UV light blocking powder made of glass, its use and production, and a preparation with it

Abstract

The present invention relates to a UV-light-blocking glass powder and its use as a UV filter, particularly in cosmetic or pharmaceutical preparations. The invention also relates to a method for producing the powder.

Description

[0001] The present invention relates to a UV-light-blocking glass powder and its use as a UV filter, particularly in cosmetic or pharmaceutical preparations or in technical applications. The invention also relates to a method for producing the powder. State of the art

[0002] It has been known for some time that the interaction of sunlight with substrates, especially skin, can lead to changes in those substrates. In the case of skin, the often desired tanning is a reaction of the body to harmful ultraviolet radiation. In this process, the melanocytes are stimulated by UV light, and the pigment melanin is produced. However, with excessively long exposure of the skin to electromagnetic radiation, the risk of burns (e.g., sunburn) and other health risks (skin aging, phototoxicity, cancer) is acute. The electromagnetic spectrum is divided into long-wavelength and low-energy infrared (780 nm - 1 mm), visible (400 nm - 780 nm), and short-wavelength, high-energy ultraviolet (100 nm - 400 nm) light. UV radiation is further categorized into three subtypes: UV-A: 400-315 nm; UV-B: 315-280 nm; UV-C: 280-100 nm.UV-A radiation is further subdivided into UV-A I (340-400 nm) and UV-A II (315-340 nm).

[0003] To protect against UV radiation, intensive research has been conducted on sunscreens over the last 50 years. The active ingredient in these sunscreens is the UV filter, which can consist of organic molecules (chemical filters, chromophores) or inorganic materials (physical filters, e.g., titanium(IV) oxide or zinc(II) oxide). A distinction is made between UV-A filters, UV-B filters, and broad-spectrum filters, which cover both UV ranges. Sunscreens require an appropriate ratio of UV-A and UV-B filters. The UV-A protection should comprise at least one-third of the stated total sun protection factor (SPF). A critical wavelength of 370 nm is defined for assessing the necessary requirements for UV-A and UV-B protection. When this high-energy UV radiation strikes a UV filter, it can be blocked through absorption, scattering, or reflection.The protective effect in conventional sunscreens is achieved primarily (>90%) through absorption, not reflection or scattering. Organic chromophores have the advantage of effectively absorbing high-energy UV-B radiation by adapting their delocalized π-electron system. Mechanistically, an electron from the highest occupied molecular orbital (HOMO) is excited into an unoccupied orbital by the absorption of a photon of a suitable wavelength. Scattering only plays a role in organic UV filters if the organic chromophore is insoluble in the formulation medium and scattering occurs at the particulate dispersion. However, even then, the contribution of scattering to the sunscreen effect is small. A problem with organic UV filters is the often low stability of the organic molecules under sunlight, also known as photostability.To prevent the organic molecules from changing due to sunlight, photostables are needed as additives, or the organic molecules are enclosed in special capsules for protection, which are also intended to prevent the molecules from penetrating the skin (e.g. US 2007 / 0196290 A, US 2012 / 0156834 A).

[0004] Modern sunscreens must meet various requirements, such as a) protecting health from harmful UV radiation and b) cosmetic compatibility and aesthetics. Furthermore, sunscreens should also be environmentally friendly, as large quantities of them enter the water, for example, when swimming. Tourist destinations are particularly affected by the release of these substances into the sea, leading to pollution of marine organisms. Because there is evidence that corals are damaged by the organic UV filters oxybenzone and octinoxate, sunscreens containing these ingredients are legally banned in some countries, such as Palau and Hawaii.

[0005] Well-known inorganic UV filters in sunscreens are titanium dioxide and zinc oxide, which are widely used and efficiently block UV light through absorption, scattering, and reflection. Unlike organic UV filters, these do not have molecular orbitals, but rather energy bands determined by their crystal structure. When a photon of a suitable wavelength strikes the crystal, an electron is promoted from the valence band to the conduction band. The wavelength of the photon corresponds to the band gap, a term frequently used in the semiconductor industry.

[0006] Inorganic UV filters are mostly used in powder form; therefore, they are referred to as particulate UV filters in this disclosure. Different groups can be distinguished depending on the size of the particles in the powder: Microparticulate titanium(IV) oxide and zinc(II) oxide, with particle sizes starting at approximately 200 nm, are opaque and visible on the skin as a white layer, which is considered cosmetically unappealing. Titanium(IV) oxide, in particular, scatters light extensively, acting as a diffuser.

[0007] Transparency can be achieved through the use of nanoparticulate metal oxides (10-100 nm for TiO2 and 30-200 nm for ZnO). However, nanoparticles are subject to public scrutiny due to differing opinions regarding their interaction with the human body. This has already led to initial regulatory changes in Europe. Although the Australian Department of Health concluded in a 2017 scientific report that the health benefits outweigh the existing risks, the European Chemicals Agency (ECHA) issued a regulation in 2020, which came into force in October 2021, restricting the use of titanium(IV) dioxide in the cosmetics industry. In mixtures containing more than 1% titanium(IV) dioxide with an aerodynamic diameter <10 µm, the product must be labeled as carcinogenic if there is a risk of inhalation.This is particularly the case with sunscreens that are marketed as sprays.

[0008] Another disadvantage of particulate TiO2 and ZnO is their intrinsic property as photocatalysts and their potential to form free radicals (e.g., reactive oxygen species, ROS). To minimize this, these two compounds are used in coatings in sunscreens. The maximum concentration of such inorganic oxides is regulated in many countries and is generally 25%.

[0009] According to the REACH Regulation, a nanoparticle is characterized by a chemical substance or material having a particle size of 1-100 nm in at least one dimension. The Biocidal Products Regulation contains specific provisions for nanomaterials. According to a Commission Recommendation published on 10 June 2022 on the definition of nanomaterials, a nanomaterial is a naturally occurring, process-derived, or manufactured material consisting of solid particles, either occurring independently or as identifiable constituent particles in aggregates or agglomerates, where at least 50% of these particles have a number size distribution smaller than 100 nm.

[0010] It is known from the prior art to use UV-blocking glasses and glass ceramics as powders in cosmetic and / or medical products (e.g., DE 10161075 C, DE 10201747 C). The UV-blocking effect of the glass ceramics disclosed therein is too weak for these glass ceramics to be suitable as UV protection in sunscreens.

[0011] Other glasses and glass-ceramics strongly colored by transition metal ions contain a high proportion of boron trioxide. Boron trioxide is a glass former and is considered important for the stability of these types of glass.

[0012] Substances intended for use in cosmetics must not contain any components that could potentially leach out and be harmful to the user. Therefore, it is important to use powders packaged in chemically stable glass containers from which, for example, boron trioxide cannot leach out in significant quantities.

[0013] It would be desirable to provide a particulate UV filter for protecting the skin, in particular, from UV radiation, which does not exhibit the disadvantages of the prior art. These disadvantages include, in particular: (i) the intense inherent color (white) of the particles used, with grain sizes between 100 nm and 20 µm; (ii) the "membrane permeability" of the particles, i.e., their potential penetration of the skin, as discussed with sunscreens that use nanoparticulate pigments; and (iii) the photocatalytic properties of the materials. Specifically, the UV protection should be based on a material that is not a nanomaterial as defined above. Furthermore, the glass should be chemically stable, which here means that no components are leached out that could be potentially harmful to the user. Description of the invention

[0014] The present invention relates to powders of special UV-blocking, phase-separated glasses and their use as inorganic UV filters, particularly in sunscreens.

[0015] In a first aspect, the invention relates to a powder comprising or consisting of particles of phase-separated glass of defined composition, wherein the median value d 50 the particle size is in a range of 0.15 to 25 µm and the phase-separated glass contains at least one transition metal compound.

[0016] In a second aspect, the invention relates to uses of the powder according to the invention.

[0017] In a third aspect, the invention relates to a preparation, in particular a preparation with UV protection properties, comprising the powder according to the invention and a formulation that incorporates the powder. Advantageously, the preparation according to the invention is a cosmetic preparation, preferably a cosmetic sunscreen. In particular, the invention relates to the non-medical use of the powder or preparation according to the invention in or as a cosmetic sunscreen.

[0018] In a fourth aspect, the invention relates to the powder or preparation according to the invention for use in medicine, preferably for use in the prophylactic treatment of skin diseases, in particular skin diseases caused by UV radiation.

[0019] In a fifth aspect, the invention relates to a method for producing a powder according to the invention.

[0020] According to a first aspect of the invention, the problem is solved by a powder comprising or consisting of particles made of phase-separated glass, wherein the median value d 50 the particle size is in the range of 0.15 to 25 µm and the phase-separated glass contains at least one transition metal compound, wherein the transition metal compound comprises a titanate and transition metal cation(s), wherein the glass contains the following oxide-based components in wt.%: SiO2 45 bis 70 B2O3 < 5 Al2O3 0 bis 12 and the total content of the components forming the transition metal compound is 6 to 30 wt.%.

[0021] The particle size (grain size) of the powder according to the invention is determined by means of laser diffraction in accordance with ISO 13320:2020 and is based on the phenomenon that the angular distribution of the intensity of the scattered light by a particle depends on the particle size, which is subsequently referred to as the diameter of an assumed sphere-like shape.

[0022] For the purposes of this description, the term "diameter" refers to the maximum extent of the particle. In the case of spherical particles, the diameter is simply the diameter of the sphere. In the case of ellipsoidal or plate-shaped particles, the diameter is measured at the point of maximum extent, for example, along the major axis of an ellipsoid.

[0023] Within the scope of the invention, the median value d 50 particle size (also “d 50-value") in the range of 0.15 to 25 µm. In advantageous advanced training courses, the d 50 -value in the range of 0.15 to 20 µm, preferably in the range of 0.25 to 20 µm, particularly preferably in the range of 0.35 to 15 µm, and most preferably in the range of 0.4 to 10 µm or 0.4 to 7 µm. The d 50 The -value indicates that 50% of the measured particles are equal to or smaller than the specified value.

[0024] The median value d 50 The particle size is at least 0.15 µm, preferably at least 0.25 µm, to ensure that the proportion of particles with a size < 100 nm in the powder is as low as possible. In an advantageous embodiment, the median value d 50 The particle size should be at least 0.3 µm, preferably at least 0.35 µm, more preferably at least 0.4 µm, more preferably at least 0.5 µm, more preferably at least 0.7 µm, and more preferably at least 1 µm. The median value d 50The particle size is a maximum of 25 µm. This upper limit is determined by application requirements. It should not be exceeded, as otherwise the particles in the powder become too large, which can lead to particle sedimentation in an intermediate or finished product and / or cause the product to have a peeling effect on the skin. Furthermore, in some applications, the particles should not be visible on the skin. However, in some cosmetic applications, a peeling effect may be desirable. In a preferred further training, the median value d 50 The particle size must not exceed 20 µm, especially when the powder is used in a preparation that remains temporarily on the skin, e.g., a cream. The upper limit of the d 50 The value can advantageously be at most 15 µm, preferably at most 10 µm. Some advantageous variants can have a median value d 50have a particle size of no more than 7 µm or no more than 5 µm.

