WO2007002030A2

WO2007002030A2 - Low-dust pigments

Info

Publication number: WO2007002030A2
Application number: PCT/US2006/023898
Authority: WO
Inventors: David Schlossman; Yun Shao; Frank Mazella; Carl Orr
Original assignee: Kobo Products, Inc.
Priority date: 2005-06-20
Filing date: 2006-06-20
Publication date: 2007-01-04
Also published as: WO2007002030A3

Abstract

A range of low-dust or dust-free powder-derived products is provided for cosmetics and other uses to avoid hazards arising from liberation during handling. The products can be made by employing suitable quantities of hydrophilic solvents or binders.

Description

LOW-DUST PIGMENTS

Field Of The Invention The present invention relates to cosmetic manufacturing processes incorporating micronized pigments highly subject to entrainment in the air, particularly low dust pigments useful in the preparation of dispersions for use in cosmetics compositions.

Background Of The Invention Powders of various ultrafine particle sizes have, in the cosmetics industry uses in numerous applications. Powder materials such as pigments, fillers and the like are often useful in fine and ultrafine particle sizes, which may be measured in microns or nanometers for the particular properties they may bring to cosmetic emulsions, dispersions and other products. However, it has now been recognized, pursuant to the invention, that some materials may be problematic in cosmetic applications if, during manufacturing, for example, they are handled in such a way as to result in some of the material becoming airborne. More specifically, powder materials that contain dust particles that can become airborne during processing, end use or other handling, and may be harmful to personnel and others who come into contact with the airborne particulates and who may inhale or otherwise ingest the dust. One useful pigment whose commercial forms may create dust levels is D&C Black No. 2 (carbon black). This material was recently approved for cosmetic use by the FDA and prior to the present application. See the Federal Register of July 28, 2004 (69 FR 44927) and October 8, 2004 (69 FR 60307). In its pure form, D&C Black No. 2 is usually supplied as a fluffy, fine-particle product which can easily become airborne and may pose a health hazard to a technician, equipment operator or other individual handling it. At least one jurisdiction, namely the California Office of Environmental Health and Hazard Assessment (OIHHA) has listed "Carbon Black (airborne, unbound particles of respirable size)" (CAS No, 1333- 86-4) as a carcinogenic substance. The International Agency for Research on Cancer ("IARC") has stated that the respirable fraction is "that fraction of an aerosol with an aerodynamic diameter suitable for penetration into the alveoli/gas exchange region of the lung (typically <10 μm)" (pp. 171- 172, Volume 65, IARC Monographs on the Evaluation of Carcinogenic Risks to Human, 1996). However, it is noted that this reference is, apparently, to liquid materials as opposed to solid particles.

Despite the potential health risks, carbon black pigment powder has desirable properties and is appealing to cosmetic chemists and others. Accordingly, as has been discovered in connection with the present invention, there is an unrecognized need to address the problem of dusting. Similar problems and needs may arise with other powders.

While it is generally known to pelletize carbon black powder to reduce the dust content propensity of the product to release dust into the air. However, commercially available pelletized carbon black products are hard and difficult to effectively disperse in liquids or other powders, such for example as are employed in the cosmetics industry.

Summary Of The Invention

In one aspect, the invention provides a non-dusting powder product, with a mean size in the range of about 0.01 mm (10 μm) to about 10 mm optionally in the range of 1 - 5 mm. In useful embodiments, the powder is a pigment such as a black pigment and comprises loosely bound agglomerations of, for example, microfϊne particles. During processing, the inventive agglomerated pigment is, even under the gentlest forces present in normal cosmetic manufacturing processes, easily dispersed into the other applicable ingredients in a manner substantially as effective as conventional pigment. Useful pigments include, for example, carbon black powder such as D&C Black No. 2. The powder treatment product desirably is particulate and may take the form of flakes, prills, beads or granules that are aesthetic, free flowing and have desirable properties for being manually or automatically handled. In one embodiment, the powder is treated to be free of, or have a low dust content.

