Color-changing microcapsule comprising pigment core and pressure breakable wall layer, and preparation method therefor

Abstract

According to the present invention, provided is a core-shell structured chromic microcapsule having a size of 50-1,500 m, comprising: a core comprising a colorant core (A) and an optional inner color layer (B); and a shell comprising a pressure sensitive destructible wall layer (C) encompassing the core, an optional outer color layer (D) and an optional outermost protective layer (E), wherein the colorant core allows a high content of a colorant to be contained, and the pressure sensitive destructible wall layer comprises carbon dioxide particles and a binder comprising one or more wall-forming materials and one or more lipid-base materials. The chromic microcapsule according to the present invention has high colorant content, has excellent storage durability, maintenance durability and color-hiding property of the inner color layers, is easily destroyed by pushing, rubbing, polishing or scrubbing with the hands or a tool (cotton fabric, sponge or paper) so as to express the color of the inner color layers, and can maintain stability for a long time even if being added into a carrier.

Claims

1. A color-changing microcapsule having an average diameter of 50 to 1500 m and having a core-shell structure, wherein the core consists of a pigment core (A) and the shell is a pressure breakable wall layer (C); wherein the pigment core (A) has an average diameter of 30 to 800 m and consists of: at least one colorant, and a binder for the core consisting of at least one wall forming material consisting of starch and at least one lipid-based material, wherein said lipid-based material is ceramide, lecithin or hydrogenated lecithin; and wherein the pressure breakable wall layer (C) has a thickness of 10 to 500 m and consists of: titanium dioxide particles, and a binder for the wall layer consisting of at least one wall forming material and at least one lipid based material.

2. The color-changing microcapsule according to claim 1, wherein the pressure breakable wall layer (C) consists of: 5 to 99% by weight of titanium dioxide particles; 0.1 to 30% by weight of at least one wall forming material; and 0.1 to 30% by weight of at least one lipid based material.

3. The color-changing microcapsule according to claim 1, wherein the average diameter is 100 to 800 m.

4. The color-changing microcapsule according to claim 1, wherein the wall-forming material is a hydrophilic polymer capable of forming a hydrogen bond with water or an alcohol compound.

5. The color-changing microcapsule according to claim 1, wherein the colorant is an inorganic pigment or an organic pigment.

6. The color-changing microparticle according to claim 5, wherein the colorant is at least one colorant selected from the group consisting of yellow iron oxide, red iron oxide, black iron oxide, chromium oxide green, chromium hydroxide green and ultramarine blue microcapsule.

7. The color-changing microcapsule according to claim 5, wherein the colorant is titanium dioxide.

8. A color-changing microcapsule having an average diameter of 50 to 1500 m and having a core-shell structure, wherein the core consists of a pigment core (A) and an inner color layer (B), and the shell is a pressure breakable wall layer (C); wherein the pigment core (A) has an average diameter of 30 to 700 m and consists of: at least one colorant for the core, and a binder for the core consisting of starch and at least one lipid-based material, wherein said lipid-based material is ceramide, lecithin or hydrogenated lecithin; wherein the one inner color layer (B) consists of: at least one colorant for the inner color layer, and a binder for the inner color layer consisting of at least one wall forming material and at least one lipid-based material; and wherein the pressure breakable wall layer (C) has a thickness of 10 to 500 m and consists of: titanium dioxide particles, and a binder for the wall layer consisting of at least one wall forming material and at least one lipid based material.

9. The color-changing microcapsule according to claim 8, wherein the colorant is an inorganic pigment or an organic pigment.

10. A color-changing microcapsule having an average diameter of 50 to 1500 m and having a core-shell structure, wherein the core consists of a pigment core (A) and the shell is a pressure breakable wall layer (C); wherein the shell consists of one or both of: one or more outer color layers (D), and an outermost protective layer (E); wherein the pigment core (A) has an average diameter of 30 to 800 m and consists of: at least one colorant, and a binder for the core consisting of at least one wall forming material consisting of starch and at least one lipid-based material, wherein said lipid-based material is ceramide, lecithin or hydrogenated lecithin; wherein the pressure breakable wall layer (C) has a thickness of 10 to 500 n and consists of: titanium dioxide particles, and a binder for the wall layer consisting of at least one wall forming material and at least one lipid based material; wherein said one or more outer color layers (D) surrounds the pressure breakable wall layer (C) and comprises: at least one colorant for an outer color layer, and a binder for the color layer consisting of at least one wall forming material and at least one lipid-based material; and wherein the outermost protective layer (E) surrounds the pressure breakable wall layer and consists of: at least one shell-forming polymer selected from the group consisting of shellac, polyacrylate, polymethacrylate, cellulose ether, cellulose ester, and polystyrene maleic anhydride copolymer and mixtures thereof.

11. The color-changing microcapsule according to claim 10, wherein the colorant is an inorganic pigment or an organic pigment.

12. A method for preparing the color-changing microcapsules according to claim 1, comprising steps of: (I) preparing the pigment core (A) containing the colorant and the binder for the core, and (II) coating the pigment core (A) prepared in the above step (I) with a solution prepared by dispersing or dissolving titanium dioxide particles and the binder for the wall layer in a solvent, in order to form the pressure breakable wall layer (C) after removing the solvent.

13. The method according to claim 12, wherein the solvent is selected from the group consisting of methylene chloride, methanol, and ethanol.

