Process for preparing UV shielding dispersions for wet grinding

Abstract

A process for producing an aqueous dispersion of a water-insoluble solid organic UV-blocking compound, comprising the steps of: providing water, a dispersant, and a powder containing the water-insoluble solid organic UV-blocking compound; providing an aqueous dispersant solution, by adding the dispersant to water in an amount of 0.001 to 0.25% by weight relative to the total weight of the aqueous dispersant solution, leaving a remainder of the dispersant; using an in-line disperser, dispersing the powder containing the water-insoluble solid organic UV-blocking compound in the aqueous dispersant solution to obtain a first aqueous dispersion; adding the remainder of the dispersant to the first aqueous dispersion to obtain a second aqueous dispersion; and further dispersing the second aqueous dispersion to obtain an aqueous dispersion of a water-insoluble solid organic UV-blocking compound, wherein the total amount of the dispersant is greater than 0.25% by weight relative to the total weight of the aqueous dispersant solution.

Description

[Technical Field]

[0001] The present invention relates to a process for producing an aqueous suspension of an insoluble organic UV absorber using an inline disperser. Foaming is reduced by optimizing the dispersant level and feeding process in the mixing device. This process is economical and reduces EHS measures in the plant. The resulting suspension is suitable for wet grinding in a stirred-media mill to obtain a micronized UV shielding agent for use in cosmetic sunscreens. [Background technology]

[0002] Micronized organic UV absorber dispersions are well described in the literature. Particulate organic UV absorbers suitable for use in cosmetic sunscreens are described, for example, in International Publication No. 95 / 22959A1, International Publication No. 97 / 03643A1, International Publication No. 2009 / 077356A1, and International Publication No. 2015 / 155158A1.

[0003] Generally, some commonly used UV absorbers are insoluble in water. However, the manufacture of products using such water-insoluble UV absorbers requires them to be dispersed as finely as possible in water. Therefore, the process for dispersing such UV absorbers has been a constant challenge for improvement in recent years.

[0004] In particular, the use of dispersants has been a subject of research for many years. International Publication No. 97 / 03643A1 provides a method for producing a composition of micronized organic UV absorbers, comprising grinding the UV absorber in the presence of an alkyl polyglucoside. International Publication No. 2009 / 068469A1 shows more grinding aids.

[0005] Therefore, slurry formation is a crucial step in the large-scale production of finely powdered organic UV shielding agent dispersions. As described above, particulate UV absorbers are water-insoluble crystalline substances and are obtained as low-density powders with dust-explosive properties. Safety measures must be taken when such powders are introduced into containers containing a liquid phase.

[0006] One of the problems in dispersing the aforementioned UV-blocking agent is foam formation. Because the density of the powder is lower than its true density, the powder contains air. When the UV-blocking agent powder is wetted with a liquid, the air in the bulk phase is released, thus creating foam. Furthermore, the use of dispersants, especially surfactants, also promotes foam formation. Foaming can also occur if the process or equipment used for mixing and homogenizing the suspension is not suitable. Foam hinders any stable and robust wet grinding process in a stirred-media mill. Therefore, preventing foam formation in the process of dispersing the aforementioned UV-blocking agent is a challenge.

[0007] In International Publication No. 2009 / 003934A1, the dispersion is prepared by grinding the UV shielding agent in the presence of an antifoaming agent in an apparatus containing zirconium oxide grinding beads stabilized with yttrium. International Publication No. 2017 / 198806A1 describes the wet grinding of organic UV shielding agent suspensions in more detail. A formulation is prepared containing water, a dispersant, and an antifoaming agent, and the UV shielding agent powder is added to form a slurry. This slurry is pre-ground using a colloidal mill and then finely ground to an average particle size d50 of 100-170 nm in a stirred medium mill.

[0008] However, using an antifoaming agent means it becomes part of the product formulation, and this is not always acceptable to customers.

[0009] International Publication No. 2018 / 069200A1 presents a wet grinding process in a stirred-media mill without the use of defoaming agents. The UV shielding agent suspension is prepared in a vessel by slowly adding the UV shielding agent powder to a water / alkyl polyglucoside mixture. Before the start of the grinding process, the suspension is degassed while being gently stirred in a heating / cooling cycle. It is claimed that foaming during wet grinding can be controlled by selecting a specific particle size in the UV shielding agent suspension. Further reduction of foaming can be achieved by using a specific alkyl polyglucoside as a dispersant.

[0010] However, the degassing process before wet grinding, as described in International Publication No. 2018 / 069200A1, is expensive and time-consuming, especially on a manufacturing scale. [Overview of the Initiative] [Problems that the invention aims to solve]

[0011] Therefore, an object of the present invention is to provide a scalable process for dispersing a water-insoluble solid organic UV shielding agent in an aqueous phase without adding an antifoaming agent to the aqueous phase and without including a degassing step in the process. [Means for solving the problem]

[0012] Surprisingly, it was found that this objective could be solved by a process in which an aqueous dispersant solution is provided in which the amount of dispersant is in the range of 0.001 to 0.25% by weight relative to the total weight of the aqueous dispersant solution, and then UV shielding powder is dispersed in this aqueous dispersant solution to obtain a first aqueous dispersion, after which the remaining dispersant is added. This concentration range is related to the activity level of the dispersant in the liquid before the addition of the powder.

[0013] The advantageous technical effect of the present invention is that an aqueous UV absorber dispersion can be prepared by significantly reducing or even completely suppressing the formation of foam, thereby eliminating the need for any further degassing step, and as a result, a method for rapidly and efficiently wetting a water-insoluble solid organic UV absorber is obtained.

Brief Description of the Drawings

[0014] [Figure 1] It is a schematic diagram of the device configuration used in Examples CE1, CE2, IE1 and IE2. [Figure 2] It is a photograph of the aqueous phase and the generated foam in Comparative Example CE1. [Figure 3] It is a photograph of the aqueous phase and the generated foam in Comparative Example CE1. [Figure 4] It is a photograph of the number of particles with a diameter of 500 μm or more (left-handed sieve) and the number of particles in the range of 200 to 500 μm in diameter (right-handed sieve) for Probes A to D in Comparative Example CE2.

