Non-nano-sized iron oxide particles, a method for manufacturing the same, and a cosmetic composition containing the same

Abstract

The present invention relates to non-nano-sized iron oxide particles, a method for manufacturing the same, a cosmetic composition containing the same, and the use of the same as a pigment in a cosmetic composition.

Description

Technology Field

[0001] The present invention relates to non-nano-sized iron oxide particles, a method for manufacturing the same, a cosmetic composition containing the same, and the use of the same as a pigment in a cosmetic composition. Background Technology

[0002] Iron oxide particles are a type of mineral that is abundant in nature. Examples that may be mentioned include goethite, which is composed of hydrated iron oxide (III) and has the chemical formula α-FeO(OH), i.e., yellow iron oxyhydroxide; hematite, which is composed of iron oxide (III) and has the chemical formula α-Fe2O3, i.e., red iron oxide; and brown iron oxide, which is composed of a mixture of goethite and hematite.

[0003] The object of the present invention is to synthesize iron oxide particles, for example, iron oxide particles composed of goethite, hematite, or a mixture of goethite and hematite, preferably goethite, which are non-nanosized and comply with future European regulations regarding the size of pigments used in cosmetics. These new regulations, scheduled to take effect in 2027, require that particles introduced into cosmetic formulations, particularly pigments, have a size greater than 100 nm in all dimensions for more than 50% of the number of primary particles (corresponding to D50). Natural or synthetic pigments currently used in the industry, particularly goethite, comply with current regulations and are nanosized, meaning that at least one of their dimensions is less than 100 nanometers. However, such nanosized pigments will no longer be usable under the restrictions imposed by future regulations.

[0004] Consequently, there is a need to find new synthetic routes for producing non-nano-sized iron oxide particles, particularly iron oxide particles having a color according to a value range corresponding to a reference color. Annex IV of the European Union Regulation (EC) 1223 / 2009 on Cosmetics lists, for example, color index numbers of iron oxide particles.

[0005] Iron oxide particles can be synthesized in various ways, as described in the literature, particularly by precipitation synthesis.

[0006] The applicant has now discovered that by using at least one iron complexing agent present in the form of a counterion of at least one starting iron(III) salt or as an additive in a basic aqueous solution in the same or different form as the starting counterion, the growth of iron oxide particles is promoted, thereby promoting the production of non-nanosized iron oxide particles that meet the purpose of the new regulation. Although not intended to be bound by theory, the complexing agent in solution appears to stabilize the iron in the solution by forming one or more complexes. Thus, the presence of at least one complexing agent can alter the dissolution-precipitation equilibrium of the particles during the formation of iron oxide. Such complexes allow a specific amount of iron to remain in the solution, thereby sustaining the growth of the formed iron oxide particles. As the rate of iron oxide formation slows down, the particle size increases during the Ostwald aging stage. According to a specific embodiment, by using a complexing agent having a high complexing constant, the complex becomes more stable in the solution, thereby maintaining the concentration of iron in the solution significantly, which will aid in particle growth.

[0007] According to a first embodiment, the present invention relates to a method for producing non-nano-sized iron oxide particles, wherein the iron oxide particles may be goethite particles, hematite particles, or a mixture of goethite and hematite particles.

[0008] (a) (i) a basic aqueous solution comprising at least one complexing agent and an aqueous ferric solution comprising at least one iron(III) salt (wherein the at least one complexing agent is the same as or different from the counterion of the at least one iron(III) salt), or

[0009] (ii) an aqueous iron solution comprising an iron(III) salt complex comprising a basic aqueous solution, at least one iron(III) salt, and a complexing agent existing in the form of a counterion of said at least one iron(III) salt.

[0010] A step of preparing a basic iron aqueous suspension by mixing;

[0011] (b) A step of heating the basic iron aqueous suspension obtained in step (a) to a temperature of 50°C to 350°C to obtain a precipitate of iron oxide;

[0012] (c) Step of separating, washing, and drying the precipitate obtained in step (b).

[0013] Includes

[0014] According to a second aspect, the present invention relates to non-nanosized iron oxide particles obtained through a method according to the present invention, wherein the iron oxide particles are goethite particles, hematite particles, or a mixture of goethite and hematite particles, preferably goethite particles.

[0015] According to a third aspect, the present invention relates to non-nanosized iron oxide particles, wherein the iron oxide particles are goethite particles or a mixture of goethite and hematite particles, and are characterized in that the median size between the small and large dimensions of the primary particles is greater than 100 nanometers.

[0016] According to a fourth embodiment, the present invention relates to a cosmetic composition comprising iron oxide particles according to the present invention.

[0017] According to the fifth embodiment, the present invention relates to the use of iron oxide particles according to the present invention as a pigment in a cosmetic composition.

[0018] Unless otherwise noted, any reference to a range of values ​​in the description and / or claims implies that the range boundaries are included. The use of the term "strictly" implies that the value is not included.

[0019] Accordingly, the present invention relates to a method for manufacturing non-nano-sized iron oxide particles, wherein the iron oxide particles may be goethite particles, hematite particles, or a mixture of goethite and hematite particles, and

[0020] (a) (i) a basic aqueous solution comprising at least one complexing agent, and an aqueous iron solution comprising at least one iron(III) salt, particularly an iron(III) salt (wherein the at least one complexing agent is the same as or different from the counterion of the at least one iron(III) salt), or

[0021] (ii) an aqueous iron solution comprising an iron(III) salt complex comprising a basic aqueous solution, at least one iron(III) salt, and a complexing agent existing in the form of a counterion of said at least one iron(III) salt.

[0022] A step of preparing a basic iron aqueous suspension by mixing;

[0023] (b) A step of heating the basic iron aqueous suspension obtained in step (a) to a temperature of 50°C to 350°C to obtain a precipitate of iron oxide;

[0024] (c) Step of separating, washing, and drying the precipitate obtained in step (b).

[0025] Includes

[0026] In the context of the present invention, the term " Non-nano sized particles" refers to solid primary particles in which the minimum and maximum dimensions are greater than 100 nm for more than 50% of the sample based on number (D50 > 100 nm). Preferably, all particle dimensions have a size greater than 100 nm for more than 50% of the sample based on number (D50 > 100 nm). The particles are in a crystalline state.

[0027] In the context of the present invention, the term " primary particles " refers to the initial source particles of lumps or aggregates or mixtures thereof as defined in the ISO 80004-1:2023 standard. Conversely, lumps and aggregates are referred to as secondary particles.

[0028] In the context of the present invention, the term " Ignition agent " refers to a compound capable of forming one or more complexes with iron in solution. The complexing agent can be a monodentate or polydentate ligand and is considered a ligand whose functional group can coordinate with iron.

[0029] In particular, the at least one complexing agent is water-soluble and comprises at least one functional group selected from the group consisting of carboxylic acid, thiocarboxylic acid, amine, alcohol, ether, sulfonic acid, phosphonic acid, phosphoric acid, polymer, basic forms thereof, and mixtures thereof.

[0030] The at least one complexing agent used in step (a)(i) is selected particularly from the group consisting of acetic acid, lactic acid, oxalic acid, glycine, 2,6-pyridinedicarboxylic acid, citric acid, nitrilotriacetic acid, polyethylene glycol (PEG), hydroxyethylethylenediaminetriacetic acid (HEDTA), ethylenediaminetetraacetic acid (EDTA), basic forms thereof, and mixtures thereof.

[0031] Preferably, the at least one complexing agent used in step (a)(i) is selected from the group consisting of oxalic acid, citric acid, HEDTA, EDTA, basic forms thereof, and mixtures thereof, and preferably is oxalic acid or citric acid or basic forms thereof.

[0032] In particular, the at least one complexing agent used in step (a)(i) has a log(K) of 1 to 30, preferably 3 to 26, particularly 3 to 25, much more preferably 19 to 25, and this log(K) corresponds to the largest log(K) among log(K1), log(K2) and log(K3).

[0033] In the context of the present invention, the term "log(K)" refers to the logarithm of the total complexing constant of an iron complex in solution, that is, the constant of an iron complex combined with one, two, or three ligands derived from iron(III).

[0034] At least two complexing agents may be used in step (a)(i). In particular, two complexing agents, for example, a mixture of acetic acid and oxalic acid, as well as their basic forms, are used in step (a)(i).

[0035] Alternatively, and preferably, a single complexing agent is used in step (a)(i).

[0036] The number of equivalents of the at least one complexing agent used in step (a)(i) may be in the range of 0.1 to 10 equivalents, preferably 1 to 3 equivalents, and this number of equivalents depends on the number of functional groups and the complexing power of the at least one complexing agent. A person skilled in the art may select an appropriate number of equivalents.

[0037] The concentration of the at least one complexing agent present in the basic aqueous solution is generally 0.01 mol.L -1 to 1.00 mol.L -1 , preferably 0.10 mol.L -1 Up to 0.50 mol.L-1 , more preferably 0.10 mol.L -1 Up to 0.30 mol.L -1 am.

[0038] The at least one iron (III) salt used in step (a)(i) is selected from the group consisting particularly of ferric chloride, ferric nitrate and ferric sulfate, preferably ferric chloride and ferric sulfate.

[0039] The concentration of at least one iron(III) salt present in the ferric aqueous solution is generally 0.10 mol.L -1 to 1.20 mol.L -1 , preferably 0.10 mol.L -1 Up to 0.80 mol.L -1 am.

[0040] The iron(III) salt complex used in steps (a)(ii) is, in particular, ferric ammonium oxalate trihydrate, ferric sodium ethylenediaminetetraacetate, or ferric citrate.

