Cosmetic titanium dioxide particles and their preparation

Abstract

This invention relates to a method for preparing cosmetic titanium dioxide pigment particles, comprising the following steps: a) providing uncoated titanium dioxide pigment particles, and b) coating the uncoated titanium dioxide pigment particles with a bio-based oil to prepare cosmetic titanium dioxide pigment particles; the invention also relates to cosmetic titanium dioxide pigment particles comprising titanium dioxide pigment particles coated with bio-based oil, wherein the cosmetic titanium dioxide pigment particles comprise titanium dioxide pigment particles coated with bio-based oil, and the content of bio-based oil is from 0.01 wt.% to 0.5 wt.% based on the total weight of the cosmetic titanium dioxide pigment particles.

Description

Technical Field

[0001] This invention relates to a method for producing cosmetic titanium dioxide pigment particles, cosmetic titanium dioxide pigment particles obtainable by this method, and a cosmetic titanium dioxide pigment particle. This invention also relates to a method for manufacturing a cosmetic formulation, a cosmetic formulation obtainable by this method, and the use of the cosmetic titanium dioxide pigment particles or the cosmetic formulation of this invention in cosmetic applications. Background Technology

[0002] Titanium dioxide, also known as titanium white, is a white pigment used in high-end applications. As a pigment, titanium dioxide pigment particles for cosmetics have various uses, such as in cosmetics. When used in cosmetics and other products, TiO2 pigment particles are sometimes coated with an organic coating. Typically, these coated pigment particles are produced by... The coated pigment particles are formed by simply mixing them with an organic coating and the final product. These coated pigment particles typically have a thick coating, or if only a small amount of organic compound is used, the coating is uneven. A thicker coating results in particles with a higher carbon content, which is undesirable. Furthermore, the above method can lead to undesirable agglomeration of the pigment particles, thereby reducing the optical quality of the final product. In addition, the resulting pigment particles have poor dispersion properties, leading to reduced brightness in the final cosmetic product.

[0003] Therefore, it would be ideal to have a method for producing cosmetic titanium dioxide pigment particles that have improved dispersion properties, low carbon content, and / or enhanced brightness of the final product. Furthermore, in applications such as cosmetics, a neutral color appearance is preferred. Summary of the Invention

[0004] The technical objective of this invention is to provide a method, a titanium dioxide pigment particle for cosmetics, and a cosmetic formulation that can overcome the above-mentioned problems.

[0005] This objective is achieved by a method for producing cosmetic titanium dioxide pigment particles coated with bio-based oils. Furthermore, this objective is also achieved by cosmetic titanium dioxide pigment particles comprising the bio-based oil-coated titanium dioxide pigment particles according to the present invention, and a cosmetic formulation according to the present invention.

[0006] The inventors were surprised to discover that a cosmetic titanium dioxide pigment particle coated with bio-based oil has satisfactory b... It can improve the brightness of cosmetic formulations. In addition, its carbon content, loss on drying, and loss on ignition are all good.

[0007] The first aspect of the present invention relates to a method for producing titanium dioxide pigment particles for cosmetic use, comprising, preferably, the following steps:

[0008] a) Provide uncoated titanium dioxide pigment particles, and

[0009] b) Coating the uncoated titanium dioxide pigment particles with bio-based oil to produce titanium dioxide pigment particles for cosmetic use.

[0010] Bio-based oils according to the present invention refer to a class of oils derived from renewable biological sources, such as plants, algae, animals, or other organic materials. Unlike traditional petroleum-based oils derived from fossil fuels, bio-based oils are produced from biomass through extraction, fermentation, or other bioconversion methods. These bio-based oils are generally environmentally sustainable and minimize the carbon footprint associated with their production. Therefore, bio-based oils are oils obtained from sustainable sources. Bio-based oils include refined bio-based oils. These oils can have positive effects when used in cosmetics because they help reduce, for example, skin irritation or other adverse reactions. For example, the use of polydimethylsiloxane (PDMS) can be reduced or completely avoided.

[0011] Uncoated titanium dioxide pigment particles should be understood as titanium dioxide pigment particles that have neither undergone organic nor inorganic coating.