Modes for Carrying Out the Invention

[0015] Definition Where used herein and in the appended claims, the singular forms “a” and “an” also include their respective plural forms unless the context clearly indicates otherwise. In relation to the present invention, the terms “about” and “approximately” refer to a range of precision that a person skilled in the art would understand to be such that the technical effect of the feature in question is still ensured. This term typically represents a deviation of ±20%, preferably ±15%, more preferably ±10%, and even more preferably ±5% from the given numerical value. The term “comprising” should be understood to be non-limiting. For the purposes of the present invention, the term “consisting of” is considered a preferred embodiment of the term “comprising of.” Hereinafter, where a group is defined as including at least a certain number of embodiments, this also means that the group is preferred from only these embodiments. Furthermore, terms such as “first,” “second,” “third,” or “(a),” “(b),” “(c),” “(d),” etc., and similar terms in this specification and the claims are used to distinguish similar elements and do not necessarily describe a continuous or chronological order. Terms used in this manner are interchangeable under appropriate circumstances, and it should be understood that embodiments of the present invention described herein may be carried out in an order other than that described or illustrated herein. Where terms such as “first,” “second,” “third,” or “(a),” “(b),” “(c),” “(d),” “i,” “ii,” etc., relate to a method, use, or assay step, unless otherwise specified in this application, there may be no time interval between these steps or inconsistent time intervals, i.e., these steps may be performed simultaneously, or there may be time intervals of a few seconds, a few minutes, a few hours, a few days, a few weeks, a few months, or even several years between such steps. Because specific methods, procedures, reagents, etc., described herein are subject to change, it should be understood that the present invention is not limited to them.The technical terms used herein are for the sole purpose of describing specific embodiments and are not intended to limit the scope of the invention, and it should be understood that the scope of the invention is limited only by the appended claims. Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those generally understood by those skilled in the art.

[0016] As used herein, the term "does not comprise (free of)" means that, in the context that the composition of the present invention does not comprise a particular compound or a particular group of compounds which may be a group combined under a collective term, the composition does not comprise the compound or group of compounds in an amount exceeding 0.8% by weight of the total weight of the composition. Furthermore, it is preferable that the composition according to the present invention does not comprise the compound or group of compounds in an amount exceeding 0.5% by weight, and preferably, the composition does not comprise the compound or group of compounds at all.

[0017] When referring to the weight percentage of a composition and its components, it should be understood that, according to the present invention, the total amount of components does not exceed 100% (rounded to ±1%).

[0018] The terms “sunscreen composition” or “sunscreen” refer to any topical product that absorbs, reflects, and scatters a specific portion of UV radiation. Therefore, it should be understood that the term “sunscreen composition” encompasses not only sunscreen compositions but also any cosmetic compositions that protect against UV rays. The term “topical product” refers to a product applied to the skin, which may be, for example, a spray, lotion, cream, oil, foam, powder, or gel. According to the present invention, a sunscreen composition may contain one or more activators, such as organic and inorganic UV shielding agents, and other components or additives, such as emulsifiers, emollients, viscosity modifiers, stabilizers, preservatives, or fragrances.

[0019] The term "daily care composition" refers to any topical product used as a daily care product for the human body, such as the face or body, which can absorb, reflect, and scatter a specific portion of UV radiation. A daily care composition may contain one or more activators, such as organic and / or inorganic UV shielding agents, and other components or additives, such as emulsifiers, emollients, viscosity modifiers, stabilizers, preservatives, or fragrances. A preferred daily care composition is one according to the present invention, such as a leave-on facial and body care product.

[0020] Leave-on products suitable for the face and body include, for example, sunscreen compositions, decorative preparations, and skincare preparations.

[0021] Suitable decorative preparations include, for example, lipstick, nail polish, eyeshadow, mascara, dry and moisturizing makeup products, blush, powder, depilatory agents, and sunscreens.

[0022] Suitable skincare preparations include, for example, moisturizing, refining, and lifting preparations. The listed daily care compositions may be in the form of creams, ointments, pastes, foams, gels, lotions, powders, makeup products, sprays, sticks, or aerosols. Because the daily care compositions contain UV-blocking agents, they are therapeutic daily care compositions.

[0023] As used herein, the terms “UV shielding agent” or “ultraviolet shielding agent” refer to organic or inorganic compounds that can absorb, reflect, and scatter ultraviolet radiation produced by sunlight. UV shielding agents can be classified as UV-A, UV-B, or broadband shielding agents according to their UV protection curve. Preferably, the term “UV shielding agent” includes or consists of any UV shielding agent as defined in Annex VI (version of 3 December 2020) of European Parliament and Council Regulation (EC) No. 1223 / 2009.

[0024] The water-soluble UV screening agent has a solubility in water of at least 2% by weight, preferably at least 3% by weight, more preferably at least 5% by weight.

[0025] The prefix Cn~Cm represents, in each case, the possible number of carbon atoms of the group.

[0026] “C 12 ~C 15 The term “alkyl benzoate” refers to an ester of benzoic acid and a fatty alcohol containing a C 12 ~C 15 alkyl chain. The C 12 ~C 15 alkyl chain is defined as an alkyl chain having a chain length of C 12 , C 13 , C 14 or C 15 .

[0027] As used herein, the term “Cn~Cm carboxylic acid” refers, in each case, to a straight-chain or branched carboxylic acid having n~m carbon atoms, for example, 6~24 carbon atoms.

[0028] As used herein, the term “Cn~Cm alcohol” refers, in each case, to a straight-chain or branched alcohol having n~m carbon atoms, for example, 3~24 carbon atoms or 6~24 carbon atoms or 1~22 carbon atoms.

[0029] As used herein, the term “C2~C 12 dicarboxylic acid” refers, in each case, to a dicarboxylic acid having 2~12 carbon atoms, for example, succinic acid, glutaric acid, adipic acid or sebacic acid.