[0041] Any water-soluble iron(III) salt of the concentration described above and any complexing agent having the previously described log(K) can be used in the method according to the present invention.

[0042] The concentration of the iron(III) salt complex present in the ferric aqueous solution is generally 0.5 mol.L -1 Up to 1.7 mol.L -1 am.

[0043] The basic aqueous solution used in step (a)(i) or (ii) may include an alkali agent selected from the group consisting of lithium hydroxide, sodium hydroxide, potassium hydroxide, rubidium hydroxide, cesium hydroxide, and mixtures thereof, preferably sodium hydroxide, potassium hydroxide, and mixtures thereof.

[0044] The concentration of the alkali agent present in the basic aqueous solution is generally 0.7 mol.L -1 Up to 5.1 mol.L -1 , preferably 0.8 mol.L -1 Up to 1.6 mol.L -1 am.

[0045] Alternatively, the basic aqueous solution used in step (a)(i) or (ii) may include a water-soluble organic base, such as 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU), water of ammonia, or 4-dimethylaminopyridine (DMAP).

[0046] Preferably, the pH of the basic aqueous solution used in step (a)(i) or (ii) is 7 to 14.

[0047] At the end of step (a), a precipitate of iron(III) hydroxide Fe(OH)3 is obtained.

[0048] In particular, in step (b), heating of the basic iron aqueous suspension is carried out at a temperature of 50°C to strictly less than 200°C, preferably 100°C to 150°C, or greater than 50°C, preferably 50°C to 350°C, much more preferably 100°C to 350°C.

[0049] In particular, in step (b), the heating of the basic iron aqueous suspension is carried out for at least 24 hours, preferably 24 to 48 hours, and much more preferably 24 to 72 hours.

[0050] Generally, during step (b), the pressure is 1 to 100 bar, particularly 1 to 50 bar, preferably 1 to 10 bar.

[0051] Alternatively, step (b) can be performed at atmospheric pressure.

[0052] Preferably, step (b) comprises heating the basic iron aqueous suspension to a temperature of 50°C to strictly less than 200°C, preferably 100°C to 150°C, or to a temperature greater than 50°C, preferably 50°C to 350°C, much more preferably 100°C to 350°C, and at a pressure of 1 to 100 bar, particularly 1 to 50 bar, preferably 1 to 10 bar, or at atmospheric pressure.

[0053] The separation of step c) is generally performed at least once by filtration or centrifugation, preferably by centrifugation, for example at 6000 rpm.

[0054] In step c), the precipitate can be washed with water, especially pure water, particularly several times, preferably 3 to 6 times.

[0055] In step c), the precipitate can be dried in an oven, for example at 100°C for one day.

[0056] A person skilled in the art can adjust the pH, temperature range, and / or pressure range to obtain the desired iron oxide particles.

[0057] Preferably, the iron oxide particles are goethite particles.

[0058] In a specific embodiment, the non-nanosized iron oxide particles are non-nanosized goethite particles. In particular, the pH of the basic aqueous solution used in step (a)(i) or (ii) is generally 12 to 14, preferably 14, and / or the concentration of the alkylating agent present in the basic aqueous solution is generally 0.7 mol.L -1 Up to 5.1 mol.L -1 , preferably 0.8 mol.L -1 Up to 1.6 mol.L -1and / or; in step (b), heating of the basic iron aqueous suspension is carried out at a temperature of 50°C to strictly less than 200°C, preferably 100°C to 150°C, in particular for at least 24 hours, preferably 24 to 48 hours, much more preferably 24 to 72 hours; and / or; step (b) is carried out at a pressure of 1 to 100 bar, in particular 1 to 50 bar, preferably 1 to 10 bar, or at atmospheric pressure.

[0059] expression " Strictly 200 ℃ under This means that the temperature is less than 200℃ but not equal to 200℃.

[0060] The above non-nanosized goethite particles are particularly in the form of needles or rods, preferably in the form of rods.

[0061] In another specific embodiment, the non-nanosized iron oxide particles are non-nanosized hematite particles. In particular, the pH of the basic aqueous solution used in step (a)(i) or (ii) is 7 to 14, preferably 7 to 11.5, and / or the concentration of the alkylating agent present in the basic aqueous solution is generally 0.7 mol.L -1 to 0.9 mol.L -1 , preferably 0.8 mol.L -1 and / or; in step (b), heating of the basic iron aqueous suspension is performed at a temperature greater than 50°C, preferably 100°C to 350°C, in particular for at least 24 hours, preferably 24 to 48 hours, much more preferably 24 to 72 hours; and / or; step (b) is performed at a pressure of 1 to 100 bar, in particular 1 to 50 bar, preferably 1 to 10 bar, or at atmospheric pressure.

[0062] The subject of the present invention is also non-nano-sized iron oxide particles obtained through the method of the present invention, said iron oxide particles are goethite particles, hematite particles, or a mixture of goethite and hematite particles, preferably goethite particles.

[0063] The present invention also relates to non-nano-sized iron oxide particles, wherein the iron oxide particles are goethite particles or a mixture of goethite and hematite particles, and are characterized in that the median size of the small and large dimensions of the primary particles is greater than 100 nm.

[0064] In the context of the present invention, the term "number median size" refers to 50% of particles of a specific size based on the number. For example, the number median size of primary particles greater than 100 nm means that 50% of these particles, based on the number, have a size greater than 100 nm. The number median sizes of small and large dimensions of primary particles, for example, using a scanning electron microscope (SEM), particularly 50 mm 2 It can be measured by electron imaging using a JEOL JSM 7100F microscope equipped with an Oxford Instruments analysis system.

[0065] In particular, the number median size of the small dimensions of the primary particles is 100 nm to 200 nm, preferably 100 nm to 175 nm, and the ratio of the number median size of the large dimensions of the primary particles to the small dimensions is greater than 3.

[0066] In the context of the present invention, the term " Small dimensions of primary particles " refers to, for example, the "width" or "thickness" of primary particles observed in SEM images.

[0067] In the context of the present invention, the term " Large dimensions of primary particles " refers to, for example, the "length" of primary particles observed in SEM images.

[0068] In particular, non-nanosized iron oxide particles are goethite particles having the following L*, a*, and b* values ​​when measured in CIELAB units using a Konica Minolta CM-5 spectrophotometer in reflection mode, specifically according to the ISO / CIE 11664-4:2019 standard, preferably with "10° observer" and "D65 light source" parameters:

[0069] - In the overall tone, the L* value is 42 to 58, the a* value is 7 to 16, and the b* value is 34 to 53, or

[0070] - In white gradient shades, L* values ​​are 64 to 73, a* values ​​are 2 to 7, and b* values ​​are 19 to 34.

[0071] The present invention also relates to a cosmetic composition comprising iron oxide particles according to the present invention.

[0072] According to a specific embodiment, the composition comprises iron oxide particles according to the present invention in an amount of 0.1% to 90% by weight based on the total weight of the composition. The cosmetic composition may be particularly suitable for topical application.

[0073] The above composition may include other additives common in the field, such as preservatives, pH adjusters, antimicrobial agents, fragrances, UV blockers, and mixtures thereof.

[0074] The invention that is the subject of this patent application also relates to the use of iron oxide particles according to the present invention as a pigment in cosmetic compositions. The term " pigment It should be understood that the composition includes iron oxide particles according to the present invention intended to impart color to the composition. Brief explanation of the drawing

