Patent Application
20250170035
The present invention relates to a modified clay comprising a clay and a phospholipid, a method of preparing such modified clays, their use, and cosmetic formulations comprising said modified clay.
Modified clay is used in a range of different products, such as, cosmetics, paints, detergent, refractory varnish, thixotropic fluids, and adsorbents of organic pollutants in soil, water and air. Known modified clays, also frequently referred to as organoclays, are often produced via an organophylization process. In an organophylization process, hydrophilic natural clay can be treated with, for example, a synthetic organic compound, such as a quaternary ammonium, to produce a lipophilic modified clay.
There is a drive to move away from chemical treatments, such as the use of synthetic quaternary ammonium, to produce modified clays that comprise natural materials. This move to natural materials is in part based on the increasing need to use products that are environmentally friendly. However, the replacement of synthetic components is also driven by drawbacks associated with the products comprising such modified clays. For example, modified clays are widely used in cosmetics, and compounds such as synthetic quaternary ammonium can lead to skin irritation. The replacement of synthetic quaternary ammonium with naturally sourced compounds, whilst maintaining the desirable modification of clay remains a challenge.
It is therefore desirable to provide alternative modified clay. In particular, it is desirable to provide modified clay using a naturally sourced compound.
The present invention is defined in the appended claims.
The present invention provides a modified clay comprising a clay and a phospholipid, wherein the clay comprises a swellable clay; and the modified clay comprises less than about 20 cmol/kg of cations not including sodium cations.
The invention further provides a method of preparing a modified clay using an organophylization process, comprising the treatment of clay with a phospholipid, wherein the clay comprises swellable clay, and wherein the weight ratio of phospholipid to swellable clay is between about 0.30 to about 1.20.
In a further embodiment the invention provides a modified clay according to such method.
The invention further provides the use of such modified clay as a thickener.
In a further embodiment the invention provides a cosmetic composition comprising such modified clay.
Certain embodiments of the present invention may provide one or more of the following advantages:
The details, examples and preferences provided in relation to any particular one or more of the stated aspects of the present invention apply equally to all aspects of the present invention. Any combination of the embodiments, examples and preferences described herein in all possible variations thereof is encompassed by the present invention unless otherwise indicated herein, or otherwise clearly contradicted by context.
The disclosure will further be illustrated by reference to the following figures:
It is understood that the following description and references to the figures concern exemplary embodiments of the present invention and shall not be limiting the scope of the claims.
The present invention is based on the surprising finding that phospholipids can be used to treat clay to obtain a modified clay product with desired properties. The use of phospholipids to treat clay, wherein the clay comprising a swellable clay. The use of such clays allows modified clays to be obtained without the use of synthetic compounds such as quaternary ammonium.
In some embodiments, the clay portion of the modified clay comprises swellable clay in an amount of about 70 wt. % or more, about 71 wt. % or more, about 72 wt. % or more, about 73 wt. % or more, about 75 wt. % or more, about 78 wt. % or more, about 80 wt. % or more, about 82 wt. % or more, about 85 wt. % or more, about 88 wt. % or more, about 90 wt. % or more, about 92 wt. % or more, about 95 wt. % or more, about 98 wt. % or more, about 99 wt. % or more, based on the total weight of clay.
The amount of swellable clay present in the modified clay as a proportion of the clay can be determined using any known method. For example, in one method, a calcination step is carried out on the modified clay to eliminate the organic compound and to isolate the clay. For determination of the clay composition, powder X-ray diffraction with Rietveld refinement was carried out (Profex BGMN 4.3.5). Refinement of the spectra started at 8° 2Θ to avoid interpretation of clay mineral basal reflections. Spectra was obtained using Cu Ka radiation. No internal standards were used for quantification of XRD patterns. This method is used to determine the peak intensity of the clay of a modified clay (I(MC)) and the unmodified clay (I(UC)). In some embodiments, the ratio of I(MC)/I(UC) is at least 1.1, or at least 1.2, or at least 1.3, or at least 1.4, or at least 1.5.