[0030] As used herein, the term “dialkyl ether” refers, in each case, to a straight-chain or branched dialkyl ether having a total of 12~36 carbon atoms and containing at least one ether moiety.

[0031] The term "C6~C" used in this specification 22 The term "alcohol carbonate ester" refers in each case to a linear or branched alcohol carbonate ester having 6 to 22 carbon atoms and containing at least one functional group consisting of two adjacent carbonyl groups with alkoxy groups.

[0032] As used herein, the term "alkyl" refers in each case to a linear or branched alkyl group having, for example, 1 to 18 carbon atoms. Examples of alkyl groups include methyl, ethyl, n-propyl, isopropyl, n-butyl, 2-butyl, isobutyl, tert-butyl, n-pentyl, 1-methylbutyl, 2-methylbutyl, 3-methylbutyl, 2,2-dimethylpropyl, 1-ethylpropyl, n-hexyl, 1,1-dimethylpropyl, 1,2-dimethylpropyl, 1-methylpentyl, 2-methylpentyl, 3-methylpentyl, 4-methylpentyl, 1,1-dimethylbutyl, 1,2-dimethylbutyl, 1,3-dimethylbutyl, 2,2-dimethylbutyl, 2,3-dimethylbutyl, 3,3-dimethylbutyl, 1-ethylbutyl, 2-ethylbutyl, 1,1,2-trimethylpropyl, 1,2,2-trimethylpropyl, 1-ethyl-1-methylpropyl, and 1-ethyl-2-methylpropyl.

[0033] As used herein, the term “alkoxy” refers in each case to a linear or branched alkyl group having typically 1 to 20 carbon atoms bonded via an oxygen atom. Examples of alkoxy groups include methoxy, ethoxy, n-propoxy, isopropoxy, n-butyloxy, 2-butyloxy, isobutyloxy, tert-butyloxy, and similar groups.

[0034] As used herein, the term "carboxyalkyl" includes carboxymethyl, carboxyethyl, carboxypropyl, carboxyisopropyl, carboxybutyl, carboxyisobutyl, carboxyamyl, carboxyhexyl, carboxyheptyl, carboxyoctyl, carboxyisooctyl, carboxynonyl, carboxydecyl, carboxyundecyl, carboxydodecyl, carboxytetradecyl, carboxyhexadecyl, and carboxyoctadecyl, with carboxymethyl being preferred.

[0035] As used herein, the term "cycloalkyl" typically refers in each case to a monocyclic or alicyclic group having 3 to 10 or 5 to 8 carbon atoms, such as cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl, cyclooctyl, cyclononyl, and cyclodecyl, or cyclopropyl, cyclobutyl, cyclopentyl, and cyclohexyl.

[0036] As used herein, the term “substituted” means that a hydrogen atom bonded to a specified atom is replaced by a substituent specifically described, provided that the substitution results in a stable or chemically feasible compound. Unless otherwise specified, a substituted atom may have one or more substituents, each substituent being independently selected.

[0037] The term "insoluble solid organic UV shielding agent" refers to multiple particles of a single type of UV shielding agent having a specific particle size distribution.

[0038] The particle size of the UV shielding agent in this invention is defined by the particle size distribution of a group of particles, which can be characterized based on particle volume (mass). Volume-based distributions can be obtained by laser diffraction, and many commercially available instruments are available, for example, from Anton Paar (PSA series), Microtrac MRB (Sync), or Malvern Panalytical (Mastersizer series). The numerical results characterizing the particle size distribution will vary within a somewhat narrow range depending on the sensitivity and resolution of the selected instrument. Those skilled in the art understand how to handle these deviations, and such instruments are routinely used in R&D and quality control laboratories.

[0039] As used herein, the term “dispersion” refers to a system in which scattered particles of one material are dispersed in a continuous phase of another material. The states of matter of these two phases may be the same or different. A particular subtype of dispersion is a “suspension,” in which solid elements are dispersed in a fluid (i.e., undissolved).

[0040] Description of the Invention The present invention relates to a process for producing an aqueous dispersion of a water-insoluble solid organic UV shielding compound, a) A step of providing water, preferably distilled water, most preferably redistilled water, a dispersant, and a powder containing a water-insoluble solid organic UV shielding compound; b) A step of providing an aqueous dispersant solution, wherein the dispersant is added to water in an amount of 0.001 to 0.25% by weight relative to the total weight of the aqueous dispersant solution, and the amount of dispersant remaining is left; c) A step of using an in-line disperser to disperse a powder containing a water-insoluble solid organic UV shielding compound in an aqueous dispersant solution to obtain a first aqueous dispersion; d) The step of adding the remaining amount of dispersant to the first aqueous dispersion to obtain a second aqueous dispersion; e) The step of further dispersing the second aqueous dispersion to obtain an aqueous dispersion of a water-insoluble solid organic UV shielding compound, The present invention provides a process in which the total amount of the dispersant is greater than 0.25% by weight relative to the total weight of the aqueous dispersant solution.

[0041] This process is controlled in particular by the concentration of the dispersant used in the aqueous phase before the dispersion step. Preferably, this process is carried out using recirculation. In such a preferred embodiment, the aqueous dispersion is added again in step c). Therefore, preferably, the concentration of the dispersant is kept constant in the range of 0.001 to 0.25% by weight of the total weight of the aqueous dispersant solution until step c) is completed, i.e., until the total amount of water-insoluble solid organic UV shielding agent is added, thereby recirculating the dispersion. After the completion of step c), the remaining dispersant is added in step d).

[0042] Preferably, in step b), the dispersant is added in an amount of less than 0.24% by weight, preferably less than 0.2% by weight, and most preferably less than 0.15% by weight, relative to the total weight of the aqueous dispersant solution. When the dispersant is added in an amount of less than 0.24% by weight, foaming is significantly reduced. When the dispersant is added in an amount of less than 0.15% by weight, foaming is suppressed.