[0075] Fig. 1. Diffraction pattern of iron oxide particles of Comparative Example 1 not containing a complexing agent. FIG. 2. SEM measurement results and particle count of iron oxide particles of Comparative Example 1 not containing a complexing agent. 2a. 20,000x magnification, 1 μm scale; 2b. 40,000x magnification, 100 nm scale. 2c. Particle ratio distribution according to size for small and large dimensions based on number, shown for 100 particles, and median size values ​​for small and large dimensions of the particles. FIG. 3. Diffraction pattern of iron oxide particles of Example 3 according to the present invention, containing 3 equivalents of ammonium hydroxide per 1 equivalent of iron. FIG. 4. SEM measurement results and particle count of iron oxide particles of Example 3 according to the present invention, containing 3 equivalents of ammonium hydroxide per 1 equivalent of iron. 4a. 20,000x magnification, 1 μm scale; 4b. 40,000x magnification, 100 nm scale. 4c. Particle ratio distribution according to size for small and large dimensions based on number, shown for 100 particles, and median size values ​​for small and large dimensions of the particles. FIG. 5. Diffraction pattern of iron oxide particles of Example 4 according to the present invention, containing 3 equivalents of ammonium hydroxide per 1 equivalent of iron. FIG. 6. SEM measurement results and particle count of iron oxide particles of Example 4 according to the present invention, containing 3 equivalents of ammonium hydroxide per 1 equivalent of iron. 6a. 20,000x magnification, 1 μm scale; 6b. 40,000x magnification, 100 nm scale. 6c. Particle ratio distribution according to size for small and large dimensions based on number, shown for 100 particles, and median size values ​​for small and large dimensions of the particles. FIG. 7. Diffraction pattern of iron oxide particles of Example 5 according to the present invention, containing 1 equivalent of oxalic acid dihydrate per 1 equivalent of iron. FIG. 8. SEM measurement results and particle count of iron oxide particles of Example 5 according to the present invention, containing 1 equivalent of oxalic acid dihydrate per 1 equivalent of iron. 8a. 20,000x magnification, 1 μm scale; 8b. 40,000x magnification, 100 nm scale. 8c. Particle ratio distribution according to size for small and large dimensions based on number, shown for 100 particles, and median size values ​​for small and large dimensions of the particles. FIG. 9. Diffraction pattern of iron oxide particles of Example 6 according to the present invention, containing 1 equivalent of citric acid monohydrate per 1 equivalent of iron. FIG. 10. SEM measurement results and particle count of iron oxide particles of Example 6 according to the present invention, containing 1 equivalent of citric acid monohydrate per 1 equivalent of iron. 10a. 20,000x magnification, 1 μm scale; 10b. 40,000x magnification, 100 nm scale. 10c. Particle ratio distribution according to size for small and large dimensions based on number, shown for 100 particles, and median size values ​​for small and large dimensions of the particles. FIG. 11. Diffraction pattern of iron oxide particles of Example 7 according to the present invention, comprising 1 equivalent of sodium ethylenediaminetetraacetate per 1 equivalent of iron. FIG. 12. SEM measurement results and particle count of iron oxide particles of Example 7 according to the present invention, comprising 1 equivalent of sodium ethylenediaminetetraacetate per 1 equivalent of iron. 12a. 20,000x magnification, 1 μm scale; 12b. 40,000x magnification, 100 nm scale. 12c. Particle ratio distribution according to size for small and large dimensions based on number, shown for 100 particles, and median size values ​​for small and large dimensions of the particles. FIG. 13. Diffraction pattern of iron oxide particles of Example 8 according to the present invention, containing 1 equivalent of EDTA per 1 equivalent of iron. FIG. 14. SEM measurement results and particle count of iron oxide particles of Example 8 according to the present invention, containing 1 equivalent of EDTA per 1 equivalent of iron. 14a. 20,000x magnification, 1 μm scale; 14b. 40,000x magnification, 100 nm scale. 14c. Particle ratio distribution according to size for small and large dimensions based on number, shown for 100 particles, and median size values ​​for small and large dimensions of the particles. FIG. 15. Diffraction pattern of iron oxide particles of Example 9 according to the present invention, comprising 1 equivalent of acetic acid and 1 equivalent of oxalic acid dihydrate per 1 equivalent of iron. FIG. 16. SEM measurement results and particle count of iron oxide particles of Example 9 according to the present invention, comprising 1 equivalent of acetic acid and 1 equivalent of oxalic acid dihydrate per 1 equivalent of iron. 16a. 20,000x magnification, 1 μm scale; 16b. 40,000x magnification, 100 nm scale. 16c. Particle ratio distribution according to size for small and large dimensions based on number, shown for 100 particles, and median size values ​​for small and large dimensions of the particles. FIG. 17. Diffraction pattern of iron oxide particles of Example 17 according to the present invention, containing 1 equivalent of HEDTA per 1 equivalent of iron. FIG. 18. SEM measurement results and particle count of iron oxide particles of Example 17 according to the present invention, containing 1 equivalent of HEDTA per 1 equivalent of iron. 18a. 20,000x magnification, 1 μm scale; 18b. 40,000x magnification, 100 nm scale. 18c. Particle ratio distribution according to size for small and large dimensions based on number, shown for 100 particles, and median size values ​​for small and large dimensions of the particles. FIG. 19. Diffraction pattern of iron oxide particles of Example 19 according to the present invention, containing 3 equivalents of oxalic acid dihydrate per 1 equivalent of iron. FIG. 20. SEM measurement results and particle count of iron oxide particles of Example 19 according to the present invention, containing 3 equivalents of oxalic acid dihydrate per 1 equivalent of iron. 20a. 20,000x magnification, 1 μm scale; 20b. 40,000x magnification, 100 nm scale. 20c. Particle ratio distribution according to size for small and large dimensions based on number, shown for 100 particles, and median size values ​​for small and large dimensions of the particles. FIG. 21. Diffraction pattern of iron oxide particles of Example 20 according to the present invention, containing 3 equivalents of citric acid monohydrate per 1 equivalent of iron. FIG. 22. SEM measurement results and particle count of iron oxide particles of Example 20 according to the present invention, containing 3 equivalents of citric acid monohydrate per 1 equivalent of iron. 22a. 20,000x magnification, 1 μm scale; 22b. 43,000x magnification, 100 nm scale. 22c. Particle ratio distribution according to size for small and large dimensions based on number, shown for 100 particles, and median size values ​​for small and large dimensions of the particles. FIG. 23. Diffraction pattern of iron oxide particles of Example 21 according to the present invention, containing 3 equivalents of EDTA per 1 equivalent of iron. FIG. 24. SEM measurement results and particle count of iron oxide particles of Example 21 according to the present invention, containing 3 equivalents of EDTA per 1 equivalent of iron. 24a. 20,000x magnification, 1 μm scale; 24b. 40,000x magnification, 100 nm scale. 24c. Particle ratio distribution according to size for small and large dimensions based on number, shown for 100 particles, and median size values ​​for small and large dimensions of the particles. FIG. 25. Diffraction pattern of iron oxide particles of Example 22 according to the present invention, comprising 0.1 equivalents of polyethylene glycol per 1 equivalent of iron. FIG. 26. SEM measurement results and particle count of iron oxide particles of Example 22 according to the present invention, comprising 0.1 equivalents of polyethylene glycol per 1 equivalent of iron. 26a. 20,000x magnification, 1 μm scale; 26b. 40,000x magnification, 100 nm scale. 26c. Particle ratio distribution according to size for small and large dimensions based on number, shown for 100 particles, and median size values ​​for small and large dimensions of the particles. FIG. 27. Diffraction pattern of iron oxide particles of Example 23 according to the present invention, containing 2 equivalents of oxalic acid dihydrate per 1 equivalent of iron. FIG. 28. SEM measurement results and particle count of iron oxide particles of Example 23 according to the present invention, containing 2 equivalents of oxalic acid dihydrate per 1 equivalent of iron. 28a. 20,000x magnification, 1 μm scale; 28b. 40,000x magnification, 100 nm scale. 28c. Particle ratio distribution according to size for small and large dimensions based on number, shown for 100 particles, and median size values ​​for small and large dimensions of the particles. FIG. 29. Diffraction pattern of iron oxide particles of Comparative Example 2 not containing a complexing agent. FIG. 30. SEM image and particle count of iron oxide particles of Comparative Example 2 not containing a complexing agent. 30a. 20,000x magnification, 1 μm scale; 30b. 40,000x magnification, 100 nm scale. 30c. Particle ratio distribution according to size for small and large dimensions based on number, shown for 100 particles, and median size values ​​for small and large dimensions of the particles. Specific details for implementing the invention

[0076] Examples

[0077] The present invention is illustrated in a non-limiting manner by the following examples. Comparative examples are also described below.

[0078] Materials and Methods

[0079] - XRD The composition of the synthesized iron oxide particles was analyzed by X-ray diffraction (XRD). Measurements were performed using a nickel filter. This method provided rapid quantitative information regarding the composition and crystallinity of the material.

[0080] Scanning Electron Microscope (SEM) The morphology and particle size of the iron oxide particles were analyzed using SEM. The samples to be analyzed were prepared by the French National Laboratory of Metrology and Testing (Laboratoire National de It was performed in a manner similar to the protocols generally applied in research conducted by et d'Essais (LNE). Ghomrasni et al., Powder Technology, 2000, 359, 226-237; et al., Meas. Sci. Technol. 26, 2015, 085601, 15 pages ).

[0081] - Sample preparation for SEM measurement : 10 mg of the powder to be analyzed was dispersed in 5 mL of ethanol. The resulting dispersion was placed in an ultrasonic bath and treated for 1 minute. Then, one drop was applied onto a silicon substrate using a spin coater at a slow rotation speed (3 seconds at 1000 rpm), followed by rapid drying of the plate and removal of the ethanol by applying a high rotation speed (2 seconds at 3000 rpm). Subsequently, the powder-deposited plate was metal-coated with gold and palladium, and 50 mm 2 The analysis was performed using a JEOL JSM 7100F microscope equipped with an Oxford Instruments analysis system.

[0082] - SEM measurement Several images of the powder were taken across the entire support. Two photos were taken at low magnification (20,000x, 1 micrometer scale) to observe the particle distribution, and four photos were taken at high magnification (40,000x, 100 nanometer scale) for particle counting.

[0083] - Number of particles For each sample, two counts were performed: one to measure the small dimensions of the particles, and the other to measure the large dimensions. The "width" and "length" of the primary particles visible in the SEM image are considered the small and large dimensions, respectively. Specifically, the SEM image provides only the two-dimensional appearance of the particles. The small dimension is a combination of the particle's width and thickness, and the large dimension is a combination of the particle's length and width. For both counts, 300 dimensions were measured using ImageJ software by defining the measurement scale based on the scale of the SEM image. Using this software, a statistical distribution of the measured sizes, including the mean, minimum, and maximum sizes, was obtained in 1 nm intervals. The inventors retrieved the data and processed it in Excel to obtain the distribution percentage based on the number of particles by size, presented for 100 particles, as well as the median size value.

[0084] - color : The color tone of the powder is Müller ( The values ​​were determined using a milling method. Two types of milling (one full tone and one white gradient tone) were performed to determine the L*, a*, and b* values ​​in the CIELab color space, as well as the dyeing power of the pigment.