14. The method according to claim 12, wherein coating step (II) is carried out in a fluidized bed process.

15. A method for preparing the color-changing microcapsules according to claim 8, comprising the steps of: (I) preparing the pigment core (A) containing the colorant for the core and the binder for the core, (II) coating the pigment core (A) prepared in step (I) with a solution prepared by dispersing or dissolving the colorant for the inner color layer and the binder for the inner color layer in a solvent, in order to form particles with an inner color layer (B) after removing the solvent, and (III) coating the particles obtained in step (II) with a solution prepared by dispersing or dissolving titanium dioxide particles and the binder for the wall layer in a solvent, in order to form the pressure breakable wall layer (C) after removing the solvent.

16. The method according to claim 15, wherein coating steps (II) and (III) are carried out in a fluidized bed process.

17. The method according to claim 15, wherein the solvent in coating steps (II) and (III) is selected from the group consisting of methylene chloride, methanol, and ethanol.

18. A method for preparing the color-changing microcapsules according to claim 10, comprising the steps of: (I) preparing the pigment core (A) containing the colorant for the core and the binder for the core, (II) coating the pigment core (A) prepared in the above step (I) with a solution prepared by dispersing or dissolving titanium dioxide particles and the binder for the wall layer in a solvent, in order to form particles with pressure breakable wall layer (C) after removing the solvent, (III) coating the particles obtained in the step (II) with a solution prepared by dispersing or dissolving the colorant for the outer color layer and the binder for the outer color layer in a solvent, in order to form particles with outer color layer (D) after removing the solvent, and (IV) coating the particles obtained in the step (II) or (III) with a solution prepared by dispersing or dissolving the shell-forming polymer in a solvent, in order to form outermost protective layer (E) after removing the solvent.

19. The method according to claim 18, wherein coatings steps (II), (III) and (IV) are carried out in a fluidized bed process.

20. The method according to claim 18, wherein the solvent in coating steps (II), (III) and (IV) is selected from the group consisting of methylene chloride, methanol, and ethanol.

Description

BRIEF DESCRIPTION OF DRAWINGS

(1) FIG. 1 is a schematic diagram illustrating a typical structure of color-changing microcapsule of the present invention.

(2) FIG. 2 is a schematic diagram showing the core containing pigment core, inner color layer, and pressure breakable wall structure surrounding the core.

(3) FIG. 3 is a schematic diagram showing double layer structure of the pigment core and pressure breakable wall structure surrounding the core.

MODE OF INVENTION

(4) The first object of the present invention is to provide a color-changing microcapsule having an average diameter of 50 to 1500 m and a core-shell structure, wherein said core comprises a pigment core (A) and an optional inner color layer (B) The aforementioned shell comprises a pressure breakable wall layer (C), an optional outer color layer (I)) and an optional outermost protective layer (E).

(5) Specifically, the present invention provides a color-changing capsule having an average diameter range of 50 to 1000 m and having a core-shell structure, wherein said core comprises (A) a pigment core, and includes (C) a pressure breakable wall layer.

(6) (A) a pigment core having an average diameter of 30 to 700 m and comprising: more than one colorant, and a binder comprising at least one wall forming material and at east one lipid based material; and

(7) (C) a pressure-breakable wall layer g a thickness of 10 to 500 m and comprising: titanium dioxide particles, and a binder comprising at least one wall forming material and at least one lipid based material.

(8) According to a preferred embodiment of the present invention, said core may comprise an inner color layer (B) as follows:

(9) (A) a pigment core having an average diameter of 30 to 700 m and comprising: at least one colorant, and a binder comprising at least one wall forming material and at least one lipid based material;

(10) (B) any inner color layer comprising: at least one colorant, and a binder comprising at least one wall forming material and at east one lipid based material.

(11) According to another preferred embodiment of the present invention, the aforementioned shell may comprise one or both of the following outer color layer (D) and outermost protective layer (E)

(12) (D) Any outer color layer surrounding the pressure-breakable wall layer and comprising: one or more colorant, and a binder comprising at least one wall forming material and at least one lipid-based material; and

(13) (E) any outermost protective layer surrounding the pressure-breakable wall layer or the outer color layer and comprising: a shell-forming polymer selected from the group consisting of shell rock, polyacrylates, polymethacrylates, cellulose ethers, cellulose ester polystyrene-maleic anhydride copolymers and mixtures thereof.

(14) A second object of the present invention is to provide a process for producing color-changing microcapsules comprising a pressure-breakable wall layer comprising the steps of:

(15) (a) preparing a pigment core (A) containing a colorant and a binder,

(16) (b) optionally, coating the pigment core (A) particles with a solution in which a colorant and a binder are dispersed or dissolved to form an inner color layer (B),

(17) (c) coating the particles obtained in the step (b) with a solution in which titanium dioxide particles and a binder are dispersed or dissolved to form a pressure breakable wall layer (C),

(18) (d) optionally, coating the particles obtained in the step (c) with a solution dispersed or dissolved in the same or different colorants and binders as those used in steps (a) and (b) to form an outer color layer, and

(19) (e) optionally, coating the particles obtained in steps (c) and (d) of with a solution in which a shell-forming polymer is dispersed or dissolved to form an outermost protective layer (D),

(20) wherein the binder described above comprises a wall-forming material and a lipid-based material, wherein the wall-forming material and the lipid-based material described above are the same or different from each other.