[0043] Suitable dispersants include, in particular, polyglycerol alkyl esters, preferably polyglycerol monoalkyl esters, and preferably the following formula C n H 2n+1 O(C6H 10 O5) x H (In the formula, n is an integer in the range of 8 to 16, and x is the glucoside portion (C6H 10 This is the average polymerization level of O), which is in the range of 1.4 to 1.6. The alkyl polyglucoside or ester thereof having the property. More preferred dispersants are disclosed in International Publication No. 2009 / 7068469A1.

[0044] According to the present invention, it is preferable that the polyglycerol monoalkyl ester has an average degree of polymerization of glycerol of 5 or more.

[0045] In one preferred embodiment, at least one polyglycerol monoalkyl ester is selected from the group consisting of decaglyceryl caprate, decaglyceryl monolaurate, decaglyceryl myristate, decaglyceryl oleate, decaglyceryl stearate, decaglyceryl isostearate, hexaglyceryl caprate, hexaglyceryl laurate, hexaglyceryl myristate, hexaglyceryl oleate, hexaglyceryl stearate, hexaglyceryl isostearate, pentaglyceryl caprate, pentaglyceryl laurate, pentaglyceryl myristate, pentaglyceryl oleate, pentaglyceryl stearate, pentaglyceryl isostearate, and combinations thereof. In a particular preferred embodiment, at least one polyglycerol monoalkyl ester is decaglyceryl monolaurate (INCI: polyglyceryl-10 laurate).

[0046] Polyglycerol monoalkyl esters with an HLB (hydrophilic-lipophilic balance) of 14.5 or higher are preferred, and those with an HLB of 15 or higher are more preferred. The HLB value is given by the formula HLB = 20·M h / M (In the formula, M h It is determined by (where M is the molecular weight of the hydrophilic portion of the molecule, and M is the molecular weight of the entire molecule).

[0047] If the HLB of the polyglycerol monoalkyl ester is less than 14.5, it may take longer to disperse the finely powdered methylenebis-benzotriazolyltetramethylbutylphenol in the aqueous phase component. Examples of polyglycerol monoalkyl esters with an average degree of polymerization of 5 or more and an HLB of 14.5 or more include decaglyceryl caprate, decaglyceryl monolaurate, decaglyceryl myristate, decaglyceryl oleate, decaglyceryl stearate, decaglyceryl isostearate, hexaglyceryl laurate, pentaglyceryl laurate, pentaglyceryl myristate, pentaglyceryl stearate, and pentaglyceryl oleate. Examples of polyglycerol monoalkyl esters with an HLB of 15 or more include decaglyceryl caprate and decaglyceryl monolaurate. Particularly preferred are polyglyceryl monolaurate, especially decaglyceryl monolaurate and decyl glucoside.

[0048] Preferably, alkyl polyglucoside is of formula C n H 2n+1 O(C6H 10 O5) x C1-C of the H compound 12 Esters, i.e., C1-C 12 Carboxylic acid is converted to the glucoside portion (C6H 10 The ester is formed by reacting formic acid, acetic acid, propionic acid, butyric acid, sulfosuccinic acid, citric acid, or tartaric acid with one or more free pH groups of (C6H). 10 It is preferable that it is formed by reacting with one or more free OH groups of O).

[0049] A preferred alkyl polyglucoside according to the present invention is an alkyl polyglucoside known by the INCI name "decyl glucoside" [CAS 68515-73-1], for example, C 8~16Alkyl polyglucosides, such as those available from BASF as PlantaCare 2000 UP, are used. Preferably, the dispersant is an alkyl glucoside, more preferably a polyalkyl glucoside, and most preferably the active compound in Plantacare® 2000 UP. It should be understood that the term "dispersant" as used herein refers to an active surface-active compound. Therefore, for example, if the dispersant is added as an aqueous solution, only the amount of the surface-active compound in that solution is relevant.

[0050] The term "insoluble solid organic UV shielding agent" refers to a UV shielding agent that does not dissolve in water and cosmetic oils at 25°C. In contrast, a water-soluble UV shielding agent has a water solubility of at least 2% by weight, preferably at least 3% by weight, and more preferably at least 5% by weight, while an oil-soluble UV shielding agent is C 12 ~C 15 The solubility in common cosmetic oils such as alkyl benzoate, dibutyl adipate, diisopropyl sebacate, phenethyl benzoate, or dicaprylyl carbonate is at least 2% by weight, preferably at least 5% by weight, and more preferably at least 7% by weight.

[0051] The insoluble solid organic UV shielding agent is preferably selected from the group consisting of tris-biphenyltriazine, 1,1'-(1,4-piperazinediyl)bis[1-[2-[4-(diethylamino)-2-hydroxybenzoyl]phenyl]methanone, phenylenebis-diphenyltriazine, and 2,2'-methylenebis[6-(2H-1,2,3-benzotriazol-2-yl)-4-(2,4,4-trimethylpentan-2-yl)phenol].

[0052] Tris-biphenyltriazine has the following structure: [ka]

[0053] 1,1'-(1,4-piperazinediyl)bis[1-[2-[4-(diethylamino)-2-hydroxybenzoyl]phenyl]methanone has the following structure: [ka]

[0054] Phenylenebis-diphenyltriazine has the following structure: [ka]

[0055] 2,2'-Methylenebis[6-(2H-1,2,3-benzotriazol-2-yl)-4-(2,4,4-trimethylpentan-2-yl)phenol] has the following structure: [ka]

[0056] According to one embodiment of the present invention, the insoluble solid organic UV shielding agent is 1,1'-(1,4-piperazinediyl)bis[1-[2-[4-(diethylamino)-2-hydroxybenzoyl]phenyl]methanone.

[0057] According to another embodiment of the present invention, the insoluble solid organic UV shielding agent is tris-biphenyltriazine. Tris-biphenyltriazine (also known as TBPT) is a broad-spectrum UV shielding agent that performs well across the entire UV-A and UV-B spectrum.

[0058] According to another embodiment of the present invention, the insoluble solid organic UV shielding agent is 2,2'-methylenebis[6-(2H-1,2,3-benzotriazol-2-yl)-4-(2,4,4-trimethylpentan-2-yl)phenol]. 2,2'-methylenebis[6-(2H-1,2,3-benzotriazol-2-yl)-4-(2,4,4-trimethylpentan-2-yl)phenol] is a very effective broadband UV shielding agent that covers the entire UV-A and UV-B spectrum.