[0085] - Preparation of full shades and white gradient shades : 0.050 g of the pigment to be analyzed was milled with 0.450 g of a waxy milling base as described above to obtain the full shade. "Mühle-Ingelsmann ( The mixture was crushed and milled three times at 100 revolutions per minute using an Engelsmann glass plate mill. The resulting formulation was placed between two glass plates spaced 1 mm apart and analyzed using a Konica Minolta CM-5 spectrophotometer in reflection mode with "10° observer" and "D65 light source" parameters. A white gradient hue was obtained by milling 0.215 g of the total hue formulation with 0.285 g of a milled mixture of 30% TiO2 in a waxy milling base. The mixture was crushed and milled twice at 40 revolutions per minute in a Müller mill. The resulting formulation was also placed between two glass plates spaced 1 mm apart and measured using a Konica Minolta CM-5 spectrophotometer in reflection mode with "10° observer" and "D65 light source" parameters.

[0086] - Waxy base for pigment milling and color measurement compared to desirable internal standards

[0087] Starting material %

[0088] wax 14.35

[0089] polymer 22.50

[0090] oil 30.75

[0091] Gelling agent 32.20

[0092] antioxidants 0.20

[0093] Overall color tone

[0094] 3.6 g of the waxy base described above is taken, and 0.4 g of pigment is incorporated into it. It is milled three times at 100 revolutions per minute using a "Müller-Ingelsmann" glass plate mill. Measurements are taken using a Konica Minolta CM-5 spectrophotometer in reflection mode with "10° observer" and "D65 light source" parameters.

[0095] Gradient shades

[0096] Starting material %

[0097] wax 10.00

[0098] polymer 15.75

[0099] oil 21.55

[0100] Gelling agent 22.55

[0101] antioxidants 0.15

[0102] titanium dioxide 30.00

[0103] Take 1.72 g of the whole color preparation and 2.28 g of the waxy preparation containing titanium dioxide. Mill twice at 40 revolutions per minute in a "Müller-Ingelsmann" glass plate mill. Measure using a Konica Minolta CM-5 spectrophotometer in reflection mode with "10° observer" and "D65 light source" parameters.

[0104] - Color measurement L*, a*, and b* values ​​were measured using a Konica Minolta CM-5 spectrophotometer in reflection mode with Spectramagic NX software, utilizing the "10° observer" and "D65 light source" parameters. Specifically, these L*, a*, and b* values ​​were measured according to the ISO / CIE 11664-4:2019 standard, which outlines the method for calculating coordinates in the CIE 1976 L*a*b* color space. Five measurements were performed for each of the two hue values. The average value is provided and then compared to a reference value. The software then provides values ​​for L*, a*, b*, C*, h, dL*, da*, db*, dC*, dH*, and dE*ab. Accordingly, the deviation from the reference value and the dyeing power of the pigment can be determined. Additionally, the white gradient hue allows for the determination of the pigment's behavior when mixed with other pigments.

[0105] Comparative Example 1: FeCl without complexing agent 3 ·6H 2 Synthesis of goethite from O

[0106] protocol : Dissolve 0.764 g of KOH in pure water to make 13.8 mL of solution (0.8 mol.L -1 ) was prepared. 0.465 g of ferric chloride hexahydrate (FeCl3.6H2O) was dissolved in pure water to make another 1.5 mL solution (1.1 mol.L -1 Fe) was prepared. The KOH solution was placed in a 23 mL autoclave equipped with a PTFE chamber, and the ferric solution was added dropwise (0.7 mol.L). -1 KOH, 0.1 mol.L -1Fe). The red suspension was mixed for 10 minutes. The autoclave was placed in an oven and heated at 50°C for 24 hours after a 2-hour temperature increase, followed by heating at 150°C for 24 hours after a 2-hour temperature increase. A yellow precipitate was formed. The precipitate was centrifuged at 12,000 rpm, washed three times with pure water, centrifuged again at 12,000 rpm, and dried in an oven at 100°C for 1 day. A yellow powder was obtained.

[0107] XRD : The peaks in the obtained diffraction pattern (Fig. 1) correspond to the signal of goethite (top diagram = experimental diffraction pattern; bottom diagram with squares = expected peaks for the goethite sample).

[0108] SEM The particles measured by SEM were nanoscale and had a needle-like shape. The median size of the small dimension was 94 nm, and 55% of the particles were nanoscale by number. The median size of the large dimension was 355 nm, and 2% of the particles were nanoscale by number (Figs. 2a, 2b, and 2c).

[0109] Color measurement : The obtained overall hue color was within the value range corresponding to the reference yellow, dE*ab = 9.97, and L*a*b* values ​​were L* = 56.07; a* = 10.45; and b* = 43.24. For the white gradient hue, the color was also within the reference range, dE*ab = 4.3, and L*a*b* values ​​were L* = 71.87; a* = 3.41 and b* = 29.39.

[0110] Comparative Example 2: Fe without a complexing agent 2 (SO 4 ) 3 .xH 2 Synthesis of goethite from O

[0111] protocol : Dissolve 0.725 g of KOH in pure water to make 13.8 mL of solution (0.80 mol.L -1 ) was prepared. 0.633 g of ferric sulfate hydrate (Fe2(SO4)3.xH2O) was dissolved in pure water to make another 1.5 mL solution (1.5 mol.L -1 Fe) was prepared. The KOH solution was placed in a 23 mL autoclave equipped with a PTFE chamber, and the ferric solution was added dropwise (0.7 mol.L). -1 KOH, 0.1 mol.L -1 Fe). The red suspension was stirred for 10 minutes. The autoclave was placed in an oven and heated at 50°C for 24 hours after a 2-hour temperature increase, followed by heating at 150°C for 24 hours after a 2-hour temperature increase. A yellow precipitate was formed. The precipitate was centrifuged at 12,000 rpm, washed three times with pure water, centrifuged again at 12,000 rpm, and dried in an oven at 100°C for 1 day. A yellow powder was obtained.

[0112] XRD : diffraction pattern obtained ( Fig. 29 The peak of ) corresponds to the signal of goethite.

[0113] SEM : The particles observed by SEM were nanoscale and had a needle-like shape. The median size of the small dimension was 93 nm, and 58% of the particles were nanoscale by number. The median size of the large dimension was 419 nm, and 3% of the particles were nanoscale by number (Figs. 30a, 30b, and 30c).

[0114] Color measurement : The obtained overall hue color was within the value range corresponding to the reference yellow, dE*ab = 7.48, and the L*a*b* values ​​were L* = 57.35; a* = 12.14; and b* = 45.93. For the white gradient hue, the color was also within the reference range, dE*ab = 2.99, and the L*a*b* values ​​were L* = 72.29; a* = 4.32 and b* = 31.46.

[0115] Example 3 according to the present invention: Synthesis of goethite from ferric ammonium hydroxide trihydrate, i.e., 3 equivalents of ammonium hydroxide to iron (140 mg).

[0116] protocol : Dissolve 0.733 g of KOH in pure water to make 13.8 mL of solution (0.8 mol.L -1 ) was prepared. 0.699 g of ferric ammonium hydroxide trihydrate (Fe(NH4C2O4)3·3H2O) was dissolved in pure water to make another 1.5 mL solution (1.1 mol.L -1 Fe) was prepared. The KOH solution was placed in a 23 mL autoclave equipped with a PTFE chamber, and the ferric solution was added dropwise (0.7 mol.L). -1 KOH, 0.1 mol.L -1 Fe). The red suspension was stirred for 10 minutes. The autoclave was placed in an oven and heated at 50°C for 24 hours after a 2-hour temperature increase, followed by heating at 150°C for 24 hours after a 2-hour temperature increase. A yellow precipitate was formed. The precipitate was centrifuged at 12,000 rpm, washed three times with pure water, centrifuged again at 12,000 rpm, and dried in an oven at 100°C for 1 day. A yellow powder was obtained.

[0117] XRD : diffraction pattern obtained ( Fig. 3 The peak of ) corresponds to the signal of goethite (top diagram = experimental diffraction pattern, bottom diagram with square = expected peak for the goethite sample).

[0118] SEM : The particles measured by SEM were non-nanosized and had an acicular shape, as expected for goethite. Dimensional analysis revealed that the median size of the small particles was 146 nm, and 20% of the particles were nanosized by number. The median size of the large particles was 731 nm, and 2% of the particles were nanosized by number ( Figs. 4a, 4b, and 4c ).

[0119] Color measurement : The obtained overall hue color was within the value range corresponding to the reference yellow, dE*ab = 9.4, and the L*a*b* values ​​were L* = 57.6; a* = 12.02; and b* = 43.81. For the white gradient hue, the color was also within the reference range, dE*ab = 3.5, and the L*a*b* values ​​were L* = 72.31; a* = 4.26 and b* = 30.06.

[0120] Example 4 according to the present invention: Synthesis of goethite from ferric ammonium hydroxide trihydrate, i.e., 3 equivalents of ammonium hydroxide to iron (150 g).

[0121] protocol : Dissolve 834.5 g of KOH in pure water to make 2.5 L of solution (5.1 mol.L -1 ) was prepared. 812.7 g of ferric ammonium hydroxide trihydrate (Fe(NH4)2O4.3H2O) was dissolved in pure water to make another 3.5 L solution (0.5 mol.L). -1 Fe) was prepared. A KOH solution was placed in a 12 L HALAR-protected reactor, and a ferric solution (2.1 mol.L) -1 of KOH, 0.3 mol.L -1Fe) was slowly added. The red suspension was stirred for 20 minutes. The reactor was heated at 50°C for 24 hours following a 5-hour temperature increase phase, and then heated at 102°C for 22 hours following a 3.5-hour temperature increase phase. A yellow precipitate was formed, and the pH of the supernatant was measured to be 14. The precipitate was filtered using a Büchner funnel, washed with 6.6 L of pure water, and then dried in an oven at 100°C for 2 days. A yellow powder was obtained.