(21) In one preferred embodiment according to the present invention, e step (b) is included.

(22) In one particular embodiment, the method of manufacture of the present invention comprises step (b) is included.

(23) In another particular embodiment, the process of the present invention comprises one or both of steps (c) and (e).

(24) Each step (a), (b), (c), (d) and (e) is carried out by a fluidized bed process or a fluidized bed coating process.

(25) In one preferred embodiment, the solution used in this step can be water, preferably purified water, or a low boiling organic solvent such as methylene chloride, methanol or ethanol as a solvent.

(26) In below, the present invention is explained in details with reference to drawings.

(27) In the present invention, the color-changing microcapsule having a core comprising a colorant, and a shell comprising a pressure-breakable wall layer, at least one inner color layer, an optional outer color layer and an optional outmost layer.

(28) FIG. 1 is a schematic diagram illustrating the structure of a color-changing microcapsule according to the present invention, wherein A represents a pigment core, B represents an inner color layer, C represents a pressure-breakable wall layer, D represents an outer color layer, and D is an outermost protective layer.

(29) Although the color-changing microcapsule illustrated in FIG. 1 has a particle size of 100350 m, the color-changing microcapsule according to the present invention a particle size is generally about 50 m or more, specifically 70 m or more, particularly 80 m or more, preferably 90 m or more, more preferably 100 m or more, and about 1500 m or less, specifically 1200 m or less, particularly 1000 m or less, preferably 800 m or less, more preferably 700 m or less.

(30) In addition, the color-changing microcapsule according to the present invention has a mean particle size of about 14280 mesh (around 1400 m50) particularly about 24150 mesh (around 800 m100 m).

(31) 1. Pigment Core

(32) In the present invention, the core of the microcapsules comprises a pigment core and a pigment core comprising at least one colorant and at least one binder comprising a wall-forming material and a lipid-based material. In pigment core, pigments can be understood to mean all kinds of colorants such as pigments, dyes and so on.

(33) The pigment core may be prepared by pulverizing, pelletizing, pulverizing, granulating, encapsulating, etc. in the form of particles, powders, granules, microspheres or microcapsules, for example, one or more coloring agents, a spray drying or fluidized bed process of a solution comprising at least one wall-forming material and at least one lipid-based material.

(34) The size of the pigment core is not particularly limited and can be suitably selected according to the final desired color-changing microcapsule. For example, the average diameter standard of the pigment core is generally about 20 m or more, particularly 30 m or more, specifically 40 m or more, preferably 50 m or more, more preferably 60 m or more, and about 600 m or less, specifically not more than 400 m, preferably not more than 300 m, and more preferably not more than 200 m.

(35) The radius of the pigment core is 50% or more, particularly 60% or more, specifically 70% or more, preferably 80% or more, more preferably 90% or more, based on the total radius of the microcapsule. Alternatively, the gross weight of the pigment core of the microcapsule is at least 30%, specifically 40% or less, especially 50% or less, preferably 60% or less, more preferably 70% or less, most preferably 80% or less, based on the total weight of the microcapsules. Therefore, the microcapsule of the present invention has a high loading amount of the colorant in one particle.

(36) For pigment core, the binder may be used in an amount that colorant will not fall apart or separated from the coating layer during the coating process and/or after the removal of solvent, typically from 1 to 30% by weight, in particular from 225% by weight, preferably 320% by weight, and more preferably 515% by weight.

(37) The colorant is a main component of the pigment core and can therefore be used in an amount of 70% by weight or more, particularly 75% by weight or more, preferably 80% by weight or more, more preferably 85% by weight or more, based on the total weight of the pigment core.

(38) The pigment core may further have one or more inner color layers surrounding the pigment core. The inner color layer may comprise, for example, a first inner color layer, a second inner color layer and a third inner color layer, wherein the colorant and binder contained in each inner color layer may be the same or different from each other. In a preferred embodiment, the core may comprise one or two inner color layers, preferably one inner color layer.

(39) When the core has a pigment core and an inner color layer, the pigment core is formed by granulation of a solution for a pigment core comprising a colorant and a binder, and the inner color layer is a solution for an inner color layer containing a colorant and a binder to coat the pigment core. The above-described coating can be carried out by a fluidized bed coating process.

(40) The content of the inner color layer may be 2080% by weight, specifically 3070% by weight, and preferably 4060% by weight based on the total amount of the core.

(41) 2. Inner Color Layer

(42) In the present invention, the pigment core may further have one or more inner color layers and said an inner color layer can be formed by coating the pigment core with a solution having a colorant and a binder, for example, by a fluidized bed coating process.

(43) The core can comprise one or more inner color layer including, for example, first inner color layer, second inner color layer and third inner color layer, etc., wherein the colorants and binders contained in each inner color layers are the same or different from each other. When the core comprises two or more inner color layers, a first inner color layer can be formed by coating the core-seed with a solution for first inner color layer comprising a first colorant and a first binder, a second inner color layer can be formed by coating the first inner color layer with a solution for second inner color layer comprising a second colorant and a second binder. Each coating process can be performed by a fluidized bed coating process. Each inner color layer can be circumferentially extended by centering the core-seed.

