Layered silicates partially modified with amino acids

Abstract

The present invention relates to a layered silicate having interlayer cations, the interlayer cations being selected from the group consisting of (a) Na + , K + , and Li + and (b) an inorganic monovalent cation comprising at least one protonated amino acid.

Description

[Technical Field]

[0001] The present invention relates to layered silicates having interlayer cations, a method for preparing the layered silicates, compositions containing at least one binder and the layered silicates, and the use of the layered silicates to improve the barrier properties of polymers or coating layers. [Background technology]

[0002] EP 0 205 281 A1 describes the treatment of layered silicates with aminocarboxylic acids, which act as cell expanders. The resulting material is described as a gel. The gel can be molded into a desired shape to form an article.

[0003] US 3,325,340 relates to a method for producing an aqueous suspension of vermiculite flakes, in which vermiculite crystals are treated with a solution containing a water-soluble salt of an ammonia cation to promote cross-expansion of the crystals in a direction perpendicular to the major cleavage planes of the crystals. In some embodiments, lysine and ornithine cations are used. Summary of the Invention [Problem to be solved by the invention]

[0004] There is currently a need for layered silicates that easily exfoliate into single clay lamellae, provide good barrier properties, and can be prepared by an economically viable method. It has been found that complete replacement of the inorganic interlayer cations of layered silicates with protonated amino acids does not easily and completely exfoliate into single clay lamellae as desired. This reduces the effectiveness of such materials in improving barrier properties. [Means for solving the problem]

[0005] The present invention provides a layered silicate having interlayer cations, the interlayer cations being (a)Na + , K. + , and Li + an inorganic monovalent cation comprising at least one of (b) an organic cation comprising at least one protonated amino acid; Including, The molar ratio of the inorganic monovalent cation (a) to the organic cation (b) is in the range of 0.20:0.80 to 0.80:0.20. DETAILED DESCRIPTION OF THE INVENTION

[0006] The layered silicates of the present invention readily, and often simultaneously, exfoliate into single lamellae. They can be prepared by economically viable methods.

[0007] Layered silicates are Na + , K. + , and Li + The layered silicates can be prepared from various layered silicates containing inorganic monovalent interlayer cations, including at least one of the following: Examples of suitable layered silicates include vermiculite, beidellite, nontronite, volkonskoite, saponite, stevensite, sauconite, bentonite, montmorillonite, hectorite, smectite, phlogopite, mica, and illite.

[0008] In some embodiments, the layered silicate is a natural layered silicate modified with a protonated amino acid.

[0009] In another embodiment, the layered silicate is a synthetic layered silicate.

[0010] In a preferred embodiment, the layered silicate is prepared by dissolving Na in water prior to modification with an organic cation. x [Mg 3-z Li y ]SiO 10 (T)2, 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 and T is independently F or OH; and x+(3-z)+y≦4 is.

[0011] In some embodiments, at least 50%, or even at least 70%, or at least 90% of the T present are F. In some embodiments, T is F 100% of the time.

[0012] The ratio of Na, Mg, and Li may vary within the ranges given above.

[0013] In preferred embodiments, the material contains lithium. In these embodiments, y is generally in the range of 0.20 to 0.70.

[0014] 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.

[0015] In synthetic layered silicates, depending on the purity of the starting material, other elements may be present in small amounts, such as iron, calcium, aluminum, potassium, boron, copper, zinc, manganese, cobalt, nickel, vanadium, gallium, zirconium, and anions such as sulfate, chloride, phosphate, carbonate, and silicate.

[0016] In the layered silicate of the present invention, the interlayer inorganic cations are less than completely replaced by organic cations having at least one protonated amino acid. Amino acids are organic compounds that have an amino group, generally a primary amino group, and a carboxylic acid group, along with a side chain, which may be a hydrocarbyl group and may optionally have additional functional groups. The amino group may be located on the carbon atom adjacent to the carboxylic acid group (alpha amino acid). In other embodiments, the amino group and the carboxylic acid may be separated by two carbon atoms (beta amino acid), three carbon atoms (gamma amino acid), four carbon atoms (delta amino acid), or even more carbon atoms. In a preferred embodiment, the amino acid is an alpha 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. Alpha amino acids are chiral and may exist in L- or D-form. For the purposes of the present invention, alpha amino acids in L- and D-forms are equally suitable. However, naturally occurring alpha amino acids generally exist in L-form.