[0122] XRD : diffraction pattern obtained ( Fig. 5 The peak of ) corresponds to the signal of goethite (top diagram = experimental diffraction pattern, bottom diagram with square = expected peak for the goethite sample).

[0123] SEM : The particles measured by SEM were non-nanosized and had an acicular shape, as expected for goethite. Dimensional analysis revealed that the median size of the small particles was 174 nm, and 32% of the particles were nanosized by number. The median size of the large particles was 1041 nm, and 3% of the particles were nanosized by number ( Figs. 6a, 6b, and 6c ).

[0124] Color measurement : The obtained overall hue color was within the value range corresponding to the reference yellow, dE*ab = 6.98, and L*a*b* values ​​were L* = 54.6; a* = 13.63; and b* = 45.07. For the white gradient hue, the color was also within the reference range, dE*ab = 4.31, and L*a*b* values ​​were L* = 70.69; a* = 5.75 and b* = 27.61.

[0125] Example 5 according to the present invention: Using 1 equivalent of oxalic acid dihydrate with respect to iron FeCl 3 ·6H 2 Synthesis of goethite from O.

[0126] protocol : Dissolve 0.700 g of KOH and 0.196 g of oxalic acid dihydrate in pure water to make 13.3 mL of solution (0.8 mol.L -1 KOH and 0.1 mol.L -1 Oxalic acid dihydrate) was prepared. 0.428 g of ferric chloride hexahydrate (FeCl3.6H2O) was dissolved in pure water to make another 2 mL solution (0.8 mol.L). -1 A basic solution (Fe) was prepared. The basic solution was placed in a 23 mL autoclave equipped with a PTFE chamber, and a ferric solution was added dropwise (0.7 mol.L). -1 KOH, 0.1 mol.L -1 oxalic acid dihydrate, and 0.1 mol.L -1 Fe). The red suspension was mixed for 10 minutes. An autoclave was placed in an oven and heated at 50°C for 24 hours after a 2-hour temperature increase phase, followed by heating at 150°C for 24 hours after a 2-hour temperature increase phase. A yellow precipitate was formed, and the pH of the supernatant was measured to be 14. The precipitate was centrifuged at 6,000 rpm, washed three times with pure water, centrifuged again at 6,000 rpm, and dried in an oven at 100°C for 1 day. A yellow powder was obtained.

[0127] XRD : diffraction pattern obtained ( Fig. 7 The peak of ) corresponds to the signal of goethite (top diagram = experimental diffraction pattern, bottom diagram with square = expected peak for the goethite sample).

[0128] SEM :The particles observed by SEM were non-nanosized and had an acicular shape, as expected for goethite. The median small size was 115 nm, and 36% of the particles by number were nanosized. The median large size was 569 nm, and 3% of the particles by number were nanosized ( Figs. 8a, 8b, and 8c ).

[0129] Color measurement : The obtained overall hue color was within the value range corresponding to the reference yellow, dE*ab = 12.67, and L*a*b* values ​​were L* = 56.04; a* = 10.19; and b* = 40.32. For the white gradient hue, the color was also within the reference range, dE*ab = 3.77, and L*a*b* values ​​were L* = 71.49; a* = 3.81 and b* = 29.59.

[0130] Example 6 according to the present invention: Using 1 equivalent of citric acid monohydrate with respect to iron FeCl 3 ·6H 2 Synthesis of goethite from O.

[0131] protocol : Dissolve 0.758 g of KOH and 0.325 g of citric acid monohydrate in pure water to make 13.3 mL of solution (0.9 mol.L -1 KOH and 0.1 mol.L -1 Citric acid monohydrate) was prepared. 0.427 g of ferric chloride hexahydrate (FeCl3.6H2O) was dissolved in pure water to make another 2 mL solution (0.8 mol.L). -1 A basic solution (Fe) was prepared. The basic solution was placed in a 23 mL autoclave equipped with a PTFE chamber, and a ferric solution was added dropwise (0.7 mol.L). -1 KOH, 0.1 mol.L -1 citric acid monohydrate, and 0.1 mol.L -1Fe). The red suspension was mixed for 10 minutes. An autoclave was placed in an oven and heated at 50°C for 24 hours after a 2-hour temperature increase phase, followed by heating at 150°C for 24 hours after a 2-hour temperature increase phase. A yellow precipitate was formed, and the pH of the supernatant was measured to be 14. The precipitate was centrifuged at 6,000 rpm, washed three times with pure water, centrifuged again at 6,000 rpm, and dried in an oven at 100°C for 1 day. A yellow powder was obtained.

[0132] XRD : diffraction pattern obtained ( Fig. 9 The peak of ) corresponds to the signal of goethite (top diagram = experimental diffraction pattern, bottom diagram with square = expected peak for the goethite sample).

[0133] SEM : The particles observed by SEM were non-nanosized and had a needle-like shape. The median size of the small dimension was 109 nm, and 41% of the particles were nanosized by number. The median size of the large dimension was 850 nm, and 3% of the particles were nanosized by number ( Figs. 10a, 10b, and 10c ).

[0134] Color measurement : The obtained overall hue color was within the value range corresponding to the reference yellow, dE*ab = 7.61, and L*a*b* values ​​were L* = 55.96; a* = 11.19; and b* = 45.58. For the white gradient hue, the color was also within the reference range, dE*ab = 3.15, and L*a*b* values ​​were L* = 70.73; a* = 4.45 and b* = 29.59.

[0135] Example 7: Synthesis of goethite from ferric sodium EDTA, i.e., 1 equivalent of sodium EDTA to iron

[0136] protocol : Dissolve 0.550 g of KOH in pure water to make 10 mL of solution (0.8 mol.L-1 ) was prepared. 0.440 g of ferric sodium ethylenediaminetetraacetate (Fe-EDTA-Na) was dissolved in pure water to make another 1 mL solution (1.2 mol.L -1 Fe) was prepared. The KOH solution was placed in a 16 mL autoclave equipped with a PTFE chamber, and the ferric solution was added dropwise (0.7 mol.L). -1 KOH, 0.1 mol.L -1 Fe). The red suspension was stirred for 10 minutes. The autoclave was placed in an oven and heated at 50°C for 24 hours after a 2-hour temperature increase, followed by heating at 150°C for 24 hours after a 2-hour temperature increase. A yellow precipitate was formed. The precipitate was centrifuged at 12,000 rpm, washed three times with pure water, centrifuged again at 12,000 rpm, and dried in an oven at 100°C for 1 day. A yellow powder was obtained.

[0137] XRD : diffraction pattern obtained ( Fig. 11 The peak of ) corresponds to the signal of goethite (top diagram = experimental diffraction pattern, bottom diagram with square = expected peak for the goethite sample).

[0138] SEM : The particles observed by SEM were non-nanosized and rod-shaped. The median size of the small dimension was 147 nm, and 30% of the particles were nanosized by number. The median size of the large dimension was 505 nm, and 9% of the particles were nanosized by number ( FIGS. 12a, 12b, and 12c ).

[0139] Color measurement : The obtained overall hue color was within the value range corresponding to the reference yellow, dE*ab = 1.56, and the L*a*b* values ​​were L* = 54.95; a* = 15.28; and b* = 52.66. For the white gradient hue, the color was also within the reference range, dE*ab = 3.07, and the L*a*b* values ​​were L* = 71.32; a* = 5.41 and b* = 29.15.

[0140] Example 8 according to the present invention: FeCl using 1 equivalent of EDTA with respect to iron 3 ·6H 2 Synthesis of goethite from O.

[0141] protocol : Dissolve 0.731 g of KOH and 0.448 g of ethylenediaminetetraacetic acid in pure water to make 13.3 mL of solution (0.8 mol.L -1 KOH and 0.1 mol.L -1 Ethylenediaminetetraacetic acid) was prepared. 0.426 g of ferric chloride hexahydrate (FeCl3.6H2O) was dissolved in pure water to make another 2 mL solution (0.8 mol.L). -1 A basic solution (Fe) was prepared. The basic solution was placed in a 23 mL autoclave equipped with a PTFE chamber, and a ferric solution was added dropwise (0.7 mol.L). -1 KOH, 0.1 mol.L -1 ethylenediaminetetraacetic acid, and 0.1 mol.L -1 Fe). The red suspension was stirred for 10 minutes. The autoclave was placed in an oven and heated at 50°C for 24 hours after a 2-hour temperature increase, followed by heating at 150°C for 24 hours after a 2-hour temperature increase. A yellow precipitate was formed, and the pH of the supernatant was measured to be 14. The precipitate was centrifuged at 6,000 rpm, washed three times with pure water and once with ethanol, centrifuged again at 6,000 rpm, and dried in an oven at 100°C for 1 day. A yellow powder was obtained.

[0142] XRD : diffraction pattern obtained ( Fig. 13 The peak of ) corresponds to the signal of goethite (top diagram = experimental diffraction pattern, bottom diagram with square = expected peak for the goethite sample).

[0143] SEM : The particles observed by SEM were non-nanosized and had a needle-like shape. The median size of the small dimension was 105 nm, and 44% of the particles were nanosized by number. The median size of the large dimension was 662 nm, and 4% of the particles were nanosized by number ( FIGS. 14a, 14b, and 14c ).

[0144] Color measurement : The obtained overall hue color was within the range corresponding to the standard yellow, dE*ab = 13.29, and L*a*b* values ​​were L* = 57.3; a* = 9.88; and b* = 40.09. For the white gradient hue, the color was also within the standard range, dE*ab = 3.67, and L*a*b* values ​​were L* = 71.81; a* = 3.77 and b* = 30.01.