(44) The binder can be used in an amount that colorant will not fall apart or separate from the layer during the coating process and/or after the removal of solvent, and generally can be used in an amount selected from 0.5-15% by weight, preferably 110% by weight, particularly 1.59% by weight, and more particularly 28% by weight in the terms of total weight of inner color layer.

(45) The colorant is the main ingredient of inner color layer, and therefore, is used, in terms of total weight of inner color layer, in an amount of at least 40% by weight, preferably at least 75% by weight and more preferably at least 95% by weight of the inner color layer.

(46) The inner color layer may be included in an amount of 2080% by weight, preferably 3070% by weight and especially 4060% by weight, based on the total weight of the core.

(47) 3. Pressure-Breakable Wall Layer or Titanium Dioxide Particle Layer

(48) The color-changing microcapsule of the present invention has a pressure-breakable wall layer or pressure-breakable titanium dioxide particle layer, wherein the titanium dioxide particles are discontinuously dispersed in the layer and linked to each other by a binder.

(49) In the context of the present invention, the term pressure-breakable or pressure-friable means that a rupture can be easily made by pressing, rubbing, wiping and/or scrubbing with hand or an implement such as cloths, sponge or paper.

(50) In the present invention, a pressure-breakable titanium dioxide particles layer can comprise particles of titanium dioxide and a binder, and said binder can comprise a wall-forming material and a lipid based material.

(51) In the pressure-breakable wall layer of the present invention, it is believed that the titanium dioxide particles lodged in the wall-forming materials will break the pressure-breakable wall layer in an irreversible manner and facilitate or increase the disintegration or dissolution of said wall layer. Further, it is also estimated that titanium dioxide particles do a critical role for the strength, the durability, the pressure-breakability, and the after-feeling of the wall layer.

(52) The titanium dioxide particle layer, of which thickness can vary depending on the amount of titanium dioxide used and/or the type of binder, may have a thickness of usually 10 m or more, preferably 20 m or more, more preferably 30 m or more, particularly 40 m or more, commonly 500 m or less, preferably 400 m or less, more preferably 300 m or less, particularly 200 m or less.

(53) Alternatively, the titanium dioxide particle layer can have a content of 2555% by weight, preferably 3050% by weight, particularly 3545% by weight in term of the total weight of microcapsule.

(54) In the present invention the mean diameter or size of titanium dioxide particles is not specifically limited but has a mean diameter of usually 10 nm20 m, preferably 50 nm10 m, more preferably 100 nm5 m, and particularly 150 nm5 m. The mean diameter or size of less than 10 nm of titanium dioxide particles may result to a decrease in the pressure-breakable ability, and the mean diameter of more than 20 m may make difficult the formation of titanium dioxide particles layer. Titanium dioxide particles having a first particle size of less than the above range but having a second particle size falling down the above particle size range can be applicable in the present invention.

(55) The content of titanium dioxide particles in the pressure-breakable wall layer can be selected from usually 4099% by weight, preferably 5095% by weight, more preferably 6090% by weight, particularly 7095% by weight, in terms of total weight of the pressure-breakable wall layer.

(56) 4. Outer Color Layer

(57) The color-changing microcapsule additionally comprises an optional outer color layer onto the pressure-breakable titanium dioxide particles layer. The outer color layer can be formed by coating the titanium dioxide particles layer with a solution having a colorant and a binder, for example, by the fluidized bed process.

(58) The colorant and binder used in the outer color layer can be the same or different from those used in the inner color layer.

(59) In general, the outer color layer is given to impart a visual color different from white color issued from the titanium dioxide particle layer and/or the color of inner color layer. Therefore, a colorant in the outer color layer can be used in an amount that does not disturb the color developed by the inner color layer when the microcapsules are applied to skins.

(60) The content of an outer color layer can be selected, in terms of the total weight of core, from 160% by weight, preferably 250% by weight, more preferably 340% by weight, particularly 430% by weight. However, the content of a colorant in the outer color layer may be selected, in terms of total weight of colorants in the inner color layer, from 0.015% by weight, preferably 0.054.5% by weight, more preferably 0.14% by weight, particularly 0.53.5% by weight.

(61) The content of a colorant in an outer color layer may be additionally increased if the color of the outer color layer would not disturb the color of the inner color layer. A person skilled in the art can choose the color and content of a colorant in an outer color layer in an appropriate manner by considering the color and content of colorants contained in inner color layers and the desired color to be finally developed.

(62) 5. Outermost Protective Layer

(63) Microcapsule of the present invention can comprise a protective outermost protective layer onto a pressure-breakable wall layer or an additional outer color layer to protect the microcapsule against moisture in the air during storage or to ensure a long period stability of the microcapsule in a cosmetic carrier such as water, alcohol, etc.

(64) The outermost protective layer can be made from at least one selected from the group consisting of shellac, polyacrylate, polymethacrylate, cellulose ether, cellulose ester and polystyrene-maleic anhydride copolymer.

(65) The content of said outermost protective layer is selected, in terms of total weight of microcapsule, from 0.120.0% by weight and preferably 0.515% by weight. When the content of the outermost shell is less than 0.1% by weight, the shell coating may be meaningless, and when it is more than 20.0% by weight, a feeling of foreign substances may be caused.

(66) The thickness of the outermost protective layer is usually at least 5 m preferably 10 m or more, more preferably 15 m or more, especially 20 m or more, usually at most 200 m, preferably 150 m or less, more preferably 120 m or less, but it is not strictly limited.

