Layered silicate modified with an amino acid moiety

Abstract

The present invention relates to a layered silicate having interlayer cations, wherein the interlayer cations comprise a) inorganic monovalent cations comprising at least one of Na + , K + , and Li + , and b) organic cations comprising at least one protonated amino acid.

Description

[0001] This invention relates to layered silicates having interlayer cations, methods for preparing said layered silicates, compositions comprising at least one binder and said layered silicates, and the use of said layered silicates for improving the barrier properties of polymers or coatings.

[0002] EP 0205281 A describes the treatment of layered silicates with aminocarboxylic acid, which acts as a foam expander. The resulting material is described as a gel. This gel can be molded into a desired shape to form an object.

[0003] US 3325340 relates to a method for producing an aqueous suspension of vermiculite flakes, wherein vermiculite crystals are treated with a solution of a water-soluble salt containing ammonium cations to promote cross-swelling of the crystals in a direction perpendicular to the principal cleavage planes of the crystals. In some embodiments, lysine and ornithine cations are used.

[0004] There is a persistent need for layered silicates that can be easily delaminated into single clay lamellae, providing good barrier properties and being prepared by economically viable methods. It has been found that inorganic interlayer cations, which completely replace layered silicates with protonated amino acids, cannot be easily or completely delaminated into single clay lamellae as needed. This reduces the effectiveness of these materials for improving barrier properties.

[0005] This invention provides a layered silicate having interlayer cations, wherein the interlayer cations comprise

[0006] a) Inorganic monovalent cations, including Na + K + and Li + At least one of, and

[0007] b) An organic cation containing at least one protonated amino acid.

[0008] The molar ratio of inorganic monovalent cation a) to organic cation b) is in the range of 0.20:0.80 to 0.80:0.20.

[0009] The layered silicate of the present invention readily and, in many cases, spontaneously delaminates into single lamellae. This layered silicate can be prepared by economically feasible methods.

[0010] This layered silicate can be prepared from various layered silicates having inorganic monovalent interlayer cations, wherein the inorganic monovalent interlayer cations include Na. + K+ and Li + At least one of the following. Examples of suitable layered silicates include vermiculite, beidellite, nontronite, volchonskoite, saponite, stevensite, sauconite, bentonite, montmorillonite, hectorite, smectites, phlogopite, mica, and illite.

[0011] In some implementations, the layered silicate is a naturally occurring layered silicate modified with protonated amino acids.

[0012] In other embodiments, the layered silicate is a synthetic layered silicate.

[0013] In a preferred embodiment, the layered silicate has a composition of Na prior to modification with organic cations. x [Mg 3-z Li y Si4O 10 (T)2, where

[0014] x is in the range of 0.40 to 0.90.

[0015] y is in the range of 0.00 to 0.90.

[0016] z is in the range of 0.20 to 0.90.

[0017] T independently represents either F or OH each time it appears, and

[0018] x+(3-z)+y≤4.

[0019] In some implementations, at least 50%, or even at least 70%, or at least 90% of the occurrences of T represent F. In some implementations, T represents F in 100% of the occurrences.

[0020] The ratio of Na, Mg, and Li can vary within the range shown above.

[0021] In a preferred embodiment, the material contains lithium. In these embodiments, γ is typically in the range of 0.20 to 0.70.

[0022] In a further preferred embodiment, x is in the range of 0.55 to 0.80, y is in the range of 0.40 to 0.60, and z is in the range of 0.40 to 0.60.

[0023] In the synthesis of layered silicates, other elements may be present in small amounts, depending on the purity of the starting material. Examples of these elements include iron, calcium, aluminum, potassium, boron, copper, zinc, manganese, cobalt, nickel, vanadium, gallium, zirconium, and anions such as sulfate, chloride, phosphate, carbonate, and silicate.

[0024] In the layered silicates of this invention, the interlayer inorganic cations are not completely exchanged by organic cations containing at least one protonated amino acid. An amino acid is an organic compound containing an amino group (usually a primary amino group) and a carboxylic acid group, as well as a side chain (which may be a hydrocarbon group), optionally containing additional functional groups. The amino group may be located at a carbon atom adjacent to the carboxylic acid group (α-amino acid). In other embodiments, the amino group and the carboxylic acid may be separated by two carbon atoms (β-amino acid), three carbon atoms (γ-amino acid), four carbon atoms (δ-amino acid), or even more carbon atoms. In a preferred embodiment, the amino acid is an α-amino acid. Examples of suitable amino acids include alanine, arginine, asparagine, aspartic acid, cysteine, glutamine, glutamic acid, glycine, histidine, isoleucine, leucine, lysine, methionine, phenylalanine, proline, serine, threonine, tryptophan, tyrosine, and valine. α-amino acids are chiral, and they may exist in either an L-configuration or a D-configuration. For the purposes of this invention, both L- and D-configurations of α-amino acids are equally suitable. However, naturally occurring α-amino acids usually exist in the L configuration.

[0025] In a preferred embodiment, the amino acid comprises at least one of lysine, ornithine, and β-alanine.