[0145] Example 9 according to the present invention: FeCl using 1 equivalent of acetic acid and 1 equivalent of oxalic acid dihydrate with respect to iron 3 ·6H 2 Synthesis of goethite from O.

[0146] protocol : Dissolve 0.707 g of KOH, 0.088 mL of acetic acid, and 0.214 g of oxalic acid dihydrate in pure water to make 13.3 mL of solution (0.8 mol.L -1 KOH, 0.1 mol.L -1 acetic acid, and 0.1 mol.L -1 Oxalic acid dihydrate) was prepared. 0.427 g of ferric chloride hexahydrate (FeCl3.6H2O) was dissolved in pure water to make another 2 mL solution (0.8 mol.L). -1A basic solution (Fe) was prepared. The basic solution was placed in a 23 mL autoclave equipped with a PTFE chamber, and a ferric solution was added dropwise (0.7 mol.L). -1 KOH, 0.1 mol.L -1 Acetic acid, 0.1 mol.L -1 oxalic acid dihydrate, and 0.1 mol.L -1 Fe). The red suspension was stirred for 10 minutes. The autoclave was placed in an oven and heated at 50°C for 24 hours after a 2-hour temperature increase, followed by heating at 150°C for 24 hours after a 2-hour temperature increase. A yellow precipitate was formed, and the pH of the supernatant was measured to be 14. The precipitate was centrifuged at 6,000 rpm, washed three times with pure water and once with ethanol, centrifuged again at 6,000 rpm, and dried in an oven at 100°C for 1 day. A yellow powder was obtained.

[0147] XRD : diffraction pattern obtained ( Fig. 15 The peak of ) corresponds to the signal of goethite (top diagram = experimental diffraction pattern, bottom diagram with square = expected peak for the goethite sample).

[0148] SEM : The particles observed by SEM were non-nanosized and had a needle-like shape. The median size of the small dimension was 127 nm, and 27% of the particles were nanosized by number. The median size of the large dimension was 557 nm, and 4% of the particles were nanosized by number ( FIGS. 16a, 16b, and 16c ).

[0149] Color measurement : The obtained overall hue color was within the value range corresponding to the reference yellow, dE*ab = 12.87, and the L*a*b* values ​​were L* = 56.71; a* = 10.14; and b* = 40.28. For the white gradient hue, the color was also within the reference range, dE*ab = 3.89, and the L*a*b* values ​​were L* = 71.98; a* = 3.84 and b* = 29.61.

[0150] do Table I This summarizes the results obtained from the embodiments according to the present invention and the comparative examples mentioned above.

[0151] Table I. Ferric ammonium hydroxide trihydrate is 0.3 mol.L -1 It exists at a concentration of, and the concentration of KOH is 2.1 mol.L -1 Except for Example 4, KOH (0.7 mol.L -1 Various iron(III) salts (0.1 mol.L) in the presence of ) -1 Characterization of iron oxide (III) obtained from ) (1** corresponds to the small dimension of the particle; L* corresponds to the large dimension of the particle; concentration corresponds to the value of the type present in the basic ferric aqueous suspension of step a).

[0152]

[0153] Example 10 according to the present invention: FeCl using 1 equivalent of acetic acid with respect to iron 3 .6H 2 Synthesis of goethite from O.

[0154] protocol : Synthesis of goethite from FeCl3·6H2O using 1 equivalent of acetic acid per 1 equivalent of iron in a manner similar to the protocol of Example 5. The obtained results are as follows: Table II It is recorded in.

[0155] XRD : The peaks of the obtained diffraction pattern correspond to the signal of goethite.

[0156] SEM : The particles observed by SEM were non-nanosized and had a needle-like shape. The median size of the small dimension was 105 nm, and 43% of the particles were nanosized by number. The median size of the large dimension was 450 nm, and 5% of the particles were nanosized by number.

[0157] Color measurement : The obtained overall hue color was within the value range corresponding to the reference yellow, dE*ab = 12.3, and the L*a*b* values ​​were L* = 56.34; a* = 10.05; and b* = 40.86. For the white gradient hue, the color was also within the reference range, dE*ab = 4.11, and the L*a*b* values ​​were L* = 71.98; a* = 3.68 and b* = 29.45.

[0158] Example 11 according to the present invention: FeCl using 1 equivalent of lactic acid with respect to iron 3 .6H 2 Synthesis of goethite from O.

[0159] protocol : Synthesis of goethite from FeCl3·6H2O using 1 equivalent of lactic acid per 1 equivalent of iron in a manner similar to the protocol of Example 5. The obtained results are as follows: Table II It is recorded in.

[0160] XRD : The peaks of the obtained diffraction pattern correspond to the signal of goethite.

[0161] SEM : The particles observed by SEM were non-nanosized and had a needle-like shape. The median size of the small dimension was 111 nm, and 39% of the particles were nanosized by number. The median size of the large dimension was 426 nm, and 1% of the particles were nanosized by number.

[0162] Color measurement : The obtained overall hue color was within the value range corresponding to the reference yellow, dE*ab = 9.64, and the L*a*b* values ​​were L* = 55.17; a* = 10.91; and b* = 43.2. For the white gradient hue, the color was also within the reference range, dE*ab = 6.8, and the L*a*b* values ​​were L* = 72.28; a* = 2.9 and b* = 26.45.

[0163] Example 12 according to the present invention: FeCl using 1 equivalent of glycine with respect to iron 3 .6H 2 Synthesis of goethite from O.

[0164] protocol : Synthesis of goethite from FeCl3·6H2O using 1 equivalent of glycine per 1 equivalent of iron in a manner similar to the protocol of Example 5. The obtained results are as follows: Table II It is recorded in.

[0165] XRD : The peaks of the obtained diffraction pattern correspond to the signal of goethite.

[0166] SEM : The particles observed by SEM were non-nanosized and had a needle-like shape. The median size of the small dimension was 104 nm, and 47% of the particles were nanosized by number. The median size of the large dimension was 402 nm, and 5% of the particles were nanosized by number.

[0167] Color measurement : The obtained overall hue color was within the value range corresponding to the reference yellow, dE*ab = 12.22, and the L*a*b* values ​​were L* = 55.36; a* = 10.06; and b* = 40.76. For the white gradient hue, the color was also within the reference range, dE*ab = 4.81, and the L*a*b* values ​​were L* = 72.12; a* = 3.35 and b* = 28.75.

[0168] Example 13 according to the present invention: FeCl using 1 equivalent of 2,6-pyridinedicarboxylic acid with respect to iron 3 ·6H 2 Synthesis of goethite from O.

[0169] protocol : Synthesis of goethite from FeCl3·6H2O using 1 equivalent of 2,6-pyridinedicarboxylic acid per 1 equivalent of iron in a manner similar to the protocol of Example 5. The results obtained are as follows: Table II It is recorded in.

[0170] XRD : The peaks of the obtained diffraction pattern correspond to the signal of goethite.

[0171] SEM : The particles observed by SEM were non-nanosized and had a needle-like shape. The median size of the small dimension was 117 nm, and 35% of the particles were nanosized by number. The median size of the large dimension was 513 nm, and 6% of the particles were nanosized by number.

[0172] Color measurement : The obtained overall hue color was within the value range corresponding to the reference yellow, with dE*ab = 13.95, and L*a*b* values ​​were L* = 55.69; a* = 9.69; and b* = 39.06. For the white gradient hue, the color was also within the reference range, with dE*ab = 5.43, and L*a*b* values ​​were L* = 72.08; a* = 3.26 and b* = 27.91.

[0173] Comparative Example 14: Using 1 equivalent of 5-sulfosalicylic acid dihydrate with respect to iron FeCl 3 ·6H 2 Synthesis of goethite from O.

[0174] protocol : Synthesis of goethite from FeCl3·6H2O using 1 equivalent of 5-sulfosalicylic acid per 1 equivalent of iron in a manner similar to the protocol of Example 5. The results obtained are as follows: Table II It is recorded in.

[0175] XRD : The peaks of the obtained diffraction pattern correspond to the signal of goethite.

[0176] SEM :The particles observed by SEM were nano-sized and had a needle-like shape. The median size of the small dimension was 90 nm, and 66% of the particles were nano-sized by number. The median size of the large dimension was 276 nm, and 1% of the particles were nano-sized by number.

[0177] Color measurement : The obtained overall hue color was within the value range corresponding to the reference yellow, dE*ab = 7.95, and L*a*b* values ​​were L* = 55; a* = 10.94; and b* = 45.06. For the white gradient hue, the color was also within the reference range, dE*ab = 4.52, and L*a*b* values ​​were L* = 72.31; a* = 3.57 and b* = 29.09.

[0178] Example 15 according to the present invention: FeCl using 1 equivalent of nitrilotriacetic acid with respect to iron 3 .6H 2 Synthesis of goethite from O.

[0179] protocol : Synthesis of goethite from FeCl3·6H2O using 1 equivalent of nitrilotriacetic acid per 1 equivalent of iron in a manner similar to the protocol of Example 5. The obtained results are as follows: Table II It is recorded in.

[0180] XRD : The peaks of the obtained diffraction pattern correspond to the signal of goethite.

[0181] SEM : The particles observed by SEM were non-nanosized and had a needle-like shape. The median size of the small dimension was 102 nm, and 48% of the particles were nanosized by number. The median size of the large dimension was 732 nm, and 3% of the particles were nanosized by number.