[0017] In a preferred embodiment, the amino acids include at least one of lysine, ornithine, and beta-alanine.

[0018] As described above, in the layered silicate of the present invention, the interlayer inorganic cations are less than completely exchanged with organic cations containing at least one protonated amino acid. Less than 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.

[0019] In a preferred embodiment, the molar amount of the protonated amino acid corresponds to 20 to 85% of the cation exchange capacity of the layered silicate, more preferably 25 to 70% of the cation exchange capacity, and even more preferably 30 to 65% of the cation exchange capacity.

[0020] In a further embodiment of the layered silicate of the present invention, the molar ratio of the inorganic monovalent cation (a) to the organic cation (b) is preferably in the range of 0.25:0.75 to 0.75:0.25, more preferably 0.30:0.70 to 0.70:0.30.

[0021] In a more preferred embodiment, the inorganic cations of alternating layers are exchanged to different degrees with protonated amino acids.For example, in some embodiments, between multiple layers, the interlayer cations alternately contain more than 60 mol% of organic cations (b) and more than 60 mol% of inorganic cations (a).Particularly preferred, between multiple layers, the interlayer cations alternately contain more than 70 mol% of organic cations (b) and more than 70 mol% of inorganic cations (a).The concept of regular or semi-regular interlayer structuring of different cations in the interlayer stack of layered silicates (interlayer stack of layered silicates) describes the statistically alternating occurrence of cation occupancy in the interlayer space of 2:1 phyllosilicate.This means that, on average, every other interlayer (interlayer) has the same type of interlayer cation, and preferably, each interlayer (interlayer) has only one type of cation. By way of example and in simplified terms, this means that the first interlayer (interlayer) contains only inorganic cations. Then, in turn, a different type of cation, e.g., an amino acid cation, is present in the next interlayer (interlayer). In an ideal embodiment, the next interlayer (interlayer) is again identical to the first interlayer (interlayer), and the fourth interlayer (interlayer) is identical to the second interlayer (interlayer). Because 2:1 layer silicates are highly complex materials, defects can occur, and therefore the interlayer structuring is said to be regular even when the corresponding structure exists on a statistical average. The presence of an interlayered structured phase is visualized by the presence of superstructure reflections in powder x-ray diffractograms. This has a d value, which corresponds to the total interplanar spacing of the fully exchanged phase. By way of example and in simplified terms, this corresponds to the sum of the interlayer distances between the first and second layers.

[0022] The delamination of the amino acid-modified layered silicates can be identified via small-angle X-ray scattering (SAXS). SAXS can be used to determine the d-spacing of the delaminated gel. Due to delamination, these d-spacings are typically greater than 100 Å. SAXS data were measured using a "Double Ganesha AIR" system (SAXSLAB, Denmark). The X-ray source of this laboratory-based system is a rotating anode (copper, MicroMax 007HF, Rigaku, Japan) that provides a microfocused beam. Data are recorded using a position-sensitive detector (PILATUS 300K, Dectris). Samples of the delaminated amino acid-layered silicates were prepared by adding a defined amount of ultrapure water to the dried, partially modified amino acid-layered silicates, which resulted in gel formation. After equilibration for one week, SAXS patterns were recorded using a 1 mm glass capillary.

[0023] The present invention also relates to a method for preparing a layered silicate, the method comprising: (i) providing a layered silicate having interlayer cations, wherein the interlayer cations are Na + , K. + , and Li + having inorganic monovalent cations including at least one of (ii) determining the cation exchange capacity of layered silicates; (iii) contacting the layered silicate with a 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 the amount of the protonated amino acid corresponds to 20-80% of the cation exchange capacity of the layered silicate.

[0024] With respect to the layered silicate provided in step (i) of the present process, the same considerations as above apply. In a preferred embodiment, the layered silicate has the composition Na x [Mg 3-z Li y ]SiO 10 (T)2, 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 and T is independently F or OH; and x+(3-z)+y≦4 is.