The dust control treatment may be a treatment as described herein or equivalent or comparable treatment such as will be apparent to one of skill in the art in light of this disclosure. Usefully the product is readily dispersible in liquids, e.g. aqueous media, lipophilic or silicone oils, or emulsions or in powder products after comminution to a desired particle size. Such dispersibility can be obtained by providing the product adequate softness to be easily ground or milled to have a desired particle size characteristics, as for example are employed in the cosmetics industry. A desirable softness can generally be obtained with a content of water, of solvent or of binder in the powder product of from about 5 to about 60 percent by weight.

In another aspect, the invention provides a method of treatment of commercially available dust-containing carbon black pigment, for example, UNIPURE BLACK LC902 from LCW Inc., to reduce or eliminate potentially harmful dust or with a view to providing an innocuous, aesthetic product.

Detail Description Solvent Treatment

One embodiment of the treatment method comprises the addition of a suitable proportion of a hydrophilic solvent to the carbon black pigment powder, or other dust- containing powder to render it non-dusting. In one useful embodiment, a proportion of from about 10 to about 90 percent by weight of hydrophilic solvent, based on the weight of the resultant composition, is employed. In another embodiment, the proportion can be from about 30 to about 70 percent hydrophilic solvent, the balance being carbon black pigment powder. Other ingredients may be added to this composition as described herein or as will be apparent to those skilled in the art. Pursuant to a further embodiment of the invention, approximately equal weight of solvent to pigment can be employed.

A suitable hydrophilic organic solvent, or mixture of solvents can be selected from the group consisting of alkyl alcohols including methyl, ethyl, isopropanol, and other lower alkyl alcohols having not more than about 10 carbon atoms, polyhydric alcohols including butylene glycol, glycerol and lower alkyl dihydric or trihydric alcohols having not more than about 12 carbon atoms, and aqueous solutions of the foregoing hydrophilic organic solvents. Such aqueous solutions can employ any suitable concentration of alcohol in water, for example a concentration from about 10% to about 100%, (i.e. anhydrous alcohol). In a useful embodiment, the concentration of alcohol is from about 10 to about 30 % by weight. Employing a polyhydric alcohol can be advantageous in reducing or controlling possible bacterial contamination of the pigment product.

A water soluble or dispersible natural or synthetic dispersant, for example polysorbate 20 or ammonium polyacrylate, can also be added in a proportion helpful in providing adequate dust and better dispersibility, for example a proportion of from about 0.01 to about 10 percent, optionally from about 0.5 to about 5 percent by weight of the resultant composition. Many other suitable dispersants will be apparent to those skilled in the art in light of the disclosure herein.

If desired, the low-dust carbon black particulate product of the invention can be dried to remove solvent and/or water and provide the product with a desired hardness in a range providing good dust-free handling characteristics and permitting ready reduction to a quality powder for dispersion in cosmetics or other target end product formulations. The invention includes cosmetics or other product formulation processes which comprise such reduction to powder and the cosmetics or other products of the formulation processes.

EXAMPLE:

Preparation of Prilled Carbon Black Employing an Aqueous Hvdrophilic Solvent.

50 g of a 25% w/w solution of butylene glycol in deionized water (12.5 g butylene glycol; 37.5 g water) are added to 50 g carbon black #2 under agitation until the carbon black forms into flakes or prills. Snow-flake like particles can also be formed. If desired, the product is dried to partially remove water or volatile solvent.

Binder Treatment

As an alternative to using a hydrophilic solvent, one or more of various binder materials can be employed to convert the noxious carbon black powder to an aesthetic non- dusting or low dust particulate product. Comparable amounts of hydrophobic or amphoteric liquid, solid or semi-solid binder can be used in similar processes to provide alternative flake, grill or granular products which ay be more or less useful in various end products according to the compatibility of the binder with the end product. Suitable binders can comprise one or more materials selected from the following groups: a) waxes including natural waxes, metal soaps, synthetic waxes, and petroleum waxes; b) wax-like polymers including polyethylene glycols and pololefin and other hydrocarbons resins; c) cosmetic liquids including natural and synthetic oils, esters, hydrocarbons and silicone fluids; and d) polymers or oligomers of hydroxy fatty acid acids, e.g. polyhdroxystearic acid or glyceryl-6 polyricinoleate.