[0025] The d 99 The particle size value can be a useful measure for the suitability of a powder as an inorganic UV filter in sunscreens, as it defines and limits the maximum particle size. 99 The value indicates that 99% of the measured particles are equal to or smaller than the specified value. 99 The particle size value is preferably in the range of 0.25 to 100 µm, more preferably from 0.25 to 75 µm, particularly preferably from 0.5 to 50 µm, and more preferably from 1 to 20 µm or 1 to 15 µm. 99 The particle size value is preferably at least 0.25 µm, more preferably at least 0.5 µm, preferably at least 1 µm or at least 2 µm. The d 99The particle size value is preferably at most 100 µm. Particularly when using the powder in a preparation that remains temporarily on the skin, e.g., a cream, the upper limit of the particle size can be increased. 50 Advantageous values ​​of at most 75 µm, more preferably at most 50 µm, more preferably at most 40 µm, more preferably at most 30 µm, and preferably at most 20 µm. Advantageous variants may have a d 99 -particle size value of at most 15 µm or at most 10 µm.

[0026] Depending on the manufacturing process, for example the grinding process used, the particles made of phase-separated glass can have different shapes, such as irregularly broken, round, plate-shaped (flakes, mica), fibrous.

[0027] The powder according to the invention comprises a phase-separated glass. For the purposes of this invention, a phase-separated glass is a glass comprising at least two phases, wherein at least the first phase is amorphous and wherein the at least two phases have formed from a common starting glass. The further phase(s) may be amorphous or crystalline. The at least two phases differ in their composition and / or their state and thus in their optical properties. A phase-separated glass is therefore a multiphase glass.

[0028] In a first advantageous embodiment of a phase-separated glass, the glass is formed by phase separation and / or demixing of the glass components of a base glass—preferably by a targeted heat treatment—in which the first amorphous phase forms a glass matrix. A second phase is also in an amorphous state and exists, for example, in the form of droplet-like structures within the glass matrix formed from the first phase. The two phases have different compositions. Thus, in a demixed glass, the demixed amorphous regions of the second phase form the structures of the phase-separated glass.

[0029] In another advantageous embodiment of a phase-separated glass, the material is a glass-ceramic. Here, a second phase is in the crystalline state, i.e., it exists as a crystalline phase within the glass matrix formed from the first amorphous phase. Thus, "glass-ceramic" is understood to be a material that has both an amorphous and a crystalline phase. In a glass-ceramic, the crystallites of the second phase form the structures of the phase-separated glass. A glass-ceramic according to the invention can be formed from a starting glass, which is preferably crystallized in a controlled manner by a targeted temperature treatment. Advantageously, the crystallization occurs through crystal formation within the volume of the starting glass, a process known as "controlled bulk crystallization."

[0030] In the case of phase-separated glass, especially demixed glass and / or glass-ceramics, targeted temperature treatment of the starting glass is an optional measure that can be omitted if the second phase forms in the starting glass even without this step.

[0031] Combinations of the variants described above are also possible and advantageous, for example, a phase-separated glass consisting of three phases, in which a second amorphous phase and a third crystalline phase are embedded in a glass matrix containing the amorphous first phase. A variant in which the second phase has both amorphous and crystalline components is also advantageous; that is, a variant in which crystals are present in a demixed, otherwise amorphous second phase.

[0032] A phase-separated glass and a glass-ceramic, i.e., a phase-separated glass, have in common that they exhibit spatial long-range order. These structures are formed in situ.

[0033] The structures formed or present in the phase-separated glass (segregation and / or crystals and / or colloids) can have a size in the nanometer range, which is described in more detail below. These structures have a different composition than the first phase and therefore different optical properties. As a result, radiation, especially UV radiation, is not only absorbed in these structures but can also be scattered by them, so that the structures can therefore also be described as scattering centers. Overall, the structures have optical properties comparable to those of TiO2 and / or ZnO nanoparticles. However, since the structures are present in larger particles (median value d 50Since the glass powders according to the invention are bound in the range of 0.15 to 25 µm, they do not exhibit the disadvantages and problems associated with nanoparticles. In addition to the effect of pure absorption by the phase-separated glass (see below), the scattering effect can also be utilized without the use of primary / actual nanoparticles. By selecting a phase-separated glass with a suitable transition metal compound, particularly high UV blocking, i.e., low transmission in the UV range of the spectrum < 400 nm, can be achieved without the known disadvantages (potential membrane penetration and strong whitening). Thus, this invention provides a new inorganic particulate UV filter that is not nanoparticulate and therefore does not fall under the ECHA Regulation of 2020 / 2021.

[0034] The proportions of absorption and scattering with respect to UV blocking can be specifically modified by adjusting the size of the structures in the second phase and, if applicable, subsequent phases. In the case of larger structures, the scattering component can increase.

[0035] The size of the structures can preferably be determined using scanning electron microscopy, transmission electron microscopy or small-angle X-ray scattering, or, in the case of crystalline phases, in a known manner using X-ray diffraction analysis.

[0036] The average size of the structures of the second phase and, if applicable, further phases, is preferably in the range of 1 to 2000 nm, preferably from 1 to 1000 nm, preferably from 2 to 500 nm, more preferably from 5 to 450 nm, for example from 10 to 400 nm, from 15 nm to 350 nm, from 20 nm to 300 nm, from 25 nm to 250 nm, or from 30 nm to 200 nm. Such average structure sizes are advantageous for achieving the desired low transmission of the phase-separated glass in the UV region of the spectrum, i.e., the desired UV blocking.

[0037] The average feature size of the second phase is preferably at least 1 nm, for example at least 2 nm, at least 5 nm, at least 10 nm, at least 15 nm, at least 20 nm, at least 25 nm, at least 30 nm, at least 50 nm, at least 75 nm, or at least 100 nm. The average feature size of the second phase can preferably be at most 2000 nm, for example at most 1500 nm, at most 1000 nm, at most 500 nm, at most 450 nm, at most 400 nm, at most 350 nm, at most 300 nm, at most 250 nm, at most 200 nm, or in variants at most 100 nm, at most 50 nm, at most 30 nm, or at most 20 nm.

[0038] The average size of the structures can be determined with regard to the d 50 The value of the powder particles must be chosen appropriately. For example, with finer powders, a particle size of d can be used. 50in the range of 0.15 to 20 µm, advantageously 0.5 to 15 µm, if the average size of the structures is in the range of 1 to 1000 nm, preferably from 1 to 500 nm.

[0039] In an advantageous embodiment, the average feature size of the second phase can be, for example, 20 to 1000 nm, 25 to 500 nm, 30 to 400 nm, 50 to 350 nm, or 100 to 300 nm. The average feature size of the second phase is preferably at least 20 nm, at least 25 nm, at least 30 nm, at least 50 nm, at least 75 nm, or at least 100 nm. The average feature size of the second phase can preferably be at most 1000 nm, for example, at most 500 nm, at most 450 nm, at most 400 nm, at most 350 nm, at most 300 nm, at most 250 nm, or at most 200 nm.

[0040] In an advantageous embodiment, the average feature size of the second phase can, for example, be in the range of 1 to 50 nm, 2 to 30 nm, or 5 to 20 nm. The average feature size of the second phase is preferably at least 1 nm, for example at least 2 nm, at least 5 nm, at least 10 nm, or at least 15 nm. The average feature size of the second phase can preferably be at most 50 nm, for example at most 40 nm, at most 35 nm, at most 30 nm, at most 25 nm, or at most 20 nm.

[0041] The degree of UV blocking can be "controlled" by the volume fraction of the different phases of the phase-separated glass.

[0042] According to an advantageous embodiment, the particles of the powder comprise an amorphous first phase in a proportion of 70 to 99.9 vol.% and a second phase in a proportion of 0.1 to 30 vol.%, wherein the second phase has structures in the form of amorphous demixed regions and / or crystals.

[0043] The volume fraction of the amorphous first phase in the powder particles is preferably in the range of 70 to 99.9 vol.%, for example 75 to 99.9 vol.%, 80 to 99 vol.%, 85 to 98 vol.%, or 90 to 95 vol.%. The proportion of the amorphous first phase in the powder particles is preferably at least 70 vol.%, at least 75 vol.%, at least 80 vol.%, at least 85 vol.%, and in some variants at least 90 vol.%, at least 95 vol.%, at least 98 vol.%, or at least 99 vol.%. The proportion of the first phases can, in some embodiments, be at most 99.9 vol.%, at most 99.5 vol.%, at most 99 vol.%, at most 98 vol.%, at most 95 vol.%, and in some variants at most 90 vol.%, at most 85 vol.%, or at most 80 vol.%.

[0044] The proportion of the second phase in the powder particles is preferably in the range of 0.1 to 30 vol.%, for example, 0.1 to 25 vol.%, 0.5 to 20 vol.%, 1 to 20 vol.%, 2 to 15 vol.%, or 5 to 10 vol.%. The proportion of the second phase in the particles is preferably at least 0.1 vol.%, at least 0.5 vol.%, at least 1 vol.%, at least 2 vol.%, or at least 5 vol.%, for example, at least 10 vol.%, and in some variants at least 15 vol.%, at least 20 vol.%, or 25 vol.%. In some embodiments, the proportion of the second phases can be at most 30 vol.%, at most 25 vol.%, at most 20 vol.%, at most 15 vol.%, and in some variants at most 10 vol.%, at most 5 vol.%, at most 2 vol.%, or at most 1 vol.%.

[0045] The volume fractions of the different phases are advantageously determined by X-ray diffraction analysis in the case of crystalline structures or with the help of scanning electron microscopy images.

[0046] The invention provides a silicate glass that has reduced or very low transmission in the spectral range < 400 nm, a so-called UV-blocking glass.

[0047] Within the scope of the disclosure, a “silicate glass” is a glass whose main glass former is SiO2, wherein the SiO2 content is 45 to 70 wt.%. To ensure that the glass powder according to the invention does not release significant amounts of boron trioxide in application, the glass according to the invention contains less than 5.0 wt.% B2O3 and, in preferred embodiments, is free of B2O3. The glass may contain 0 to 12 wt.% Al2O3. The total content of the components for the formation of the transition compound in the glass is 6 to 30 wt.%.