[0026] As mentioned above, in the layered silicates of the present invention, the interlayer inorganic cations are not completely exchanged by organic cations containing at least one protonated amino acid. "Not completely exchanged" is defined as a degree of exchange corresponding to less than 100% of the cation exchange capacity of the layered silicate before treatment with the protonated amino acid. The cation exchange capacity is suitably determined using barium chloride according to DIN EN ISO 11260:2017-04.

[0027] In a preferred embodiment, the molar amount of protonated amino acids corresponds to 20 to 85% of the cation exchange capacity of the layered silicate, more preferably 25 to 70%. Most preferably, the molar amount of protonated amino acids corresponds to 30 to 65% of the cation exchange capacity.

[0028] In a further embodiment of the layered silicate of the present invention, the molar ratio of inorganic monovalent cation a) to organic cation b) is preferably in the range of 0.25:0.75 to 0.75:0.25, more preferably in the range of 0.30:0.70 to 0.70:0.30.

[0029] In a further preferred embodiment, the inorganic cations in the alternating layers are exchanged with protonated amino acids to varying degrees. For example, in some embodiments, the interlayer cation alternation between layers comprises more than 60 mol% organic cations (b) and more than 60 mol% inorganic cations (a). Particularly preferred is that the interlayer cation alternation between layers comprises more than 70 mol% organic cations (b) and more than 70 mol% inorganic cations (a). The concept of ordered or semi-ordered interstratification of different cations within the interlayers of a layered silicate stack describes the occurrence of statistically alternating cation occupancy in the interlayer space of a 2:1 phyllosilicate. This means that, on average, every other interlayer has the same type of interlayer cations, and preferably each interlayer has only one type of cation. For example, and in short, this means that the first interlayer contains only inorganic cations. Then, a different type of cation, such as amino acid cations, is present in the next interlayer. In an idealized embodiment, the next interlayer is then identical to the first interlayer again, and the fourth interlayer is identical to the second interlayer. Because 2:1 layered silicates are highly complex materials and prone to defects, the interstratification is also described as ordered when a corresponding structure exists on a statistical average. The presence of the interstratified phase is visible in powder X-ray diffraction patterns through the appearance of superstructure reflection. This has a d-value, which corresponds to the summated interplanar spacings of the fully exchanged phases. For example, and in short, this corresponds to the sum of the interlayer distances of the first and second layers.

[0030] The layering of amino acid-modified layered silicates can be identified by small-angle X-ray scattering (SAXS). SAXS can be used to determine the d-intervals of the layered gels. Typically, these d-intervals are due to the layering. SAXS data were measured using the “Double Ganesha AIR” system (SAXSLAB, Denmark). This lab-based system uses a rotating anode (copper, MicroMax 007HF, Rigaku Corporation, Japan) as the X-ray source to provide a micro-focused beam. Data were recorded using a position-sensitive detector (PILATUS 300K, Decris). Layered amino acid-layered silicate samples were prepared by adding a specified amount of ultrapure water to dried, partially modified amino acid-layered silicate to induce gel formation. After equilibration for one week, SAXS patterns were recorded in a 1 mm glass capillary.

[0031] This invention also relates to a method for preparing layered silicates. The method includes...

[0032] i) Providing a layered silicate having an interlayer cation, wherein the interlayer cation comprises an inorganic monovalent cation containing Na + K + and Li + At least one of them,

[0033] ii) Determine the cation exchange capacity of the layered silicate.

[0034] iii) Contact the layered silicate with the protonated amino acid in an aqueous environment, wherein the molar amount of the protonated amino acid corresponds to less than 100% of the cation exchange capacity of the layered silicate, and wherein the amount of the protonated amino acid corresponds to 20 to 80% of the cation exchange capacity of the layered silicate.

[0035] For the layered silicate provided in step i) of this method, the same considerations as described above apply. In a preferred embodiment, the layered silicate has a composition of Na prior to modification with organic cations. x [Mg3-zLi y Si4O 10 (T)2, where

[0036] x is in the range of 0.40 to 0.90.

[0037] y is in the range of 0.00 to 0.90.

[0038] z is in the range of 0.20 to 0.90.

[0039] T independently represents either F or OH each time it appears, and

[0040] x+(3-z)+y≤4.

[0041] In some implementations, at least 50%, or even at least 70%, or at least 90% of the occurrences of T represent F. In some implementations, T represents F in 100% of the occurrences.

[0042] The ratio of Na, Mg, and Li can vary within the range shown above.

[0043] In a preferred embodiment, the material contains lithium. In these embodiments, γ is typically in the range of 0.20 to 0.70.

[0044] In a further preferred embodiment, x is in the range of 0.55 to 0.80, y is in the range of 0.40 to 0.60, and z is in the range of 0.40 to 0.60.

[0045] In the synthesis of layered silicates, other elements may be present in small amounts, depending on the purity of the starting material. Examples of these elements include iron, calcium, aluminum, potassium, boron, copper, zinc, manganese, cobalt, nickel, vanadium, gallium, zirconium, and anions such as sulfate, chloride, phosphate, carbonate, and silicate.