[0012] The second aspect of the present invention relates to a type of titanium dioxide pigment particles for cosmetics that can be obtained by the inventive method described above for producing titanium dioxide pigment particles for cosmetics.

[0013] A third aspect of the present invention relates to a cosmetic titanium dioxide pigment particle comprising, preferably, the following components: titanium dioxide pigment particles coated with 0.01 wt.% to 0.5 wt.%, preferably 0.1 wt.% to 0.45 wt.%, more preferably 0.15-0.4 wt.%, of bio-based oil, based on the total weight of the cosmetic titanium dioxide pigment particles.

[0014] The titanium dioxide pigment particles for cosmetics of the present invention exhibit excellent performance when dispersed in cosmetic formulations. They enhance brightness, thereby allowing for a reduction in the amount of titanium dioxide particles used in cosmetic formulations. Furthermore, this is also a sign of improved tinting strength. In addition, cosmetics… The carbon content of the pigment particles can be kept at a low level, resulting in favorable drying and ignition loss characteristics.

[0015] A fourth aspect of the present invention relates to a method for manufacturing a cosmetic formulation, comprising, preferably, the following steps:

[0016] a) Provide uncoated titanium dioxide pigment particles;

[0017] b) Coating the titanium dioxide pigment particles with a bio-based oil to manufacture titanium dioxide pigment particles for cosmetic use; and

[0018] c) Mix the coated cosmetic titanium dioxide pigment particles with the ingredients of the cosmetic formulation, preferably selected from water, oil, emulsifier, silicone, solvent, pigment, rheology modifier (such as thickener), stabilizer, antioxidant, preservative, pH adjuster, filler, wetting agent and / or combination thereof.

[0019] By using the methods described herein, cosmetic compositions with beneficial properties such as increased brightness can be produced. Furthermore, the content of potential irritants and / or unsustainable compounds in the manufactured cosmetic formulations can be reduced.

[0020] In a fifth aspect, the present invention relates to a cosmetic formulation that can be obtained by the method according to the fourth aspect.

[0021] In a sixth aspect, the present invention relates to a cosmetic formulation comprising titanium dioxide pigment particles for cosmetic use according to the present invention.

[0022] In a seventh aspect, the present invention relates to the use of the titanium dioxide pigment particles for cosmetics of the present invention or the cosmetic formulation of the present invention in cosmetic applications, preferably in color cosmetics. Detailed Implementation

[0023] These and other aspects, features, and advantages of the invention will become apparent to those skilled in the art upon reading the following detailed description and claims. Each feature of one aspect of the invention may be applied to any other aspect of the invention. Numerical ranges stated in the format "from x to y" include the mentioned numerical values ​​as well as values ​​within the corresponding range of measurement precision known to those skilled in the art. If multiple preferred numerical ranges are stated in this format, all ranges formed by various combinations of endpoints are also included.

[0024] The pigment particles of this invention consist of titanium dioxide pigment and a bio-based oil coating. As used herein, "titanium dioxide pigment" or "titanium-based pigment particles" refers to titanium dioxide pigment obtained by the sulfuric acid or chlorination process and optionally milled. Furthermore, the pigment may exist in rutile, anatase, or brookite crystal structures, typically rutile or anatase. Rutile is particularly suitable compared to anatase due to its lower photocatalytic activity and higher refractive index. Preferably, the titanium dioxide pigment, by weight of the total particles, consists of at least 98 wt.%, preferably at least 99 wt.%, of rutile.

[0025] Within the scope of this invention, the titanium dioxide pigment particles have a certain native particle size, enabling them to scatter visible light, ideally achieving a high scattering rate. The particle size is the median particle size d50 (hereinafter referred to as d50) ranging from 200 nm to 400 nm, measured by a centrifugal sedimentation apparatus.

[0026] The titanium dioxide particles of the present invention are preferably spherical with an aspect ratio between 1.1 and 1.6, more preferably with an average aspect ratio between 1.2 and 1.4. The particles are preferably convex. Preferably, the titanium dioxide particles of the present invention are not plate-like.

[0027] In a first aspect, the present invention relates to a method for producing the aforementioned titanium dioxide pigment particles for cosmetic use.