[0048] Known glasses with comparable UV-blocking properties contain a high proportion of B₂O₃ (> 5 wt%) and / or Al₂O₃ (> 15 wt%), i.e., components considered important for stability as network formers in the respective glass system. The inventors have found that it is possible to significantly reduce the B₂O₃ content, preferably to replace it completely, while simultaneously maintaining a low Al₂O₃ content, still resulting in a phase-separated glass containing at least one transition metal compound, wherein the transition metal compound comprises a titanate and transition metal cation(s). The glass according to the invention is chemically resistant and exhibits at least the same level of UV blocking as borosilicate glasses with the same or a comparable transition metal compound. This was surprising.

[0049] To provide a UV-blocking glass powder, i.e., to adjust the desired transmission or absorption properties of the glass powder, the phase-separated glass contains at least one transition metal compound, wherein the transition metal compound comprises a titanate and transition metal cation(s). Within the scope of the invention, transition metals are defined as elements of the periodic table that possess an incomplete d-subshell or form ions with an incomplete d-subshell, and additionally include the elements from the zinc group of the periodic table. Thus, transition metals within the meaning of the invention include the elements of groups 3 to 12 of the periodic table, including lanthanides and actinides.

[0050] Among the transition metals in a transition metal compound, those that can form ions exhibiting electron transitions in the UV range, i.e., those that absorb at least in the UV range of the spectrum, are advantageous. A transition metal whose ions or compounds show strong absorption of UV radiation, i.e., radiation with a wavelength < 400 nm, is preferred.

[0051] A phase-separated glass containing at least one transition metal compound comprises a titanate (i.e., an anionic titanium oxide) with further transition metal cation(s). Preferably, at least one transition metal compound consists of a titanate with further transition metal cation(s). Advantageously, the (further) transition metal cation can be a polyvalent cation, wherein the cation in the titanate compound is preferably present to a large extent in the oxidation state or in a low oxidation state. The further transition metal cation can advantageously be selected from the group consisting of iron (Fe), manganese (Mn), cobalt (Co), copper (Cu), and / or cerium (Ce). Zinc (Zn) ions can also be advantageous. An advantageous titanate variant comprises Fe(II) cations and / or Mn(II) cations. In addition to oxides, sulfides of iron and / or manganese can also be advantageously included.

[0052] In an advantageous embodiment, the phase-separated glass comprises ilmenite complexes, ilmenite crystals, ilmenite mixed complexes, and / or ilmenite solid solutions as transition metal compounds, particularly as titanates. Such ilmenite crystals or ilmenite complexes have the formula FeTiO3; this compound is thus a titanate. In ilmenite mixed complexes or ilmenite solid solutions, manganese ions can advantageously be present in addition to iron ions, resulting in the formula (Fe x Mn y )TiO3, where x + y = 1. Complexes or mixed complexes and crystals or mixed crystals differ in that no crystalline structures can be detected in the phase containing the complexes using conventional analytical methods.

[0053] When the invention refers to ilmenite complex, ilmenite crystal, ilmenite mixed complex and / or ilmenite mixed crystal, this does not only include compounds with the idealized stoichiometric composition (Fe x Mn y )TiO3, but also ilmenite-related compounds with different ratios of (Fe,Mn) to Ti, for example ulvöspinel ((Fe,Mn)2TiO4) and ferropseudobrookite ((Fe,Mn)Ti2O5). As in ilmenite, the transition metal cations of iron and – if present – ​​manganese in the ilmenite-related compounds are predominantly in the lower oxidation state, i.e., iron as Fe(II) and manganese as Mn(II).

[0054] An advantageous variant of the phase-separated glass comprises a transition metal oxide containing titanium and iron. This can advantageously be crystals and / or complexes of ilmenite (FeTiO3). Another advantageous variant of the phase-separated glass comprises a transition metal oxide containing titanium, iron, and manganese. This can advantageously be ilmenite solid solutions (Fe x Mn y These are TiO3 or corresponding ilmenite mixed complexes, where x + y = 1. The absorption behavior of the phase-separated glass can be specifically adjusted by the proportion of the aforementioned complexes, crystals, mixed complexes, or mixed crystals, their composition, and their structure size.

[0055] The transition metal compound, i.e., the transition metal oxide (here, titanate), advantageously exists within the structures (separated amorphous regions or crystallites) of the second phase of the phase-separated glass or forms the structures of the second phase. Particularly preferably, the second phase can comprise or consist of ilmenite complexes, ilmenite crystals, ilmenite mixed complexes, and / or ilmenite mixed crystals.

[0056] Furthermore, it may also be possible and advantageous if a transition metal compound, i.e. a transition metal oxide, is present in different concentrations in both the amorphous first phase of the phase-separated glass and in the structures of the second phase of the phase-separated glass, according to one variant.

[0057] The structures of the second phase thus have a different composition than the first phase and consequently different optical properties. Due to the presence of at least one transition metal compound in the phase-separated glass, incident radiation, especially UV radiation, is absorbed. Incident radiation, particularly UV radiation, can be scattered by the structures of the phase-separated glass, increasing the probability that the scattered radiation will be absorbed by the at least one transition metal compound. In this way, a synergistic effect can occur between the UV-absorbing transition metal compound and the structures (segregation and / or crystals) of the second phase, leading to a significantly reduced UV transmission of the powder from the phase-separated glass.

[0058] The higher absorption capacity of preferred phase-separated glasses with transition metal compounds can be explained by various models, without being definitively committed to these statements: If the second phase consists of crystallites, such as FeTiO3 in the ilmenite structure, this can increase the absorption many times over. However, if the second phase is also amorphous and demixed, the ions with electron transitions in the UV range can be found in both the demixed second phase and the main phase, the first phase, or statistically distributed between both phases. If a concentration occurs in one phase, the distance between different ions is reduced, and the chance of charge-transfer complexes is increased. A third hypothesis would be the increase in ions with electron transitions in the UV range in an oxidative environment, e.g., the transition from Fe(II), i.e., Fe 2+ , on Fe(III), i.e. Fe 3+ .

[0059] The disclosure describes the use of a phase-separated silicate glass containing a transition metal compound comprising a titanate and transition metal cation(s). Such a glass exhibits sufficient chemical resistance. Advantageously, the silicate glass can be an aluminosilicate glass, alkali silicate glass, alkali-alkaline earth silicate glass, or alkaline earth silicate glass. The underlying silicate glass without the transition metal compound is hereinafter also referred to as the "base glass".

[0060] The phase-separated glass is therefore based on a base glass and a contained transition metal compound, which is formed in situ by phase separation, i.e., demixing and / or crystallization, in the glass from starting components of the transition metal compound.

[0061] In order for the desired transition metal compound to form in the base glass of the phase-separated glass, the necessary starting components of the transition metal compound (hereinafter referred to as "starting components") should be present in sufficient quantities. For the sake of consistency, the starting components are specified as simple oxides. Within the scope of the invention, the cations of the starting components are each specified in a notation known to those skilled in the art for glass formulations and are represented with oxygen as the anion in a charge-balanced manner. However, this does not mean that the cations in the resulting phase-separated glass must be present in a high oxidation state. For example, iron cations can be present in the divalent and trivalent oxidation states, and manganese cations can be present, for example, in the divalent and tetravalent oxidation states.Therefore, the designation "Fe₂O₃" does not mean that only Fe(III) species are present in the glass. Rather, "Fe₂O₃" is used to indicate the total content of all iron species in the glass, regardless of their oxidation state. If the phase-separated glass contains ilmenite (mixed) crystals or ilmenite (mixed) complexes, then, for example, Fe(II) species are present in the crystals or complexes. In the amorphous phase, however, iron can exist as Fe(II), Fe(III), or in both oxidation states. The same applies to MnO₂ and other transition metal compounds with polyvalent ions. For clarity, the elemental name of a component, e.g., "iron," is also used in the description of the glass composition. This stands in for, e.g., "iron cations" and does not mean that iron is present in its elemental form in the glass. The same applies to "manganese."

[0062] The total content of the starting components for the formation of the transition metal compound in a base glass is preferably in the range of 6 to 30 wt.%, more preferably in the range of 8 to 27 wt.% or between 10 and 25 wt.%. Even if the proportion is given in wt.% on an oxide basis, this does not mean that the transition metal compound(s) in the glass must also be present in oxide form. The proportion can advantageously be at least 6 wt.%, for example at least 7 wt.%, advantageously at least 8 wt.%, and particularly advantageously at least 10 wt.%, so that the powder produced from phase-separated glass exhibits sufficient UV blocking. Preferably, the proportion is at most 30 wt.%, for example at most 27 wt.%, and advantageously at most 25 wt.%. An excessively high proportion is disadvantageous because otherwise too little remains for glass-forming and network-transforming glass components, and glass formation becomes unlikely.

[0063] In a preferred embodiment, the total content of the starting components of the transition metal compound comprises TiO2 and Fe2O3, and optionally MnO2. In a particularly preferred embodiment, the total content of the starting components of the transition metal compound consists of at least 80%, preferably at least 90%, and preferably at least 95% TiO2 and Fe2O3, and optionally MnO2.

[0064] In an advantageous embodiment, ilmenite complexes, ilmenite mixed complexes, ilmenite crystals, and / or ilmenite solid solutions or ilmenite-related compounds (see above) are formed from the starting components in the phase-separated glass. In an advantageous variant, ilmenite complexes and / or crystals are formed from the starting components TiO₂ and Fe₂O₃, which may preferably be present in the second phase of the phase-separated glass. In another advantageous variant, crystals or solid solutions are formed from the starting components TiO₂ and Fe₂O₃, and optionally MnO₂, in the phase-separated glass, which are part of the second phase or constitute the second phase of the phase-separated glass. This crystalline phase comprises ilmenite crystals (FeTiO₃) or ilmenite solid solutions, preferably (Fe x Mn y)TiO3 mixed crystals, where x + y =1. An advantageous phase-separated glass with ilmenite (mixed) complexes or ilmenite (mixed) crystals is characterized by a particularly high UV absorption.

[0065] For the formation of ilmenite (mixed) complexes or ilmenite (mixed) crystals, an advantageous glass may advantageously contain 3 to 12 wt.%, and advantageously 5 to 10 wt.% TiO₂. An advantageous lower limit of 3 wt.% TiO₂ should not be undercut so that a sufficient amount of the desired transition metal compound is present in the glass for UV blocking. Advantageously, the lower limit may be at least 4 wt.%, at least 5 wt.%, or at least 6 wt.%. An advantageous upper limit of TiO₂ may be at most 12 wt.%, for example, at most 10 wt.% or at most 9 wt.%, and in some variants at most 8 wt.%.