[0046] When the layered silicate is a synthetic layered silicate, it is suitably prepared by a method comprising the following steps:

[0047] a) Provides a mixture comprising a Na compound, a Mg compound, a Li compound, and a Si compound, wherein said compounds are selected from carbonates, halides, and oxides, and wherein the molar ratio of Na:Mg:Li:Si is in the range of 0.4 to 0.9:2.1 to 2.6:0.0 to 0.9:4.0.

[0048] b) Heating the mixture to a temperature above 1100°C to form a homogeneous liquid.

[0049] c) Cool the mixture to a temperature below 1000°C for at least 0.5 hours.

[0050] In step a), a mixture of Na, Mg, Li, and Si compounds is provided. This compound is provided in the form of oxides, halides, or carbonates. In typical embodiments, alkali metal salts / alkaline earth metal salts, alkaline earth metal oxides, and silicon oxides are used, preferably binary alkali metal fluorides / alkaline earth metal fluorides, alkaline earth metal oxides, and silicon oxides, preferably LiF, NaF, MgF2, MgO, or quartz. In further preparation embodiments, the material of the present invention is prepared from a mixture of sodium carbonate, lithium carbonate, magnesium oxide, magnesium fluoride, and silicon dioxide (quartz). The molar ratio of the starting compounds reflects the molar composition of the prepared layered material. Therefore, the molar ratio of the metal compounds used as starting materials is selected to achieve the molar composition of the layered material as described above.

[0051] The relative proportions of the starting compounds can be, for example, 0.4 to 0.6 moles of F in the form of alkali metal / alkaline earth metal fluorides per mole of silicon dioxide. - And 0.4 to 0.6 moles of alkaline earth metal oxide per mole of silica, preferably 0.45 to 0.55 moles of F in the form of alkali metal / alkaline earth metal fluoride per mole of silica. - And 0.45 to 0.55 moles of alkaline earth metal oxide per mole of silica, particularly preferably 0.5 moles of alkali metal / alkaline earth metal fluoride per mole of silica. - And 0.5 moles of alkaline earth metal oxides per mole of silicon dioxide.

[0052] Preferably, the starting compounds have high purity. In a preferred embodiment, each starting compound has a calcium oxide content of less than 2.00% by weight. More preferably, each starting compound has an iron oxide content of less than 0.05% by weight.

[0053] In step b), the mixture of starting compounds is heated to a temperature above 1100°C to form a homogeneous liquid. Heating is preferably carried out in an open or closed crucible.

[0054] Typically, high-melting-point crucibles made of chemically inert or slowly reacting metals, preferably molybdenum or platinum, are used.

[0055] Heating is typically performed in a high-frequency induction furnace. If necessary, the crucible is protected from oxidation by a protective atmosphere (e.g., argon), reduced pressure, or a combination of both. This is not necessary for precious metals such as platinum.

[0056] In step b), the mixture is heated to a temperature above 1100°C. The temperature must be above the melting temperature of the reaction mixture to obtain a homogeneous liquid. Typically, the temperature range in the second step is 1100°C to 1700°C, preferably 1300°C to 1600°C. Typically, this step lasts for 60 to 240 minutes, preferably 75 to 180 minutes.

[0057] In step c), the mixture is cooled to a temperature below 1000°C over a period of at least 0.5 hours, preferably at least 2.0 hours. Thereafter, the material is typically cooled to ambient temperature.

[0058] In the second step of the method of the present invention, the cation exchange capacity of the layered silicate is determined. As mentioned above, the cation exchange capacity is suitably determined using barium chloride according to DIN EN ISO 11260:2017-04.

[0059] In the third step, the layered silicate is contacted with protonated amino acids in an aqueous environment, wherein the molar amount of protonated amino acids corresponds to less than 100% of the cation exchange capacity of the layered silicate, and the amount of protonated amino acids corresponds to 20 to 80% of the cation exchange capacity of the layered silicate.

[0060] For amino acids, the same standards and preferences as described above apply. In a preferred embodiment, the amino acid comprises at least one of lysine, ornithine, and β-alanine. Treatment of layered silicates with protonated amino acids is typically carried out in an aqueous environment. Suitably, the amino acid is protonated with an inorganic acid, such as hydrochloric acid, hydrobromic acid, sulfuric acid, or nitric acid, or an organic acid, such as acetic acid, oxalic acid, formic acid, carbonic acid, malic acid, citric acid, or sulfonic acid.

[0061] In a typical implementation, layered silicates are added to water or to an aqueous liquid containing at least 70% by weight of water to form a slurry. Suitably, approximately 1 to 15% by weight of the layered silicates are calculated based on the weight of the water or aqueous liquid. Protonated amino acids may be added to the water or aqueous liquid before or after the addition of the layered silicates. The amino acids may be added in a protonated form, for example, as hydrochloride. Alternatively, the amino acids may be protonated in the aqueous liquid by adding a suitable amount of an acid, such as hydrochloric acid, hydrobromic acid, sulfuric acid, or nitric acid. Examples of suitable organic acids include acetic acid, oxalic acid, formic acid, carbonic acid, malic acid, citric acid, and sulfonic acid. The pH of the aqueous phase is suitably in the range of 4-8.