[0025] In some embodiments, at least 50%, or even at least 70%, or at least 90% of the T present are F. In some embodiments, T is F 100% of the time.

[0026] The ratio of Na, Mg, and Li may vary within the ranges given above.

[0027] In preferred embodiments, the material contains lithium. In these embodiments, y is generally in the range of 0.20 to 0.70.

[0028] 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.

[0029] Depending on the purity of the starting material, other elements may be present in small amounts in the synthetic layered silicates, such as iron, calcium, aluminum, potassium, boron, copper, zinc, manganese, cobalt, nickel, vanadium, gallium, zirconium, and anions such as sulfate, chloride, phosphate, carbonate, and silicate.

[0030] When the layered silicate is a synthetic layered silicate, the layered silicate is suitably prepared by a method comprising the steps of: (a) Providing a mixture containing a Na compound, a Mg compound, a Li compound, and a Si compound, wherein these compounds are selected from carbonates, halides, and oxides, and the molar ratio of Na:Mg:Li:Si is in the range of 0.4-0.9:2.1-2.6:0.0-0.9:4.0. (b) heating the mixture to a temperature above 1100°C to form a homogeneous liquid; (c) cooling the mixture to a temperature of less than 1000°C for a period of at least 0.5 hours.

[0031] In step (a), a mixture of Na compounds, Mg compounds, Li compounds, and Si compounds is provided. These compounds are provided in the form of oxides, halides, or carbonates. In a typical embodiment, alkali metal salts / alkaline earth metal salts, alkaline earth oxides, and silicon oxides are used, preferably binary alkali fluorides / alkaline earth fluorides, alkaline earth oxides, and silicon oxides, preferably LiF, NaF, MgF2, MgO, and quartz. In a further preferred embodiment, 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 layered material to be prepared. Therefore, the molar ratio of the metal compounds used as starting materials is selected to achieve the above-mentioned molar composition of the layered material.

[0032] The relative proportions of the starting compounds are, for example, 0.4 to 0.6 moles of F in the form of alkali / alkaline earth fluorides per mole of silicon dioxide. - and 0.4 to 0.6 moles of alkaline earth oxide per mole of silicon dioxide, preferably 0.45 to 0.55 moles of F in the form of alkali / alkaline earth fluoride per mole of silicon dioxide. - and 0.45 to 0.55 moles of alkaline earth oxides per mole of silicon dioxide, particularly preferably 0.5 moles of F in the form of alkali / alkaline earth fluorides per mole of silicon dioxide. -and 0.5 moles of alkaline earth oxide per mole of silicon dioxide.

[0033] Preferably, the starting compounds are of 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.

[0034] 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.

[0035] Typically, a high melting crucible made of a chemically inert or slow reacting metal, preferably molybdenum or platinum, is used.

[0036] Heating is typically carried out in a high frequency induction furnace. If necessary, the crucible is protected from oxidation by a protective atmosphere (e.g., argon), a vacuum, or a combination of both measures. For precious metals such as platinum, this is not necessary.

[0037] 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 so that a homogeneous liquid is obtained. Generally, the temperature range in the second step is 1100°C to 1700°C, preferably 1300 to 1600°C. Generally, the duration of this step is 60 to 240 minutes, preferably 75 to 180 minutes.

[0038] 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, after which the material is typically cooled to ambient atmosphere.

[0039] 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 in accordance with DIN EN ISO 11260:2017-04.

[0040] In the third step, the layered silicate is contacted with a 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 the amount of the protonated amino acid corresponds to 20-80% of the cation exchange capacity of the layered silicate.

[0041] The same requirements and preferred conditions as above apply to amino acids.In a preferred embodiment, amino acids include at least one of lysine, ornithine, and β-alanine.The treatment of layered silicate with protonated amino acids is generally carried out in an aqueous environment.Suitably, amino acids are protonated with inorganic acids, such as hydrochloric acid, hydrobromic acid, sulfuric acid, or nitric acid, or with organic acids, such as acetic acid, oxalic acid, formic acid, carbonic acid, malic acid, citric acid, and sulfonic acid.