In some embodiments, the modified clay comprises clay and a phospholipid, where the clay comprises a swellable clay. In some embodiments the weight ratio of the phospholipid over the swellable clay is between about 0.30 to about 1.20. In some examples, the weight ratio of the phospholipid over the swellable clay is about 0.35 to about 1.15, about 0.40 to about 1.10, about 0.45 to about 1.05, about 0.50 to about 1.00, about 0.55 to about 0.95, about 0.60 to about 0.90, about 0.65 to about 0.85, or about 0.70 to about 0.80.
The weight of phospholipid can be measured by any known method. It may be measured by measuring the phosphore thanks to a colorimetric dosage method, for example as disclosed in the PhD thesis of T. Bardeau, Phospholipides biosourcés riches en acides gras omega 3 pour la formulation de liposomes, December 2015.
According to the present disclosure, the modified clay comprises less than about 20 cmol/kg of cations not including sodium cations. In other words, the addition of the amounts of all cations in the modified clay, except sodium cations, results in less than 20 cmol/kg of cations in the modified clay (not including sodium cations). For example, the modified clay comprises less than about 18 cmol/kg, less than about 16 cmol/kg, less than about 14 cmol/kg, less than about 12 cmol/kg, less than about 10 cmol/kg, less than about 8 cmol/kg, less than about 6 cmol/kg, less than about 5 cmol/kg, less than about 4 cmol/kg, less than about 2 cmol/kg of cations (not including sodium cations). In some embodiments the modified clay is free from cations (not including sodium cations).
The cations (not including sodium cations) are determined using any method known in the art. For example, the amount of cations can be determined by first establishing the Cation Exchange Capacity (CEC) of the samples, which is tested using a Cu-Triethylenetetramine solution buffered with CaCO3. In a CaCO3 buffered solution, dissolution of carbonates should be prevented. For CEC determination:
0.2 g of material was dispersed in 30 ml of 3.33 mmol/I Cu-Triethylenetetramine solution;
Samples are tested in double determination.
UV-ViS spectrophotometry was applied for analyzing Cu-Triethylenetetramine concentration, as described in Decher et al., A new Measure for active clay in green sand, as published by the American Foundry Society in 2020.
After cation exchange, soluble and exchangeable cations were determined from the exchange solution as follows:
In some examples, the cations in the modified clay (without sodium cations) may be one or more of magnesium, calcium, and potassium.
In a preferred embodiment, the modified clay has a Cation Exchange Capacity (CEC) of no more than 50 cmol/kg. For example, the modified clay has a Cation Exchange Capacity (CEC) of no more than 45 cmol/kg, or for example, no more than 40 cmol/kg. Preferably, the modified clay has a Cation Exchange Capacity (CEC) of no more than 35 cmol/kg, or even no more than 30 cmol/kg. More preferably, the modified clay has a Cation Exchange Capacity (CEC) of no more than 27 cmol/kg, or no more than 26 cmol/kg.
Preferably, the modified clay has a Cation Exchange Capacity (CEC) of at least 1 cmol/kg, for example at least 5 cmol/kg.
For example, the modified clay has a Cation Exchange Capacity (CEC) of at least 1 cmol/kg and no more than 50 cmol/kg. Preferably the modified clay has a Cation Exchange Capacity (CEC) of at least 1 cmol/kg and no more than 45 cmol/kg, or of at least 5 cmol/kg and no more than 27 cmol/kg.
In some embodiments the modified clay has a Cation Exchange Capacity (CEC) of the unmodified clay (UC) minus the Cation Exchange Capacity (CEC) of the modified clay (MC) of least 45 cmol/kg, or of at least 47 cmol/kg, or of at least 49 cmol/kg.
In a preferred embodiment, the modified clay comprises less than about 2 cmol/kg of potassium (K+) cations. For example, the modified clay comprises less than about 1.9 cmol/kg of potassium (K+) cations, or for example, less than about 1.8 cmol/kg of potassium (K+) cations, or less than about 1.7 cmol/kg of potassium (K+) cations, or less than about 1.6 cmol/kg of potassium (K+) cations, or less than about 1.5 cmol/kg of potassium (K+) cations. For example, the modified clay comprises at least about 0.1 cmol/kg of potassium (K+) cations, or at least about 0.2 cmol/kg of potassium (K+) cations, or at least about 0.3 cmol/kg of potassium (K+) cations, or at least about 0.4 cmol/kg of potassium (K+) cations, or at least about 0.5 cmol/kg of potassium (K+) cations, or at least about 1.0 cmol/kg of potassium (K+) cations.