[0062] Layered silicates are appropriately treated with protonated amino acids at temperatures ranging from 5°C to 95°C for 10 minutes to 10 hours with stirring or agitation.

[0063] In a general embodiment of the method, the amount of protonated amino acids corresponds to 20 to 80%, preferably 25 to 70%, and more preferably 30 to 65% of the cation exchange capacity of the layered silicate.

[0064] After treatment with protonated amino acids, layered silicates can optionally be separated from aqueous liquids, for example by centrifugation or by drying.

[0065] Typically, the layered silicates of this invention are substantially completely separated in an aqueous environment. If necessary, small amounts of impurities in the unseparated material can be removed by suitable separation methods, such as centrifugation.

[0066] In some embodiments, the method for preparing layered silicates includes one or more washing steps with water. In exemplary embodiments, the layered silicates are washed with water or an aqueous washing solution before or after treatment with protonated amino acids. In some embodiments, the conductivity of the aqueous dispersion of the layered silicates can be reduced by known methods, such as by dialysis or by centrifugation, followed by removal of the supernatant and replacement of the supernatant with deionized water.

[0067] As mentioned above, the layered silicate of the present invention is highly suitable for improving the barrier properties of composite materials. Therefore, the present invention also relates to compositions comprising at least one adhesive and the layered silicate of the present invention.

[0068] Adhesives are typically materials that can form layers on a substrate.

[0069] Examples of adhesives include organic polymers and resins, prepolymers, and monomers capable of forming polymers. Adhesives can be of natural or synthetic origin, or they can be synthetically modified natural materials. Examples of adhesives are polyurethanes, polycarbonates, polyamides, polyacrylates, polyesters, polyolefins, rubbers, polysiloxanes, polyvinyl alcohol, polylactide, polysaccharides, polylysine, polystyrene, polyalkylene oxides, and polyepoxides, and combinations thereof.

[0070] Preferably, the adhesive comprises at least one aqueous polymer solution or aqueous polymer dispersion. Polymers used in aqueous media typically contain cationic or anionic groups. Examples of adhesives in aqueous media include proteins, polysaccharides, polylysine, polyacrylates, polyvinyl esters, polyvinyl alcohol, polyethylene oxide, oxidized polyolefins, and maleated polyolefins, and combinations thereof.

[0071] In some embodiments, the composition is a liquid composition that can be applied as a coating to a substrate. When the liquid composition contains water or an organic solvent as a diluent, the composition is dried by evaporation of the water or solvent after being applied to the substrate to form a coating.

[0072] The substrate to be coated can be any suitable substrate receiving the coating. Examples of suitable substrate materials are polymers such as polyesters, polyacrylates, polyvinyl chloride, and polyolefins, as well as paper, cardboard, wood, textiles, and metals. In some embodiments, the substrate is a polymer foil, such as polymer foil suitable for food packaging. In other embodiments, the substrate can be in the form of a tray, container, or bottle suitable for food or beverage packaging. In a further embodiment, the substrate can be a metallic substrate to be protected from corrosion, such as an iron, steel, copper, or aluminum substrate. The substrate can also be in the form of a laminate comprising two or more layers of different materials. Furthermore, the coating itself can form an inner or outer layer in a multilayer material.

[0073] The weight ratio of the binder in the composition to the layered silicate of the present invention is typically in the range of 3:97 to 97:3, preferably 7:93 to 93:7.

[0074] Incorporating the layered silicates of the present invention into the adhesive can be done using conventional techniques, such as mixing, stirring, extrusion, kneading processes, rotor-stator processes (Dispermat, Ultra-Turrax, etc.), grinding processes, or jet dispersion, and depends on the viscosity of the adhesive.

[0075] In a further embodiment, the present invention relates to the use of layered silicates according to the invention for improving the barrier properties of polymer layers or coatings. When included in a polymer layer or coating, the layered silicates of the present invention significantly improve the barrier properties of the layer. Related barrier properties include the permeation of gases and liquids through the layer. Improved barrier properties mean reduced permeation of gases, liquids, fats, greases, aromas, and other materials through the layer. Examples of gases that reduce permeation include oxygen, carbon dioxide and carbon monoxide, water vapor, helium, argon, hydrogen, and nitrogen. Reduced permeation is particularly important in the food and beverage packaging industry.

[0076] The layered silicates of the present invention are also suitable for improving the flame-retardant properties of polymers and potentially flammable organic matrix materials. In a typical embodiment, the layered silicates of the present invention are mixed with a polymer or organic matrix material to provide a composite material comprising the polymer or organic matrix material, wherein the layered silicates of the present invention are distributed in particulate form. In some embodiments, the number of particles per unit volume is at least about 2 particles / 100 μm. 3 For example, at least approximately 5 particles / 100μm 3 For example, at least approximately 8 particles / 100μm 3 For example, at least approximately 10 particles / 100 μm 3 For example, at least approximately 15 particles / 100 μm 3 Or at least approximately 20 particles / 100μm3 Examples of suitable matrix materials and polymers include natural or synthetic polymers or mixtures thereof. Polymers may be, for example, thermoplastic or thermosetting. The term "polymer" as used herein includes homopolymers and copolymers, as well as crosslinked and / or entangled polymers and elastomers, such as natural or synthetic rubbers and mixtures thereof. Specific examples of suitable polymers include, but are not limited to, polyolefins of any density, such as polyethylene and polypropylene, polycarbonate, polystyrene, polyester, acrylonitrile-butadiene-styrene copolymers, nylon, polyurethane, ethylene-vinyl acetate polymers, and any mixtures thereof, whether crosslinked or uncrosslinked. Other organic matrix materials include resins and bitumen. In addition to the layered silicates of this invention, other known flame-retardant additives may be present, such as char forming agents, drip suppressants, heat absorbers, and ignition suppressants.