[0042] In a typical embodiment, the layered silicate is added to water or an aqueous liquid containing at least 70% by weight of water to form a slurry. Suitably, about 1-15% by weight of the layered silicate is used, calculated on the weight of the water or aqueous liquid. The protonated amino acid may be added to the water or aqueous liquid before or after the addition of the layered silicate. The amino acid may be added in a protonated form, for example, as a hydrochloride salt. Alternatively, the amino acid may be protonated in the aqueous liquid by adding an appropriate amount of acid, for example, 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.

[0043] Treatment of the layered silicate with the protonated amino acid is suitably carried out at a temperature in the range of 5° C. to 95° C. for a period of 10 minutes to 10 hours, with stirring or agitation.

[0044] In a typical embodiment of the method, the amount of protonated amino acid corresponds to 20 to 80%, preferably 25 to 70%, more preferably 30 to 65% of the cation exchange capacity of the layered silicate.

[0045] After treatment with the protonated amino acid, the layered silicate may optionally be separated from the aqueous liquid, for example by centrifugation or by drying.

[0046] Generally, the layered silicates of the present invention will essentially completely exfoliate in an aqueous environment, and if desired, small amounts of impurities of non-exfoliated material may be removed by a suitable separation process, such as centrifugation.

[0047] In some embodiments, the method for preparing the layered silicate includes one or more washing steps with water. In exemplary embodiments, the layered silicate is washed with water or an aqueous washing liquid before or after treatment with a protonated amino acid. In some embodiments, the conductivity of the aqueous dispersion of the layered silicate can be reduced by known methods, such as dialysis or centrifugation, followed by removal of the supernatant and replacement with deionized water.

[0048] As mentioned above, the layered silicates of the present invention are highly suitable for improving the barrier properties of composite materials. Therefore, the present invention also relates to a composition comprising at least one binder and the layered silicates of the present invention.

[0049] A binder is generally a substance that can form a layer on a substrate.

[0050] Examples of binders include organic polymers and resins, prepolymers, and monomers capable of forming polymers. Binders can be of natural or synthetic origin, or can be synthetically modified natural substances. Examples of binders are polyurethanes, polycarbonates, polyamides, polyacrylates, polyesters, polyolefins, rubbers, polysiloxanes, polyvinyl alcohols, polylactic acids, polysaccharides, polylysines, polystyrenes, polyalkylene oxides, and polyepoxides, and combinations thereof.

[0051] Preferably, the binder comprises at least one aqueous polymer solution or aqueous polymer dispersion. Polymers for aqueous media often have cationic or anionic groups. Examples of binders in aqueous media include proteins, polysaccharides, polylysines, polyacrylates, polyvinyl esters, polyvinyl alcohols, polyethylene oxides, oxidized polyolefins, and maleated polyolefins, and combinations thereof.

[0052] In some embodiments, the composition is a liquid composition that can be applied as a coating to a substrate. If the liquid composition contains water or an organic solvent as a diluent, the composition is dried after application to the substrate by evaporation of the water or solvent to form a coating layer.

[0053] The substrate to be coated may be any substrate suitable for receiving a coating layer. Examples of suitable substrate materials include polymers, such as polyesters, polyacrylates, polyvinyl chlorides, and polyolefins, as well as paper, cardboard, wood, textile materials, and metals. In some embodiments, the substrate is a polymer foil, such as a polymer foil (polymer film) suitable for food packaging. In other embodiments, the substrate may be in the form of a tray, container, or bottle suitable for packaging food or beverages. In further embodiments, the substrate may be a metal substrate to be protected against corrosion, such as an iron, steel, or copper substrate, or an aluminum substrate. The substrate may also be in the form of a laminate, comprising two or more layers of different materials. Furthermore, the coating layer may itself form an inner or outer layer in a multi-layer material.

[0054] The weight ratio of the binder to the layered silicate of the present invention in the composition is generally in the range of 3:97 to 97:3, and preferably in the range of 7:93 to 93:7.

[0055] The incorporation of the layered silicates of the present invention into the binder may be carried out by conventional techniques, such as mixing, stirring, extruding, kneading, rotor-stator methods (Dispermat, Ultra-Turrax, etc.), crushing, or jet dispersion, depending on the viscosity of the binder.