In a preferred embodiment, the modified clay comprises more than about 40 cmol/kg of sodium (Na+) cations. For example, the modified clay comprises more than about 42 cmol/kg of sodium (Na+) cations, or for example, more than about 44 cmol/kg of sodium (Na+) cations. Preferably, the modified clay comprises more than about 45 cmol/kg of sodium (Na+) cations, or more preferably, more than about 50 cmol/kg of sodium (Na+) cations. In some examples, the modified clay comprises no more than about 100 cmol/kg of sodium (Na+) cations, or for example, no more than about 150 cmol/kg of sodium (Na+) cations, or no more than about 150 cmol/kg of sodium (Na+) cations.
In some examples, the modified clay comprises less than 10 wt. % Fe2O3, less than 8 wt. % of Fe2O3, less than 6 wt. % Fe2O3, less than 4 wt. % Fe2O3, or less than 2 wt. % Fe2O3, based on the total weight of the modified clay. The amount of Fe2O3 in the modified clay has been determined by X-ray fluorescence analysis (XRF) after preparing a fused Li-tetraborate sample, as described ISO-12677. In summary, the powdered sample is fused with a flux to destroy its mineralogical and particulate composition. The resultant melt is cast into the shape of a glass bead which is then introduced into an XRF spectrometer. The intensities of the fluorescent X-rays of the required elements in the bead are measured and the chemical composition of the sample is analysed by reference to previously determined calibration graphs and applying corrections for inter-element effects. The calibration equations and inter-element corrections are established from beads produced from Certified Reference Materials (CRMs).
The LOI (Loss on Ignition) might be needed to perform the X-ray fluorescence analysis. The LOI refers to the mass loss of a combustion residue whenever it is heated in an air or oxygen atmosphere to high temperatures. The LOI is expressed as a weight percentage of the dry mass (dried at 110±10° C.). The dried test sample is then heated in a furnace to a constant mass at (1000±50° C.). The difference in mass before and after the ignition process is used to calculate the loss on ignition.
In some embodiments, the swellable clay is selected from smectite clay, a trioctahedral smectite clay or a dioctahedral smectite clay, wherein the trioctahedral smectite clay is selected from one or more of saponite, hectorite or laponite, and the dioctahedral smectite clay is selected from one or more of montmorillonite, bentonite, nontronite, or beidelleite. A swellable clay is generally understood to be a clay that is prone to large volume changes in water, in particular to volume increases.
In some embodiments, the clay comprises non-swellable components. Non-swellable components are generally understood not to increase its volume in water. In some embodiments the non-swellable components are selected from feldspar, quartz, opal, mica, kaolinite, calcite and mixtures thereof.
In some embodiments, the clay portion of the modified clay comprises non-swellable clay in an amount of about 27 wt. % or less, about 25 wt. % or less, about 22 wt. % or less, about 20 wt. % or less, about 18 wt. % or less, about 15 wt. % or less, about 12 wt. % or less, about 10 wt. % or less, about 8 wt. % or less, about 5 wt. % or less, about 3 wt. % or less, about 2 wt. % or less, about 1 wt. % or less, based on the total weight of clay.
According to the present specification, clay may also be referred to as unmodified clay. In other words, unmodified clay as disclosed herein is clay that has not been modified to comprise a phospholipid.
In some embodiments the phospholipid is between two sheets of clay to form the modified clay. In some embodiments the distance between the two sheets of clay is at least 20 angstroms. For example, the distance (basal spacing d001) between the two sheets of clay is at least 25 angstroms, at least 26 angstroms, at least 27 angstroms, at least 28 angstroms, at least 29 angstroms, at least 30 angstroms, at least 35 angstroms. In some examples, the distance between the two sheets of clay is no more than 40 angstroms. The distance between the two sheets can be measured by XRD.
Phospholipids according to the present disclosure may be selected from a cationic phospholipid, a zwitterionic phospholipid, a non-ionic phospholipid or combinations thereof. In some embodiments, the phospholipid is a zwitterionic phospholipid.