(67) 6. Colorant or Coloring Agent

(68) In the present invention, colorant include any synthetic or natural, or organic or inorganic pigments, dyes or lakes, and any colorants approved for use in cosmetics by CTFA and the FDA used in cosmetic formulations.

(69) In the present invention, the colorant may be water-soluble or water-dispersible, or oil-soluble or oil-dispersible or with limited solubility in water.

(70) In the present invention, thus the term colorant refers to organic pigments such as dyes selected from any of the well-known FD&C or D&C dyes, inorganic pigments such as metal oxides, or lakes such as the ones based on cochineal carmine, barium, strontium, calcium or aluminum and any combination (blend) thereof.

(71) In the present invention, the following colorants can be mentioned:

(72) carmin of cochenille;

(73) organic pigments of azoiques, anthraquinoniques, indigoides, xantheniques, pyreniques, quinoliniques, de triphenylmethane, de fluorane colorants; and

(74) of acid colorants such as azoiques, anthraquinoniques, indigoides, xantheniques, pyreniques, quinoliniques, de triphenylmethane, de fluorane colorants, insoluble salts of sodium, potassium, calcium, baryum, aluminum, zirconium, strontium, titanium, these colorants may include at least one carboxylic or sulfonic acid group.

(75) As to particular examples of organic pigments, those having the following trade names can be mentioned:

(76) D&C Blue n 4, D&C Brown n 1, D&C Green n 5,

(77) D&C Green n 6, D&C Orange n 4, D&C Orange n 5, D&C Orange n 10,

(78) D&C Orange n 11, D&C Red n 6, D&C Red n 7, D&C Red n 17, D&C Red n 21, D&C Red n 22, D&C Red n 27, D&C Red n 28, D&C Red n 30, D&C Red n 31, D&C Red n 33, D&C Red n 34, D&C Red n 36, D&C Violet n 2, D&C Yellow n 7, D&C Yellow n 8, D&C Yellow n 10, D&C Yellow n 11, FD&C Blue n 1, and

(79) FD&C Green n 3, FD&C Red n 40, FD&C Yellow n 5, FD&C Yellow n 6.

(80) In preferred embodiments, the colorant is an inorganic pigment, more preferably a metal oxide.

(81) Advantageously, the colorants of the multi-layer microcapsules are primary metal oxides selected from iron oxides, titanium dioxide, aluminum oxide, zirconium oxides, cobalt oxides, cerium oxides, nickel oxides, tin oxide or zinc oxide, or composite oxides, more preferably an iron oxide selected from red iron oxide, yellow iron oxide or black iron oxide, or a mixture thereof.

(82) A person skilled in the art knows how to choose colorants and combinations of colorants to produce a desired color effect or color change.

(83) In preferred embodiments, if white is the desired color to be developed by the color-changing microcapsule, a white colorant such as titanium dioxide can be chosen as a colorant for inner color layer. In such case, the inner color layer may be substantially the same or similar to the titanium dioxide particles layer, and thus, it can be understood that a titanium dioxide particle layer can simultaneously plays both roles of an inner color layer and pressure-breakable wall layer.

(84) Meanwhile, a color may be achieved from one colorant alone, but most colors can be generally achieved from mixed colorants by changing the composition of colorants. Therefore, in the context of the present invention, the term a (the) colorant may cover both of one colorant and a mixture of colorants, if there is no specific restriction.

(85) In a preferred embodiment, the above-described core and pressure breakable wall layer may be made at least in part as metal oxides, preferably as titanium dioxide for core iron oxide and pressure breakable wall layer.

(86) 7. Binder

(87) In general, it is difficult to form a coating layer by using only colorant component or particles without using any binder. Further, even if a coating layer without a binder is formed with difficulty, such coating layer may be easily damaged or ruptured or any components or particles may be easily removed from the coating layer. Therefore, a binder is commonly employed in order to proceed the coating process and to improve the durability of coating layer.

(88) In the present invention, the binder comprises both of a wall-forming polymer as a wall-forming material and a lipid-base material as coating base.

(89) In general, the coating base refers to a hydrophilic coating base, a hydrophobic coating base, or lipid-based coating base. Since the hydrophilic coating base may be extracted together with colorant into cosmetic carrier and the hydrophobic coating base may give a feeling of foreign substances due to its tow strong film property, it is preferable to employ a lipid-base coating base.

(90) According to a particular embodiment of this invention, such lipid based material may have amphiphilic properties, that is to say having an apolar part and a polar part. Such lipid-based material can include at least one or several C.sub.12-C.sub.22 fatty acids chain such as selected from stearic acid, palmitic acid, oleic acid, linoleic acid, linolenic acid, etc. and mixtures thereof. Preferably these fatty acids chains are hydrogenated. Eventually, these fatty acid chains may be the apolar part of a lipid-based material. According to a particular embodiment of the invention, said lipid-based materials can be selected form the group consisting of a phospholipid such as phosphatidylcholine, phosphatidylethanolamine, phosphatidic acid or phosphatidylserine, a sphingolipid such as sphingosine-1-phosphate or sphingomyelin and ceramide, preferably ceramide or lecithin which is a phospholipid mixture, particularly hydrogenated lecithin.

(91) One of the advantages of such lipid-based materials is that they can also act as wall-forming materials. Thus, in a particular variation of the present invention, the binder comprised with lipid-based materials alone does not depart from the scope of the present invention, with no or little use of a wall-forming polymer such as a hydrophilic polymer.