[0028] In a preferred embodiment, the amount of bio-based oil used in step b) is 0.1 wt.% to 2.0 wt.% of the total weight of the uncoated titanium dioxide pigment particles, preferably 0.1 wt.% to 1.0 wt.%, more preferably 0.2 wt.% to 0.5 wt.%, and even more preferably 0.3 wt.% to 0.4 wt.%.

[0029] Using this dosage of bio-based oil is advantageous because it enables the production of coated titanium particles with a low carbon content. The low carbon content is beneficial for the performance of coated TiO2 pigment particles, particularly in terms of drying loss and ignition loss, which are important properties for cosmetic applications. With this lower dosage of bio-based oil, well-dispersible TiO2 particles in cosmetic formulations can still be obtained, thereby improving brightness, i.e., L in CIELAB measurements. value.

[0030] Furthermore, this amount of bio-based oil can still provide Homogeneous coating of pigment particles with bio-based oil.

[0031] Preferably, the content of other compounds (such as water) is less than 2.0 wt.% of the total weight of the uncoated titanium dioxide pigment particles and bio-based oil during the coating step, preferably less than 1.0 wt.%, and more preferably less than 0.9 wt.%.

[0032] This is also important for the drying and ignition losses of the final coated TiO2 pigment particles.

[0033] Further preferably, the average particle size (D50) of the coated cosmetic titanium dioxide pigment particles is in the range of... to Within the range, preferably to .

[0034] Furthermore, the titanium dioxide pigment particles preferably do not contain metal oxide and / or metal-like oxide layers. This means that there are no other layers containing alumina, zirconium oxide, silicon dioxide, tin oxide, cerium oxide, or mixtures thereof.

[0035] In one embodiment, the titanium dioxide pigment particles exist in anatase or rutile crystal structures, preferably in rutile crystal structures.

[0036] Using a Perkin Elmer Lambda 950 spectrometer, following the CIE 1931 standard observer (2°) measurement principle, C standard light was used to analyze the bio-based oils. The value was measured.

[0037] In a preferred embodiment, the bio-based oil's b The value (measured according to the CIE 1931 standard observer (2°) measurement principle) is less than 10, preferably less than 8.

[0038] In another preferred embodiment, the bio-based oil is a plant-based oil, preferably b. The value (measured according to the 1931 CIE standard observer (2°) measurement principle) is below 10, preferably below 8 for vegetable-based oils.

[0039] According to a preferred embodiment, the vegetable-based oil is selected from the group consisting of soybean oil, sesame oil, rice germ oil, avocado oil, moringa oil, sunflower seed oil, rapeseed oil, grape seed oil, or mixtures thereof, preferably sesame oil, rice germ oil, moringa oil, sunflower seed oil, rapeseed oil, grape seed oil, or mixtures thereof, and more preferably rice germ oil.

[0040] Using these oils can give the resulting cosmetic titanium dioxide pigment particles excellent brightness.

[0041] Further preferably, step b) is carried out by homogenizing cosmetic titanium dioxide pigment particles with bio-based oil at 1,000 rpm to 3,000 rpm, preferably 2,000 rpm.

[0042] Further preferably, the homogenization process is carried out for 1 to 600 seconds, more preferably 20 to 420 seconds, and even more preferably 30 to 300 seconds.

[0043] In addition, a screening step can be optionally performed, using a sieve, preferably with a mesh size of 400. to More preferably 600 to .

[0044] Homogenizing TiO2 pigment particles, even with the use of very small amounts of bio-based oil, helps to achieve homogeneous coating of titanium dioxide pigment particles.

[0045] It should be understood that any features and / or aspects discussed below in conjunction with the titanium dioxide particles for cosmetic use of the present invention are analogous to the methods described above.

[0046] In a second aspect, the present invention relates to a cosmetic titanium dioxide pigment particle that can be obtained by the method of the present invention described above.

[0047] It should be understood that any features and / or aspects discussed above in conjunction with the methods described above and below (especially the third aspect) regarding titanium dioxide pigment particles for cosmetics are analogous to the second aspect.