[0182] Color measurement : The obtained overall hue color was within the value range corresponding to the reference yellow, dE*ab = 15.08, and the L*a*b* values ​​were L* = 57.78; a* = 9.3; and b* = 38.46. For the white gradient hue, the color was also within the reference range, dE*ab = 4.88, and the L*a*b* values ​​were L* = 72.06; a* = 3.38 and b* = 28.58.

[0183] Comparative Example 16: FeCl using 1 equivalent of salicylic acid relative to iron 3 ·6H 2 Synthesis of goethite from O.

[0184] protocol : Synthesis of goethite from FeCl3·6H2O using 1 equivalent of salicylic acid per 1 equivalent of iron in a manner similar to the protocol of Example 5. The obtained results are as follows: Table II It is recorded in.

[0185] XRD : The peaks of the obtained diffraction pattern correspond to the signal of goethite.

[0186] SEM : The particles observed by SEM were nano-sized and had a spherical shape. The median size of the small dimension was 61 nm, and 94% of the particles were nano-sized by number. The median size of the large dimension was 134 nm, and 12% of the particles were nano-sized by number.

[0187] Color measurement : The obtained overall hue color was within the value range corresponding to the reference yellow, dE*ab = 11.58, and the L*a*b* values ​​were L* = 57.87; a* = 10.05; and b* = 41.36. For the white gradient hue, the color was also within the reference range, dE*ab = 5.26, and the L*a*b* values ​​were L* = 72.18; a* = 3.02 and b* = 28.43.

[0188] Example 17 according to the present invention: FeCl using 1 equivalent of hydroxyethylethylenediamine-triacetic acid (HEDTA) with respect to iron 3 ·6H 2 Synthesis of goethite from O.

[0189] protocol : Synthesis of goethite from FeCl3·6H2O using 1 equivalent of hydroxyethylethylenediaminetriacetic acid (HEDTA) per 1 equivalent of iron in a manner similar to the protocol of Example 5. The obtained results are as follows: Table II It is recorded in.

[0190] XRD : diffraction pattern obtained ( Fig. 17 The peak of ) corresponds to the signal of goethite (top diagram = experimental diffraction pattern; bottom diagram with square = expected peak for the goethite sample).

[0191] SEM : The particles observed by SEM were non-nanosized and rod-shaped. The median size of the small dimension was 149 nm, and 19% of the particles were nanosized by number. The median size of the large dimension was 863 nm, and 6% of the particles were nanosized by number ( FIGS. 18a, 18b, and 18c ).

[0192] Color measurement : The obtained overall hue color was within the range corresponding to the standard yellow, dE*ab = 13.23, and L*a*b* values ​​were L* = 56.1; a* = 9.98; and b* = 39.8. For the white gradient hue, the color was also within the standard range, dE*ab = 4.12, and L*a*b* values ​​were L* = 70.85; a* = 3.88 and b* = 28.82.

[0193] Comparative Example 18: FeCl using 1 equivalent of isodium 4,5-dihydroxy-1,3-benzene-disulfonic acid monohydrate (Tiron) relative to iron 3 ·6H 2 Synthesis of goethite from O.

[0194] protocol : Synthesis of goethite from FeCl3·6H2O using 1 equivalent of isodium 4,5-dihydroxy-1,3-benzenedisulfonic acid monohydrate (Tiron) per 1 equivalent of iron in a manner similar to the protocol of Example 5. The results obtained are as follows: Table II It is recorded in.

[0195] XRD : The peaks of the obtained diffraction pattern correspond to the signal of goethite.

[0196] SEM : The particles observed by SEM were nano-sized and had a needle-like shape. The median size of the small dimension was 96 nm, and 56% of the particles were nano-sized by number. The median size of the large dimension was 322 nm, and 3% of the particles were nano-sized by number.

[0197] Color measurement : The obtained overall hue color was within the value range corresponding to the reference yellow, dE*ab = 19.1, and L*a*b* values ​​were L* = 53.1; a* = 7.27; and b* = 34.34. For the white gradient hue, the color was also within the reference range, dE*ab = 5.81, and L*a*b* values ​​were L* = 70.61; a* = 2.81 and b* = 27.48.

[0198] Example 19 according to the present invention: FeCl using 3 equivalents of oxalic acid dihydrate with respect to iron 3 ·6H 2 Synthesis of goethite from O.

[0199] protocol : Dissolve 1.405 g of KOH and 0.586 g of oxalic acid dihydrate in pure water to make 13.3 mL of solution (1.6 mol.L -1 KOH and 0.3 mol.L -1 Oxalic acid dihydrate) was prepared. 0.429 g of ferric chloride hexahydrate (FeCl3.6H2O) was dissolved in pure water to make another 2 mL solution (0.8 mol.L). -1A basic solution (Fe) was prepared. The basic solution was placed in a 23 mL autoclave equipped with a PTFE chamber, and a ferric solution was added dropwise (1.4 mol.L). -1 of KOH, 0.3 mol.L -1 oxalic acid dihydrate, and 0.1 mol.L -1 Fe). The red suspension was mixed for 10 minutes. An autoclave was placed in an oven and heated at 50°C for 24 hours after a 2-hour temperature increase phase, followed by heating at 150°C for 24 hours after a 2-hour temperature increase phase. A yellow precipitate was formed, and the pH of the supernatant was measured to be 14. The precipitate was centrifuged at 6,000 rpm, washed three times with pure water, centrifuged again at 6,000 rpm, and dried in an oven at 100°C for 1 day. A yellow powder was obtained.

[0200] XRD : diffraction pattern obtained ( Fig. 19 The peak of ) corresponds to the signal of goethite (top diagram = experimental diffraction pattern, bottom diagram with square = expected peak for the goethite sample).

[0201] SEM : The particles observed by SEM were non-nanosized and had a needle-like shape. The median size of the small dimension was 124 nm, and 37% of the particles were nanosized by number. The median size of the large dimension was 521 nm, and 2% of the particles were nanosized by number ( FIGS. 20a, 20b, and 20c ).

[0202] Color measurement : The obtained overall hue color was within the value range corresponding to the reference yellow, dE*ab = 11.83, and L*a*b* values ​​were L* = 57.65; a* = 10.12; and b* = 41.78. For the white gradient hue, the color was also within the reference range, dE*ab = 3.31, and L*a*b* values ​​were L* = 71.98; a* = 4.02 and b* = 30.51.

[0203] Example 20 according to the present invention: FeCl using 3 equivalents of citric acid monohydrate with respect to iron 3 ·6H 2 Synthesis of goethite from O.

[0204] protocol : Synthesis of goethite from FeCl3·6H2O using 3 equivalents of citric acid monohydrate per 1 equivalent of iron in a manner similar to the protocol of Example 19. The results obtained are as follows: Table II It is recorded in.

[0205] XRD : diffraction pattern obtained ( Fig. 21 The peak of ) corresponds to the signal of goethite (top diagram = experimental diffraction pattern, bottom diagram with square = expected peak for the goethite sample).

[0206] SEM : The particles observed by SEM were non-nanosized and rod-shaped. The median size of the small dimension was 155 nm, and 26% of the particles were nanosized by number. The median size of the large dimension was 701 nm, and 11% of the particles were nanosized by number ( FIGS. 22a, 22b, and 22c ).

[0207] Color measurement : The obtained overall hue color was within the value range corresponding to the reference yellow, dE*ab = 20.44, and the L*a*b* values ​​were L* = 42.17; a* = 15.54; and b* = 35.02. For the white gradient hue, the color was also within the reference range, dE*ab = 13.43, and the L*a*b* values ​​were L* = 64.9; a* = 6.9 and b* = 19.6.

[0208] Example 21 according to the present invention: FeCl using 3 equivalents of EDTA with respect to iron 3 ·6H 2 Synthesis of goethite from O.

[0209] protocol : Synthesis of goethite from FeCl3·6H2O using 3 equivalents of EDTA per 1 equivalent of iron in a manner similar to the protocol of Example 19. The results obtained are as follows: Table II It is recorded in.

[0210] XRD : diffraction pattern obtained ( Fig. 23 The peak of ) corresponds to the signal of goethite (top diagram = experimental diffraction pattern, bottom diagram with square = expected peak for the goethite sample).

[0211] SEM : The particles observed by SEM were non-nanosized and had a needle-like shape. The median size of the small dimension was 137 nm, and 33% of the particles were nanosized by number. The median size of the large dimension was 502 nm, and 6% of the particles were nanosized by number ( FIGS. 24a, 24b, and 24c ).

[0212] Color measurement : The obtained overall hue color was within the value range corresponding to the reference yellow, dE*ab = 13.5, and L*a*b* values ​​were L* = 56.91; a* = 9.87; and b* = 39.74. For the white gradient hue, the color was also within the reference range, dE*ab = 4.06, and L*a*b* values ​​were L* = 71.97; a* = 3.87 and b* = 29.28.

[0213] Example 22 according to the present invention: regarding iron 0.1 Equivalent amount polyethylene glycol (PEG) Using FeCl 3 ·6H 2 Synthesis of goethite from O.