[0066] Furthermore, an advantageous glass may contain 2 to 15 wt.%, advantageously 3 to 13 wt.%, of iron oxide, expressed as Fe₂O₃. Fe₂O₃ comprises the sum of the proportions of iron(II) oxide (FeO) and iron(III) oxide. An advantageous lower limit of 2 wt.%, advantageously at least 3 wt.%, for Fe₂O₃ should not be undercut so that a sufficient amount of the desired transition metal compound for UV blocking is present in the glass. Advantageously, the lower limit may be at least 4 wt.%, at least 5 wt.%, or at least 6 wt.%. An advantageous upper limit of Fe₂O₃ may be at most 15 wt.%, for example, at most 13 wt.% or at most 12 wt.%, and for some variants at most 11 wt.%.

[0067] The proportion of manganese oxide, expressed as MnO₂, in an advantageous glass can be 0 to 10 wt.%, advantageously 0.5 to 8 wt.%, and preferably 1 to 6 wt.%. MnO₂ comprises the sum of the proportions of manganese(II) oxide (MnO) and manganese(IV) oxide (MnO₂), as well as any other manganese oxide species that may be present. An advantageous lower limit for MnO₂ can be 0.5 wt.%, preferably at least 1 wt.%. MnO₂-free variants are possible and advantageous. An advantageous upper limit for MnO₂ can be at most 10 wt.%, or at most 8 wt.%, or at most 7 wt.%, or at most 6 wt.%.

[0068] The starting components TiO2, Fe2O3 and / or MnO2 can be present in the silicate base glass (see below) in the aforementioned proportions, resulting in an application glass.

[0069] In order for ilmenite (mixed) complexes or ilmenite (mixed) crystals to form as a transition metal compound in phase-separated glass, it is advantageous to select the molar fractions of TiO2 on the one hand and the sum of the molar fractions of iron (based on FeO) and optionally manganese (based on MnO) on the other hand appropriately.

[0070] In principle, phase-separated glass can contain other transition metal compounds besides the aforementioned (mixed) complexes and (mixed) crystals, for example FeS, Fe2S3.

[0071] As described above, the transition metal compound is present in a silicate glass, for example aluminosilicate glass, alkali silicate glass, alkali-alkaline earth silicate glass, alkaline earth silicate glass,

[0072] The main glass former in these glasses is SiO2. Optional components such as Al2O3 and, to a very limited extent, B2O3 can be added as further glass formers. However, variants without Al2O3 and / or B2O3 are also possible. Furthermore, advantageous glasses contain at least one network modifier, preferably selected from R2O (i.e., Li2O, Na2O, K2O, Cs2O, and / or Rb2O) and RO (i.e., MgO, CaO, BaO, and / or SrO). Depending on the total proportion of the transition metal compound or the starting components for the formation of the transition metal compound and other components, for example, refining agents, the sum of glass formers and network modifiers can be > 50 to 94 wt.%, advantageously 60 to 92 wt.%, and advantageously 70 to 90 wt.% in an advantageous embodiment. The sum of glass formers and network converters is advantageously more than 50 wt.%, preferably at least 60 wt.% or at least 65 wt.%, in some variants at least 70 wt.% or at least 75 wt.%.-% or at least 80 wt.%. An advantageous upper limit for the sum may be at most 94 wt.%, preferably at most 92 wt.% or at most 90 wt.%.

[0073] In an advantageous embodiment, the sum of the glass formers, i.e., SiO₂ + B₂O₃ + Al₂O₃, can be in the range of 45 to 89 wt.%, advantageously in the range of 60 to 87 wt.%, and advantageously in the range of 65 to 90 wt.%. The sum of SiO₂ + B₂O₃ + Al₂O₃ is advantageously at least 45 wt.%, preferably at least 50 wt.%, at least 55 wt.%, or at least 60 wt.%. An advantageous upper limit for the sum can be at most 89 wt.%, preferably at most 87 wt.%, at most 85 wt.%, or at most 83 wt.%.

[0074] The glass according to the invention contains SiO2 with a content of 45 to 70 wt.%. A minimum content of 45 wt.% should not be undercut, as otherwise too little glass-forming component is present and the chemical stability of the glass is too low. An upper limit of 70 wt.% should not be exceeded, as otherwise the melting temperature and viscosity of the melt are too high, and the proportions of other components are also too low. In an advantageous embodiment, the glass has a SiO2 content of at least 47 wt.% or at least 50 wt.%. In an advantageous embodiment, the content can optionally be at most 67 wt.%, advantageously at most 65 wt.%, and advantageously at most 63 wt.%. An advantageous range for SiO2 can be 47 to 65 wt.%.

[0075] The glass may contain Al₂O₃ in a concentration of 0–12 wt.% to improve glass stability. If the glass is to contain Al₂O₃, the component may advantageously be present in a concentration of at least 0.1 wt.% or at least 0.2 wt.%, preferably at least 0.5 wt.% or at least 1 wt.%. Since too much Al₂O₃ can be problematic, the concentration is limited to a maximum of 12 wt.%. Advantageously, the concentration may be a maximum of 10 wt.%, 8 wt.%, or 7 wt.%. An advantageous range may be 0 to 10.0 wt.%. To improve the stability of the glass, it may be advantageous for some variants if the glass contains more than 5 wt.%, preferably at least 5.5 wt.%, or at least 6 wt.% of Al₂O₃. For such variants, an advantageous range may be, for example, 5.5 to 12 wt.%. In an advantageous embodiment, particularly in cosmetic and / or medical applications, the glass may be free of Al₂O₃.

[0076] The glass may contain B₂O₃ in a proportion of 0 to < 5 wt.% to improve meltability and glass formation. If the glass is to contain B₂O₃, the component may advantageously be present in a proportion of at least 0.1 wt.% or at least 0.2 wt.%, preferably at least 0.5 wt.%. Within the scope of the invention, the content is limited to less than 5 wt.%, in particular < 5.0 wt.%, to ensure that no significant amounts of boron trioxide are released from the powder. Phase-separated glasses with < 5 wt.% B₂O₃ are referred to as "boron-reduced" within the scope of the disclosure. Advantageously, the content may be a maximum of 4.5 wt.%, 4 wt.%, 3 wt.%, or 1 wt.%. For use in cosmetic and / or medical applications, an advantageous variant is B₂O₃-free.

[0077] An optional component in the glass is P₂O₃, which may be present in amounts from 0 to < 5 wt%. Preferably, this component may be present in amounts less than 2 wt%, preferably a maximum of 1 wt% or a maximum of 0.5 wt%. Preferably, the phase-separated glass is free of P₂O₅.

[0078] The glass may contain alkali metal oxide (R2O, total of alkali metal oxides Li2O+Na2O+ K2O+Cs2O+Rb2O) and / or alkaline earth metal oxide (R'O, total of alkaline earth metal oxides MgO+CaO+BaO+SrO) as network converters with a content of 0 to 25 wt.%, which is advantageous for glass formation.

[0079] In an advantageous embodiment, the sum of the network converters, i.e., R₂O + R'O, can be 5 to 25 wt.%, advantageously 5 to 20 wt.%, advantageously 7 to 17 wt.%. R'O and R₂O can be in the range of 0 to 25 wt.%. The sum of R₂O + R*O is advantageously at least 5 wt.%, advantageously at least 7 wt.%, and / or advantageously at most 25 wt.%, advantageously at most 20 wt.%, advantageously at most 18 wt.%.

[0080] wt.%, advantageously not more than 17 wt.% or not more than 15 wt.%.

[0081] The glass may contain alkali metal oxide (R₂O) in a proportion of 0 to 25 wt.% to improve the glass's meltability and reduce its viscosity. If the glass is to contain R₂O, the component may advantageously be present in a proportion of at least 0.5 wt.% or at least 1 wt.%, preferably at least 1.5 wt.%, and particularly preferably at least 2 wt.% or at least 5 wt.%. Since too much R₂O reduces chemical resistance, the content is limited to a maximum of 25 wt.%, 20 wt.%, 17 wt.%, or 15 wt.%. An advantageous range may be 1 to 20 wt.% or 5 to 20 wt.%. In one embodiment, the glass may be free of R₂O, i.e., free of Li₂O and / or free of Na₂O and / or free of K₂O and / or free of Cs₂O and / or free of Rb₂O.

[0082] The limits mentioned above for R₂O apply accordingly to the individual alkali metal oxides, i.e., Li₂O, Na₂O, K₂O, Cs₂O, and Rb₂O. For cost reasons, the glass preferably contains Na₂O and / or K₂O. However, the limits written below also apply accordingly to Cs₂O and / or Rb₂O. An advantageous range for Na₂O can be 0 to 15 wt.%. An advantageous range for K₂O can be 0 to 15 wt.%. An advantageous range for Li₂O can be 0 to 5 wt.%.

[0083] The glass may contain alkaline earth metal oxide (R'O) in a proportion of 0 to 25 wt.% to improve the glass's meltability and reduce its viscosity. If the glass is to contain R'O, the component may advantageously be present in a proportion of at least 0.5 wt.% or at least 1 wt.%, preferably at least 1.5 wt.%, and particularly preferably at least 2 wt.%. Since too much R'O increases the risk of the formation of undesired crystal phases, the content is limited to a maximum of 25 wt.%, 20 wt.%, 17 wt.%, 15 wt.%, or 10 wt.%. An advantageous range may be 1 to 20 wt.% or 1 to 15 wt.%. In one embodiment, the glass is free of R'O, i.e., free of MgO and / or free of CaO and / or free of BaO and / or free of SrO.

[0084] The limits mentioned above for R'O apply accordingly to the individual alkaline earth metal oxides, i.e., MgO, CaO, and SrO. For BaO, these limits apply when the glass is used in technical applications. In cosmetic and medical applications, it may be advantageous to use lower proportions of BaO in the range of 0 to 5 wt.% or to omit BaO entirely. An advantageous range for CaO may be 0 to 20 wt.% or 0 to 10 wt.%. An advantageous range for SrO may be 0 to 15 wt.%.

[0085] In an advantageous embodiment, the second phase or the phase-separated glass can contain less than 5 mol%, preferably at most 4 mol%, preferably at most 3 mol%, preferably at most 2 mol%, preferably at most 1 mol% MgO, and preferably be free of MgO except for impurities (for MgO, a maximum of 0.3 mol%). Magnesium ions, as divalent ions, can replace transition metal cations in the transition metal compound, e.g., in the ilmenite (mixed) crystal, but do not themselves contribute, or only to a minor extent, to the reduction in transmission. Therefore, the MgO content is advantageously limited.