Phospholipids are a class of lipids that comprise a hydrophilic “head” portion and one or more hydrophobic “tail” portions. The phospholipid may comprise one hydrophilic tail portion. Alternatively, the phospholipid may comprise two hydrophilic tail portions.
The hydrophobic tail portions may be substituted or unsubstituted alkyl chains with at least one carbon atom. In some embodiments the hydrophobic tail is derived from fatty acids.
In some embodiments, the hydrophilic head portion may comprise a quaternary ammonium group. In some embodiments, the nitrogen atom of the quaternary ammonium group is attached to at least two methyl groups. In some embodiments, the nitrogen atom of the quaternary ammonium group is attached to three methyl groups. In some embodiments, the nitrogen atom of the quaternary ammonium group is attached to at least two hydrogen atoms. In some embodiments, the nitrogen atom of the quaternary ammonium group is attached to three hydrogen atoms.
Without wishing to be bound by theory, it is considered that in the case of a cationic phospholipid and a zwitterionic phospholipid, the hydrophilic head portion links to the clay resulting in the modified clay.
In some embodiments the phospholipid is phosphatidylcholine, phosphatidylethanolamine, or phosphatidylserine. In some embodiments, the phospholipid is phosphatidylcholine. In some embodiments, the phospholipid is phosphatidylethanolamine. In some embodiments, the phospholipid is phosphatidylserine.
In some embodiments, the phospholipid is from a natural source. In some embodiments the phospholipid is from lecithin and the lecithin is from a natural source. In some embodiments the phospholipid may be from one or more vegetable source, one or more animal source, or a mixture thereof.
In some embodiments the vegetable source is selected from the oils of soybean, sunflower, rapeseed, corn, rice bran, cottonseed, barley, flaxseed, jangli badam seed, palash seed, papaya seed, peanut, sesame, cacao beans, carrot seeds, coriander see, oats, durum wheat, walnut, niger seed, avocado fruit, olive fruit, garlic palm, cucurbirt, camelina, hemp and mixtures thereof.
In some embodiments, the animal source is selected from egg yolk, such as: duck egg yolk, goose egg yolk, quail egg yolk, turkey egg yolk, ostrich egg yolk; milk, such as cow's milk, ewe's milk, goat milk; bovine brain.
In some embodiments the phospholipid is lecithin, and the natural source is selected from soyabean, sunflower oil, rapeseed oil, or mixtures thereof.
The method of preparing a modified clay according to the present invention involves utilising the organophylization process. The organophylization used herein is a process typically used to chemically modify natural clays with surfactants to obtain hydrophobic clays. In the present invention, the organophylization process is used to provide a modified clay by treating clay with a phospholipid. In some embodiments, the weight ratio of phospholipid to swellable clay is between about 0.30 to about 1.20. In some examples, the weight ratio of phospholipid to swellable clay is about 0.35 to about 1.15, about 0.40 to about 1.10, about 0.45 to about 1.05, about 0.50 to about 1.00, about 0.55 to about 0.95, about 0.60 to about 0.90, about 0.65 to about 0.85, or about 0.70 to about 0.80.
In one embodiment the organophylization process is a dry process. For example, the dry process can be carried out as depicted in
In one embodiment the organophylization process is a wet process. For example, the wet process can be carried out as depicted in
In one embodiment, the organophylization process is a dry process and carried out by mixing the clay and the phospholipid; and treating the mixture at a temperature of about 30° C. to about 70° C. for at least 1 h.
In some embodiments the steps of the organophylization process are carried out sequentially and in some embodiments the steps of the organophylization process are carried out simultaneously. For example, in a sequentially process, the mixing is carried out in the first step and the treating is carried out in a second step. For example, in a simultaneous process, both the mixing step and the treating step are carried out at the same time at a specific temperature.
In some embodiments, the heat treatment step does not change the moisture content of the mixture. In some embodiments the heat treatment is performed at a constant moisture content. For example, the heat treatment may be carried out in a closed system to ensure no loss of moisture. Such a closed system may be, for example, a closed vial or a closed plastic bag.