[0056] In a further embodiment, the present invention relates to the use of the layered silicate of the present invention to improve the barrier properties of a polymer layer or coating layer. When incorporated into a polymer layer or coating layer, the layered silicate of the present invention substantially improves the barrier properties of the layer. Relevant barrier properties include gas and liquid permeability through the layer. Improved barrier properties mean reduced permeability of gases, liquids, fats, grease, flavorings, and other substances through the layer. Examples of gases whose permeability is reduced include oxygen, carbon dioxide, and carbon monoxide, water vapor, helium, argon, hydrogen, and nitrogen. Reduced permeability is particularly important in the field of food and beverage packaging.

[0057] 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 into a polymer or organic matrix material to provide a composite material containing a polymer or organic matrix material, in which the layered silicates of the present invention are distributed in the form of particles. In some embodiments, the number of particles per unit volume is 100 μm 3 At least about 2 particles per 100 μm 3 At least about 5 particles per 100 μm 3 At least about 8 particles per 100 μm 3 At least about 10 particles per 100 μm 3 At least about 15 particles per 100 μm 3The average particle size is at least about 20 particles per 1000 particles. Examples of suitable matrix materials and polymers include natural or synthetic polymers or mixtures thereof. The polymer may be, for example, thermoplastic or thermosetting. The term "polymer" as used herein includes homopolymers and copolymers, and includes 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 silicate of the present invention, other known flame retardants may be present, as may char formers, drip suppressants, heat absorbers, and ignition suppressants.

[0058] The articles that can be formed from the present compositions are varied and numerous, including electrical cable sheaths, electrical cables coated or sheathed with the polymeric composition, and housings and plastic components for consumer electronics (e.g., computers, monitors, printers, photocopiers, keyboards, handhelds, telephones, mobile phones, handheld computers, network interfaces, plenums, and televisions), and roofing felts. [Example]

[0059] Example 1.1 Process (a) Formula Na 0.6 [Mg 2.4 Li 0.6 ]SiO 10The layered material of F2 was prepared from a mixture of sodium carbonate (82.23 g, 99.9% purity), lithium carbonate (57.33 g, 99.9% purity), magnesium oxide (145.95.8 g, 98.0% purity), magnesium fluoride (161.15 g, 99.9% purity), and silicon dioxide (621.63 g, 99.9% purity). The mixture of raw materials was heated to 1530°C in a platinum crucible to form a homogeneous melt and held at this temperature for 2 hours. After this time, the melt was poured into a ceramic crucible. The ceramic crucible with the melt was placed in a furnace and allowed to cool to a temperature of 400°C over a period of 6 hours.

[0060] Process (b) 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 a temperature of 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 processed in an IKA ULTRA-TURRAX™ T 25 using a S25N 18G disperser at a speed of 10,000 rpm for 10 minutes. Thereafter, the dispersion was dried by evaporating the water, and the residue was crushed into powder.

[0061] The powder was analyzed by SAXS as described above, and the d-spacing was 430 Å, indicating complete delamination.

[0062] Example 1.2 Example 1.2 was prepared similarly to Example 1.1, except that D-lysine hydrochloride was used instead of L-lysine hydrochloride.

[0063] Example 2 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 a temperature of 80°C, and L-ornithine hydrochloride was added to the sodium layered silicate dispersion. 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 processed in an IKA ULTRA-TURRAX™ T 25 using a dispersing tool S25N 18G at a speed of 10,000 rpm for a period of 10 minutes. Thereafter, the dispersion was dried by evaporation of water, and the residue was crushed into a powder.

[0064] Example 3 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 a temperature of 80°C, and L-lysine hydrochloride was added to the sodium layered silicate dispersion. 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 processed in an IKA ULTRA-TURRAX™ T 25 using a dispersing tool S25N 18G at a speed of 10,000 rpm for a period of 10 minutes. Thereafter, the dispersion was dried by evaporation of water, and the residue was crushed into a powder.

[0065] Example 4 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 a temperature of 80°C, and L-ornithine hydrochloride was added to the sodium layered silicate dispersion. 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 processed in an IKA ULTRA-TURRAX™ T 25 using a dispersing tool S25N 18G at a speed of 10,000 rpm for a period of 10 minutes. Thereafter, the dispersion was dried by evaporation of water, and the residue was crushed into a powder.