[0048] In a third aspect, the present invention relates to a cosmetic titanium dioxide pigment particle comprising titanium dioxide pigment particles coated with 0.01 wt.% to 0.5 wt.%, preferably 0.1 wt.% to 0.45 wt.%, more preferably 0.15 to 0.4 wt.%, of a bio-based oil (based on the total weight of the cosmetic titanium dioxide pigment particle).

[0049] It should be understood that any features and / or aspects discussed above in conjunction with the method of the present invention are analogous to the described cosmetic titanium dioxide particles.

[0050] The use of bio-based oils makes these particles particularly suitable for cosmetic applications. Furthermore, their low carbon content results in excellent performance in terms of weight loss on drying and weight loss on ignition.

[0051] In a preferred embodiment, the cosmetic titanium dioxide pigment particles according to the second and third aspects, when used in the cosmetic formulations described in the Examples section, have a brightness L The value is at least 50, preferably at least 60, and more preferably at least 64.

[0052] This advantageous brightness L The particles of this invention have been shown to have good dispersibility in cosmetic formulations. Therefore, the amount of cosmetic TiO2 pigment particles can be reduced in cosmetic formulations to achieve the same brightness as cosmetic formulations that do not use the pigment particles of this invention.

[0053] Further preferably, the cosmetic titanium dioxide pigment particles contain up to 2.0 wt.%, more preferably up to 1.0 wt.%, and more preferably 0.9 wt.% of compounds other than titanium dioxide pigment particles and bio-based oils.

[0054] bio-based oils b The values ​​were measured using a Perkin Elmer Lambda 950 spectrometer, applying the "1931 CIE Standard Observer (2°) Measurement Principle, Standard Light Source C".

[0055] In a preferred embodiment, the bio-based oil's b The value (measured according to the 1931 CIE standard observer (2°) measurement principle, using standard light source C) is less than 10, preferably less than 8.

[0056] In another preferred embodiment, the bio-based oil is a plant-based oil, preferably b. The value (measured by standard light source C according to the 1931 CIE standard observer (2°) measurement principle) is below 10, preferably below 8 for plant-based oils.

[0057] In another preferred embodiment, the bio-based oil is a natural oil, preferably b. The value (measured by standard light source C according to the 1931 CIE standard observer (2°) measurement principle) is below 10, preferably below 8 for natural oils.

[0058] Further preferred is the titanium dioxide pigment particles for cosmetics with b... The value (measured according to the CIELAB powder method in the instruction manual) is less than 10, preferably less than 7, more preferably less than 4, and even more preferably less than 2.

[0059] According to a preferred embodiment, the vegetable-based oil is selected from the group consisting of soybean oil, sesame oil, rice germ oil, avocado oil, moringa oil, sunflower seed oil, rapeseed oil, grape seed oil, or mixtures thereof, preferably sesame oil, rice germ oil, moringa oil, sunflower seed oil, rapeseed oil, grape seed oil, or mixtures thereof, and more preferably rice germ oil.

[0060] In another embodiment, the titanium dioxide pigment particles do not contain metal oxide and / or metal-like oxide layers.

[0061] Preferably, the drying loss of the titanium dioxide pigment particles for cosmetics is less than 0.5 wt.%, more preferably less than 0.3 wt.%, and even more preferably in the range of 0.01 to 0.3 wt.%; and / or

[0062] The loss on ignition of titanium dioxide pigment particles for cosmetic use is less than 0.5 wt.%, preferably less than 0.4 wt.%, more preferably in the range of 0.01 to 0.4 wt.%; and / or

[0063] The carbon content of the titanium dioxide pigment particles for cosmetic use is less than 0.5 wt.%, preferably less than 0.4 wt.%, and more preferably in the range of 0.01 to 0.4 wt.%.

[0064] In a preferred embodiment, the bio-based oil coating is a homogeneous coating.

[0065] In a fourth aspect, the present invention relates to a method for manufacturing a cosmetic formulation, comprising, preferably, the following steps:

[0066] a) Provide uncoated titanium dioxide pigment particles;

[0067] b) Coating titanium dioxide pigment particles with bio-based oils to manufacture titanium dioxide pigment particles for cosmetic use; and

[0068] c) Mixing the coated cosmetic titanium dioxide pigment particles with the ingredients of the cosmetic formulation, preferably selected from the group consisting of water, oil, emulsifier, silicone, solvent, pigment, rheology modifier (such as thickener), stabilizer, antioxidant, preservative, pH adjuster, filler, wetting agent and / or combinations thereof.

