GB2026860A - Cosmetic sticks - Google Patents

Abstract

Cosmetic powder is compressed into a rod or stick rigid enough to withstand breakage when rubbed on the skin at one end but friable enough to transfer a layer of powder to the skin. Friable adhesive e.g. watersoluble cellulose-based is normally present in otherwise conventional cosmetic formulation.

Description

SPECIFICATION Cosmetic This invention relates to a cosmetic material of the type which is worn usually on or near the face as a powdery layer.

Loose powder cosmetics have been known throughout historical times. Typically they are blown onto the person, or are loosely dabbed on by, for example, fur or hair brushes or pads.

It is also conventional to provide such powders compressed, for example as flat thin tablets each usually held in a surrounding shallow metal tray called a godet. Thus, they are commercially available various brands of eye shadow, face powder, blusher or the like materials. Typically such material is transferred from the compressed tablet, either by fingers or a suitable brush, in such a manner as to remove powder form the relatively soft surface of the compressed tablet but maintain the body of the tablet in an integral unbroken form. To assist in maintaining the integrity of the tablet, it is conventional to add, prior to compressing the powders, small amounts of a lubricant with a permanent oily or fatty base. Such lubricants are called binders in this art.

However, both of the conventional methods described above present problems when a layer of powder is to be applied to an area on or near the face. As far as loose powder is concerned, there is loss of powder and arrival of undesired powder on clothes or furniture. There is also the danger that loose powder will agglomerate into lumps under adverse storage conditions. As far as the compressed tablet within its surrounding godet is concerned, there is loss of powder on the transfer means (whether a finger or a brush) and there is an inaccessible remainder around the inner edge of the godet after a period of use. Also, however effective the binder, there is eventual break-up of the tablet when its surface area becomes large in relation to its thickness, after a period of use.

We have now realised that these various problems can be alleviated or overcome if the compressed powder material is supplied as a rod or stick, that is to say where the length is greater than the diameter.

Such a rod or stick can either be held as such in the fingers, or (more preferably) can be held at one end in a suitable holder.

Powdery materials in stick form are known in other context, for example as blackboard chalk. This is usually based on Plaster of Paris, that is to say Calcium Sulphate which in its anhydride form is mixed with water, thereafter cast into suitable sticks without compression, and then caused or allowed to convert to a rigid dihydrate form as it subsequently dries out. Such a stick apparently keeps its shape by virtue of the physico-chemical mechanisms during hydration whereby interlocking crystals are formed. However, it is capable of losing powder from its surface when the chalk is drawn across a blackboard.

Such cast materials where such a radical chemical or physico-chemical change takes place in the powder are generally too hard (and often too variable) to use in the context in the present invention.

Moreover, attempts to use the existing compressed-disc formulations to form a rod have in our experience been unsuccessful. If the rods are compressed enough to hold their shape, which in any case involves inconveniently high pressures for the manufacturing line, they are not powdery enough for adequate release on the face. If, on the other hand, such skin release is the key criterion, the rods tend to break up in use. The present invention in one aspect provides a rod or stick of compressed powder of cosmetic material, with length greater than, and preferably from two or three times that of, the maximum diameter, the rod being rigid enough to withstand breakage when one end is rubbed on the skin while also being friable enough to transfer a layer of the powder to the skin at the same time.

Preferably the rod contains, in addition to the powder cosmetic and any optional pigmenting or perfume components, a friable adhesive disseminated throughout the rod and left after evaporation of a volatile liquid carrier medium, acting as a solvent or dispersant.

A suitable friable adhesive can be a cellulose derivative. These cellulose derivatives can be.dispersed in water to form a flowing gel with a viscosity of about 1,000-1,500 centipoise. Typical of these cellulose derivatives is Hydroxy propyl cellulose, a non ionic water soluble cellulose ether or Sodium carboxy methyl cellulose. Provided that as in the above instance, there is adequate dispersion of the friable material, true solution is not essential.

Where necessary the solution or dispersion should contain a preservative against microbial infection.

Certain polylmers for example polyvinyl pyrrolidone and resins are other suitable materials for use as binders provided that there is a suitable solvent available.

The liquid carrier could be an otherwise inert organic liquid, toxicity being not of major importance since it is effectively all evaporated by the time the cosmetic is used. Typical organic solvents could be hydrocarbon solvents of suitable boiling range e.g. low boiling paraffinic materials and ethyl alcohol. However, water of aqueous solutions are quite usable in the practice of this invention, especially where the adhesive is cellulosic in nature.