In some embodiments, the mixture is heat treated at about 30° C., about 35° C., about 40° C., about 45° C., about 50° C., about 55° C., about 60° C., or about 65° C. In some examples, the mixture is heat treated for about 1 h to about 24 h, about 2 h to about 24 h, about 3 h to about 24 h, about 4 h to about 23 h, about 5 h to about 22 h, about 6 h to about 21 h, about 7 h to about 20 h, about 8 h to about 19 h, about 9 h to about 18 h, about 10 h to about 17 h, about 11 h to about 16 h, about 12 h to about 15 h, about 11 h to about 14 h, or about 12 h to about 13 h. For example, the mixture is treated at 30° C. for about 3 h, about 4 h, about 5 h, about 6 h, about 7 h, about 8 h, about 9 h, about 10 h, about 11 h, about 12 h, about 13 h, about 14 h, about 15 h, about 16 h, about 17 h, about 18 h, about 19 h, about 20 h, about 21 h, about 22 h, about 23 h, about 24 h. For example, the mixture is treated at 40° C. for about 3 h, about 4 h, about 5 h, about 6 h, about 7 h, about 8 h, about 9 h, about 10 h, about 11 h, about 12 h, about 13 h, about 14 h, about 15 h, about 16 h, about 17 h, about 18 h, about 19 h, about 20 h, about 21 h, about 22 h, about 23 h, about 24 h. For example, the mixture is treated at 50° C. for about 3 h, about 4 h, about 5 h, about 6 h, about 7 h, about 8 h, about 9 h, about 10 h, about 11 h, about 12 h, about 13 h, about 14 h, about 15 h, about 16 h, about 17 h, about 18 h, about 19 h, about 20 h, about 21 h, about 22 h, about 23 h, about 24 h.
In some embodiments, the method according to the invention comprises a drying step. In some embodiments, a drying step is carried out to obtain a product with a moisture content of about 5 wt. % or less, based on the total weight of the product. For example, a drying step is carried out to obtain a product with a moisture content of about 4.5 wt. % or less, about 4.0 wt. % or less, about 3.5 wt. % or less, about 3.0 wt. % or less, about 2.5 wt. % or less, about 2.0 wt. % or less, about 1.5 wt. % or less, or about 1.0 wt. % or less, based on the total weight of the product. In some examples, a drying step is carried out to obtain a moisture content of about 0.5 wt. %, about 0.5 wt. % or more, about 0.6 wt. %, about 0.6 wt. % or more, about 0.7 wt. %, about 0.7 wt. % or more, about 0.8 wt. %, about 0.8 wt. % or more, about 0.9 wt. %, about 0.9 wt. % or more based on the total weight of the product. In some examples, the moisture content is between about 5 wt. % and 0.5 wt. % based on the total weight of the product.
In some embodiments the drying step is carried out at a temperature of about 30° C. to about 70° C. For example, the drying step is carried out at a temperature of about 35° C. to about 65° C., about 40° C. to about 60° C., or about 45° C. to about 55° C. For example, the drying step is carried out at a temperature of about 35° C., about 40° C., about 45° C., about 50° C., about 55° C., about 60° C., or about 65° C.
In some embodiments the modified clay according to the invention is used as a thickener, wherein the thickener is an organic phase thickener. In some examples the organic phase thickener is a cosmetic organic phase thickener.
In some embodiments, the cosmetic formulation is foundation, nail polish, deodorant, antiperspirant, sun care product, mascara, eyeliner and/or lipstick. The cosmetic formulation may comprise an oil. The oil used may be any oil that is suitable for use in a cosmetic formulation. Possible oils include, but are not limited to, coco-caprylate/caprate, dicaprylyl ether, C11-C13 alkane, caprylic/capric triglyceride, macadamia ternifolia seed oil, C9-C12 alkane, isododecane, isohexadecane, C15-C19 alkane, dimethicone 2 cst, dimethicone 5 cst.
The details, examples and preferences provided in relation to any particular aspect of the present invention apply equally to all aspects of the present invention. Any combination of the embodiments, examples and preferences described herein in all possible variations thereof are encompassed by the present invention unless otherwise indicated herein, or otherwise clearly contradicted by context.