[0069] It should be understood that any features and / or aspects described above that relate to other aspects of the invention are equally applicable to this aspect.

[0070] In one embodiment, the rheology modifier is a thickener.

[0071] Preferably, the filler is mica, talc, or a combination thereof.

[0072] In a fifth aspect, the present invention relates to a cosmetic formulation that can be obtained by the aforementioned cosmetic formulation manufacturing method.

[0073] It should be understood that any features and / or aspects discussed above in conjunction with other aspects of the invention are equally applicable to this aspect.

[0074] In a sixth aspect, the present invention relates to a cosmetic formulation comprising titanium dioxide pigment particles for cosmetic use according to the present invention.

[0075] It should be understood that any features and / or aspects discussed above in conjunction with other aspects of the invention are equally applicable to this aspect.

[0076] The cosmetic formulation of the present invention has excellent brightness L Preferably, the cosmetic formulation is a water-in-oil emulsion (W / O), an oil-in-water emulsion (O / W), or a powder form.

[0077] In a seventh aspect, the present invention relates to the use of the titanium dioxide pigment particles for cosmetics of the present invention or the cosmetic formulation of the present invention in cosmetic applications, preferably in color cosmetics.

[0078] It should be understood that any features and / or aspects discussed above in conjunction with other aspects of the invention are equally applicable to this aspect.

[0079] Preferably, the pigment particles of the present invention or the cosmetic formulations of the present invention are used in cosmetics, foundations, BB creams, blushes, nail polishes, hair dyes, skin brighteners, concealers, pressed powders, stage makeup, personal care products, face creams, lotions, mascaras, soaps and / or eyeshadows.

[0080] Experimental Section

[0081] Example

[0082] Uncoated rutile titanium dioxide pigment particles (300 g, commercially available K2071, from Kronos Titan GmbH) were mixed with 0.3 wt.% bio-based oil (oils used are listed in Table 2). First, the mixture was pre-homogenized by spatula stirring. Subsequently, it was homogenized for 30 seconds at 2,000 rpm in a high-speed mixer (SpeedMixer DAC 600.2 VAC, from Hausschild). The resulting mixture was then passed through a mesh with a mesh size of [insert mesh size here]. The mixture was sieved through a screen. Finally, the sieved mixture was mixed in a Nobilta-Mischer NOB 130 mixer (from Hosokawa Alpine) at a speed of 1,000 to 2,000 rpm for 1 minute to obtain titanium dioxide pigment particles for cosmetic use.

[0083] The cosmetic was formulated into a standard foundation (ALL DAY LONG - purchased from Brenntag) using titanium dioxide pigment particles, in which Kronos' TiO2 K1171 was replaced by the TiO2 pigment described herein, and the results were analyzed.

[0084] Comparative example

[0085] Comparative Example 1 is an uncoated K2071 pigment commercially available from Kronos Titan GmbH.

[0086] The preparation method of Comparative Example 2 is as follows: all components of standard foundation (ALL DAY LONG - All-day long-lasting foundation - purchased from Brenntag, TiO2-free K1171 (Kronos)) are provided, as well as K2071 and soybean oil based on 0.3 wt.% of TiO2 pigment, and each component is homogenized at 2,000 rpm for 1 minute.

[0087] CIELAB Measurement

[0088] For cosmetic formulations:

[0089] L a and b The method for determining the value is as follows:

[0090] cosmetic formulations The wet film thickness was applied (using an Erichsen coating blade (Rakel)) onto a black Leneta test card (Leneta black plastic card P121-14). After drying for 48 hours, the L of the cosmetic formulation was measured using a Byk-Gardner spherical gloss spectrophotometer. a and b Color values. Measurement results are shown in Tables 1 and 2.

[0091] For powders:

[0092] L a and b The method for determining the value is as follows:

[0093] Measurements were performed according to DIN EN ISO 11664-4:201 1-07 and DIN EN ISO 787-25:2007 standards. For pigment powder measurements, the powder was pressed into powder tablets with a matte surface. Reflectance data were measured using an X-Rite VS450 colorimeter. The measurement results are shown in Table 3.

