WO2020136290A1

WO2020136290A1 - Thermochromic container for depilatory compositions

Info

Publication number: WO2020136290A1
Application number: PCT/ES2019/070752
Authority: WO
Inventors: Eduardo LÓPEZ ALCAY
Original assignee: Viokox, S.A.
Priority date: 2018-12-24
Filing date: 2019-11-06
Publication date: 2020-07-02
Also published as: EP3903627A4; EP3903627A1; ES1225956Y; ES1225956U

Abstract

The invention relates to a container for depilatory compositions, which is made from a plastic material and is characterised in that its composition includes at least one thermochromic material containing two or more reversible thermochromic compositions, the first in a concentration of 0.1-8% and the second in a concentration of 0.05-8% by weight of the thermochromic material, both being heat-sensitive at a temperature above 40°C but at different temperatures from one another, such that the first is heat-sensitive in a lower temperature range than the second. Owing to the thermochromic properties of the container of the invention, the container is able to change colour according to the temperature applied to it, once heated, indicating the suitable moment of use and the moment for non-use.

Description

DESCRIPTION

THERMOCROMIC CONTAINER FOR DEPILATORY COMPOSITIONS Object and technical sector of the invention

The invention is framed in the field of cosmetics, specifically hair removal, and is aimed at a container with thermochromic properties for hair removal compositions.

Background of the Invention

Very different products for removing superfluous body hair are known in the field of hair removal, apart from shaving. One type of composition, the most common, requires initial heating before being applied to the skin in a generally molten state, known as hot waxes. Once applied, it is allowed to solidify before being removed from the skin along with unwanted hair. This is known in the art field as epilation, since the hair is plucked from the skin at the root (patent ES2442918 T3). They can also be found in the prior art, being in common use, warm waxes in which there is also a prior heating but at a lower temperature and wax bands that extend and apply in the area to be depilated, which use a support material to facilitate its withdrawal (international application W09730608 A1; ES2123430 B1).

Some of the most innovative compositions are in emulsion or cream form, and can be applied to the skin at room temperature. The cream includes a substance that breaks down hair keratin. Conventionally, such compositions are applied to the skin in areas where unwanted hair is present, leaving them in that area for a predetermined time to allow the hair keratin to degrade. Finally, the composition along with the degraded hairs are removed from the skin, usually with an instrument such as a sponge or a spatula that drags it. Such compositions are known in the art field as depilatory creams (patent EP2355788 B1).

Depilatory wax compositions, which need pre-heating, can give burn problems if the necessary caution is not followed and the instructions for use are not followed properly, especially in hot waxes.

Normally the problem of these waxes is usually due to the fact that the consumer does not have a reference of the temperature reached by the wax until it is not used on the body, causing burns. Thus, the products that exist in the market either do not inform the consumer of the temperature change of the product to be applied or only report when the use or non-use temperature has been reached. However, they do not report the temperature at which it should be used for proper temperature and should not be used for overheating in the same product. An example is found in patent ES2189990, where a container for depilatory wax is described that includes an applicator with a thermochromic compound to indicate the application temperature, which changes color between 40 ° C and 60 ° C. However, the invention described in ES2189990 has limitations: within waxes that need heating, there are fat-soluble waxes and water-soluble waxes, and the applicator with a thermochromic compound does not work correctly for the former, since it does not allow to correctly visualize the change of the pigment in repeated uses by the wax film that remains in the applicator during use.

To solve the problems detected in the state of the art, and to avoid possible burns with these depilatory products, a package has been developed that informs the consumer by simple observation of the moment in which he can make good use of the wax and in which it cannot It is recommended for being at inadequate temperature conditions, either low or very high. The packaging proposed here has this information available to the user through a triple color change and the intensity of said color:

Originally, the product cannot be used and the color of the container is observed at room temperature;

At the first color change due to change in one of the pigments, the product is fit for use; and

When certain areas of the container begin to appear where it changes color again to a different one due to the color change of a second pigment, the product is too hot in those areas and there is a risk of burns, so it is recommended not to use until it is tempered.

General description of the invention

The present invention refers to a container for depilatory compositions (such as warm waxes and hot waxes), which is made of a plastic material that has thermochromic properties, characterized in that said container Plastic comprises in its composition at least one thermochromic material (dye type, for example masterbach, called in Spanish master dye) that contains two or more reversible thermochromic or thermosensitive compositions (pigments), the first in a concentration of 0.1-8% and the second in a concentration of 0.05% - 8% by weight of the total weight of the thermochromic material, both being sensitive to heat at a temperature above 40 ° C (still cold for wax application) but different between Yes, in such a way that the first one is sensitive to heat in a temperature range lower than the second.

Thanks to the thermochromic properties of the container object of the invention, said container shows the ability to change color according to the temperature applied to it, after heating. As the container is specially designed to contain depilatory compositions, such as waxes that must be heated for use, the purpose of the color change and its intensity is to notify the consumer of the temperature that the container acquires when heated, in such a way that by simple observation it is possible to check its temperature to know if it is ideal for the use and / or application of the wax it contains.

The type of plastic material for the wax container is not particularly limited. However, the material from which the container is made can be of many different types of plastics, preferably selected from the group consisting of: polypropylene (PP), polyethylene (PE), polystyrene (PS), polycarbonate and a combination thereof. . Preferably it is manufactured at a maximum temperature of 200 ° C.

The depilatory composition is preferably a warm or hot depilatory wax. It should be understood in this way that any embodiment of the container, where the pigments are added, is suitable for the product it contains, that is, depending on the temperature suitable for use or the excess temperature for each type of wax used, in such a way that adjusts the composition of the thermochromic material according to the temperature of use.