[0059] Therefore, most preferably, the water-insoluble solid organic UV shielding compound is 2,2'-methylenebis[6-(2H-1,2,3-benzotriazol-2-yl)-4-(2,4,4-trimethylpentan-2-yl)phenol] (MBBT) or 2,4,6-tris([1,1'-biphenyl]-4-yl)-1,3,5-triazin (triazin) (TBPT).

[0060] In the process according to the present invention, the powder preferably consists of a water-insoluble solid organic UV shielding compound. Preferably, the powder has a bulk density of 200 to 800 kg / m³. 3 The range is as follows. More preferably, the powder has a median particle size D50 in the range of 30 to 400 μm (this particle size is measured by laser diffraction using a Mastersizer 3000 (Malvern Panalytical)) and / or a particle size D90 determined by laser diffraction in the range of 100 to 1000 μm. This ensures that the surface of the water-insoluble solid organic UV shielding agent is large enough to allow the shielding agent to disperse in water. Background information on the laser diffraction method and the method for determining the particle size distribution of the UV shielding agent powder can be found in International Publication No. 2018 / 069200A1.

[0061] Step c) is performed using an in-line disperser. In-line dispersers are a well-known means of achieving rapid incorporation of powder into a liquid and are commercially available, for example, from IKA GmbH & Co.KG, Ystral GmbH and Netzsch GmbH & Co.KG. Essentially, an in-line disperser consists of a mixing chamber connected to a powder supply unit (i.e., a powder fluidization device). The liquid passes quickly through the mixing chamber, creating a drag force. The powder is drawn into the mixing chamber and degassed to some extent before contact with the liquid. This improves the wetting process and reduces the formation of stable bubbles in the dispersion. Safety measures are reduced because explosive dust in the container is avoided. Therefore, preferably, in step c), the powder is added under vacuum. In this regard, the term “added under vacuum” as used herein refers to a process step or device that generates a pressure lower than the ambient pressure, thereby generating a driving force for adding the powder, preferably a fluidized powder. Such a lower internal pressure is generated, for example, by an in-line disperser in operation. Lower internal pressure is used to assist the movement of powder, preferably fluidized powder, from the powder supply to the dispersion chamber of the inline disperser, thereby increasing the overall dispersion efficiency of the device and process. Preferably, rapid degassing of the water-insoluble solid organic UV shielding powder is performed in the container, and this degassing is further enhanced by using a high-energy mixer / agitator for slurry homogenization in the container. Furthermore, the inline disperser is suitable for continuous processes and can be easily installed within the process.

[0062] Therefore, the device for carrying out the process of the present invention includes an inline dispenser, the inlet of which is connected to a supply container that holds a liquid phase. The line connected to the supply container includes an inlet device for introducing a dispersant into the supply line. This inlet device may include an inlet pump and an inlet valve. Finally, the powder inlet of the inline disperser is preferably connected to a powder fluidization device, and the introduction of the dispersant is located downstream of the inline disperser.

[0063] In a preferred embodiment of the device of the present invention, the outlet of the inline disperser is connected to a supply container. However, in this case, the outlet line preferably extends into the supply container in the form of a dip pipe. Furthermore, in such a preferred embodiment, the dispersant is added upstream of the supply container. Such a preferred embodiment configuration is suitable for carrying out the process of the present invention from the viewpoint of recycling, in which the dispersion formed in the inline disperser is redispersed by being added to the supply container.

[0064] Preferably, the feed container includes a mixer, most preferably a jet mixer. Surprisingly, it has been found that the jet mixer can significantly reduce the appearance of bubbles in the feed container, even when the device is used in recirculation mode, i.e., by connecting the outlet of the inline disperser to the feed container, despite the faster mixing speed applied. Thereafter, the air introduced by the powder in the inline disperser is released into the feed container. Without a jet mixer, large bubbles form, further hindering the process and reducing efficiency. Thus, the jet mixer improves process efficiency by eliminating the formation of large bubbles.

[0065] Therefore, the process of the present invention provides a preferred powder addition rate in step c), in the range of 20 to 200 kg / min, more preferably in the range of 100 to 150 kg / min, and most preferably in the range of 130 to 140 kg / min. Preferably, in step c), the powder is a fluidized powder. Thus, the process of the present invention is significantly faster than processes that include a degassing step, such as those described in, for example, International Publication No. 2018 / 069200A1.

[0066] Preferably, the inline disperser includes a high-shear mixer. More preferably, in step c), the high-shear mixer is operated at a rotational speed in the range of 2000 to 4000 rpm, preferably 2500 to 3600 rpm, and most preferably 2900 to 3100 rpm. This range has been found to yield the best results with respect to process step c). This range is effective in dispersing the water-insoluble solid organic UV shielding agent even at low levels of dispersant, such as that provided in step b).

[0067] Preferably, steps c) and e) are performed in the same device or even within the same device. Therefore, preferably step e) is performed using an inline disperser, preferably an inline disperser including a high-shear mixer. More preferably, in step e), the high-shear mixer is operated at a rotational speed in the range of 2500 to 4500 rpm, preferably 3000 to 4000 rpm, and most preferably 3500 to 3700 rpm. Most preferably, steps c) and e) are performed using the same in-line disperser, preferably an in-line disperser including a high-shear mixer. This simplifies the configuration used to perform the process. Such a configuration is advantageous when the process is performed as a recirculation process.

[0068] As described above, preferably, step c) is performed using an input pump. Steps d) and e) can be performed in parallel. This makes the process even more efficient. Moreover, the dispersant is uniformly dispersed in the aqueous phase while avoiding undesirable effects due to concentration. Preferably, dispersion is not performed during steps a) and b).

[0069] Preferably, the process of the present invention is carried out at a temperature in the range of 15 to 45°C, more preferably 20 to 30°C.