If the solid binder is not easily comminuted with agitation or blending elevated temperature can be employed to soften the binder.

A further alternative is to employ a liquid, solid or semisolid surfactants to convert the carbon black powder, e.g. D&C Black # 2 to render it non-dusting. Suitable surfactants can comprise one or more materials selected from the group consisting of anionic and non- ionic surfactants. Some examples of suitable surfactants, which may be used alone or in combination include silicone polyether, alkanoamide and ethoxylated alcohol. Many others are known and can be employed. The surfactant material can be employed in a manner similar to that described for the hydrophilic solvent or binder with the difference that relatively smaller proportion can be adequate, for example from about 0.1 to about 10 percent by weight of the carbon black product.

Where a wax or oil binder is employed, drying will usually not be appropriate, but heating may be employed to soften the binder or lower its viscosity, if desired. If a somewhat volatile liquid, for example a silicone is employed, drying to a suitable hardness may be employed, if desired, as described above.

Various cosmetically compatible ingredients, or ingredients compatible with other end-product uses, may be included in the low-dust products of the invention, if desired. However, the invention also includes embodiments of particulate-low dusts product as described herein which consist of or consist essentially of the specific ingredients described.

By providing a range of a low-dust or non-dusting particulate carbon products, prepared from various ones of a wide range of ingredients having a diversity of physico- chemical characteristics, the invention permits a suit able low-dust or non-dusting particulate carbon product to be selected for a particular purpose. Thus, products made from hydrophilic solvents can be employed in aqueous-base cosmetics or in the aqueous phase of an emulsion or dispersion cosmetic. Comparably, low-dust or non-dusting particulate carbon products prepared from waxes, lipophilic oils or silicone fluids can beneficially be employed in cosmetic formulations or phases having a wax, lipophilic oil or silicone fluid base respectively. The proportion can be sufficient to introduce into the cosmetic formulation or cosmetic phase the amount of carbon powder, as embodied in the inventive low-dust particulate product, that would conventionally be used, for example from about 0.1 to about 20 percent by weight of the cosmetic formulation or phase. The invention includes embodiments wherein the amount is from about 0.5 to about 10 percent by weight of the formulation or phase. If desired, a proportion of one or more other cosmetic ingredients in the formulation can be reduced to compensate for the presence of the solvent or binder in the novel particulate carbon product of the invention.

Additional Pigment Powders

Optionally, any desired proportion of another pigment powder or powers may be added to the carbon black powder, for example from about 10 to about 90 percent by weight of the resultant composition. The proportion of polyhydric alcohol employed can then be based upon the weight of the resultant composition. Usefully the added pigments are selected to provide, in combination with the carbon black pigment, a desired end product color. For example, various combinations of blue, green and white pigments may be added for a blue-black eye shadow. Other selections of pigments for desired color effects will be apparent to those skilled in the art. The invention includes embodiments wherein such other pigments are also treated or processed by the methods of the invention, along with the carbon black powder pigment, whereby undesired dust contained such other pigments can also be controlled. A wide range of other pigments or powder materials may be employed additively with the carbon black powder being admixed therewith either before or after a dust-control treatment pursuant to the invention. Such other pigments include inorganic pigments and organic pigments, pigment extenders and fillers, including talc, mica and barium sulfate and other insoluble powder materials employed in the cosmetics arts. Some suitable inorganic pigments which may be employed include: titanium dioxide; zinc oxide; iron oxide; alumina oxide; chromium oxide; mango violet; ultramarines, composites of metal oxides or of a metal oxide and an inorganic salt and any other inorganic pigment powder useful in the cosmetic or other relevant arts. If desired, prior to employment in the present invention, powders such as titanium dioxide, zinc oxide and other inorganic pigments or fillers, may be treated with silica, alumina, boron nitride or other known inorganic coatings, singly or in combinations.