(92) The amount of the lipid-based material to be used can be determined by considering the type and amount of other components such as coloring agent and or titanium dioxide particles as well as wall-forming materials. However, in general, the content of the lipid-based material is in the range of 0.130% by weight, in particular 0.225% by weight, preferably 0.320% by weight, and more preferably, may be selected from 0.420% by weight. If the content of the lipid base material is 0.1% by weight or more, the durability may be lowered and the durability and stability of processing and storage may deteriorate.

(93) In the present invention, the wall-forming polymer is selected from hydrophilic polymers. The term hydrophilic polymers means a polymer which can form hydrogen bond with water or alcohol compounds (especially elected from lower alcohols, glycol and polyol), particularly those having OH, NH and SH bonds in the molecule.

(94) Said hydrophilic polymer can be selected from the following polymers or mixture thereof:

(95) acrylic or methacrylic acid homopolymers or copolymers or salts and esters thereof and in particular the products sold under the names Versicol F or Versicol K by the company Allied Colloid, Ultrahold 8 by the company Ciba-Geigy, and polyacrylic acids of Synthalen K type, and salts, of polyacrylic acids, especially sodium salts (corresponding to the INCI name sodium acrylate copolymer) and more particularly a crosslinked sodium polyacrylate (corresponding to the INCI name sodium acrylate copolymer (and) caprylic/capric triglycerides) (sold under the name Luvigel EM by the company);

(96) copolymers of acrylic acid and of acrylamide (sold in the form of the sodium salt thereof under the names Reten by the company Hercules), the sodium polymethacrylate (sold under the name Darvan No. 7 by the company Vanderbilt), and the sodium salts of polyhydroxycarboxylic acids (sold under the name Hydagen F by the company Henkel);

(97) polyacrylic acid/alkyl acrylate copolymers, preferably modified or unmodified carboxyvinyl polymers; the copolymers most particularly preferred according to the present invention are acrylate/C.sub.10-C.sub.30-alkylacrylate copolymers (INCI name: Acrylates/C.sub.10-30 Alkylacrylate Cross polymer) such as the products sold by the company Lubrizol under the tradenames Pemulen TR1, Pemulen TR2, Carbopol 1382 and Carbopol ETD2020, and even more preferentially Pemulen TR-2;

(98) alkylacrylic/alkylmethacrylic acid copolymers and their derivatives notably their salts and their esters, such as the copolymer of ethyl acrylate, methyl methacrylate and low content of methacrylic acid ester with quaternary ammonium groups (provided under the tradename of EUDRAGIT RSPO from Evonik Degussa);

(99) AMPS (polyacrylamidomethylpropanesulfonic acid partially neutralized with aqueous ammonia and highly crosslinked) (sold by the company Clamant);

(100) AMPS/acrylamide copolymers such as the products Sepigel or Simulgel sold by the company SEPPIC, especially a copolymer of INCI name Polyacrylamide (and) C13-14 Isoparaffin (and) Laureth-7;

(101) polyoxyethylenated AMPS/alkyl methacrylate copolymers (crosslinked or non-crosslinked) of the type such as Aristoflex HMS sold by the company Clamant;

(102) anionic, cationic, amphoteric or nonionic chitin or chitosan polymers;

(103) cellulose polymers and derivatives, preferably other than alkylcellulose, chosen from hydroxyethylcellulose, hydroxypropylcellulose, hydroxymethylcellulose, ethylhydroxyethylcellulose and carboxymethylcellulose, and also quaternized cellulose derivatives; in a preferred embodiment, the cellulose polymers is a carboxymethylcellulose;

(104) Starch polymers and derivatives, eventually modified; in a preferred embodiment, the starch polymer is a natural starch;

(105) vinyl polymers, for instance polyvinylpyrrolidones, copolymers of methyl vinyl ether and of malic anhydride, the copolymer of vinyl acetate and of crotonic acid, copolymers of vinylpyrrolidone and of vinyl acetate; copolymers of vinylpyrrolidone and of caprolactam; polyvinyl alcohol,

(106) modified polymers of natural origin, such as galactomannans and derivatives thereof, such as konjac gum, gellan gum, locust bean gum, fenugreek gum, karaya gum, gum tragacanth, gum arabic, acacia gum, guar gum, hydroxypropyl guar, hydroxypropyl guar modified with sodium methylcarboxylate groups (Jaguar XC 97-1, Rhodia), hydroxypropyltrimethylammonium guar chloride, and xanthan derivatives;

(107) alginates and carrageenans;

(108) glycoaminoglycans, hyaluronic acid and derivatives thereof; and

(109) mucopolysaccharides such as hyaluronic acid and chondroitin sulfates, and mixtures thereof.

(110) Preferably, the hydrophilic polymers according to the present invention can be selected from the group consisting of polysaccharides and its derivatives, homopolymers or copolymers of acrylic or methacrylic acid or salts and esters thereof, and their mixture. Said polysaccharides and derivatives can be selected from chitosan polymers, chitin polymers, cellulose polymers, starch polymers, galactomannans, alginates, carrageenans, mucopolysaccharides, and their derivatives, and the mixture thereof.