In certain embodiments, the modified clay, method of preparing the modified clay and/or use of the modified clay may have one or more of the following effects:
The present disclosure may be described by one or more of the following numbered paragraphs:
In the following examples, except if specified otherwise, the clay (unmodified clay, UC) used was bentonite (B) with a smectite content of 72% and 14 cmol/kg of cations not including sodium cations. B has a CEC of 79 cmol/kg. B is made up of the following (Table 1, as measured by XRF):
In Example 6, the clay used was bentonite (C) with a smectite content of 60% and 9 cmol/kg of cations not including sodium cations. C has a CEC of 68 cmol/kg. C is made up of the following (Table 2, as measured by XRF):
In Example 7, the clay used was bentonite (D) with a smectite content of 89% and 12 cmol/kg of cations not including sodium cations. D has a CEC of 100 cmol/kg. D is made up of the following (Table 3, as measured by XRF):
The phospholipid used was soy lecithin (L), comprising different percentages of phosphatidylcholine (PC) as shown in Table 4.
B, C and D were treated with varying amounts of L using the dry organophylization process according to
The viscosity in Table 4 and 5 was measured using a Viscometer QC-100 (Anton Paar) and carrying out the following procedure:
The viscosity in Table 4 was measured in a polar oil (caprilic/capric triglycerides oil), whereas the viscosity in Table 5 was measured in an apolar oil (dipropylheptyl carbonate, for example Cetiol® for all from BASF).
The swelling index in Table 4 was measured by taking 2 g of MC in 100 ml of polar oil (caprilic/capric triglycerides oil) in a graduated cylinder. The volume of the MC that swelled is noted after 24 h in mL/2 g.
A good swelling index is considered to be 7 or more. A good viscosity is considered to be 350 Po or more. As can be seen from Table 4 only Example 4 (Ex.4) and example 5 (Ex.5) demonstrate a combination of good viscosity and a good swelling index in polar oil. It can be seen that Example 7 demonstrates an excellent viscosity and Example 6 demonstrate a slightly improved viscosity versus the comparative examples, in polar oil. It is shown that a clay comprising a swellable clay in an amount of 70 wt. % or more (Ex. 4 and Ex.5) demonstrate a better viscosity than a clay comprising a swellable clay in an amount of less than 70 wt. % (Ex.6).
It can also be seen that a modified clay having a low amount of potassium cations (no more than about 2 cmol/cm3) demonstrates the best viscosities in polar oil.
On the contrary, it was even more surprisingly seen that a modified clay comprising a high amount of sodium cations (more than 40 cmol/kg) demonstrate the best viscosities, both in polar and apolar oil.
It can also be seen that the difference of CEC, before and after organophilisation, i.e. the difference between the CEC of the clay (unmodified clay) and the CEC of the modified clay, if it is at least 45 cmol/kg, demonstrate a better viscosity in polar oil.
As can be seen from Table 5, Examples 5 and 7 demonstrate the best viscosities in apolar oil, whereas examples 4, 6 and 8 demonstrate acceptable viscosities in apolar oil.
As seen from Table 6, the ratio of PC/swellable is higher than for the comparative examples. It is considered that a high ratio of PC/swellable of at least 0.30 generally achieves a combination of good viscosity and a good swelling index.
It is shown in Table 7 that the organoclays of Ex. 4, Ex.5 and Ex.7 have an important interlayer distance (d001), that means the modified clay has a paraffin type configuration in the interlayer space, as described in Christidis, The concept of layer charge of smectites and its implications for important smectite-water properties, EM U Notes in Mineralogy, 11, 2011.
In addition, the intensity of the peak indicates a homogeneous distribution of the phospholipid between the sheets of the clay. The combination of the two parameters, and more especially the intensity of the peak, traduce a good swelling of the organoclay.
It is also shown in Table 7 that the organoclays of Ex. 4, Ex.5, and Ex.7 have a high ratio of the intensity of the peak over the intensity over the same corresponding peak of the clay (i.e. the unmodified clay). It is shown that a value of at least 1.1, and even preferably of at least 1.5, greatly improves the viscosity when the organoclay is added in polar and/or apolar oil.
| Number | Date | Country | Kind |
|---|---|---|---|
| 22305196.2 | Feb 2022 | EP | regional |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/EP2023/054621 | 2/23/2023 | WO |
