymer composite material 1989 in Toyota research laboratories of Japan. 25 in nanoscale dispersion. The composite material is synthe Manufacturers have filled polymers with particles in order sized by dispersing HN(CH2)COO-montmorillonite to improve the stiffness and toughness of materials, to in Nylon-6, in which amino carboxylic acid is provided as enhance their barrier properties and their resistance to fire an intercalating agent and the polymers are formed between and ignition. Addition of particulate fillers sometimes the layers of the amino acid intercalated clay by condensing imparts drawbacks to the resulting composites Such as 30 caprolactam monomers to Nylon-6 polymer. The amino brittleness or opacity. An interesting aspect of the use of carboxylic acid intercalating agent renders the modified clay nanofillers is the very low amount of filler that has to be compatible for Nylon-6. However, these modified montmo added to the polymer in order to be effective. In this way, the rillonite is unsuitable for nonpolar polymers such as poly undesired effects due to the introduction of the traditional ethylene and polypropylene. amounts of inorganic additives, which are very high, can be 35 Japanese Patent Publication No. 8-53572 provides other avoided. The improvements in thermal, mechanical, optical, organic onium ions as intercalating agents to mix with permeability and flammability properties of polymer/clay layered silicate that can easily disperse in polyolefin resin. nanocomposites are significantly higher than those achieved However, the organic onium ions can only enlarge the in traditional filled polymers. interlayer distances to an amount between 13.2 and 22.7°. A A member of layered silicate clays commonly used in the 40 and the interaction between the intercalating agent and the production nanoclays is montmorillonite (MMT). These polyolefin is too weak to exfoliate the layered structure. clays have layered lattice structures in which the tactoids The paper published by Chou, et al. (Macromolecular (crystallites) consist of Stacked two dimensional oxyanions Rapid Communications, vol. 26 (23): 2005; pp. 1841-1845) separated by layers of hydrated cations. The oxygen atoms discloses a method for intercalation of divalent smectite define layers containing two sheets of tetrahedral sites and a 45 clays with alkali salts of alkyl carboxylic acids resulting in central sheet of octahedral sites. The 2:1 relation between clays with basal spacing of 43 A. This paper provides a the tetrahedral and the octahedral sheets in a layer defines method to produce expanded clay in the absence quaternary 2:1 layered silicates. FIG. 1 shows a typical 2:1 layered ammonium salts. silicate the layer is made up of a central octahedral sheet, The prior art fails to teach a method to produce expanded usually occupied by aluminum or magnesium, Sandwiched 50 clays by using water Soluble acids containing carboxyl to between two sheets of tetrahedral silicon sites. These groups without the use of hazardous chemicals such as layers organize themselves to form the stacks with a regular quaternary ammonium salts as ionic exchanging agents. gap between them, called interlayer or gallery. The metallic Additionally, the prior art fails to teach a two step interca cations hold these stacks together also giving the natural lation process to produce expanded clays using an alkali Salt hydrophilic character to the structure.