[0086] The glass may contain ZnO in a proportion of 0 to 10 wt.%. In the glass, ZnO exhibits a comparable effect to alkaline earth metal oxides. Advantageously, the glass may contain a maximum of 8 wt.%, 5 wt.%, 3 wt.%, or 1 wt.% of ZnO. In one embodiment, the glass is free of ZnO.

[0087] The glass can contain ZrO2 in a proportion of 0 to 2 wt.%. Advantageously, the glass can contain a maximum of 1 wt.% or a maximum of 0.5 wt.% ZrO2. In one embodiment, the glass is free of ZrO2.

[0088] In a particularly advantageous embodiment, the phase-separated glass comprises SiO2 as a glass former, optionally Al2O3, and optionally a small proportion of B2O3, wherein the B2O3 is < 5 wt.%. Furthermore, the phase-separated glass optionally contains at least one network converter, in particular selected from R2O (i.e., Li2O, Na2O, K2O, Cs2O, Rb2O) and R'O (i.e., MgO, CaO, BaO, SrO). The phase-separated glass also has a total content of the components forming the transition metal compound, i.e., for the formation of the titanate with transition metal cation(s), of 6 to 30 wt.%.

[0089] An advantageous phase-separated glass may, for example, contain the following components (wt% based on oxides): Komponente Anteil (Gew.-%) SiO2 45-70 Al2O3 0-12 B2O3 <5 TiO2 3-12 Fe2O3 2-15 MnO2 0-10 Sum R2O+R'O 5-25 Sum R2O 0-25 Sum R'O 0-25

[0090] An advantageous phase-separated glass may, for example, contain the following components (wt% based on oxides): Komponente Anteil (Gew.-%) SiO2 45-70 Al2O3 0-12 B2O3 < 5 Li2O 0-5 Na2O 0-20 K2O 0-20 CaO 0-20 BaO 0-5 SrO 0-15 ZnO 0-8 TiO2 3-12 ZrO2 0-2 Fe2O3 3-15 MnO2 0-10 Sum R2O+R'O 5-20 Sum R2O 0-20 Sum R'O 0-20

[0091] An advantageous example of a phase-separated glass may, for example, have the following components (wt% oxide-based): Komponente Anteil (Gew.-%) SiO2 45-65 Al2O3 2-12 B2O3 < 5 Na2O 0-15 K2O 0-15 CaO 0-10 BaO 0-5 ZnO 0-5 TiO2 5-10 ZrO2 0-2 Fe2O3 5-13 MnO2 0-8 Sum R2O+R'O 5-20 Sum R2O 5-20 Sum R'O 0-10

[0092] According to one embodiment of the present invention, the glass according to the invention is also preferably free of other components not mentioned in the claims or the description; that is, according to such an embodiment, the glass consists essentially of the components listed above, whereby individual components not mentioned as preferred or less preferred may be excluded. The expression "consist essentially of" means that other components are present at most as raw material impurities and / or process-related impurities, but are not intentionally added to the glass composition as individual components.

[0093] Preferably, the phase-separated glass or the powder formed from it is free of the following elements or their compounds: Cr, Ni, Cd, Pb, Hg, As, Sb, Be, Ag, Sn, TI, as these are toxic and / or have allergenic potential. If a glass is free of the aforementioned elements, ions, or their compounds, a powder made from this glass can be used as a particulate inorganic UV filter in cosmetic and pharmaceutical preparations intended to provide protection against UV radiation.

[0094] When this description states that the glass is free of a component or does not contain a certain component, this means that the component is not added, but is present only as an impurity due to raw materials or the process in which the glass may be used. The sum of the aforementioned problematic heavy metal impurities is advantageously less than 100 ppm, preferably less than 50 ppm.

[0095] Advantageous phase-separated glass is toxicologically safe. In particular, the heavy metal content meets the stringent regulatory requirements for cosmetics. The concentration of the glass powder in the product is preferably less than 2 ppm (Pb), 0.1 ppm (Cd), 0.1 ppm (Hg), 0.5 ppm (As), and / or 0.5 ppm (Sb). These values ​​are ppm by weight.

[0096] Furthermore, the chemical inertness of glass powder means that when used in a chemical, especially cosmetic or pharmaceutical, formulation, the powder remains unchanged for more than two years, no sedimentation occurs, and the pH of the formulation is not shifted towards strongly alkaline or strongly acidic. A preferred pH range is 5.5 to 6.3. Consumer demands for aesthetics, such as transparent or brownish sunscreens, can also be met by selecting a suitable glass and formulation.

[0097] The advantage of phase-separated glass is its chemical resistance, allowing it to be used as a powder with a d 50-Particle size of 2.5 ± 0.5 µm in a bioelution test with artificial sweat solution releases less than 0.3% B₂O₃. Advantageously, less than 0.2% B₂O₃ is released; preferably, the released B₂O₃ is below the detection limit of 0.1%.

[0098] The extraction / release of B2O3 from the powder was carried out in a bioelution test, as described below in connection with the exemplary embodiments. Reference is made to these to avoid repetition.

[0099] The amount of boron trioxide or other substances that could be leached from glass powders depends on the particle size of the powder. One indicator of this is the d 50 -value. One option for the application described in the disclosure are particles with a d 50 = 10 µm. In experiments with these specifically described phase-separated glasses with particle size d 50However, at a particle size of 10 µm, it had been shown that no conclusions could be drawn due to the lower extraction rate. Therefore, the powder was tested with a particle size of d. 50 Measured = 2.5 + / - 0.5 µm.

[0100] Compared to powders made from single-phase glasses, advantageous phase-separated glasses exhibit lower transmission in the UV region of the spectrum. The invention focuses on "external transmission," which includes losses due to absorption, reflection, scattering, etc.

[0101] In an advantageous embodiment, the phase-separated glass powder exhibits a maximum transmission of 25% at a wavelength of 370 nm, based on a composite sample with a thickness of 1 mm, a powder concentration of 1 wt%, and a d 50The particle size is approximately 2.5 ± 0.5 µm. Particularly advantageous variants exhibit a transmission of at most 20%, preferably at most 15%, preferably at most 10% at a wavelength of 370 nm. Preferred variants exhibit a transmission of at most 8%, preferably at most 6%, preferably at most 5% or at most 3% at a wavelength of 370 nm.

[0102] In an advantageous embodiment, the phase-separated glass powder exhibits a maximum transmission of 15% at a wavelength of 315 nm, based on a composite sample with a thickness of 1 mm, a powder concentration of 1 wt%, and a d 50The particle size is 2.5 ± 0.5 µm. Some advantageous variants exhibit a transmission of at most 12%, preferably at most 10%, preferably at most 8% at a wavelength of 315 nm. Particularly advantageous variants exhibit a transmission of at most 6%, preferably at most 5%, preferably at most 4% at a wavelength of 315 nm. Preferred variants exhibit a transmission of at most 3% at a wavelength of 315 nm, or for some variants preferably at most 2% or at most 1%.

[0103] Powders consisting of or comprising particles of phase-separated glass with such advantageous transmission properties can be described as UV-blocking powders or glass powders, or as particulate inorganic UV filters. The low UV transmission is due to absorption, scattering, and reflection processes within the powder and depends on the particle size, the size of the structures, and the composition of the phase-separated glass.

[0104] The statement “d 50 The specification "2.5 + / - 0.5 µm" in the context of transmission determination does not mean that the powder must be used in this particle size in the applications. However, since the transmission of a powder depends on the particle size used, i.e., the particle size, this is 50 The value is given as a reference value for characterizing the transmission behavior. If a powder to be measured has a different value, the following applies: 50If the particle size has a certain value, the measured transmission can be compared to the reference size d. 50 from 2.5 + / - 0.5 µm, whereby the conversion factor is determined empirically.

[0105] The transmission behavior of the powder is determined on composite samples within the scope of the invention, as described below in connection with the exemplary embodiments. Reference is made to these descriptions to avoid repetition.

[0106] The fact that the particles are made of phase-separated glass does not necessarily mean that the particles consist of 100% phase-separated glass, although this may be the case in some embodiments of the invention; in this case, the powder consists of particles made of phase-separated glass. In an advantageous embodiment of the invention, the surface of the particles may have a chemical modification, in particular a functionalization, which advantageously comprises hydrophobic or hydrophilic organosilane groups; in this case, the powder comprises particles made of phase-separated glass.

[0107] The particles thus consist at least predominantly of phase-separated glass, for example, 85–100% by weight, and in particular at least 85% by weight depending on the specific surface area. Proportions not consisting of phase-separated glass can, for example, be attributed to one or more functionalizations of the particle surface made of phase-separated glass, such as silanization, and are preferably in the range of 0 to 15% by weight. This allows, in particular, the creation of a more hydrophobic or a more hydrophilic surface, for example, to counteract particle precipitation in a preparation. The surface functionalization can comprise or consist of hydrophobic and / or hydrophilic organosilane groups.

[0108] The particles preferably consist of at least 85 wt.% phase-separated glass, for example at least 90 wt.%, at least 95 wt.%, at least 98 wt.%, or at least 99 wt.%, for example at 100 wt.%. The particles can consist of at most 100 wt.% phase-separated glass, for example at most 99 wt.%, at most 98 wt.%, at most 95 wt.%, at most 90 wt.%, or at most 85 wt.%. The particles preferably consist of 85 to 100 wt.% phase-separated glass, for example at most 85 to 99 wt.%, 90 to 98 wt.%, or 90 to 95 wt.%.

[0109] The weight fraction of a surface functionalization of the particles, for example, silanization, is preferably in the range of 0 to 15 wt.%, for example, 1 to 15 wt.%, 2 to 10 wt.%, or 5 to 10 wt.%, based on the total weight of the particles. The weight fraction of a surface functionalization of the particles, for example, silanization, can be, for example, at least 1 wt.%, at least 2 wt.%, at least 5 wt.%, at least 10 wt.%, at least 12 wt.%, or at least 14 wt.%, based on the total weight of the particles. The weight fraction of a surface functionalization of the particles, for example, silanization, can be, for example, at most 15 wt.%, at most 10 wt.%, for some variants at most 5 wt.%, at most 2 wt.%, or at most 1 wt.%, for example, 0 wt.%.