Some suitable organic pigments include aluminum, barium, calcium an zirconium lakes of FD&C and D&C grades of Red No. 6, Red No. 7, Red No. 21, Red No. 27 and Yellow No. 5. Other suitable inorganic or organic pigments will be known or be or become apparent to those skilled in the art. Though not usually believed necessary, if desired, the flake, prill or granular particulate pigment product of the invention can be air-blasted or winnowed to remove residual fine dust, should such be present. The separation can play an air velocity sufficient to effect separation yet low enough to avoid undesired displacement of the desired beads or prills. A gas other than air could used if desired. Such air-driven separation methods are difficult to perform on the dust-containing commercial product whose small particle size renders the desired primary particles prone to air-entrainment and undesired dispersal in even very light or air currents.

Other Powders Treated It will be understood that while the invention has largely been described, for illustrative purposes with reference to carbon black powder pigment, and by way of a specific commercially useful example, D&C Black # 2, other pigment powders can be used in place of or in addition to carbon black. Of particular interest would be alternative dust-liberating carbon powders that are approved or become approved in the future by an appropriate regulatory agency, such as the FDA in the US, for cosmetic or other human exposure use. Thus, should other ones of the non-carbon black powders described or suggested herein suffer from dusting problems, they can be treated by the methods of the invention in the same way as has been described for carbon black, subject to any modifications that one skilled in the art may be treated alone or in admixture with carbon black and the resultant non-dusting, or low dust comminutable product may be employed alone or together with the carbon black product of the invention. It will be understood that the invention can be applied to a wide range of other dust-bearing powders, including pigments, fillers and the like regardless of color.

Cosmetics Formulations The novel low-dust or non-dusting carbon black product of the invention preferably prepared from D&C Black No. 2, can be employed in a desired cosmetic or other formulation including a formulation selected from the group consisting of eyeliner, brush-on-brow, eye shadow, mascara, lipstick, blushers and rouge, makeup and foundation, and nail enamel. The invention is of particular advantage when employed with eye cosmetics including eyeliner, brush-on-brow, eye shadow, and mascara as these products may conventionally contain relatively high proportions of black pigment, for example from about 2% to about 10% weight of the formulation. Pursuant to the present invention this pigment can be provided by employing a similar proportion by weight of the inventive low-dust particulate carbon product. Some ingredients which may be employed in eye cosmetics include, without limitation, eyeliner pencils: hydrogenated palm glycerides, hydrogenated palm kernal glycerides, hydrogenated cottonseed oil, synthetic japan wax, myristyl lactate, carnauba, isopropyl myristate, quaternium 18 bentonite, silica, methylparaben, propylparaben, butylparaben, BHT, BHA, citric acid, D&C Black No. 2, iron oxides, ultramarine blue and titanium dioxide; wet and dry eyeliner: talc, mica, lauroyl lysine, zinc stearate, bismuth oxychloride, isopropyl isostearate, dismethicone copolyo, stearic acid , triethanolamine, propylparaben, butylparaben, methylparaben, titanium dioxide, brown iron oxide, yellow iron oxide, D&C Black No. 2, black iron oxide, red iron oxide, ultramarine blue; and mascara: water, paraffin, acacia, stearic acid, beeswax, carnuba, glyceryl stearate, triethanolamine, hydroxyethylcellulose, rosin, ethoxydiglycol, panthenol, simethicone, methylparaben, etylparaben, propylparaben, phenoxyethanol, titanium dioxide, D&C Black No. 2, iron oxides.

Other Applications The invention also has particular application in other fields where carbon black powder is a desirable product, but carbon dust formation may be problematic or hazardous to personnel and it is desirable to employ a product which voids these problems. For example the particulate carbon products of the invention replace carbon powder in foodstuffs, over-the-counter pharmaceutical products, medicaments, ethical pharmaceutical products, health aids, nutritional supplements and rubber products including tires, hoses and the like.