[0066] Example 5 Process (a) Formula Na 0.65 [Mg 2.35 Li 0.65 ]SiO 10 The layered material of F2 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). The mixture of raw materials was heated to 1530°C in a platinum crucible to form a homogeneous melt and held at this temperature for 2 hours. After this time, the melt was poured into a ceramic crucible. The ceramic crucible with the melt was placed in a furnace and allowed to cool to a temperature of 400°C over a period of 6 hours.

[0067] Process (b) 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 a temperature of 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 processed in an IKA ULTRA-TURRAX™ T 25 using a S25N 18G disperser at a speed of 10,000 rpm for 10 minutes. Thereafter, the dispersion was dried by evaporating the water, and the residue was crushed into powder.

[0068] Example 6 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 a temperature of 80°C, and L-ornithine hydrochloride was added to the sodium layered silicate dispersion. 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 processed in an IKA ULTRA-TURRAX™ T 25 using a S25N 18G disperser at a speed of 10,000 rpm for 10 minutes. Thereafter, the dispersion was dried by evaporating the water, and the residue was crushed into powder.

[0069] Example 7 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 a temperature of 80°C, and L-lysine hydrochloride was added to the sodium layered silicate dispersion. 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 processed in an IKA ULTRA-TURRAX™ T 25 using a S25N 18G disperser at a speed of 10,000 rpm for 10 minutes. Thereafter, the dispersion was dried by evaporating the water, and the residue was crushed into powder.

[0070] Example 8 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 a temperature of 80°C, and L-ornithine hydrochloride was added to the sodium layered silicate dispersion. 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 processed in an IKA ULTRA-TURRAX™ T 25 using a S25N 18G disperser at a speed of 10,000 rpm for 10 minutes. Thereafter, the dispersion was dried by evaporating the water, and the residue was crushed into powder.

[0071] Example 9 Process (a) Formula Na 0.80 [Mg 2.2 Li 0.8 ]SiO 10The layered material of F2 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 g, 99.9% purity), and silicon dioxide (619.83 g, 99.9% purity). The mixture of raw materials was heated to 1530°C in a platinum crucible to form a homogeneous melt and held at this temperature for 2 hours. After this time, the melt was poured into a ceramic crucible. The ceramic crucible with the melt was placed in a furnace and allowed to cool to a temperature of 400°C over a period of 6 hours.

[0072] Process (b) 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 a temperature of 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 processed in an IKA ULTRA-TURRAX™ T 25 using a S25N 18G disperser at a speed of 10,000 rpm for 10 minutes. Thereafter, the dispersion was dried by evaporating the water, and the residue was crushed into powder.

[0073] Example 10 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 a temperature of 80°C, and β-alanine hydrochloride was added to the sodium layered silicate dispersion. 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 processed in an IKA ULTRA-TURRAX™ T 25 using a S25N 18G disperser at a speed of 10,000 rpm for 10 minutes. Thereafter, the dispersion was dried by evaporating the water, and the residue was crushed into powder.

[0074] Example 11 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 a temperature of 80°C, and L-ornithine hydrochloride was added to the sodium layered silicate dispersion. 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 processed in an IKA ULTRA-TURRAX™ T 25 using a S25N 18G disperser at a speed of 10,000 rpm for 10 minutes. Thereafter, the dispersion was dried by evaporating the water, and the residue was crushed into powder.

[0075] Example 12 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 a temperature of 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 processed in an IKA ULTRA-TURRAX™ T 25 using a S25N 18G disperser at a speed of 10,000 rpm for 10 minutes. Thereafter, the dispersion was dried by evaporating the water, and the residue was crushed into powder.

[0076] Example 13 (comparison) 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 a temperature of 80°C, and L-lysine hydrochloride was added to the sodium layered silicate dispersion. 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 processed in an IKA ULTRA-TURRAX™ T 25 using a S25N 18G disperser at a speed of 10,000 rpm for 10 minutes. Thereafter, the dispersion was dried by evaporating the water, and the residue was crushed into powder.