[0110] A second aspect of the invention relates to the use of a powder according to the invention consisting of or comprising particles of a phase-separated glass in one or more of the following areas: - in a preparation, in particular a preparation with UV protection properties, for application to the skin, especially in a cosmetic product. This use is described further below in connection with the description of another aspect of the invention. The statements made there apply accordingly to the use of the powder according to the invention. - in medicine, in particular for providing a pharmaceutical preparation for application to the skin, preferably for the treatment of skin diseases caused by UV radiation. This medical use is described further below in connection with the description of another aspect of the invention. The statements made there apply accordingly to the use of the powder according to the invention. - in technical applications as a UV light blocking component in plastic products or coatings with filter properties for UV light, for example UV protection films (yellow light films), plastic bottles - for example for juices -, visors, sunglasses, covers for light sources that release UV radiation when generating light, for example compact fluorescent lamps, fluorescent tubes, etc.

[0111] The powder according to the invention can be used in technical applications as a UV-light blocking component in plastic products that have filter properties for UV light. For this purpose, the powder can, for example, be added to the plastic raw material during the production of the plastic products or applied to the product as a component of a coating.

[0112] The powder according to the invention, its features and advantageous embodiments have already been described above. Reference is made to these descriptions to avoid repetition.

[0113] One advantageous application is the use of the powder according to the invention in UV protection films, for example yellow light films, which can be applied to glass elements to reduce UV transmittance. Yellow light films can be used, for example, in medical devices, laboratories, photo studios, printing plants, reprographic rooms, paint shops, and museums to protect people, specimens, exhibits, chemicals, etc. from UV radiation.

[0114] Another advantageous use is the application of the powder according to the invention in sunglasses, masks (for example, fencing masks), or visors, such as helmet visors for motorcyclists, skiers, pilots, and astronauts. In transparent visors or sunglasses containing the powder according to the invention, this provides UV protection for the eyes and skin.

[0115] Another advantageous use can be in plastic bottles to protect the contents, such as juices, from UV radiation-induced degradation.

[0116] It is also possible and advantageous to use the powder according to the invention in covers for light sources that emit UV radiation, for example compact fluorescent lamps and / or fluorescent tubes, in order to filter out the UV radiation released by the light sources during light generation and to keep it away from the environment.

[0117] In a third aspect, the invention relates to a preparation, particularly for application to the skin. This preparation comprises the powder according to the invention and a formulation that incorporates the powder. The powder, a particulate inorganic UV filter, provides UV protection within the preparation. Therefore, the preparation can be described as a "preparation with UV protection properties".

[0118] The powder according to the invention, its features and advantageous embodiments have already been described above. Reference is made to these descriptions to avoid repetition.

[0119] The formulation incorporates the powder according to the invention and thus forms the basis of the preparation according to the invention. Advantageously, the formulation can be selected from the group consisting of suspension, emulsion, paste, ointment, gel, cream, lotion, milk, solution, wax / fat mass, oil, powder, foam, and spray. Accordingly, the finished preparation according to the invention can also advantageously be a suspension, emulsion, paste, cream, lotion, ointment, milk, solution, wax / fat mass, oil, gel, powder, foam, spray, etc.

[0120] In addition to the powder according to the invention, the preparation in an advantageous embodiment may contain at least one further component, preferably selected from the group comprising dyes and pigments, antioxidants, vitamins, stabilizers, emulsifiers, preservatives, fragrances, self-tanning additives, skin conditioners (e.g. moisturizers, exfoliating additives), additives for water resistance of the formulation, etc.

[0121] In a particularly advantageous embodiment, the proportion of the powder according to the invention in the preparation is in the range of 0.1 to 20 wt.%, preferably in the range of 0.5 to 10 wt.%. The lower limit of 0.1 wt.% should not be undercut, as otherwise the desired UV blocking will not be achieved. Advantageously, the proportion of the powder according to the invention in the preparation can be at least 0.3 wt.%, for example at least 0.5 wt.%, at least 0.7 wt.%, or at least 1 wt.%. The upper limit of 20 wt.% should not be exceeded to ensure that the powder is well incorporated into the formulation and that the preparation is stable over the long term. Advantageously, the proportion of the powder according to the invention in the preparation can be at most 17 wt.%, for example at most 15 wt.%, at most 12 wt.%, or at most 10 wt.%. In some advantageous embodiments, the proportion can even be at most 7 wt.%, at most 5 wt.%, or at most 3 wt.%.

[0122] To achieve the desired UV protection in the preparation, the concentration of the powder used is selected according to its UV blocking capacity. The lower the powder's transmission in the relevant UV range, the lower the concentration can be in the preparation. Although absorption plays the primary role in UV protection, positive effects can also be achieved through scattering and reflection. Scattering correlates with the fourth power of the wavelength, meaning that short-wavelength, high-energy light is scattered more effectively than long-wavelength, low-energy light.

[0123] In an advantageous embodiment, the preparation comprising a powder according to the invention exhibits a transmission of at most 15% at a wavelength of 370 nm, based on a reference cream as a formulation with an input concentration of powder according to the invention of 1 wt%, on a sample thickness of 0.12 mm and on a d 50 The particle size is 2.5 ± 0.5 µm. Some advantageous variants exhibit a transmission of at most 12% or at most 10%, preferably at most 7%, preferably at most 5% at a wavelength of 370 nm. Particularly advantageous variants exhibit a transmission of at most 4%, preferably at most 3% at a wavelength of 370 nm. Some advantageous variants can exhibit a transmission of at most 2%, preferably at most 1%, at a wavelength of 370 nm.

[0124] In an advantageous embodiment, the preparation comprising a powder according to the invention exhibits a transmission of at most 10% at a wavelength of 315 nm, based on a reference cream as a formulation with an input concentration of powder according to the invention of 1 wt%, on a sample thickness of 0.12 mm and on a d 50 The particle size is approximately 2.5 ± 0.5 µm. Some advantageous variants exhibit a transmission of at most 7%, preferably at most 5%, and preferably at most 3% at a wavelength of 315 nm. Preferred variants may exhibit a transmission of at most 2%, preferably at most 1%, or at most 0.5% at a wavelength of 315 nm.

[0125] The statement “d 50The specification "2.5 + / - 0.5 µm" in the context of transmission determination does not mean that the powder must be used in this particle size in the applications. However, since the transmission of a powder depends on the particle size used, i.e., the particle size, this is 50 The value is given as a reference value for characterizing the transmission behavior. If a powder to be measured has a different value, the following applies: 50 If the particle size has a certain value, the measured transmission can be compared to the reference size d. 50 from 2.5 + / - 0.5 µm, whereby the conversion factor is determined empirically.

[0126] The fact that the transmission behavior is based on a reference cream does not mean that the preparation in practice must be a cream. Rather, the reference cream is used to characterize the transmission behavior. Similarly, the reference to a powder concentration of 1% by weight serves only to characterize the transmission behavior. The powder content in a manufactured preparation can, of course, be different.

[0127] A commercially available urea cream (GREVEN) was used as a reference cream, forming a formulation for the absorption of the powder. ® UREA CREAM: O / W emulsion with urea, glycerin, and bisabolol. The preparation of the mixture and the transmission measurement method are described below in connection with the exemplary embodiments. Reference is made to these descriptions to avoid repetition.

[0128] The selected powders absorb UV-A and / or UV-B radiation in the relevant range and can also be used in combination with other (in)organic UV filters without harmful interaction.

[0129] In an advantageous further development of the preparation, the preparation comprises a further UV filter, preferably selected from the group consisting of organic UV filters, inorganic UV filters, in particular particles of titanium oxide, zinc oxide, iron oxide and / or cerium oxide.

[0130] The term "preparation with UV protection properties" preferably refers to a cosmetic preparation used to protect human or animal skin, including hair, from UV radiation. This can be a classic sunscreen, but also, for example, a daily moisturizer with sun protection, such as a face cream, or decorative cosmetics like makeup, powder, etc. The degree of UV blocking is indicated by the sun protection factor (SPF). The powder containing phase-separated glass particles in a preparation, or the preparation itself, can serve to protect the skin, in particular, from short-term and / or long-term damage. Short-term damage—also called acute damage—includes, above all, redness, sunburn, sun allergy, and phototoxic reactions.Long-term damage includes premature skin aging, especially due to UV-A radiation penetrating deep into the skin, and skin cancer.

[0131] According to the invention, a cosmetic preparation with UV light protection properties is also characterized in that it contains a powder according to the invention.

[0132] The preparation is advantageously a cosmetic product selected from the following group: classic sunscreen, day care with UV protection, for example face cream, lip cream or decorative cosmetics such as make-up, powder, etc.

[0133] Examples of beneficial cosmetic preparations with UV protection properties for application to the skin are given below based on… Fig. 2 are described as examples.

[0134] The invention also relates to the non-medical use of the powder or preparation according to the invention in or as a cosmetic sunscreen. The term "cosmetic sunscreen" is to be interpreted broadly and includes not only sunscreens in the narrower sense, which are applied to the skin for protection during particularly strong sunlight, but also, for example, daily facial care with UV protection, hair care with UV protection, lipstick with UV protection, make-up, and other decorative cosmetics with UV protection.

[0135] In a fourth aspect, the invention relates to a powder or preparation according to the invention for use in medicine. The invention relates to the powder or preparation according to the invention for use in the prophylactic treatment of skin diseases (i.e., use in medicine), in particular skin diseases caused by UV radiation. The invention also relates to the powder or preparation according to the invention for use in the prophylactic treatment of actinic keratosis, rosacea, and couperose. When used, the powder or preparation according to the invention serves in particular to protect skin cells from damage caused by UV radiation by providing a particulate inorganic UV filter.The powder or preparation according to the invention is preferably used as a medicinal product for application to the skin.

[0136] The present invention also relates to a powder or preparation according to the invention for providing a pharmaceutical preparation for application to the skin, preferably for the prophylactic treatment of skin diseases caused by UV radiation. The present invention also relates to the use of a powder or preparation according to the invention for providing a pharmaceutical preparation for application to the skin, preferably for the prophylactic treatment of skin diseases caused by UV radiation. The powder or preparation according to the invention provides, in particular, an inorganic particulate UV filter that protects skin cells from damage caused by UV radiation.

[0137] The present invention also relates to a pharmaceutical preparation, i.e., a medicinal product, for therapeutic application to the skin, comprising a powder or preparation according to the invention. The powder or preparation according to the invention serves in particular to protect skin cells from UV radiation by providing a particulate inorganic UV filter. The pharmaceutical preparation is preferably used for the prophylactic treatment of skin diseases, particularly those caused by UV radiation; preferably, the skin disease may be actinic keratosis, rosacea, or couperose. The powder or preparation according to the invention provides an inorganic particulate UV filter in the pharmaceutical preparation, which protects the skin cells from damage caused by UV radiation.