(111) In one preferred embodiment, the hydrophilic polymers can be selected from the group consisting of corn starch, (meth)acrylate or (alkyl)(meth)acrylate and its salts or copolymer of ester derivatives, particularly polymethyl methacrylate, cellulose or its derivatives such as carboxymethylcellulose (CMC), cellulose ester and ether and aminocellulose, and mixture thereof.

(112) Preferred homo- and/or co-polymer of methacrylic acid and/or methacrylic acid ester are those wherein the copolymer of methyl methacrylate and ethyl acrylate has a molecule weight from 750 to 850 kDa.

(113) The hydrophilic polymer(s) used as a wall-forming material in the present invention are not cross-linked.

(114) The amount of polymer or wall-forming polymer used can be determined by considering the type and amount of the colorant, the titanium dioxide particles and or the lipid-based material. In general, the content of the polymer or wall-forming polymer is in the range of 0.130% by weight, in particular 0.225% by weight, preferably 0.320% by weight, and more preferably, may be selected from 0.420% by weight.

(115) 8. Color-Changing Microcapsules

(116) The term microcapsule, as used herein, refers to a substantially spherical microcapsule containing at least one layered coating entrapping at least one colorant and surrounding a core chemically different from the coating.

(117) The term multi-layer microcapsule refers to a microcapsule consisting of an inner core surrounded by a coating based on one or more inner layer(s) and one outer layer. The one or more inner layer(s) forming the multi-layer coating of the multi-layer microcapsule and the single layer of the outer core microcapsule may be formed of the same or different wall-forming organic compound(s).

(118) According to the present invention, the term color-changing microcapsule or color-changing beads means a microcapsule or bead wherein the color before application is different from the color after application, this difference being visible to the naked eyes. In the present invention, a pressure-friable or pressure-breakable wall layer is provided, which can be easily ruptured by pressing, rubbing, wiping and/or scrubbing with hand or an implement such as cloths, sponge or paper.

(119) According to the present invention, at least 60%, especially at least 70%, preferably at least 80%, and more preferably at least 90% of the color changing microcapsule particles are obtained by pressing the microcapsules with a hand or tool within 1 minute, especially within 140 seconds, preferably within 130 seconds, more preferably within 120 seconds, of the coloring agents of the core after being polished and/or rubbed.

(120) 9. Fluidized-Bed Coating Process

(121) In a preferred embodiment, the microcapsules can be produced by a fluidized bed process or a similar process. While the granulation by the spray drying method induces matrix particles with granular particles by particle agglomeration or randomly dispersed core material in the polymer medium, the specificity of the fluidized bed process is to concentrate one core or one or more outer layers concentrically, then it is possible to derive an actual capsule having a core shell structure enclosed therein.

(122) Fluid bed process is disclosed by example in Fluid-Bed Coating, Teunou, E.; Poncelet, 2005, D. Food Science and Technology (BocaRaton, Fla., United States), Volume 146 Issue Encapsulated and Powdered Foods, Pages 197-212.

(123) A man skilled in the art knows how to adjust air quantity, liquid quantity and temperature allowing reproducing a microcapsule according to the invention.

(124) Preferably a fluid bed process implemented includes Wrster process and/or tangential spray process. Such process allows, contrary to pelletizing process, to conduct to spherical capsules with core surrounded by one or more circumferential layers.

(125) In the present invention, by combining two or more compounds (ex: wall forming material and lipid-based material) in the microcapsule of different hardness and/or water solubility, it is possible to adjust the time required for colorant-encapsulated microcapsules to break down on the skin so that, by varying the method or intensity of application onto the skin, it is possible to adjust the preferred coloration or gradation pattern.

(126) Thus, according to a preferred embodiment, the multi-layers coating contains at least starch as wall forming material with at least one lipid-based material and preferably lecithin.

(127) According to an advantageous embodiment, the microcapsules according to the invention include at least one monosaccharide or its derivatives and at least one polysaccharide or its derivatives. According to a preferred embodiment, the microcapsules include a core comprising a monosaccharide polyols preferably chosen from mannitol, erythritol, xylitol, sorbitol and a polysaccharides including ose (at least D-glucose unit).

(128) According to a preferred embodiment, the microcapsules include three or more colorants in different layers.

(129) According to a preferred embodiment, the microcapsules additionally includes lipid-based material chosen from phospholipids, advantageously selected from phosphoacylglycerol and in particular lecithin.

(130) In the present invention, an organic solvent may be employed in the preparation of coating solution used in the fluidized bed coating process. The organic solvent which can be used in the present invention is not specifically restricted but preferably includes methylene chloride, methanol, ethanol, and mixture thereof. It is possible to employ any organic solvent if it can dissolve or disperse the polymers and/or lipid-based materials, has a boiling point less than that water, and has a low residual toxicity.

(131) The present invention will be further explained by the examples, but is not restricted by them. Unless otherwise specified in the examples, % and ratio are based on weight, lecithin means hydrogenated lecithin, and the name of the substance or substance is given when the name of the contained substance or substance is clear.

Example 1

(132) Hydrogenated lecithin (Lipoid S 100-3), and cornstarch were added to a mixed solvent of methylene chloride and ethanol (weight ratio=1:1) and completely dissolved at about 40 C. A mixed colorant of yellow iron oxide, red iron oxide and black iron oxide was added to the resulting reaction mixture and dispersed well with a homogenizer to prepare a color layer coating liquid.