Properties

The invention enables aesthetic non-dusting or low-dust products to be provided that are safe and convenient to handle and do not generate unaesthetic or potentially hazardous airborne particles under normal handling and processing conditions employed in the cosmetics or other relevant industry. Desirably also, the inventive low-dust powder products can readily be comminuted to a desired size under conditions normal to, or easily accepted by, the respective industry. With advantage, the solvent, binder or other dust-control additive can be a cosmetically compatible material, such as those described herein, which is useful or acceptable in the end product application.

Although the foregoing present disclosure has been described in some detail by way of illustration and example for purposes of clarity of understanding, it will be readily apparent to those of ordinary skill in the art in light of the teachings of this present disclosure that certain changes and modifications may be made thereto without departing from the spirit or scope of the appended claims.

What is claimed is:

Claims

1. A method for treating a powder to provide a low-dust particulate product, said method comprising admixing a hydrophilic, hydrophobic, or amphoteric liquid, solid, or semi-solid to obtain a powder having a mean particle size of about 0.001 to about 10 mm.

2. The method of claim 1, wherein said liquid is a hydrophilic solvent.

3. The method of claim 1, wherein said liquid is a polyhydric alcohol.

4. The method of claim 1, wherein said liquid is anhydrous.

5. The method of claim 1, wherein said liquid is selected from the group consisting of water, butylene glycol, methanol, ethanol, propanol, and isopropanol.

6. The method of claim 1, wherein said liquid is selected from the group consisting of isododecane and cyclopentasilixoane.

7. The method of claim 1 , wherein said liquid is a C₂ - Ci₂ alkyl dihydric or trihydric alcohol.

8. The method of claim 1, wherein said powder is a pigment suitable for use in a cosmetic formulation.

9. The method of claim 8, wherein said pigment is D&C Black #2.

10. A low-dust particulate composition comprising a pigment and a hydrophilic, hydrophobic, or amphoteric liquid, solid, or semi-solid, wherein said pigment forms particles capable of comminution to a powder.

11. The composition of claim 10, wherein said liquid is a hydrophilic solvent.

12. The composition of claim 10, wherein said liquid is a polyhydric alcohol.

13. The composition of claim 10, wherein said liquid is anhydrous.

14. The composition of claim 10, wherein said pigment is D&C Black #2 and has a particle size below 200 nm.

15. The composition of claim 10, wherein said liquid is selected from the group consisting of water, butylene glycol, isododecane, and cyclopentasilixoane.

16. A low-dust particulate carbon composition comprising D&C Black # 2 pigment powder and about 30% to about 70% by weight of a hydrophilic solvent.

17. The composition of claim 16, wherein said hydrophilic solvent comprises an aqueous solution of a polyhydric alcohol.

18. The composition of claim 16, wherein said solvent is selected from the group consisting of water, butylene glycol, and mixtures thereof.

19. A method for making a cosmetic product, comprising:

(a) adding a hydrophilic, hydrophobic, or amphoteric liquid, solid, or semisolid to a powder; and

(b) mixing said hydrophilic, hydrophobic, or amphoteric liquid, solid, or semi-solid with said powder to form an agglomerated powder product having a mean particle size of about 0.001 to about 10 mm.

20. The method of claim 19, wherein said powder has an average diameter between 1 nm and 400 nm in size.

21. The method of claim 19, wherein said powder has an average diameter between 5 and 200 nm in size.

22. The method of claim 19, wherein said powder is carbon black.

23. The method of claim 22, further comprising the step of blending said agglomerated powder into at least one other cosmetic ingredient.

24. The method of claim 23, wherein said mixing is performed until the carbon black forms into flakes, prills, or snow-flake like agglomerations.

25. The method of claim 24, wherein said agglomerations are dried to partially remove said hydrophilic, hydrophobic, or amphoteric liquid, solid, or semi-solid.

26. The method of claim 25, wherein said mixing is done under agitation until said powder forms into soft agglomerations and further comprising the step of blending said agglomerations into another cosmetic ingredient or ingredients.