Compositions: coating or plastic – Materials or ingredients – Pigment – filler – or aggregate compositions – e.g. – stone,...
Reexamination Certificate
2001-08-31
2003-10-07
Koslow, C. Melissa (Department: 1755)
Compositions: coating or plastic
Materials or ingredients
Pigment, filler, or aggregate compositions, e.g., stone,...
C106S467000, C106S471000, C424S049000, C426S250000, C426S540000, C427S215000, C427S218000, C428S403000
Reexamination Certificate
active
06630019
ABSTRACT:
BACKGROUND OF THE INVENTION
Colorants are used in most consumer products to provide a distinctive and pleasing appearance. Food and personal care products use almost exclusively two kinds of colorants: Food, Drug and Cosmetic (“FD&C”) dyes and Drug and Cosmetic (“D&C”) dyes, because both kinds of these dyes are non-toxic. In addition to their non-toxicity, these dyes have the additional benefit of being water-soluble, and so when admixed into an aqueous consumer product they are homogeneously distributed throughout the bulk of the product to give it a uniform color.
However, these dyes may not be suitable for use in a multi-colored consumer product. Multi-colored consumer products are those that have two or more regions of contrasting color and/or consistency. Examples of multicolored products are toothpastes that are transparent or white and contain small speckles, as well as toothpastes made from two or more layers, each having its own distinctive color.
While multi-colored consumer products may be more attractive to consumers, they pose difficulties in formulation and manufacture. In particular, such products are susceptible to the effects of dye migration between the differently colored regions. “Dye migration” in this sense refers to the tendency of a dye in a multilayered product to migrate from one region of a product into an adjacent region of a product. Such migration occurs by the physical process of diffusion and is also known as “bleeding”. This migration or bleeding is undesirable because it compromises the distinctive appearance of the consumer product and prevents the product formulator from predictably controlling the aesthetics of the product.
One way to prevent dye migration is to physically separate the differently colored regions until actual use. For example, toothpaste containers have been developed for storing multi-layered toothpastes that maintain each of the layers in a separate compartment until the layers are combined as a single toothpaste product upon dispensing from the container. While this mechanical approach to the problem of dye migration is effective, such containers are expensive and increase the cost of the product.
Using alternative colorants instead of FD&C and D&C dyes may provide a chemical solution to the problem of dye migration that is considerably less expensive than the aforementioned mechanical solution. Colored pigments, which are finely powdered, water-insoluble materials that are dispersed and suspended in a consumer product are one possible alternative to the water-soluble dyes. Indeed, because they are water-insoluble these pigments are highly resistant to dye migration in aqueous compositions.
Unfortunately, most conventional colored pigments are not suitable for use in food or personal care products because of concerns relating to their toxicity. But these toxicity concerns may be managed by substituting “lake pigments” for conventional pigments. Lake pigments are colorants formed by reacting an organic dye with aluminum or calcium salt on a water-insoluble inorganic substrate. The most commonly used substrate is alumina. Lake pigments can be manufactured to be non-toxic and suitable for use in food, drugs and personal care products. However, while lake pigments are more resistant to dye migration than FD&C and D&C dyes, they still exhibit an unacceptably high level of dye migration.
Given the foregoing, there is a continuing need to develop non-toxic colorants that are both non-toxic and highly resistant to dye migration so as to make them suitable as colorant additives in multi-colored consumer products.
BRIEF SUMMARY OF THE INVENTION
The invention includes a method of forming a calcium phosphate colorant. A first step of this method is providing a calcium phosphate slurry comprising calcium phosphate particles. Aluminum hydroxide is mixed with the calcium phosphate slurry to form a premix, thereby depositing aluminum hydroxide onto the calcium phosphate particles. Thereafter, a dye is added to the calcium phosphate particles having been treated with aluminum hydroxide, wherein the dye is fixed to the calcium phosphate particles by the aluminum hydroxide.
The invention also includes a calcium phosphate colorant resistant to dye migration and comprising calcium phosphate particles, a dye, and aluminum hydroxide.
Preferred dyes include FD&C and D&C dyes.
DETAILED DESCRIPTION OF THE INVENTION
All parts, percentages and ratios used herein are expressed by weight unless otherwise specified. All documents cited herein are incorporated by reference.
The following describes preferred embodiments of the present invention, which provides calcium phosphate colorants as well as a process for making such colorants. These colorants are suitable for use in cosmetic, food, and oral care products having excellent resistance to dye migration and being non-toxic.
By “mixture” it is meant any combination of two or more substances, in the form of, for example without intending to be limiting, a heterogeneous mixture, a suspension, a solution, a sol, a gel, a dispersion, or an emulsion.
By “coated” it is meant that the specified coating ingredient covers at least a portion of the outer surface of a particle or substrate.
By “slurry” it is meant an aqueous mixture of water and at least one other component, wherein water forms the continuous phase.
By “cosmetic product” it is meant any product applied directly to an external or internal part of the body, for example without intending to be limiting, make-up, eye shadow, foundations, lipstick, nail polish, aftershaves, facial creams, shower gels, toothpastes, clown make-up, novelty Halloween costume creams and make-up, sensory perception agents, shaving cream, shampoos, bar soaps, liquid soaps, detergents, foot powders, anti-perspirants and deodorants, eye liners, body glitter, theatrical make-up, body paints, and moisturizers.
By “dentifrices” it is meant oral care products such as, without intending to be limiting, toothpastes, tooth powders and denture creams.
By “food product” it is meant any product meant to be consumed, as well as additives to food products such as, without intending to be limiting, food colorants, anti-caking and free flow agents.
By “dye” it is meant an organic colorant, derived from coal tar and petroleum-based intermediates.
By “colorant” it is meant any substance that imparts color to another material or mixture.
By “lake pigment” it is meant a colorant made by extending on an alumina substrate, a salt prepared from water-soluble straight colors by combining such color with the basic radical aluminum or calcium.
By “F&DC dyes” and “D&C dyes” it is meant any dye listed in Title 21, part 82 of the Code of Federal Regulations, the content of which is hereby incorporated by reference.
By “fixing” is meant to hold a dye permanently on a substrate by chemical or mechanical action, or a combination of both.
The ingredients of the calcium phosphate colorant as well as a method for making the colorant will now be discussed in detail. Subsequently, products that comprise the calcium phosphate colorant will be discussed and examples of such products provided.
The present calcium phosphate colorant contains calcium phosphate, aluminum hydroxide and a dye.
The calcium phosphate is present as particles and these particles may be formed from a variety of suitable calcium phosphate species such as monocalcium phosphate, also known as monobasic calcium phosphate, acid calcium phosphate, calcium biphosphate, primary calcium phosphate and CaH
4
(PO
4
)
2
; dicalcium phosphate, also known as dibasic calcium phosphate, calcium monohydrogen phosphate, secondary calcium phosphate and CaHPO
4
; dicalcium phosphate dihydrate, CaHPO
4
·2H
2
O; tricalcium phosphate, which is also referred to by the following names: tribasic calcium phosphate, tertiary calcium phosphate, bone ash, TCP and Ca
3
(PO
4
)
2
; calcium pyrophosphate, also referred to as calcium diphosphate and Ca
2
P
2
O
7
. Preferred calcium phosphate species are tricalcium phosphate, Ca
3
(PO
4
)
2
, dicalcium phosphate, CaHPO
4
,
Kostinko John A.
Pike Kathleen S.
Goodrich David M.
J. M. Huber Corporation
Koslow C. Melissa
Manlove Shalie
Nieves Carlos
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