[0094] Table 1: L of cosmetic formulations according to CE1 & 2 and Example 1 a and b value

[0095] Example sample L a b Comparative Example 1 Uncovered K 2071 63.5 9.7 15.2 Example 1 This invention relates to K 2071 coated with 0.3 wt.% soybean oil. 66.1 8.2 12.9 Comparative Example 2 K 2071+ contains 0.3 wt.% soybean oil added during the cosmetic production process. 62.4 10.4 14.8

[0096] Measurement results showed that cosmetic formulations containing TiO2 coated with soybean oil exhibited higher L... The value indicates that the brightness of the cosmetic formulation has been improved. Therefore, it can be inferred that the TiO2 coated according to Example 1 has better dispersibility in foundation compared to CE1 and CE2.

[0097] As can be seen, compared with uncoated titanium dioxide pigment particles (CE1) and foundation obtained by existing methods (CE2), the cosmetic formulation according to Example 1 has a higher brightness (L). value).

[0098] Further CIELAB measurements were performed using uncoated TiO2 (K2071) and other bio-based oils according to Examples 1 to 5.

[0099] The results obtained in this series of measurements are all based on Example 1 (brightness (%)), which is TiO2 coated with 0.3 wt.% soybean oil.

[0100] The results of these measurements are shown in Table 2.

[0101] Table 2: Brightness (%) of CE1 and Examples 2 to 5 relative to Example 1 (based on L) )

[0102] Example sample brightness(%) Comparative Example 1 Uncovered K 2071 90.2 Example 1 K 2071 coated with 0.3 wt.% soybean oil 100.0 Example 2 K 2071 coated with 0.3 wt.% sesame oil 99.0 Example 3 K 2071 coated with 0.3 wt.% Moringa oil 98.1 Example 4 K 2071 coated with 0.3 wt.% avocado oil 98.1 Example 5 K 2071 coated with 0.3 wt.% rice germ oil 100.2

[0103] It can be seen that the cosmetic formulations according to Examples 1 to 5 have higher brightness compared to uncoated titanium dioxide pigment particles (CE 1).

[0104] Table 3 shows the L of the pigment powder used in Examples 1-5 and CE 1. a and b Values. Table 3 also shows the differences in b between coated and uncoated pigment particles. Differences in values.

[0105] Table 3: b of TiO2-coated pigment powder according to Examples 1 to 5 value

[0106] Example sample b Encapsulation-b Uncovered L a b Test Series 1 Comparative Example 1 Uncovered K 2071 -- 98.6 -0.13 0.94 Example 2 K 2071 coated with 0.3 wt.% soybean oil 0.05 98.3 -0.19 0.99 Example 5 K 2071 coated with 0.3 wt.% rice germ oil 0.02 98.2 -0.17 0.96 Test Series 2 Comparative Example 1 Uncovered K 2071 -- 98.5 -0.08 0.58 Example 1 K 2071 coated with 0.3 wt.% soybean oil 0.09 98.5 -0.09 0.67 Example 2 K 2071 coated with 0.3 wt.% sesame oil 0.16 98.5 -0.1 0.74 Example 3 K 2071 coated with 0.3 wt.% Moringa oil 0.13 98.5 -0.12 0.71 Example 4 K 2071 coated with 0.3 wt.% avocado oil 0.12 98.5 -0.11 0.7

[0107] Particle size determination

[0108] The particle size of titanium dioxide particles was determined using a CPS Disc centrifuge DC 20000 model manufactured by CPS Instrument, Inc., Florida, USA. The sample preparation method is as follows: [The text abruptly ends here, likely due to an incomplete sentence or missing information.] Dry pigment particles and Sodium hexametaphosphate solution (mass fraction in water: 0.06%) The sodium hexametaphosphate was purchased from BK Giulini GmbH in Ladenburg, Germany, under the trade name Calgon N, and mixed until the first premix was homogenized. Then, 2 g of the first premix was added to a sodium hexametaphosphate solution (0.06% by mass in water), and mixed thoroughly again to obtain the second premix. The second premixed solution was used as the sample for particle size determination. The centrifuge speed was 3,000 rpm. The calibration standard parameters are as follows:

[0109] • Particle density: 1.385 g / mL

[0110] Peak particle size: 1.27 µL

[0111] • Half-width at half maximum (WHM): 0.08 µL

[0112] The fluid parameters are as follows:

[0113] • Fluid density: 1.045 g / mL

[0114] Fluid refractive index: 1.344

[0115] Fluid viscosity: 1.2 cps

[0116] Carbon content determination

[0117] Equipment: LECO CS774 carbon / sulfur analyzer, employing combustion infrared detection; analytical balance. A 0.5 g sample was weighed and combusted in an oxygen stream using radio frequency induction heating. Carbon and sulfur in the sample were oxidized to carbon dioxide (CO2) and sulfur dioxide (SO2), respectively, carried by an oxygen carrier gas through a drying reagent, and then into a non-dispersive infrared (NDIR) cell, where sulfur was detected as SO2. The gas flowed through a heated catalyst, where carbon monoxide (CO) was converted to CO2 and SO2 to sulfur trioxide (SO3), which was then removed by a filter. Carbon was subsequently detected as CO2 by another NDIR cell. No method was available for sulfur detection due to the lack of calibration. The NDIR cell is based on the principle that CO2 and SO2 absorb infrared (IR) energy at specific wavelengths in the infrared spectrum.

[0118] Determination of Loss on Drying (LOD) and Loss on Ignition (LOI)

[0119] Approximately 10 g (+ / - 1 g) of the test material was weighed and placed in a pre-ignited and equilibrated crucible. First, the material was dried in a drying oven at 105°C for two hours. Afterward, the crucible was cooled in a desiccator for 45 minutes. The proportion of volatile substances (loss on ignition) was then determined by weighing. Next, the dried sample was ignited in a muffle furnace at 800°C for half an hour. The crucible was then cooled again in a desiccator. The cooling time for the eight crucibles was approximately 1 hour to 1.5 hours. The loss on ignition (LOI) relative to the dried sample was determined by measuring the weight loss.

[0120] Table 4 shows the measurement results of pigment particles in Examples 1-5. Carbon content, loss on drying, and loss on ignition were determined.

[0121] Table 4: Measurement results of carbon content, drying loss, and ignition loss of TiO2 pigment particles coated with different bio-based oils.

[0122] Carbon content [wt.%] Drying loss [wt.%] Loss on ignition [wt.%] Example 1 0.32 0.1 0.33 Example 2 0.24 0.12 0.3 Example 3 0.42 0.12 0.34 Example 4 0.3 0.11 0.32 Example 5 0.24 0.1 0.27

[0123] As can be seen from Table 4, all the titanium dioxide pigment particles of the present invention coated with bio-based oil have excellent performance in terms of carbon content, drying loss, and ignition loss.

Claims

1. A method for producing titanium dioxide pigment particles for cosmetic use, comprising the following steps: a) Provide uncoated titanium dioxide pigment particles, and b) Coating the uncoated titanium dioxide pigment particles with bio-based oil to produce titanium dioxide pigment particles for cosmetic use.

2. The method according to claim 1, in, Based on the total weight of the uncoated titanium dioxide pigment particles and bio-based oil present in the coating step, other compounds are present only in a content of less than 2.0 wt.%, preferably less than 1.0 wt.%.

3. The method according to claim 1 or 2, in, The average particle size (D50) of the titanium dioxide pigment particles ranges from 100 nm to 500 nm, preferably from 200 nm to 400 nm; and / or The titanium dioxide pigment particles do not contain metal oxide and / or metal oxide-like layers.

4. The method according to any one of claims 1 to 3, in, The titanium dioxide pigment particles exist in anatase or rutile crystal structures, preferably in rutile crystal structures.

5. The method according to any one of claims 1 to 4, in, The bio-based oil is a plant-based oil, preferably measured using C standard light according to the 1931 CIE standard observer (2°) measurement principle. Vegetable-based oils with a value below 10, preferably below 8; and / or In step b), based on the total weight of the uncoated titanium dioxide pigment particles, 0.1 wt.% to 1.0 wt.%, preferably 0.2 wt.% to 0.5 wt.%, and more preferably 0.3 wt.% to 0.4 wt.% of bio-based oil is used.