[0077] The articles that can be formed from this composition are diverse. Examples include cable sheaths, cables coated or sheathed with the polymer composition, and housings and plastic components of electrical appliances (such as computers, monitors, printers, copiers, keyboards, pagers, telephones, mobile phones, handheld computers, network interfaces, inflatable chambers, and televisions), as well as roofing felt. Example

[0078] Example 1.1

[0079] Step a)

[0080] Na₂O₃ was prepared from a mixture of sodium carbonate (82.23 g, 99.9% purity), lithium carbonate (57.33 g, 99.9% purity), magnesium oxide (145.95 g, 98.0% purity), magnesium fluoride (161.15 g, 99.9% purity), and silicon dioxide (621.63 g, 99.9% purity). 0.6 [Mg 2.4 Li 0.6 Si4O 10 F2 is a layered material. The raw material mixture is heated to 1530°C in a platinum crucible to form a homogeneous melt and held at this temperature for 2 hours. The melt is then poured into a ceramic crucible. The ceramic crucible containing the melt is placed in an oven and cooled to 400°C over a period of 6 hours.

[0081] Step b)

[0082] After cooling to room temperature, 5.0 g of the layered material prepared in step a) was dispersed in 95.0 g of distilled water by stirring. The aqueous dispersion was heated to 80°C, and L-lysine hydrochloride was added to the sodium layered silicate dispersion. The amount of lysine hydrochloride was equal to 40% of the cation exchange capacity of the sodium layered silicate. The pH of the dispersion was adjusted to 5-6. The temperature of the dispersion was maintained for 45 minutes. The heated dispersion was then dispersed using an IKA ULTRA-500 dispersion tool equipped with an S25N18G dispersion tool. T 25 was processed at 10,000 rpm for 10 minutes. Subsequently, the dispersion was dried by evaporating water, and the residue was ground into powder.

[0083] The powder was analyzed using SAXS as described above. The d-interval was found to be... This indicates complete stratification.

[0084] Example 1.2

[0085] Example 1.2 is prepared similarly to Example 1.1. However, D-lysine hydrochloride is used instead of L-lysine hydrochloride.

[0086] Example 2

[0087] After cooling to room temperature, 5.0 g of the layered material prepared in step a) of Example 1 was dispersed in 95.0 g of distilled water by stirring. The aqueous dispersion was heated to 80°C, and L-ornithine hydrochloride was added to the dispersion of sodium layered silicate. The amount of L-ornithine hydrochloride was equal to 40% of the cation exchange capacity of the sodium layered silicate. The pH of the dispersion was adjusted to 5-6. The temperature of the dispersion was maintained for 45 minutes. The heated dispersion was then dispersed using an IKA ULTRA- with a dispersion tool S25N 18G. T 25 was processed at 10,000 rpm for 10 minutes. Subsequently, the dispersion was dried by evaporating water, and the residue was ground into powder.

[0088] Example 3

[0089] After cooling to room temperature, 5.0 g of the layered material prepared in step a) of Example 1 was dispersed in 95.0 g of distilled water by stirring. The aqueous dispersion was heated to 80°C, and L-lysine hydrochloride was added to the dispersion of sodium layered silicate. The amount of L-lysine hydrochloride was equal to 60% of the cation exchange capacity of the sodium layered silicate. The pH of the dispersion was adjusted to 5-6. The temperature of the dispersion was maintained for 45 minutes. The heated dispersion was then dispersed using an IKA ULTRA- with a dispersion tool S25N 18G. T 25 was processed at 10,000 rpm for 10 minutes. Subsequently, the dispersion was dried by evaporating water, and the residue was ground into powder.

[0090] Example 4

[0091] After cooling to room temperature, 5.0 g of the layered material prepared in step a) of Example 1 was dispersed in 95.0 g of distilled water by stirring. The aqueous dispersion was heated to 80°C, and L-ornithine hydrochloride was added to the dispersion of sodium layered silicate. The amount of L-ornithine hydrochloride was equal to 60% of the cation exchange capacity of the sodium layered silicate. The pH of the dispersion was adjusted to 5-6. The temperature of the dispersion was maintained for 45 minutes. The heated dispersion was then dispersed using an IKA ULTRA- with a dispersion tool S25N 18G. T 25 was processed at 10,000 rpm for 10 minutes. Subsequently, the dispersion was dried by evaporating water, and the residue was ground into powder.