[0077] Example 14 (Comparison) 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 a temperature of 80°C, and L-ornithine hydrochloride was added to the sodium layered silicate dispersion. The amount of L-ornithine 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 processed in an IKA ULTRA-TURRAX™ T 25 using a S25N 18G disperser at a speed of 10,000 rpm for 10 minutes. Thereafter, the dispersion was dried by evaporating the water, and the residue was crushed into powder.

[0078] The layered materials prepared are summarized in Table 1 below.

[0079] [Table 1]

[0080] Application of (sodium / amino acid)-layered silicates in barrier formulations (Sodium / amino acid)-layered silicate barrier formulation with PVOH and EVOH The sodium / amino acid layered silicates shown in Table 2 were dispersed in deionized water at a solids content of 5 wt. A solution 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)) was prepared by heating the polymer solids in deionized water at 85°C for 60 minutes. Each polymer solution was added to the sodium / amino acid layered silicate dispersion to obtain a total solids content of 5 wt. The ratio of sodium / amino acid layered silicate to polymer was adjusted to obtain 10 wt. % layered silicate in the dried film. The sodium / amino acid layered silicate and polymer dispersions were applied to a 36 μm-thick PET (polyethylene terephthalate) film using a K-hand coater. The wet film thickness of the applied coating layer was 24 μm. The coating was dried at 80° C. for 6 hours. The dry coating film thickness was approximately 1 μm unless otherwise indicated in Table 2. Oxygen transmission rates were measured at 23° C. and 75% relative humidity by weight using an OX-TRAN™ model 1 / 50. Water vapor transmission rates were measured at 75% relative humidity by weight using a PERMATRAN-W model 1 / 50.

[0081] Barrier formulations of (sodium / amino acid)-layered silicates with polyurethane dispersions The sodium / amino acid layered silicates shown in Table 2 were dispersed in deionized water at a solids content of 5 wt%. A polyurethane polymer dispersion (LIOPUR 2004-151 and LIOPUR PFL 2392, available from Synthopol Chemie) was added to the sodium / amino acid layered silicate dispersion to achieve a total solids content of 5 wt%. The ratio of sodium / amino acid layered silicate to polymer was adjusted to achieve 50 wt% layered silicate in the dry film. Using a K-hand coater, the sodium / amino acid layered silicate and polymer dispersions were applied onto 36 μm-thick PET (polyethylene terephthalate) films. The coatings were dried at 80°C for 6 hours. The thickness of the dried coating films was approximately 1 μm, unless otherwise indicated in Table 2. Oxygen transmission rates were measured using an OX-TRAN™ model 1 / 50 at 23° C. and 75% relative humidity by weight. Water vapor transmission rates were measured using a PERMATRAN-W model 1 / 50 at 75% relative humidity by weight.

[0082] (Sodium / amino acid)-layered silicate barrier formulation with cellulose and dextrin The sodium / amino acid layered silicates shown in Table 2 were dispersed in deionized water at a solids content of 5 wt%. A cellulose or dextrin polymer solution was added to the sodium / amino acid layered silicate dispersion to achieve a total solids content of 5 wt%. The ratio of sodium / amino acid layered silicate to polymer was adjusted to 95 wt% (5% cellulose and dextrin) in the dried film. The sodium / amino acid layered silicate and polymer dispersions were applied to a 36 μm-thick PET (polyethylene terephthalate) film using a K-hand coater. The coating was dried at 80°C for 6 hours. The thickness of the dried coating film was approximately 1 μm. Oxygen transmission rates were measured at 23°C and 75 wt% relative humidity using an OX-TRAN™ Model 1 / 50. Water vapor transmission rates were measured at 75 wt% relative humidity using a PERMATRAN-W Model 1 / 50.