[0214] protocol : 0.698 g of KOH and 0.919 g of molar mass in pure water (6000 g.mol) -1 Dissolve polyethylene glycol to make 13.3 mL of solution (0.80 mol.L -1 of KOH and 0.01 mol.L -1 Polyethylene glycol) was prepared. 0.428 g of ferric chloride hexahydrate (FeCl3.6H2O) was dissolved in pure water to make another 2 mL solution (0.77 mol.L). -1 A basic solution (Fe) was prepared. The basic solution was placed in a 23 mL autoclave equipped with a PTFE chamber, and a ferric solution was added dropwise (0.69 mol.L). -1 of KOH, 0.01 mol.L -1 polyethylene glycol, and 0.10 mol.L -1Fe). The red suspension was stirred for 10 minutes. The autoclave was placed in an oven and heated at 50°C for 24 hours after a 2-hour temperature increase, followed by heating at 150°C for 24 hours after a 2-hour temperature increase. A yellow precipitate was formed, and the pH of the supernatant was measured to be 14. The precipitate was centrifuged at 6,000 rpm, washed three times with pure water and once with ethanol, centrifuged again at 6,000 rpm, and dried in an oven at 100°C for 1 day. A yellow powder was obtained.

[0215] XRD : diffraction pattern obtained ( Fig. 25 The peak of ) corresponds to the signal of goethite (top diagram = experimental diffraction pattern, bottom diagram with square = expected peak for the goethite sample).

[0216] SEM : The particles observed by SEM were non-nanosized and had a needle-like shape. The median size of the small dimension was 103 nm, and 47% of the particles were nanosized by number. The median size of the large dimension was 463 nm, and 4% of the particles were nanosized by number ( FIGS. 26a, 26b, and 26c ).

[0217] The strength of the complexing agent can be measured by investigating the value of the total formation constant Kf of the complex in solution according to the following reaction equation (M = metal; L = ligand):

[0218] M + nL = mL n (1)

[0219] Kf n = [mL n ] / [M][L]" (2)

[0220] Log(Kf n ) = log ([mL n ] / [M].[L]") (3)

[0221] For a complex containing n ligands, its Kf n can be determined from the concentration values ​​of the related type, and accordingly log(Kf n ) can be obtained. The inventors have [referenced from] literature (e.g., literature [ Lange's Handbook of Chemistry; 15th Edition; Section 8 Electrolytes, Electromagnetic Force, and Chemical Equilibrium, section 8.2.2 log(Kf of the ignition agent identified in ]) n The study was conducted based on the ) value.

[0222] The inventors observed that the strength and properties of the complexing agent affect not only the size but also the shape of the formed goethite particles. Certain complexing agents, such as salicylic acid or 5-sulfosalicylic acid, inhibit the growth of large dimensions in goethite, whereas, conversely, nitrilotriacetic acid or ethylenediaminetetraacetic acid (EDTA) promoted the growth of such dimensions. Furthermore, excessively large complexing constant values ​​significantly limit or even prevent the precipitation of goethite, potentially leaving iron in a solution state. This was the case, for example, when using isodium 4,5-dihydroxy-1,3-benzenedisulfonic acid monohydrate (Tiron). Therefore, log(Kf) of the complexing agent promoting the growth of non-nano-sized particles n There is a range of values ​​for ). Preferred complexing agents according to the present invention are oxalic acid, citric acid, ethylenediaminetetraacetic acid (EDTA), and hydroxyethylethylenediamine-triacetic acid (HEDTA).

[0223] Table II. Characterization of goethite obtained from various complexing agents (L* corresponds to large particle size, l** corresponds to small particle size, G corresponds to goethite; concentration corresponds to the value of the type present in the basic ferric aqueous suspension of step a).

[0224]

[0225] Example 23 according to the present invention: FeCl using 2 equivalents of oxalic acid dihydrate with respect to iron 3 ·6H 2 Synthesis of hematite from O.

[0226] protocol : Dissolve 0.502 g of KOH and 0.282 g of oxalic acid dihydrate in pure water to make 9.2 mL of solution (0.8 mol.L -1 KOH and 0.2 mol.L-1 Oxalic acid dihydrate) was prepared. 0.307 g of ferric chloride hexahydrate (FeCl3.6H2O) was dissolved in pure water to make another 1.4 mL solution (0.8 mol.L). -1 Fe) was prepared. The KOH solution was placed in a 16 mL autoclave equipped with a PTFE chamber, and the ferric solution was added dropwise (0.7 mol.L). -1 of KOH, 0.2 mol.L -1 oxalic acid dihydrate, and 0.1 mol.L -1 Fe). The red suspension was stirred for 10 minutes. The autoclave was placed in an oven and heated at 50°C for 24 hours after a 2-hour temperature increase phase, followed by heating at 150°C for 24 hours after a 2-hour temperature increase phase. A red precipitate was formed, and the pH of the supernatant was measured to be 11.06. The precipitate was centrifuged at 6,000 rpm, washed three times with pure water and once with ethanol, centrifuged again at 6,000 rpm, and dried in an oven at 100°C for 1 day. A red powder was obtained.

[0227] XRD : diffraction pattern obtained ( Fig. 27 The peak of ) corresponds to the signal of hematite (top diagram = experimental diffraction pattern, bottom diagram with square = expected peak for the hematite sample).

[0228] SEM : The particles observed by SEM were non-nanosized and had a spherical shape. The median size of the small dimension was 187 nm, and 7% of the particles were nanosized by number. The median size of the large dimension was 250 nm, and 2% of the particles were nanosized by number ( FIGS. 28a, 28b, and 28c ).

Claims

Claim 1 A method for manufacturing non-nano-sized iron oxide particles, wherein the iron oxide particles are goethite particles, hematite particles, or a mixture of goethite and hematite particles, (a) (i) a basic aqueous solution comprising at least one complexing agent and an aqueous ferric solution comprising at least one iron(III) salt (wherein the at least one complexing agent is the same as or different from the counterion of the at least one iron(III) salt), or (ii) a step of preparing a basic iron aqueous suspension by mixing a basic aqueous solution and a ferric aqueous solution comprising an iron (III) salt complex consisting of at least one iron (III) salt and a complexing agent existing in the form of a counterion of said at least one iron (III) salt; (b) Step (a) of heating the basic iron aqueous suspension obtained in step (a) to a temperature of 50°C to 350°C to obtain a precipitate of iron oxide; (c) A method comprising the steps of separating, washing, and drying the precipitate obtained in step (b). Claim 2 The method according to claim 1, wherein the at least one complexing agent is water-soluble and comprises at least one functional group selected from the group consisting of carboxylic acid, thiocarboxylic acid, amine, alcohol, ether, sulfonic acid, phosphonic acid, phosphoric acid, polymer, basic forms thereof, and mixtures thereof. Claim 3 A method according to claim 1 or 2, wherein the at least one complexing agent used in step (a)(i) is selected from the group consisting of acetic acid, lactic acid, oxalic acid, glycine, 2,6-pyridinedicarboxylic acid, citric acid, nitrilotriacetic acid, polyethylene glycol (PEG), hydroxyethylethylenediaminetriacetic acid (HEDTA), ethylene-diaminetetraacetic acid (EDTA), basic forms thereof, and mixtures thereof. Claim 4 A method according to any one of claims 1 to 3, wherein the at least one complexing agent used in step (a)(i) is selected from the group consisting of oxalic acid, citric acid, HEDTA, EDTA, basic forms thereof, and mixtures thereof, and preferably is oxalic acid or citric acid or basic forms thereof. Claim 5 A method according to any one of claims 1 to 4, wherein the at least one complexing agent used in step (a)(i) has a log(K) of 1 to 30, preferably 3 to 26, much more preferably 19 to 25, and the log(K) corresponds to the largest log(K) among log(K1), log(K2) and log(K3). Claim 6 A method according to any one of claims 1 to 5, wherein the at least one iron (III) salt used in step (a)(i) is selected from the group consisting of ferric chloride, ferric nitrate and ferric sulfate. Claim 7 A method according to any one of claims 1 to 5, wherein the iron (III) salt complex used in step (a)(ii) is ferric ammonium oxalate trihydrate, ferric sodium ethylenediaminetetraacetate, or ferric citrate. Claim 8 A method according to any one of claims 1 to 7, wherein the basic aqueous solution comprises an alkali agent selected from the group consisting of lithium hydroxide, sodium hydroxide, potassium hydroxide, rubidium hydroxide, cesium hydroxide and mixtures thereof, preferably sodium hydroxide, potassium hydroxide and mixtures thereof. Claim 9 A method characterized in that, in any one of claims 1 to 8, the iron oxide particles are goethite particles. Claim 10 Non-nano-sized iron oxide particles obtained through the method claimed in any one of claims 1 to 9, wherein the iron oxide particles are goethite particles, hematite particles, or a mixture of goethite and hematite particles, preferably goethite particles. Claim 11 Non-nanosized iron oxide particles, wherein the iron oxide particles are goethite particles or a mixture of goethite and hematite particles, and the number average median size of the small and large dimensions of the primary particles is greater than 100 nm. Claim 12 Iron oxide particles according to claim 11, characterized in that the number median size of the small dimensions of the primary particles is 100 nm to 200 nm, and the ratio of the number median size of the large dimensions of the primary particles to the number median size of the small dimensions is greater than 3. Claim 13 The iron oxide particles of claim 11 or 12, characterized in that the iron oxide particles are goethite particles having the following L*, a*, and b* values ​​when measured in CIELAB units: - in the overall tone, the L* value is 42 to 58, the a* value is 7 to 16, and the b* value is 34 to 53, or - in the white gradient tone, the L* value is 64 to 73, the a* value is 2 to 7, and the b* value is 19 to 34. Claim 14 A cosmetic composition comprising iron oxide particles claimed in any one of claims 10 to 13. Claim 15 The use of iron oxide particles claimed in any one of claims 10 to 13 as a pigment in a cosmetic composition.

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