[0092] Example 5

[0093] Step a)

[0094] Na₂O₃ was prepared from a mixture of sodium carbonate (89.03 g, 99.9% purity), lithium carbonate (62.06 g, 99.9% purity), magnesium oxide (140.46 g, 98.0% purity), magnesium fluoride (161.03 g, 99.9% purity), and silicon dioxide (621.63 g, 99.9% purity). 0.65[ Mg 2.35 Li 0.65 Si4O 10 F2 is a layered material. The raw material mixture is heated to 1530°C in a platinum crucible to form a homogeneous melt and held at this temperature for 2 hours. The melt is then poured into a ceramic crucible. The ceramic crucible containing the melt is placed in an oven and cooled to 400°C over a period of 6 hours.

[0095] Step b)

[0096] After cooling to room temperature, 5.0 g of the layered material prepared in step a) was dispersed in 95.0 g of distilled water by stirring. The aqueous dispersion was heated to 80°C, and L-lysine hydrochloride was added to the sodium layered silicate dispersion. The amount of L-lysine hydrochloride was equal to 40% of the cation exchange capacity of the sodium layered silicate. The pH of the dispersion was adjusted to 5-6. The temperature of the dispersion was maintained for 45 minutes. The heated dispersion was then dispersed using an IKA ULTRA-5000 dispersion tool equipped with an S25N 18G dispersion tool. T 25 was processed at 10,000 rpm for 10 minutes. Subsequently, the dispersion was dried by evaporating water, and the residue was ground into powder.

[0097] Example 6

[0098] After cooling to room temperature, 5.0 g of the layered material prepared in step a) of Example 5 was dispersed in 95.0 g of distilled water by stirring. The aqueous dispersion was heated to 80°C, and L-ornithine hydrochloride was added to the dispersion of sodium layered silicate. The amount of L-ornithine hydrochloride was equal to 40% of the cation exchange capacity of the sodium layered silicate. The pH of the dispersion was adjusted to 5-6. The temperature of the dispersion was maintained for 45 minutes. The heated dispersion was then dispersed using an IKA ULTRA- with a dispersion tool S25N 18G. T 25 was processed at 10,000 rpm for 10 minutes. Subsequently, the dispersion was dried by evaporating water, and the residue was ground into powder.

[0099] Example 7

[0100] After cooling to room temperature, 5.0 g of the layered material prepared in step a) of Example 5 was dispersed in 95.0 g of distilled water by stirring. The aqueous dispersion was heated to 80°C, and L-lysine hydrochloride was added to the dispersion of sodium layered silicate. The amount of L-lysine hydrochloride was equal to 60% of the cation exchange capacity of the sodium layered silicate. The pH of the dispersion was adjusted to 5-6. The temperature of the dispersion was maintained for 45 minutes. The heated dispersion was then dispersed using an IKA ULTRA- with a dispersion tool S25N 18G. T 25 was processed at 10,000 rpm for 10 minutes. Subsequently, the dispersion was dried by evaporating water, and the residue was ground into powder.

[0101] Example 8

[0102] After cooling to room temperature, 5.0 g of the layered material prepared in step a) of Example 5 was dispersed in 95.0 g of distilled water by stirring. The aqueous dispersion was heated to 80°C, and L-ornithine hydrochloride was added to the dispersion of sodium layered silicate. The amount of L-ornithine hydrochloride was equal to 60% of the cation exchange capacity of sodium layered silicate. The pH of the dispersion was adjusted to 5-6. The temperature of the dispersion was maintained for 45 minutes. The heated dispersion was then dispersed using an IKA ULTRA- with a dispersion tool S25N 18G. T 25 was processed at 10,000 rpm for 10 minutes. Subsequently, the dispersion was dried by evaporating water, and the residue was ground into powder.

[0103] Example 9

[0104] Step a)

[0105] Na₂O₃ was prepared from a mixture of sodium carbonate (109.33 g, 99.9% purity), lithium carbonate (76.22 g, 99.9% purity), magnesium oxide (124.74 g, 98.0% purity), magnesium fluoride (160.68%, 99.9% purity), and silicon dioxide (619.83 g, 99.9% purity). 0.80 [Mg 2.2 Li 0.8 Si4O 10 F2 is a layered material. The raw material mixture is heated to 1530°C in a platinum crucible to form a homogeneous melt and held at this temperature for 2 hours. The melt is then poured into a ceramic crucible. The ceramic crucible containing the melt is placed in an oven and cooled to 400°C over a period of 6 hours.

[0106] Step b)

[0107] After cooling to room temperature, 5.0 g of the layered material prepared in step a) was dispersed in 95.0 g of distilled water by stirring. The aqueous dispersion was heated to 80°C, and β-alanine hydrochloride was added to the sodium layered silicate dispersion. The amount of β-alanine hydrochloride was equal to 40% of the cation exchange capacity of the sodium layered silicate. The pH of the dispersion was adjusted to 5-6. The temperature of the dispersion was maintained for 45 minutes. The heated dispersion was then dispersed using an IKA ULTRA-5000 dispersion tool equipped with an S25N 18G dispersion tool. T 25 was processed at 10,000 rpm for 10 minutes. Subsequently, the dispersion was dried by evaporating water, and the residue was ground into powder.