[0138] The powder, the preparation according to the invention, and their advantageous further developments have already been described in detail above. Since the statements made there apply accordingly to the use of the powder in medicine, particularly in a pharmaceutical preparation (i.e., medicinal product), and to the use of the preparation in medicine, reference is made to them to avoid repetition.

[0139] The pharmaceutical preparation and its use are primarily intended for the prophylactic treatment of skin diseases, particularly those caused by exposure of skin cells to UV radiation. UV radiation damages the DNA in skin cells. If such damage is not fully or correctly repaired by the body, permanent genetic mutations can result, increasing the risk of skin cancer. In an advantageous application, the drug can also be used for the prophylactic treatment or prevention of actinic keratosis, a precursor to squamous cell carcinoma.

[0140] In a fifth aspect, the invention relates to a method for producing a powder according to the invention consisting of or comprising particles of phase-separated glass according to the first aspect of the invention, wherein the method comprises the following steps: a) Providing a starting glass, b) Optional thermal treatment of the starting glass to obtain a phase-separated glass, c) Grinding the phase-separated glass to obtain the powder.

[0141] First, a starting glass is provided. With regard to the selection of suitable base glasses and transition metal compounds, reference is made to the above statements in connection with the description of the phase-separated glasses that form the basis of the powder according to the invention.

[0142] A starting glass is provided containing starting components for the in situ formation of a titanate transition metal compound. In an advantageous embodiment, the starting glass contains as starting components—specified as oxides—TiO₂ and oxides of iron and, optionally, manganese in a silicate base glass. To provide the starting glass, a melt was prepared from raw materials, advantageously under reducing melting conditions so that the ions, particularly cations, in the transition metal compound—preferably iron and, if present, manganese—are in a low oxidation state, and the melt was cooled.

[0143] Measures for inducing reducing melting conditions are familiar to those skilled in the art, for example, by adding reducing agents, e.g., organic reducing agents. It can be advantageous if the melting takes place at high melting temperatures, preferably in the range of 1600 to 1800°C, more preferably 1650 to 1750°C. The melting temperature can advantageously be at least 1600°C, more preferably at least 1650°C. The melting temperature can advantageously be at most 1800°C, more preferably at most 1750°C.

[0144] Optionally, the base glass can be thermally treated, for example, to obtain phase-separated glass. Thermal treatment can induce or promote segregation and / or crystal formation within the glass. By thermally treating suitable glasses with a specific heating rate, temperature, and cooling rate, the material's transmittance can be varied and adjusted over a wide range. This allows for a reduction in the required concentration of powder from phase-separated glass in subsequent applications. Slow cooling rates, for example, lead to the formation of larger and more defined crystals and / or larger segregated areas. Advantageously, the base glass is heated for a duration of 0.5 to 48 hours, advantageously 1 to 20 hours, advantageously 2 to 20 hours, and advantageously 5 to 15 hours.The duration can advantageously be at least 0.5 hours, at least 1 hour, at least 2 hours, at least 5 hours, and / or at most 48 hours, at most 20 hours, at most 15 hours. In some advantageous variants, the heating can be to temperatures corresponding to a viscosity in the range of 10. 5 up to 10 11 dPas correspond to, in some variants, the temperature of a viscosity in the range of 10 9 up to 10 11 dPas, in other variants a viscosity in the range of 10 7 up to 10 9 dPas, in other variants a viscosity in the range of 10 5 up to 10 7 dPas. The temperature at which phase separation occurs in the glass can advantageously be set to a viscosity of at least 10 5 dPas, at least 10 7 dPas, at least 10 9 dPas and / or advantageously at most 1011 dPas, maximum 10 9 dPas, maximum 10 7 The temperature of the thermal treatment can advantageously be in the range of 500 to 1000 °C, 550 to 850 °C, or 600 to 800 °C. It can also be advantageously at least 500 °C, at least 550 °C, or at least 600 °C, and / or at most 1000 °C, at most 850 °C, or at most 800 °C. If phase separation in the glass, e.g., the formation of a second amorphous or crystalline phase, occurs to the desired extent even without a thermal treatment step, a thermal treatment can be omitted.

[0145] The phase-separated glass is then ground to obtain a glass powder. The grinding process for producing a glass powder according to the invention can be carried out dry or with aqueous and non-aqueous grinding media. The milling tool can be, among other things, a ball mill, stirred ball mill, jet mill, pin mill, or a combination of two or more of these. Thus, it is possible to produce a material with a particle size (in particular, d) of 99 < 75 µm), which does not fall into the nano range and yet does not produce a peeling effect on the skin.

[0146] In an advantageous further development of the process, the process comprises a further step of chemical modification, in particular functionalization of the particle surface. Preferably, the particle surface is chemically modified by applying hydrophobic or hydrophilic organosilane groups. Brief description of the characters Fig. Figure 1 shows the spectral transmittance as a function of wavelength (lambda) of powders according to the invention and powders of comparison examples based on composite samples doped with different powders, wherein the concentration of the powder used is 1 wt.% in each case. Fig. Figure 2 shows the spectral transmittance (transmission) as a function of wavelength (lambda) of preparations according to the invention and comparative examples using cream samples, wherein the doped cream samples were doped with 1 wt% of different powders each. The transmittance of the undoped cream (blank sample) is also shown. The preparations were always made using the same method described below. Fig. Figure 3 shows a diffraction diagram of an X-ray diffractometry (XRD) measurement of two ceramicized embodiments of the invention, i.e. the glasses were subjected to a defined temperature treatment (ceramization) after their manufacture. Fig. Figure 4 shows a diffraction diagram of an X-ray diffractometry (XRD) measurement of two non-ceramized embodiments of the invention, i.e., the glasses have not undergone any heat treatment after their manufacture. Examples

[0147] To produce the glasses with the compositions according to embodiments (Examples) 1 and 2, the corresponding glass mixtures were intensively blended. These mixtures were melted at 1630°C under reducing conditions, resulting in a high proportion of the iron, manganese, and titanium species in a low oxidation state. The glass was then cast into thin ribbons and rapidly cooled. Subsequently, some of the ribbons underwent a heat treatment (ceramization), specifically, they were heated to approximately 750°C for about 6 hours and then cooled. Comparison example (Example) A was also produced as described above. Table 1 (Examples of implementation (e.g.) 1 and 2, comparison example (cf.-e.g.) A; in wt.%) 1 2 A Al2O3 6,2 7,0 5,1 B2O3 4,5 10,7 Fe2O3 10,2 10,1 10,2 K2O 9,5 10,4 8,4 MnO2 5,2 5,2 5,2 Na2O 1,8 2,2 1,2 SiO2 55,3 57,8 51,9 TiO2 7,3 7,3 7,3 Summe 100,0 100,0 100,0 TiO2+Fe2O3+MnO2 22,7 22,6 22,7 SiO2+Al2O3+B2O3 66,0 64,8 67,7 R 20 +R'O 11,3 12,6 9,6 Kristallphase (Fe x Mn y TiO3 (Fe x Mn y TiO3 (Fe x Mn y TiO3

[0148] Investigations using powder X-ray diffraction on ceramicized samples with composition according to Examples 1 and 2 showed that a second phase, which is crystalline, formed in situ as a result of the temperature treatment (see Fig. 3) The glasses produced are therefore phase-separated glasses, specifically glass ceramics. The proportion of the second phase is approximately 11 vol.%, and the average crystal size is approximately 350 nm. The crystal phase consists of ilmenite solid solutions (Fe x Mn y )TiO3, where x+y=1. Fig. Figure 3 shows the typical X-ray reflections a of ilmenite (mixed) crystals.

[0149] Example A is also a glass ceramic with the same crystal phase and similar structures in terms of volume fraction and crystal size.

[0150] Investigations using powder X-ray diffraction on non-ceramized samples with composition according to Examples 1 and 2 showed that a second phase, which is crystalline, formed in situ in the glasses even without ceramization (see Fig. 4) The X-ray reflections b in Fig. 4 can be assigned to the crystalline phase Ulvöspinel (Fe,Mn)2TiO4.

[0151] From the tempered, phase-separated glass ceramics with the composition of Examples 1 and 2 as well as Comparison Example A and structures whose type, average size and proportion were written above, the following powder was produced using a suitable wet milling process: - Example 1: according to the invention, boron-reduced, tempered, phase-separated glass ceramic: with d 50 -value of 2.5 + / - 0.5 µm, here d 50 of 2.4 µm; d 99 of 9.2 µm; preferably wet-milled (curve d in Fig. 1 and curve e in Fig. 2) - Example 2: according to the invention, boron-free, tempered, phase-separated glass ceramic: with d 50 -value of 2.5 + / - 0.5 µm, here d 50 of 2.5 µm; d 99 of 10.6 µm; preferably wet-milled (curve e in Fig. 1 and curve f in Fig. 2) - See example A: tempered, phase-separated glass ceramic: with d 50 -value of 2.5 + / - 0.5 µm, here d 50 of 2.7 µm; d 99 of 10.9 µm; preferably wet-milled (curve c in Fig. 1 and curve b in Fig. 2) Further comparison examples (cf. example) B and C - Comparative example B is a microparticulate TiO2 powder with a d 50 -value of 0.68 µm and a d90 value of 1.13 µm (curve b in Fig. 1; Curve d in Fig. 2). - Comparative example C is a nanoparticulate TiO2 powder (AEROXIDE) ® TiO2 P 25) with a primary particle size of 21 nm (TEM) and a specific surface area of ​​35 to 65 m²2 / g (BET); (curve a in Fig. 1; Curve c in Fig. 2).

[0152] To verify whether B₂O₃ can be extracted from a powder according to the invention (Examples 1 and 2), bioelution tests were performed on the aforementioned glass-ceramic powders using an artificial sweat solution with a pH of 6.5 (ASW Test: Artificial sweat solution, pH 6.5). The test with the artificial sweat solution simulates an exposure scenario upon contact with human skin, i.e., an electrolyte imbalance (too low a sodium concentration in the blood serum) resulting from dehydration, which is excreted from the body during sweating. The artificial sweat solution was prepared and used according to the EN 1811:1998 standard.

[0153] Two powders according to the invention were tested, wherein Example 1 has a reduced B₂O₃ content and Example 2 is B₂O₃-free. In addition, Comparison Example A, i.e., a phase-separated borosilicate glass with a transition metal compound (titanate with transition metal cations), was examined. The powders each exhibited a d 50 The particle size increased from approximately 2.5 µm, resulting in a very fine granulation suitable for cosmetic and / or medical products. Two powder samples each were mixed with an artificial sweat solution and extracted at 37°C for 24 hours with stirring (100 revolutions per minute). The samples were then filtered, and the boron content in the eluate was measured using ICP-OES. The boron content was converted to B₂O₃, and the mean value was determined.