It appears possible that the adhesive is well disseminated over the particle surfaces and that this gives a good bulk rigidity and resistance to fracture while being easily friable at the surface since a different type of stress is involved.

While the product in itself is the primary aspect of the present invention, a method for its production in which the cosmetic powder (and any optional prefumery or pigmenting components) is mixed with the volatile liquid carrier and the adhesive separately blended to form the solution therein or dispersion thereby, ta form a slightly moist flowable powder, this powder is compressed into suitable moulds to provide rods or sticks of a length greater than and preferably from 2 to 3 tìmes that othe mould maximum diameter, the ~ moist mass is pressed firmly into the moulds, the moulds and cast rods or sticks are separated; and the rods or sticks are caused or allowed to dry in order to remove the volatile liquid medium.

Compressed Stick Formula 1. Ref: M235 Talc 77.00 Chalk Dense 10.00 iron Oxide (Ariabel Russet) 3.00 Binder M233 10.00 100.00 Binder Wgt.

Water 100.00 Hydroxy Propyl-Cellulose 1Q.OO Preservative 0.10 Method of manufacture: weigh out colour, talc, chalk, pre-blend, add binder, reblend and pulverise, hold under air tight conditions.

Compressed Stick Formula 2.Ref: M223 % Wgt.

Talc 66.00 Chalk Dense 20.00 Iron Oxide.(Ariabel Russet) 2.0D Binder M221 12.00 100.00 Binder M221 Water 50.00 Ethyl Alcohol 45.00 Hydroxy Propyl Cellulose 5.00 100.00 Method of manufacture: As previously stated.

Compressed Stick Formula 3. Ref: M223 % Wgt.

Talc 66.00 Chalk Dense 20.00 Iron Oxide (Ariabel Russet) 2.00 Binder M232 12.00 100.00 Binder M232 Shellac 10.00 Ethyl Alcohol 100.00 Method of manufacture: As previously stated.

4. Ref: M230 % Wgt.

Talc 66.00 Chalk Dense 20.00 Iron Oxide (Ariabel Russet) 2.00 Binder M229 12.00 100.00 Binder M229 Hydrocarbon Solvent 82.00 Solvent Soluble Resin 18.00 100.00

Claims (12)

1. A rod or stick of compressed powder of cosmetic material, with length greater than the maximum diameter, the rod being rigid enough to withstand breakage when one end is rubbed on the skin while also being friable enough to transfer a layer of the powder to the skin at the same time.

2. A rod or stick as claimed in claim 1, the length of which is from 2 to 3 times its maximum diameter.

3. A rod or stick as claimed in claim 1 or 2 which contains pigmenting and/or perfume components.

4. A rod or stick as claimed in claim 1,2 or 3 which contains a friable adhesive disseminated throughout the rod by virtue of, and after evaporation of, a volatile liquid carrier medium acting as a solvent or dispersant therefor.

5. A rod or stick as claimed in claim 4, in which the said friable adhesive is a cellulose derivative capable of being dispersed in water to form a flowing gel.

6. A rod or stick as claimed in claim 5 in which the cellulose derivative is hydroxy propyl cellulose, a non-ionic water soluble cellulose ether or sodium carboxy methyl cellulose.

7. A rod or stick as claimed in any one of claims 1 to 4 in which the friable adhesive is based on polyvinyl pyrrolidone or like organic material.

8. A rod or stick as claimed in any one preceding claim which further incorporates a preservation against microbial infection.

9. A method for the production of a rod or stick as claimed in any one preceding in which (a) the cosmetic powder together with any perfumery and/or pigmenting components is mixed with the solution or dispersion of the friable adhesive material in the volatile liquid carrier to form a moistflowing powder; (b) this powder is compressed to a rod or stick of suitable dimension by means of an external mould member; (c) the mould member is removed from the said rod or stick; and (d) the rod or stick is caused or allowsto dry inwards to remove the volatile liquid medium.

10. A method as claimed in claim 9 in which the volatile liquid carrier is water or an aqueous solution and the adhesive is a cellulose derivative.

11. A method as claimed in claim 9 in which the volatile liquid carrier is an inert organic liquid.

12. A method as claimed in claim 11 in which the inert organic liquid is a hydrocarbon solvent or methyl alcohol.