[0108] Example 10

[0109] After cooling to room temperature, 5.0 g of the layered material prepared in step a) of Example 9 was dispersed in 95.0 g of distilled water by stirring. The aqueous dispersion was heated to 80°C, and β-alanine hydrochloride was added to the dispersion of sodium layered silicate. The amount of β-alanine hydrochloride was equal to 80% of the cation exchange capacity of the sodium layered silicate. The pH of the dispersion was adjusted to 5-6. The temperature of the dispersion was maintained for 45 minutes. The heated dispersion was then subjected to a dispersion using an IKA ULTRA-5000 dispersion tool equipped with an S25N 18G. T 25 was processed at 10,000 rpm for 10 minutes. Subsequently, the dispersion was dried by evaporating water, and the residue was ground into powder.

[0110] Example 11

[0111] After cooling to room temperature, 5.0 g of the layered material prepared in step a) of Example 9 was dispersed in 95.0 g of distilled water by stirring. The aqueous dispersion was heated to 80°C, and L-ornithine hydrochloride was added to the dispersion of sodium layered silicate. The amount of L-ornithine hydrochloride was equal to 40% of the cation exchange capacity of the sodium layered silicate. The pH of the dispersion was adjusted to 5-6. The temperature of the dispersion was maintained for 45 minutes. The heated dispersion was then dispersed using an IKA ULTRA- with a dispersion tool S25N 18G. T 25 was processed at 10,000 rpm for 10 minutes. Subsequently, the dispersion was dried by evaporating water, and the residue was ground into powder.

[0112] Example 12

[0113] After cooling to room temperature, 5.0 g of the layered material prepared in step a) of Example 9 was dispersed in 95.0 g of distilled water by stirring. The aqueous dispersion was heated to 80°C, and L-lysine hydrochloride was added to the dispersion of sodium layered silicate. The amount of L-lysine hydrochloride was equal to 40% of the cation exchange capacity of the sodium layered silicate. The pH of the dispersion was adjusted to 5-6. The temperature of the dispersion was maintained for 45 minutes. The heated dispersion was then dispersed using an IKA ULTRA- with a dispersion tool S25N 18G. T 25 was processed at 10,000 rpm for 10 minutes. Subsequently, the dispersion was dried by evaporating water, and the residue was ground into powder.

[0114] Example 13 (Comparative)

[0115] After cooling to room temperature, 5.0 g of the layered material prepared in step a) of Example 1 was dispersed in 95.0 g of distilled water by stirring. The aqueous dispersion was heated to 80°C, and L-lysine hydrochloride was added to the dispersion of sodium layered silicate. The amount of L-lysine hydrochloride was equal to 150% of the cation exchange capacity of the sodium layered silicate. The pH of the dispersion was adjusted to 5-6. The temperature of the dispersion was maintained for 45 minutes. The heated dispersion was then dispersed using an IKA ULTRA- with a dispersion tool S25N 18G. T 25 was processed at 10,000 rpm for 10 minutes. Subsequently, the dispersion was dried by evaporating water, and the residue was ground into powder.

[0116] Example 14 (Comparative)

[0117] After cooling to room temperature, 5.0 g of the layered material prepared in step a) of Example 5 was dispersed in 95.0 g of distilled water by stirring. The aqueous dispersion was heated to 80°C, and L-ornithine hydrochloride was added to the dispersion of sodium layered silicate. The amount of L-ornithine hydrochloride was equal to 150% of the cation exchange capacity of sodium layered silicate. The pH of the dispersion was adjusted to 5-6. The temperature of the dispersion was maintained for 45 minutes. The heated dispersion was then dispersed using an IKA ULTRA- with a dispersion tool S25N 18G. T 25 was processed at 10,000 rpm for 10 minutes. Subsequently, the dispersion was dried by evaporating water, and the residue was ground into powder.

[0118] The prepared layered materials are summarized in Table 1 below.

[0119] Table 1

[0120]

[0121]

[0122] Application of (sodium / amino acid)-layered silicates in barrier formulations

[0123] (Sodium / Amino Acid)-Layered Silicate Barrier Formulation with PVOH and EVOH

[0124] The (sodium / amino acid)-layered silicates shown in Table 2 were dispersed in deionized water at a solid content of 5 wt%. Solutions of the polymer (EVOH, ethylene-vinyl alcohol copolymer, available from Kuraray EXCEVAL AQ 4104, or PVOH, polyvinyl alcohol, available from Sigma Aldrich (Mowiol 28-98)) were prepared by heating the polymer solids in deionized water at 85°C for 60 minutes. The respective polymer solutions were added to the (sodium / amino acid)-layered silicate dispersion to achieve a total solid content of 5 wt%. The ratio of (sodium / amino acid)-layered silicate to polymer was adjusted to 10 wt% layered silicate in the dry film. The dispersion of (sodium / amino acid)-layered silicate and polymer was applied to a 36 μm thick PET (polyethylene terephthalate) film using a K-manual coating machine. The wet film thickness of the applied coating was 24 μm. The coating was dried at 80°C for 6 hours. Unless otherwise mentioned in Table 2, the thickness of the dry coating is approximately 1 μm. Using OX- Oxygen transmission rate was measured using Model 1 / 50 at 23°C and 75 wt% relative humidity. Water vapor transmission rate was measured using PERMATRAN-W Model 1 / 50 at 75 wt% relative humidity.

