Compositions: coating or plastic – Materials or ingredients – Pigment – filler – or aggregate compositions – e.g. – stone,...
Reexamination Certificate
2000-07-31
2003-01-28
Bell, Mark L. (Department: 1755)
Compositions: coating or plastic
Materials or ingredients
Pigment, filler, or aggregate compositions, e.g., stone,...
C106S424000, C106S463000, C106S464000, C106S465000, C424S063000, C424S069000
Reexamination Certificate
active
06511536
ABSTRACT:
The present invention relates to a novel pigment in thin flakes coated with calcium carbonate. More particularly, it relates to a novel pigment of flakes coated with calcium carbonate which exhibits appropriate adhesion to skin, low luster and excellent wrinkle-hiding effect, prevention of unpleasant feel due to perspiration and sebum, absorption which are particularly useful in the cosmetic field.
BACKGROUND OF THE INVENTION
Up to now, in the cosmetic field, inorganic powders such as natural mica, synthetic mica, talc, sericite and silica flakes have been used as extenders. However, they are not sufficient in terms of the functions desired in cosmetics such as adhesion to skin, spread, wrinkle-hiding effect, etc. For example, when natural mica is used as an extender, luster results and adhesion to the skin is strong, both rendering it unsatisfactory. Talc is not preferred since it may contain asbestos therein. In addition, it provides excessive sliding and its “settlement” ( i.e., the extent when applied to the skin, of satisfactory sliding in the initial stage and setting in the final stage), recently desired in cosmetics, is poor.
For example, in the case of an oil foundation containing mica, there are problems in view of unnatural high luster and of spread. In the case of mica which is coated with fine particles of titanium oxide, as compared with mica, both adhesion and spreadability are improved and better feel on skin is achieved. However, reflection of light at the layer coated with titanium oxide is high and, therefore, when the compounding amount in the foundation is increased, luster becomes high. In addition, when it is applied to the skin, luster, a reduction in masking property, degeneration of the make-up, etc. result due to perspiration and sebum secretion and they may cause a reduction of good maintenance of the make-up. Accordingly, its compounding amount with cosmetics has to be limited.
Therefore, there has been a demand especially in the cosmetic field for development of extenders where luster is appropriately controlled and spreadability and adhesion are good.
SUMMARY OF THE INVENTION
The inventors have carried out an intensive investigation for solving the above problems concerning extenders for cosmetics and have found that, when an extender having calcium carbonate coated on the surface of a flaky substrate is compounded with cosmetics such as foundation, both appropriate adhesion and spread can be achieved. Further, such extender does not express excessive luster as with mica but has a good characteristic as an extender for cosmetics where the luster is suppressed.
Thus, the present invention provides a novel pigment of thin flakes coated with fine particles of calcium carbonate, a method for manufacturing the same and cosmetics, plastic compositions, paint compositions and ink compositions containing the pigment. Preferred, but not limiting embodiments of the invention include the following (1)-(9).
(1) A pigment of thin flake substrate coated with calcium carbonate where fine particles of calcium carbonate are coated on the surface of the flake substrate;
(2) The pigment in thin flakes coated with calcium carbonate according to (1), wherein fine particles of calcium carbonate are coated in an amount of 5-70% by weight to the total amount of the pigment;
(3) The pigment in thin flakes coated with calcium carbonate according to (1) or (2), wherein the average particle size of the flake substrate is 0.5-50 &mgr;m;
(4) The pigment in thin flakes coated with calcium carbonate according to any of (1)-(3), wherein the average particle size of calcium carbonate is 200 nm or smaller;
(5) The pigment in thin flakes coated with calcium carbonate according to any of (1)-(5), wherein the pigment is treated with an organic compound;
(6) A method for the manufacture of a pigment of thin flakes coated with calcium carbonate, characterized in that, an aqueous solution of calcium salt and an aqueous solution of a carbonate are added to a suspension of a flake substrate with stirring so that calcium carbonate is coated as fine particles on the surface of the flake substrate, preferably followed by filtering, washing and drying;
(7) The method for the manufacture of a pigment in thin flakes coated with calcium carbonate according to (6), wherein a complex-forming agent is added in the coating treatment with fine particles of calcium carbonate;
(8) A cosmetic agent where the pigment in thin flakes coated with calcium carbonate according to any of (1)-(5) is contained therein; and
(9) A plastic composition, a paint composition or an ink composition where the pigment in thin flakes coated with calcium carbonate according to any of (1)-(5) is contained therein.
Upon further study of the specification and appended claims, further objects and advantages of this invention will become apparent to those skilled in the art.
The present invention will now be illustrated in further detail.
Particle size of the flake substrate used in the present invention refers to the average size of the particles' largest dimension and is preferably within a size of 0.5-50 &mgr;m with the particle size of 0.5-20 &mgr;m being particularly preferred. The average particle thickness is preferably within a range of 0.01-1.0 &mgr;m and, particularly preferably, it is 0.02-0.05 &mgr;m. When the particle size is larger than 50 &mgr;m, luster becomes disadvantageously high, whereby control of luster according to the invention is difficult. In addition, feel on use, such as appropriate adhesion, spreadability and smoothness on the skin surface, is deteriorated. The result is poor adaptability as an extender for cosmetics. There is no particular limitation as to the material for the flake substrate so far as it has a desired flake shape. Natural mica, talc, sericite, synthetic mica, silica flakes, alumina flakes, kaolin, mica coated with titanium oxide, mica coated with iron oxide, mica coated with barium sulfate, mica coated with titanium oxide and with barium sulfate and bismuth oxychloride may be exemplified. Usually, mica is preferred.
Now, a method for the manufacture of the pigment in thin flakes coated with calcium carbonate will be described. First, a suspension of the flake substrate is warmed and, with stirring, an aqueous solution of a calcium salt and an aqueous solution of a carbonate are added to this suspension. The reaction temperature at that time is appropriately selected, preferably from 20° C. (ambient temperature) to 60° C., by taking in to consideration the concentration and rate of addition of the aqueous solution of the calcium salt to be added, the growing speed of the calcium carbonate crystals and/or the size of the desired calcium carbonate coating produced. When a calcium salt having a low solubility in water is used, the aqueous solution of a calcium salt to be added may be prepared by dissolving it beforehand with the aid of hydrochloric acid or the like.
A favorable result may sometimes be achieved in the above coating treatment if a complex-forming agent for forming a complex with calcium is added. This can allow control of the size and the shape of the calcium carbonate coating particles. Examples of the complex-forming agent used therefore are oxalic acid, citric acid, tartaric acid, EDTA, sodium citrate and salts thereof. As a result of the present reaction operation, calcium carbonate is produced by the reaction of the calcium salt with the carbonate and is coated on the surface of the flake substrate as fine particles. The flake substrate coated with the fine particles of calcium carbonate is filtered, washed and dried, preferably at 100-150° C. If desired, the dried final pigment may be calcined at not higher than the decomposing point of calcium carbonate (600° C.). Examples of the calcium salt used in this coating step are calcium chloride and calcium nitrate and the use of calcium chloride is preferred. Examples of the carbonate are sodium carbonate and potassium carbonate and the use of sodium carbonate is preferred.
As a result of X-ray diffraction, it has
Noguchi Tamio
Watanabe Yukitaka
Bell Mark L.
Hailey Patricia L.
Merck Patent Gesellschaft
Millen White Zelano & Branigan P.C.
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