[0070] Preferably, the weight ratio of water to the water-insoluble solid organic UV shielding compound is in the range of 0.4 to 1.0, more preferably in the range of 0.6 to 0.8, and most preferably in the range of 0.65 to 0.75. Also preferably, after step d), the weight ratio of the dispersant to the water-insoluble solid organic UV shielding compound is in the range of 0.4 to 1.0, more preferably in the range of 0.6 to 0.8, and most preferably in the range of 0.65 to 0.75. These ratios ensure that foam formation is reduced and that the increase in viscosity of the dispersion is acceptable for an in-line disperser.

[0071] Preferably, the process according to the present invention is carried out without the addition of an antifoaming agent. Therefore, preferably, during the process according to the present invention, no antifoaming agent is present in the first aqueous dispersion, the second aqueous dispersion, and / or in the aqueous dispersion of the water-insoluble solid organic UV shielding compound of the process according to the present invention. More preferably, during the process according to the present invention, no antifoaming agent is present in the first aqueous dispersion, the second aqueous dispersion, and in the aqueous dispersion of the water-insoluble solid organic UV shielding compound of the process according to the present invention.

[0072] As used herein, the term “defoaming agent” refers to a compound that can at least partially reduce or suppress foam formation during a dispersion process. The dispersions produced by the process of the present invention are preferably suitable for further processing, i.e., further processing in the field of sunscreen production. Certain properties of the dispersion are advantageous for such further processing. Therefore, preferably, the aqueous dispersion of the water-insoluble solid organic UV shielding compound has an average particle size D50 in the range of 50 to 100 μm, more preferably in the range of 60 to 80 μm, and most preferably in the range of 68 to 75 μm. Similarly, preferably, the aqueous dispersion of the water-insoluble solid organic UV shielding compound has a particle size distribution D90 / D10 in the range of 50 to 125, more preferably in the range of 60 to 120, and most preferably in the range of 70 to 110. For further processing, as well as to ensure the best results in the transport of the slurry in the process of the present invention, the density of the dispersant in the aqueous dispersion of the water-insoluble solid organic UV shielding compound is preferably in the range of 800 to 1400 g / l, more preferably in the range of 900 to 1300 g / l, and most preferably in the range of 1000 to 1200 g / l.

[0073] Preferably, the aqueous dispersant solution obtained in step b) contains the dispersant in an amount of 0.001 to 0.24% by weight, preferably 0.01 to 0.2% by weight, and most preferably 0.1 to 0.15% by weight, based on the total weight of the aqueous dispersion.

[0074] Preferably, the first aqueous dispersion obtained in step c) contains a dispersant in an amount of 0.001 to 0.2% by weight, preferably 0.01 to 0.1% by weight, and most preferably 0.05 to 0.07% by weight, based on the total weight of the aqueous dispersion.

[0075] Preferably, the first aqueous dispersion obtained in step c) contains a water-insoluble solid organic UV shielding agent in an amount of 35-80% by weight, preferably 40-75% by weight, and most preferably 50-70% by weight, based on the total weight of the aqueous dispersion.

[0076] In the first aqueous dispersion obtained in step c, the weight ratio of the dispersant to the water-insoluble solid organic UV shielding agent is preferably 0.00001 to 0.1, more preferably 0.0001 to 0.0023, even more preferably 0.0001 to 0.0020, and particularly 0.0005 to 0.0015.

[0077] Preferably, the aqueous dispersion obtained in step e) contains a water-insoluble solid organic UV shielding agent in an amount of 10 to 65% by weight, preferably 35 to 60% by weight, and most preferably 50 to 58% by weight, based on the total weight of the aqueous dispersion.

[0078] Preferably, the aqueous dispersion obtained in step e) contains a dispersant in an amount of 1 to 50% by weight, more preferably 2 to 30% by weight, and particularly 3 to 6% by weight, based on the total weight of the aqueous dispersion.

[0079] Preferably, the aqueous dispersion obtained in step e) contains water in an amount of 10 to 65% by weight, preferably 35 to 45% by weight, based on the total weight of the aqueous dispersion.

[0080] In the aqueous dispersion obtained in step e), the weight ratio of the dispersant to the water-insoluble solid organic UV shielding agent is preferably 0.01 to 0.3, more preferably 0.05 to 0.25, and particularly 0.07 to 0.11.

[0081] In the aqueous dispersion, the weight ratio of water to the water-insoluble solid organic UV shielding compound is preferably in the range of 0.4 to 1.0, more preferably in the range of 0.6 to 0.8, and most preferably in the range of 0.74 to 0.79.

[0082] The aqueous dispersion may contain further excipients such as colorants, pH adjusters, and preservatives, which may be incorporated in step b) or added after step e). Typically, the dispersion is further processed in a colloidal mill and subsequently ground in a stirring medium mill to achieve the desired product characteristics. In the process of the present invention, foam formation is suppressed and the dispersion quality of the dispersion is already high enough to be supplied directly to the stirring medium mill, so the first step, i.e., grinding in the colloidal mill, can preferably be omitted. Therefore, the process of the present invention has the further advantage of simplifying and increasing the efficiency of post-processing steps. [Examples]

[0083] Measurement method a) Particle size Particle size was determined using laser diffraction (Malvern Mastersizer 3000, Fraunhofer model, supply pressure 0.2 bar). Further information on this particle size characterization method can be found, for example, in "Particle Characterization: Light Scattering Methods" by Renliang Xu, Kluwer Academic Publishers (ISBN 0-306-47124-8). Unless otherwise stated, all particle sizes for nano-sized insoluble organic UV absorbers are Dv50 values ​​(volume diameter, where 50% of the population is below this point and 50% is above this point) determined by light scattering.

[0084] b) Bulk density Bulk density was measured as apparent density according to DIN / EN ISO 60. Equipment for bulk density measurement is available, for example, from Landgraf Laborsysteme HLL GmbH, Germany.