[0154] In both glass-ceramic powders according to the invention, with the composition shown in Examples 1 and 2 and in the special fine grain size used here, no leached B₂O₃ can be detected in the bioeluation test with the artificial sweat solution. The B₂O₃ values ​​in the eluates are below the detection limit of 0.1% for both Example 1 and Example 2.

[0155] In the tested comparison example with composition according to comparison example A in the special fine grain size used here, 0.9% B2O3 was determined in the eluate in the bioeluation test with the artificial sweat solution.

[0156] These results show that the boron-reduced or boron-free glass ceramic powders according to the invention have high chemical stability.

[0157] Transmission measurements on composite samples with glass ceramic powders with compositions of examples 1 and 2 and with powders of comparison examples A, B and C ( Fig. 1): Composite samples were prepared with the above-mentioned powders at a powder concentration of 1 wt% and analyzed spectroscopically, taking into account an undoped monomer sample as a reference sample.

[0158] The transmission behavior of the powders was determined on composite samples within the scope of the invention as follows: For the transmission measurements, a composite sample was prepared by mixing the respective powder with a d 50A particle size of 2.5 µm + / - 0.5 µm (different particle size for comparison examples B and C as stated above) was mixed with a monomer mixture of triethylene glycol dimethacrylate, 2,6-di-tert-butyl-p-cresol, 2-hydroxy-2-methylphenylpropan-1-one, methacrylic acid, methyl methacrylate, and diphenyl(2,4,6-trimethylbenzene)phosphine oxide from Kulzer GmbH (Germany) to create a homogeneous mixture. The powder content in the sample was 1 wt% (so-called starting concentration). Round samples with a diameter of 30 mm and a thickness of 1 mm were produced, then illuminated with a xenon flash lamp for 180 seconds and cured by the resulting polymerization. The composite samples thus produced were then examined spectroscopically and analyzed taking into account a polymerized undoped pure monomer sample (i.e. a sample without powder addition) of the same thickness as a reference sample.A composite sample therefore comprises the powder to be tested embedded in a polymer matrix, which acts as a support medium. The undoped monomer used has a refractive index n. d (589nm) in the range 1.546 to 1.549.

[0159] In general, transmission measurements on powders are more difficult to perform than on solid glass samples, since in the composite sample the support medium that holds the powder also contributes to the transmission behavior of the powder-doped composite sample. Therefore, the transmission of the composite samples was determined using a dual-beam photometer (Perkin Elmer Lambda 900 / 950 UV-Vis-NIR) with an integrated integrating sphere with a wavelength of 950. An undoped, 1 mm thick reference sample (monomer sample without powder) was placed in a reference channel, where the radiation passing through the reference sample (I) was measured. Ref) was recorded while a 1 mm thick, powder-doped composite sample was placed in a sample channel in front of the integrating sphere, so that only the radiation passing through the composite sample (I) was detected in the sample channel Probe ) was recorded. From the ratio of (I Probe ) and (I Ref The transmittance or transmission in % was calculated.

[0160] A comparison of the spectral transmittance curves shows the following: Curves d (Example 1) and e (Example 2) show the transmission behavior of two boron-reduced and boron-free glass ceramics according to the invention, respectively, with ilmenite solid solutions. Curve c, on the other hand, shows a glass ceramic with a high boron content and ilmenite solid solutions. The transmission behavior is comparable over the entire wavelength range shown, with the boron-reduced and boron-free glass ceramics according to the invention tending to exhibit even higher UV blocking at the same concentration than the comparison glass ceramic.

[0161] In detail, examples 1 and 2 (curves d and e) show a transmission of less than 5% at the critical wavelength of 370 nm (example 1: 4%, example 2: 1%). At the boundary between the UV-A I and UV-A II ranges (340 nm), the transmission is also less than 5% (example 1: 3%, example 2: <1%). At the boundary between the UV-A and UV-B ranges (315 nm), the transmission is less than 4% (example 1: <3%, example 2: <0.5%).

[0162] The transmission behavior of two TiO2 powders with different particle size distributions (see examples B and C) measured on composite samples is also shown in Fig. Figure 1 shows both TiO2 powders exhibit low transmission in the UV range.

[0163] A comparison of curves d, e, and a shows that a non-nanoparticulate powder according to the invention, consisting of particles of a phase-separated glass with a transition metal compound, in particular a powder of such a glass ceramic, exhibits at least the same UV blocking performance, or even better UV blocking at the critical wavelength of 370 nm, as nanoparticulate TiO2. The powder of Example 1 is therefore a particulate inorganic UV filter. This also applies to the powder of Example 2.

[0164] Transmission measurements on a reference cream doped with powders of glass ceramics with compositions of examples 1 and 2 and with powders of comparison examples A, B and C ( Fig. 2): Using the above-mentioned powder of phase-separated glass according to Example 1 - i.e., glass ceramic: with d 50-particle size of 2.5 + / - 0.5 µm - a preparation with UV light protection properties was produced, comprising the powder according to the invention and a cosmetic formulation as a base. For this purpose, a commercially available urea cream (GREVEN) was used as the formulation. ® CREME UREA (see above) is shown here as an example mixed with 1% by weight of powder from Example 1.

[0165] The preparation was made as follows: The powder was mixed with the reference cream according to the desired concentration (here 1 wt%) and then stirred with a speed mixer for 9 minutes at 1700 revolutions per minute. The mixed preparation was applied to a three-roller mill and filled into sample vials.

[0166] The powder with particle size d 50The preparation made from 2.5 + / - 0.5 µm had a creamy consistency, spread well and evenly on the skin and left a pleasant feeling on the skin without any perceptible foreign particles.

[0167] The spectral transmittance was then determined in each case. The experimental setup for the transmittance measurements on preparations with and without powder, hereinafter referred to as "cream samples", in a dual-beam photometer (Perkin Elmer Lambda 900 / 950 UV-Vis-NIR, measured with Lambda 900) with an integrating sphere was as follows: To measure a cream sample spectroscopically, a special holder was used, comprising two quartz glass plates and a spacer that ensured a distance of 0.12 mm between the glass plates. The reference channel remained empty. In the sample channel, the empty holder without the cream sample was placed in front of the integrating sphere, so that only the radiation passing through the empty holder was measured in the sample channel (intensity 10). The cream sample was then placed in the holder in the space between the glass plates, so that the layer thickness of the cream sample was 0.12 mm, and the holder was placed in front of the integrating sphere, so that only the radiation passing through the cream sample was measured in the sample channel (intensity 10). probe ) was recorded. The transmission was calculated from the measurement data by determining the intensity I. probe was divided by the intensity I0 (transmission coefficient = I Probe / l0).

[0168] Using the powder according to Example 2 and powders from Example A, B and C with the particle sizes specified above, corresponding preparations were produced, the powder concentration being 1 wt.% in each case, and their transmittance was measured.

[0169] The results of the transmission measurements on preparations (cream samples) are in Fig.Figure 2 shows the transmission profile, with the data always referring to a sample thickness of 120 µm. Curve a shows the transmission of the pure undoped reference cream, which contained no powder (blank sample). Curve b shows the transmission profile for a preparation with powder of a phase-separated glass ceramic with a high boron content (see Example A). Curve c shows the transmission profile for a preparation with nanoparticulate TiO2 powder (see Example C), and curve d shows the transmission profile for a preparation with microparticulate TiO2 powder (see Example B). Curve e shows a first embodiment of the invention, namely the transmission of a preparation with powder from Example 1 – i.e., glass ceramic with reduced boron content. Curve f shows a second embodiment of the invention, namely the transmission profile of a preparation with powder from Example 2 – i.e., boron-free glass ceramic.

[0170] In detail, the preparations with powders according to the invention, examples 1 and 2 (curves e and f), exhibit a transmission of less than 5% (approximately 2% for both) at the critical wavelength (370 nm). At the boundary between the UV-A I and UV-A II ranges (340 nm), the transmission is approximately 1% for both preparations. At the boundary between the UV-A and UV-B ranges (315 nm), the transmission is approximately 0.5% for both preparations.

[0171] Overall, the transmission of the preparations with the glass-ceramic powders according to the invention is lower in the entire UV range than the transmission of the comparison example A.

[0172] A comparison of curves e, f, and c shows that at a concentration of 1 wt%, a non-nanoparticulate powder according to the invention, consisting of a phase-separated glass with a transition metal compound comprising a titanate and transition metal cation(s), exhibits a similarly high UV blocking effect in the UV range as nanoparticulate TiO₂ powder. The powder from Example 1 is therefore a particulate inorganic UV filter. The same applies to the powder from Example 2. The degree of UV blocking in a preparation can be specifically adjusted by varying the concentration of the powder according to the invention. That is, the UV blocking effect can be improved by increasing the concentration of the powder.

[0173] Within the scope of the invention, it was first recognized that certain non-nanoparticulate powders consisting of or comprising particles of a boron-reduced or boron-free phase-separated glass containing titanate and transition metal cation(s) can be used as inorganic particulate UV filters, exhibiting comparable UV blocking to nanoparticulate TiO2. The invention provides novel, non-nanoparticulate UV filters which, due to their high chemical resistance (e.g., no release of boron oxide in significant quantities), are particularly advantageous in cosmetic and / or pharmaceutical preparations. However, their use in technical applications (see above) is also encompassed by the invention.

[0174] Unlike organic UV filters, the powders according to the invention, consisting of or comprising particles of phase-separated glass, are not altered by exposure to sunlight, thus ensuring high photostability of the novel inorganic particulate UV filter. Furthermore, unlike known inorganic UV filters consisting of TiO2 and / or ZnO powder, the powders according to the invention, with a transition metal compound encapsulated in a glass matrix, do not exhibit photocatalytic properties, so that no free radicals (e.g., reactive oxygen species, ROS) are formed. QUOTES INCLUDED IN THE DESCRIPTION

[0000] This list of documents cited by the applicant was automatically generated and is included solely for the reader's convenience. The list is not part of the German patent or utility model application. The DPMA accepts no liability for any errors or omissions. Cited patent literature

[0000] US 2007 / 0196290 A

[0003] US 2012 / 0156834 A

[0003] DE 10161075 C

[0010] DE 10201747 C

[0010] Cited non-patent literature

[0000] EN1811, 1998

[0152]

Images