6. The method according to claim 5, in, The plant-based oil is selected from the group consisting of soybean oil, sesame oil, rice germ oil, avocado oil, moringa oil, sunflower seed oil, rapeseed oil, grape seed oil, or mixtures thereof, preferably sesame oil, rice germ oil, moringa oil, sunflower seed oil, rapeseed oil, grape seed oil, or mixtures thereof, and more preferably rice germ oil.

7. The method according to any one of claims 1 to 6, in, Step b) is performed in the following manner: The titanium dioxide pigment particles and the bio-based oil are homogenized at 1000 rpm to 3000 rpm, preferably 2000 rpm, for 1 second to 600 seconds, preferably 20 seconds to 420 seconds, more preferably 30 seconds to 300 seconds. The optional screening step using a sieve is preferably performed with a sieve size of 400 µm to 1000 µm, and more preferably with a sieve size of 600 µm to 900 µm.

8. A cosmetic titanium dioxide pigment particle obtained by the method according to any one of claims 1 to 7.

9. A type of titanium dioxide pigment particles for cosmetic use, comprising titanium dioxide pigment particles coated with bio-based oil, wherein, The content of the bio-based oil is 0.01 wt.% to 0.5 wt.%, preferably 0.1 wt.% to 0.45 wt.%, and more preferably 0.15 wt.% to 0.4 wt.%, based on the total weight of the cosmetic titanium dioxide pigment particles.

10. The cosmetic titanium dioxide pigment particles according to claim 8 or 9, In addition to the titanium dioxide pigment particles and the bio-based oil, the cosmetic titanium dioxide pigment particles contain up to 2.0 wt.%, preferably up to 1.0 wt.%, more preferably 0.9 wt.% of a compound; and / or in, The cosmetic titanium dioxide pigment particles have a b content measured according to the CIELAB powder method in the instructions. The value is less than 10, preferably less than 4; and / or The titanium dioxide pigment particles do not contain metal oxide and / or metal oxide-like layers.

11. Cosmetic titanium dioxide pigment particles according to any one of claims 8 to 10, in, The drying loss of the titanium dioxide pigment particles for cosmetic use is less than 0.5 wt.%, preferably less than 0.3 wt.%, more preferably in the range of 0.01 wt.% to 0.3 wt.%; and / or Wherein, the loss on ignition of the titanium dioxide pigment particles for cosmetic use is less than 0.5 wt.%, preferably less than 0.4 wt.%, more preferably in the range of 0.01 wt.% to 0.4 wt.%; and / or Wherein, the carbon content of the titanium dioxide pigment particles for cosmetic use is less than 0.5 wt.%, preferably less than 0.4 wt.%, more preferably in the range of 0.01 wt.% to 0.4 wt.%; and / or The coating of the bio-based oil is a homogeneous coating.

12. A method for manufacturing a cosmetic formulation, comprising the following steps: a) Provide uncoated titanium dioxide pigment particles; b) Coating the titanium dioxide pigment particles with a bio-based oil to manufacture titanium dioxide pigment particles for cosmetic use; and c) Mix the coated cosmetic titanium dioxide pigment particles with the ingredients of the cosmetic formulation, wherein the ingredients are preferably free from the group consisting of: water, oil, emulsifier, silicone, solvent, pigment, rheology modifier such as thickener, stabilizer, antioxidant, preservative, pH adjuster, filler, wetting agent, and / or combinations thereof.

13. A cosmetic formulation obtained by the method of claim 12.

14. A cosmetic formulation comprising titanium dioxide pigment particles for cosmetic use according to claims 8 to 11.

15. The cosmetic formulation according to claim 13 or 14, in, The cosmetic formulation is a water-in-oil emulsion (W / O), an oil-in-water emulsion (O / W), or a powder form.

16. Use of the cosmetic titanium dioxide pigment particles according to any one of claims 8 to 11 or the cosmetic formulation according to claim 13 or 15 in cosmetic applications, preferably for use in color cosmetics.