[0085] Overall experimental structure The following description refers to Figure 1. The inlet of the Ystral GmbH Conti-TDS 3 inline disperser was connected by an inlet line to a cylindrical container with a capacity of 250 L, a height of 127 cm, and a diameter of 50 cm. The cylindrical container was equipped with an electric mixer and a thermometer. The powder inlet of the Conti TDS 3 was connected to a powder fluidization device via a powder line. The outlet of the Conti TDS 3 was equipped with an outlet line, which was reconnected to a dip tube reaching the bottom of the container to enable recirculation. The inlet line was equipped with an input device for introducing the dispersant. The dispersant used in all examples was Plantacare® 2000 UP, commercially available from BASF SE. This material is an aqueous solution of alkyl polyglucoside and contains approximately 50% dispersant. The water-insoluble solid organic UV shielding agent used in all examples was 2,2'-methylene(Methylen)-bis-(6-(2H-benzotriazol-2-yl)-4-(1,1,3,3-tetramethylbutyl)phenol) (MBBT), which is commercially available in powder form as Tinosorb M from BASF SE. The MBBT material was a powder with a bulk density of approximately 500-600 g / L.

[0086] Comparative example CE1 85 kg of redistilled water at a temperature of 20.9°C was filled into a container. No dispersant was added to the container. The amount of dispersant added was set to 20 g / second (i.e., 10 g / second of the active compound).

[0087] The dispersion process was initiated and set to run at 3000 rpm. Within 34 seconds, 120 kg of UV-blocking agent was added, and a large amount of foam was observed. The temperature inside the container rose to 21.7°C. The addition was stopped after 34 seconds. The resulting first aqueous dispersion had a dispersant concentration of 0.165% by weight and a UV-blocking agent concentration of 58.3% by weight.

[0088] The dispersion was further dispersed at 3000 rpm for 60 seconds (i.e., without adding any further dispersants or UV shielding agents), resulting in a further increase in the temperature inside the container to 23.1°C.

[0089] The generated foam had coarse pores on its surface, and the remaining liquid phase contained finely dispersed, creamy foam (see Figures 2 and 3).

[0090] Nevertheless, the foam formation was excessively rapid and intense.

[0091] Comparative Example CE2 85 kg of re-distilled water at a temperature of 21.1°C was filled into a container. The container was filled so that the distance from the liquid surface to the top rim of the container was 80 cm. 500 g of dispersant (i.e., 250 g of active compound) was added to the container. The amount of dispersant added was set to OFF. The resulting aqueous dispersant solution had a dispersant concentration of 0.292% by weight.

[0092] Dispersion was initiated and set to run at 3000 rpm. Within 37 seconds, 120 kg of UV shielding agent was added, and the generation of a large amount of foam was observed. The generated foam had coarse pores on its surface, and the remaining liquid phase contained finely dispersed, creamy foam. The temperature inside the container rose to 21.7°C. The foam volume reached 15 cm from the foam surface to the top edge of the container.

[0093] The dispersion was further dispersed at 3000 rpm for 60 seconds (i.e., without adding any further dispersants or UV shielding agents), resulting in a decrease in foam volume and a distance of 20 cm from the foam surface to the top edge of the container.

[0094] The dispersion was further dispersed at 3000 rpm for 60 seconds (i.e., without adding any further dispersants or UV shielding agents), resulting in a decrease in foam volume and a distance of 30 cm from the foam surface to the top edge of the container. The liquid temperature was 26°C.

[0095] The remaining amount of UV shielding agent was added under dispersion (3000 rpm) within 17 seconds, and as a result, the volume of the foam was maintained such that the distance from the foam surface to the top edge of the container was 30 cm.

[0096] The dispersion was further dispersed at 3000 rpm for 50 seconds (i.e., without adding any further dispersants or UV shielding agents). Dispersion had to be stopped because the liquid density was too high, resulting in a decrease in foam volume and a distance of 35 cm from the foam surface to the top edge of the container. The liquid temperature was 28°C. The dispersant concentration of the obtained first aqueous dispersion was 0.121% by weight, and the UV shielding agent concentration was 58.5% by weight.

[0097] Finally, when the remaining dispersant (22 kg, i.e., 11 kg of the active compound) was added, the density of the liquid immediately decreased, resulting in an increase in the volume of the foam, with the distance from the foam surface to the top edge of the container reaching 27 cm. The liquid temperature was 28°C. A probe was taken (A).

[0098] Finally, the liquid was dispersed at 3000 rpm for 1 minute (probe B, 29.5°C), then dispersed again at 3000 rpm for another minute (probe C, 31.2°C), and finally dispersed again at 3600 rpm for another minute (probe D, 33.3°C).

[0099] Nevertheless, since the goal was to disperse 125 kg of MBBT per 85 kg of redistilled water, the foam generation was excessively rapid.

[0100] Example IE1 of the present invention 85 kg of re-distilled water at a temperature of 20.6°C was filled into a container. The container was filled so that the distance from the liquid surface to the top edge of the container was 80 cm. 400 g of dispersant (i.e., 200 g of active compound) was added to the container. The amount of dispersant added was set to OFF. The resulting aqueous dispersant solution had a dispersant concentration of 0.234% by weight.

[0101] First, the system was degassed by setting the in-line disperser to 600 rpm. Dispersion was started and set to 3000 rpm. Within 54 seconds, 125 kg of UV shielding agent was added, and some foam formation was observed. The generated foam had coarse pores on its surface and a creamy, finely dispersed foam in the remaining liquid phase. The temperature inside the container rose to 21.5°C. The foam volume reached a maximum distance of 32 cm from the foam surface to the top edge of the container, and reached 36 cm after the completion of dispersion. The resulting first aqueous dispersion had a dispersant concentration of 0.0951 wt% and a UV shielding agent concentration of 59.5 wt%.

[0102] With the inline disperser set to 3000 rpm, the remaining dispersant (22.1 kg, i.e., 11.05 kg of the active compound) was added at maximum speed. The liquid temperature was 21.8°C, and the distance from the foam surface to the top edge of the container was 27 cm. A probe was collected (E).