[0083] [Table 2-1] [Table 2-2]

[0084] From Table 2, it can be concluded that the layered materials of the present invention provide significantly improved barrier properties compared to layered materials in which the inorganic interlayer cations were completely exchanged with amino acids (Examples 13 and 14) or layered materials in which no exchange of inorganic interlayer cations occurred (Examples 1a, 5a, 9a). The invention according to the present disclosure includes the following aspects: <Aspect 1> A layered silicate having interlayer cations, wherein the interlayer cations are: (a)Na + 、K + , and Li + an inorganic monovalent cation comprising at least one of (b) an organic cation comprising at least one protonated amino acid; Including, the molar ratio of the inorganic monovalent cation (a) to the organic cation (b) is in the range of 0.20:0.80 to 0.80:0.20; Layered silicate. <Aspect 2> 2. The layered silicate according to embodiment 1, wherein the layered silicate is a synthetic layered silicate. <Aspect 3> 2. The layered silicate according to embodiment 1, wherein the layered silicate is a natural layered silicate modified with a protonated amino acid. <Aspect 4> 4. The layered silicate according to any one of aspects 1 to 3, wherein the protonated amino acid comprises at least one of lysine, ornithine, and alanine. <Aspect 5> The interlayer cations are, alternating between layers, greater than 60 mol % protonated amino acids and greater than 60 mol % Na + 、K + , and Li + 5. The layered silicate according to any one of embodiments 1 to 4, comprising an inorganic cation selected from: <Aspect 6> A method for preparing the layered silicate according to any one of aspects 1 to 5, comprising the steps of: (i) providing a layered silicate; (ii) determining the cation exchange capacity of the layered silicate; (iii) contacting the layered silicate with a 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 the amount of the protonated amino acid corresponds to 20-80% of the cation exchange capacity of the layered silicate; A method comprising: <Aspect 7> 7. The method of embodiment 6, wherein the amino acid comprises at least one of lysine, ornithine, and alanine. <Aspect 8> The method according to any one of claims 6 to 7, wherein the layered silicate provided in step (i) is Na x [Mg 3-z Li y ]Si 4 O 10 (T) 2 and 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 and T is independently F or OH; and x+(3-z)+y≦4 That's the method. <Aspect 9> 9. The method of any one of aspects 6 to 8, comprising the further step of drying the layered silicate. <Aspect 10> A composition comprising at least one binder and the layered silicate according to any one of embodiments 1 to 5. <Aspect 11> 11. The composition of embodiment 10, wherein the binder comprises a polymer. <Aspect 12> 12. The composition of embodiment 11, wherein the binder comprises at least one of an aqueous polymer solution and an aqueous polymer dispersion. <Aspect 13> 6. Use of the layered silicate according to any one of aspects 1 to 5 to improve the barrier properties of a polymer layer or a coating layer.

Claims

1. A modified layered silicate having interlayer cations, wherein the interlayer cations are (a) Na ＋ , K. ＋ , and Li ＋ an inorganic monovalent cation comprising at least one of (b) an organic cation comprising at least one protonated amino acid; Including, the molar ratio of the inorganic monovalent cation (a) to the organic cation (b) is in the range of 0.20:0.80 to 0.80:0.20; the layered silicate has a composition of Na x [Mg 3-z Li y ]Si 4 O 10 (T) 2 before modification with organic cations; 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 and T is independently F or OH; and x+(3-z)+y≦4 That is, Layered silicate.

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

3. 2. The layered silicate according to claim 1, wherein the layered silicate is a natural layered silicate modified with a protonated amino acid.

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

5. The interlayer cations are, alternating between layers, greater than 60 mol % protonated amino acids and greater than 60 mol % Na ＋ , K. ＋ , and Li ＋ The layered silicate according to any one of claims 1 to 3, comprising an inorganic cation selected from the group consisting of:

6. A method for preparing the layered silicate according to any one of claims 1 to 3, said method comprising the steps of: (i) providing a layered silicate; (ii) determining the cation exchange capacity of said layered silicate; (iii) contacting the layered silicate with a 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 the amount of the protonated amino acid corresponds to 20-80% of the cation exchange capacity of the layered silicate; Including, The layered silicate provided in step (i) has a composition of Na x [Mg 3-z Li y ]Si 4 O 10 (T) 2 ; 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 and T is independently F or OH; and x+(3-z)+y≦4 That's the method.

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

8. 7. The method of claim 6, comprising the further step of drying the layered silicate.

9. A composition comprising at least one binder and the layered silicate according to any one of claims 1 to 3.

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

11. The composition of claim 10 , wherein the binder comprises at least one of an aqueous polymer solution and an aqueous polymer dispersion.

12. Use of the layered silicate according to any one of claims 1 to 3 for improving the barrier properties of a polymer layer or a coating layer.

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