[0125] (Sodium / Amino Acid)-Layered Silicate and Polyurethane Dispersion Barrier Formulation

[0126] The (sodium / amino acid)-layered silicates shown in Table 2 were dispersed in deionized water at a solid content of 5 wt%. Polyurethane (LIOPUR 2004-151 and LIOPUR PFL 2392, available from Synthopol Chemie) polymer dispersions were added to the (sodium / amino acid)-layered silicate dispersion to achieve a total solid content of 5 wt%. The ratio of (sodium / amino acid)-layered silicate to polymer was adjusted to have 50 wt% layered silicate in the dry film. The dispersion of (sodium / amino acid)-layered silicate and polymer was applied to a 36 μm thick PET (polyethylene terephthalate) film using a K-manual coating machine. The coating was dried at 80°C for 6 hours. Unless otherwise mentioned in Table 2, the thickness of the dry coating was approximately 1 μm. Using OX- Oxygen transmission rate was measured using Model 1 / 50 at 23°C and 75 wt% relative humidity. Water vapor transmission rate was measured using PERMATRAN-W Model 1 / 50 at 75 wt% relative humidity.

[0127] (Sodium / Amino Acid)-Layer Silicate Barrier Formulation with Cellulose and Dextrin

[0128] The (sodium / amino acid)-layered silicate shown in Table 2 was dispersed in deionized water at a solid content of 5% by weight. A polymer solution of cellulose or dextrin was added to the (sodium / amino acid)-layered silicate dispersion to achieve a total solid content of 5% by weight. The ratio of (sodium / amino acid)-layered silicate to polymer was adjusted to 95% by weight (5% being cellulose or dextrin) in the dry film. The dispersion of (sodium / amino acid)-layered silicate and polymer was applied to a 36 μm thick PET (polyethylene terephthalate) film using a K-manual coating machine. The coating was dried at 80°C for 6 hours. The thickness of the dry coating was approximately 1 μm. Using OX- Oxygen transmission rate was measured using Model 1 / 50 at 23°C and 75% relative humidity. Water vapor transmission rate was measured using PERMATRAN-W Model 1 / 50 at 75% relative humidity.

[0129] Table 2

[0130]

[0131]

[0132] Examples marked with * are comparative examples.

[0133] Table 2 shows that the layered materials of the present invention provide significantly improved barrier properties compared to layered materials in which inorganic interlayer cations have been completely exchanged with amino acids (Examples 13 and 14) or in which inorganic interlayer cations have not been exchanged (Examples 1a, 5a, 9a).

Claims

1. A layered silicate having interlayer cations, wherein the interlayer cations comprise a) Inorganic monovalent cations, which include Na + K + and Li + At least one of, and b) An organic cation containing at least one protonated amino acid. The molar ratio of inorganic monovalent cation a) to organic cation b) is in the range of 0.20 : 0.80 to 0.80 : 0.

20. The interlayer cation alternation between layers contains more than 60 mol% protonated amino acids and more than 60 mol% of Na+. + K + and Li + Inorganic cations.

2. The layered silicate according to claim 1, wherein the layered silicate is a synthetic layered silicate.

3. The layered silicate of claim 1, wherein the layered silicate is a naturally occurring layered silicate modified with protonated amino acids.

4. The layered silicate according to any one of claims 1 to 3, wherein the protonated amino acid comprises at least one of lysine, ornithine, and alanine.

5. A method for preparing a layered silicate according to any one of claims 1 to 4, comprising: i) Provide layered silicates, ii) Determine the cation exchange capacity of the layered silicate. iii) Contact the layered silicate with protonated amino acids in an aqueous environment, wherein the amount of protonated amino acids corresponds to 20 to 80% of the cation exchange capacity of the layered silicate.

6. The method of claim 5, wherein the protonated amino acid comprises at least one of lysine, ornithine, and alanine.

7. The method according to any one of claims 5 or 6, wherein the layered silicate provided in step i) has a composition of Na x [Mg 3-z Li y Si4O 10 (T)2, where x is in the range of 0.40 to 0.

90. y is in the range of 0.00 to 0.

90. z is in the range of 0.20 to 0.

90. T independently represents either F or OH each time it appears, and x + (3-z) + y ≤ 4.

8. The method according to any one of claims 5 to 7, further comprising the step of drying the layered silicate.

9. A composition comprising at least one binder and a layered silicate according to any one of claims 1 to 4.

10. The composition of claim 9, wherein the adhesive comprises a polymer.

11. The composition of claim 10, wherein the adhesive comprises at least one aqueous polymer solution.

12. The composition of claim 10, wherein the adhesive comprises at least one aqueous polymer dispersion.

13. Use of the layered silicate according to any one of claims 1 to 4 for improving the barrier properties of polymer layers.

14. Use of the layered silicate according to any one of claims 1 to 4 for improving the barrier properties of a coating.

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