[0103] Finally, the liquid was dispersed at 3000 rpm for 3 minutes (probe F, 26.4°C, distance 27 cm), and then dispersed for a further minute at 3600 rpm (probe F, 28.6°C, distance 28 cm).

[0104] Example IE2 of the present invention 85 kg of re-distilled water at a temperature of 20.7°C was filled into a container. The container was filled so that the distance from the liquid surface to the top edge of the container was 85.5 cm. 250 g of dispersant (i.e., 125 g of active compound) was added to the container. This is 1.1% by weight of the total weight of the dispersant to be added. The amount of dispersant added was set to OFF. The resulting aqueous dispersant solution had a dispersant concentration of 0.146% by weight.

[0105] First, the system was degassed by setting the inline disperser to 600 rpm. Dispersion was started and set to 3000 rpm. Within 54 seconds, 125 kg of UV shielding agent was added. No foaming was observed, but a slight increase in liquid viscosity was observed (it was still possible to process with the inline disperser). The temperature inside the container rose to 21.5°C. The liquid volume reached 36.5 cm from the liquid surface to the top edge of the container. A probe was taken (G). The resulting first aqueous dispersion had a dispersant concentration of 0.0595 wt% and a UV shielding agent concentration of 59.5 wt%.

[0106] With the inline disperser set to 3000 rpm, the remaining dispersant (22.25 kg, i.e., 11.125 kg of the active compound) was added at maximum speed (while the next dispersion step was already underway; see below), and the viscosity of the dispersion decreased significantly. The observed increase in liquid viscosity disappeared immediately.

[0107] Finally, the liquid was dispersed at 3000 rpm for 3 minutes (probe H, 26.9°C, distance 27 cm), and then dispersed for a further 1 minute at 3600 rpm (probe I, 29°C, distance 27 cm).

[0108] summary A comparison between Comparative Example 1 and the remaining examples shows that when the total weight of the dispersant required to form each dispersion is added, foam is formed rapidly and in large quantities, making further processing of the liquid / foam system impossible.

[0109] As shown in Comparative Example 2, even when the amount of dispersant per aqueous dispersant solution was reduced to less than 0.3% by weight, a large amount of foam formation occurred. When the amount of dispersant per aqueous dispersant solution was 0.234% by weight, foam formation was significantly reduced. When the amount of dispersant per aqueous dispersant solution was 0.146% by weight, foam was no longer detectable.

[0110] [Table 1]

Claims

1. A process for producing an aqueous dispersion of a water-insoluble solid organic UV shielding compound, a) A step of providing water, a dispersant, and a powder containing the water-insoluble solid organic UV shielding compound; b) A step of providing an aqueous dispersant solution, wherein the dispersant is added to water in an amount of 0.001 to 0.25% by weight relative to the total weight of the aqueous dispersant solution, and the amount of dispersant remaining is left; c) Using an in-line disperser, disperse the powder containing the water-insoluble solid organic UV shielding compound in the aqueous dispersant solution to obtain a first aqueous dispersion; d) The step of adding the remaining amount of the dispersant to the first aqueous dispersion to obtain a second aqueous dispersion; e) The process includes the step of further dispersing the second aqueous dispersion to obtain the aqueous dispersion of the water-insoluble solid organic UV shielding compound, A process in which the total amount of the dispersant is greater than 0.25% by weight relative to the total weight of the aqueous dispersant solution.

2. The process according to claim 1 or 2, wherein in step b), the dispersant is added in an amount less than 0.24% by weight, preferably less than 0.2% by weight, and most preferably less than 0.15% by weight, relative to the total weight of the aqueous dispersant solution.

3. The process according to claim 1 or 2, wherein the powder comprises the water-insoluble solid organic UV shielding compound.

4. The process according to any one of claims 1 to 3, wherein the powder is added in step c) at a rate in the range of 50 to 200 kg / min, preferably in the range of 100 to 150 kg / min, and most preferably in the range of 120 to 130 kg / min.

5. The process according to any one of claims 1 to 4, wherein the powder in step c) is a fluidized powder.

6. The process according to any one of claims 1 to 5, wherein step c) is performed using an inline disperser including a high-shear mixer.

7. The process according to claim 7, wherein in step c), the high-shear mixer is operated at a rotational speed in the range of 2000 to 4000 rpm, preferably 2500 to 3600 rpm, and most preferably 2900 to 3100 rpm.

8. The process according to any one of claims 1 to 7, wherein step e) is performed using an inline distributor.

9. The process according to claim 8, wherein the in-line disperser includes a high-shear mixer.

10. The process according to claim 9, wherein in step e), the high-shear mixer is operated at a rotational speed in the range of 2,500 to 4,500 rpm, preferably 3,000 to 4,000 rpm, and most preferably 3,500 to 3,700 rpm.

11. The process according to any one of claims 7 to 10, wherein steps c) and e) are performed in the same high-shear mixer.

12. The process according to any one of claims 1 to 11, wherein step d) is performed using an input pump.

13. The process according to any one of claims 1 to 12, wherein the weight ratio of water to the water-insoluble solid organic UV shielding compound in the aqueous dispersion is in the range of 0.4 to 1.0, preferably in the range of 0.6 to 0.8, and most preferably in the range of 0.74 to 0.

79.

14. The process according to any one of claims 1 to 13, wherein the water-insoluble solid organic UV shielding compound is 2,2'-methylenebis[6-(2H-1,2,3-benzotriazol-2-yl)-4-(2,4,4-trimethylpentan-2-yl)phenol] (MBBT) or 2,4,6-tris([1,1'-biphenyl]-4-yl)-1,3,5-triazine (TBPT).

15. The dispersant is an alkyl glucoside, preferably of the formula C ｎ H ２ｎ＋１ O(C ６ H １０ O ５ ) ｘ H (In the formula, n is an integer in the range of 8 to 16, and x is the glucoside portion (C ６ H １０ This is the average polymerization level of O), which is in the range of 1.4 to 1.

6. The process according to any one of claims 1 to 14, wherein the alkyl glucoside having, more preferably "INCI:decyl glucoside", most preferably the active compound in Plantacare® 2000 UP.

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