(133) The mixed colorant particles were introduced into a fluidized bed coating systemGlatt GPOG 1, bottom spray) using as a pigment core, and coated with the coloring layer coating liquid to obtain pigment core particles coated with the coloring layer.

(134) Then, hydrogenated lecithin, PMMA (polymethylmethacrylate) and cornstarch paste were added to a mixed solvent of methylene chloride and ethanol (weight ratio=1:1) and dissolved at 40 C. to the resulting reaction mixture was added granular titanium dioxide and dispersed well with a homogenizer to prepare a titanium dioxide particle coating solution.

(135) The pigment core particles coated with the coloring layer were coated with the resultant titanium dioxide particle coating solution to obtain color-changing microcapsule particles having a pigment core coloring layer titanium dioxide particle layer.

(136) By using the ingredients and contents described in the below table 1, a color-changing microcapsule as shown in FIG. 2a is prepared: Mixed Pigment (Inner color layer): Yellow:Red:Black=55.18:34.48:10.34 Layer Composition: Core (Pigment coreinner color layer)TiO.sub.2 particles layer Size: 74250 m (60200 mesh) (>99.0%) Bulk Density: 1.23 g/ml.

(137) TABLE-US-00001 TABLE 1 Core Pigment Core Mixed pigment 20.0% Inner Color Mixed pigment 27.8% Layer Lecithin 0.2% Corn starch 2.0% binder Shell TiO.sub.2 Particle Titanium dioxide 44.5% Layer Lecithin 2.5% PMMA 1.5% Corn starch 1.0% binder

Example 2

(138) By using fluidized bed coating process described in example 1 with the ingredients and contents described in the below table 2 a color-changing microcapsule having 3 layers as shown in FIG. 2a is prepared: Mixed Pigment (Inner color layer): Yellow:Red:Black=60.1:28.8:11.1 Layer Composition: Core (Pigment coreInner color layer)TiO.sub.2 particles layer Size: 74250 m (60200 mesh) (>99.0%) Bulk Density: 1.32 g/ml.

(139) TABLE-US-00002 TABLE 2 Core (A-1) Pigment Mixed pigment 20.0% Core Mixed pigment 27.8% (A-2) Inner Lecithin 0.2% Color Layer Corn starch 2.0% binder Shell (B) TiO.sub.2 Titanium dioxide 44.5% Particle Lecithin 2.5% Layer PMMA 1.5% Corn starch 1.0% binder

Example 3

(140) By using fluidized bed coating process described in example 1 with the ingredients and contents described in the below table 3 a color-changing microcapsule having 3 layers as shown in FIG. 2a is prepared: Mixed Pigment (Inner color:Brown):(yellow(c33-9001):red(c33-8001):black(c33-7001)=49.2:39.9:10.9) Layer Composition: Core (Pigment coreInner color layer)TiO.sub.2 particles layer Size: 74250 m (60200 mesh) (>97.9%) Bulk Density: 1.12 g/ml.

(141) TABLE-US-00003 TABLE 3 Core Pigment core Mixed pigment 20.0% Inner Color Mixed pigment 27.8% Layer Lecithin 0.2% Corn starch binder 2.0% Shell TiO.sub.2 Particle Titanium dioxide 44.5% Layer Lecithin 2.5% PMMA 1.5% Corn starch binder 1.0%

Example 4

(142) By using the ingredients and contents described in the below table 4, a color-changing microcapsule having 2 layers as shown in FIG. 3 is prepared: Inner color: Brown Size: 62200 m (75250 mesh) (>99.8%) Bulk Density: 1.33 g/ml.

(143) TABLE-US-00004 TABLE 4 Core (A) Pigment Core *Pigment Capsule 57.40% Shell (B) TiO.sub.2 Particle Layer Titanium dioxide 38.00% PMMA 2.30% Hydrogenated Lecithin 2.30% *Pigment capsule: Pigment Capsule comprises mixed Pigment 74.38%, Mannitol 22.32%, Corn Starch 2.65%, Hydrogenated Lecithin 0.65%, and the mixed Pigment comprises Yellow Iron Oxide (SunPURO) 49.2%, Red Iron Oxide(SunPURO) 39.9% and Black Iron Oxide (SunPURO) 10.9%.

Example 5

(144) By using the ingredients and contents described in the below table 5, a color-changing microcapsule having 2 layers as shown in FIG. 3 is prepared: Inner color: Brown Mixed pigment: TiO2=50:45 Size: 62200 m (75250 mesh) (>98.15%) Bulk Density: 1.33 g/ml.

(145) TABLE-US-00005 TABLE 5 Core (A) Pigment Core *Pigment Capsule 56.5% Shell (B) TiO.sub.2 Particle Layer Titanium dioxide 39.15% PMMA 2.35% Hydrogenated Lecithin 2.00% *Pigment capsule: Pigment Capsule comprises mixed Pigment 74.31%, Mannitol 22.29%, Corn Starch 2.66%, Hydrogenated Lecithin 0.74%, and the mixed Pigment comprises Yellow Iron Oxide (SunPURO) 55.18%, Red Iron Oxide (SunPURO) 34.48% and Black Iron Oxide (SunPURO) 10.34%.

INDUSTRIAL APPLICABILITY

(146) The color-changing microcapsules according to the present invention have a high loading amount of colorant in a particle, have a high durability during storage and handling and a high masking ability of inner color as well as can maintain a long period stability.