Thus, the thermochromic material is not particularly limited to a specific or specific type; the only condition, by the nature of the invention itself, is that said thermochromic material must change color and intensity of said color in an appropriate temperature range, which is determined by the wax containing the container. Preferably, the first pigment is contained in the thermochromic material in a concentration comprised between 0.5 and 5% and the second pigment in a concentration of 0.1% -5% by weight of the total weight of the thermochromic material. When it is indicated herein that the pigment or composition is heat sensitive at a certain temperature, it is meant that this pigment changes color from its original coloration at room temperature to another coloration, even its coloration disappearing, by stimulation at indicated temperature. By using (at least) a dye with two compositions or heat-sensitive pigments, the container can show at least three colors depending on the temperature applied in heating the container, namely: 1) the color formed by the container itself base color of the container plus that of the dye formed by the two thermochromic pigments at room temperature (room temperature being understood as that between 25 ° C - 30 ° C); 2) a characteristic color after the disappearance or modification of the color of one of the thermochromic pigments when a temperature is applied that is adequate for the application of the wax; and 3) a characteristic color after the disappearance or modification of the color of the second of the thermochromic pigments when a temperature is applied that is too high for the application of the wax.

Preferably, the upper limit of temperature at which the first pigment changes color completely and reaches the maximum level of said change (the color acquired is homogeneous) coincides with the lower limit of temperature at which the second pigment begins to change. color.

The first pigment, which is the one that changes color at a temperature lower than the second, responds at temperatures equal to or greater than 40 ° C. A suitable temperature for the application of the wax (preferably warm or hot) is understood to be that between 42 ° C-64 ° C depending on the type of wax. In the most preferred embodiment, the first pigment changes color at a temperature between 40 ° C and 65 ° C, while the second pigment changes color at a temperature between 45 ° C and 70 ° C.

It is evident that the container acquires a different temperature with heating (lower) than that of the wax it contains. In this way, for example, the container, depending on its thickness and the formulation of the wax it contains, usually acquires a temperature of between 1 ° C-11 ° C less than the wax it contains. Obviously, the essence of the invention is the double change of color of the container as the heating temperature varies, informing the appropriate time of use and the prevention of non-use; in this way, the type of color that informs these moments is secondary, and depends on the type of thermochromic material chosen. However, in a particular preferred embodiment, the container with the coloring composition is purple at room temperature; the color of the first pigment disappears and the package changes to pink when the temperature is between 60-65 ° C and the color of the second pigment disappears and the package changes to white (base color) when the temperature is equal or higher at 65 ° C, preferably above 70 ° C.

Based on the above considerations, there is a wide variety of thermochromic compositions or pigments that can form part of the thermochromic material of the plastic container, such as those described in US patent 4,028,118, a document that is incorporated by reference. The determining factor is that: a) said pigments change color at appropriate temperatures; b) they change color at different temperatures, between the two covering the range of temperatures of interest for the object of the invention, and c) they change color in a wide range of temperatures, as previously specified.

Preferred embodiment example

The experimental results of tests carried out on packages prepared in accordance with the present invention are described below. The objective of the test is to check if the containers with dye or ink with thermochromic pigments have an adequate behavior to change color at the desired times and conditions with warm or hot wax, and to compare if this behavior is the same with containers. of different geometry, materials, capacity and colors.

Process

The container is purple at room temperature, while it changes to pink with the appropriate temperature of use (due to change or disappearance of the color of the first pigment) and white when it is too hot for its application (due to change or disappearance of the color of the second pigment). Three packages according to the invention, of various geometries and capacities (100 grams, 250 and 400 grams) were used and filled with two types of fat-soluble wax, allowing to cool before beginning the tests. Subsequently, the wax was heated, following the instructions for its use and subsequently at successive intervals of 20 seconds of heating with 20 seconds of rest. To heat the container, a Daewoo 800W microwave was used. The wax temperature was measured with a laboratory thermometer and the temperature of the container walls was measured with an infrared thermometer. Results

The results with the containers filled with 100g, 250g and 400g of wax can be seen in the following table:

Table 1 - Behavior of the packages according to the present invention and of the waxes they contain as a function of temperature

conclusion

After the results obtained, it was concluded that the packages presented an optimal behavior for the intended objective. Both the color change of the container and the temperature of the wax in the 250g and 400g containers are a few degrees higher than those observed for the 100g container. This difference in the temperature of the container and of the wax may be due to the homogenization of the product itself and to the geometry and thickness of the container.

Thus, the package performs well with respect to color change by temperature if the color code is explained properly in the instructions for use:

Wax suitable for depilation when the container has a homogeneous pink color;

When the white color begins to appear in the container, let the wax cool down as it is too hot for its application.

These results are extrapolar to other packaging formats of different capacities and geometries such as 250 ml jars and 120 ml bottles and other types of wax such as lipid soluble or water soluble wax.

Claims

1. A container for depilatory compositions, which is made of a plastic material, characterized in that said container comprises in its composition at least one thermochromic material containing two or more reversible thermochromic compositions, the first in a concentration comprised between 0.1 and 8% and the second in a concentration between 0.05% and 8% by weight of the total weight of the thermochromic material, both being sensitive to heat at a temperature above 40 ° C but different from each other, so that the first of them is sensitive to heat in a temperature range less than the second.

2. The container of claim 1, wherein the plastic material from which it is made is selected from the group consisting of polypropylene, polyethylene, polystyrene, polycarbonate and any combination thereof.

The container according to any one of claims 1 or 2, wherein the depilatory composition is warm or hot depilatory wax.

The container according to any one of the preceding claims, wherein the first pigment is contained in the thermochromic material in a concentration comprised between 0.5 and 5% and the second pigment in a concentration of 0.1% -5% by weight of the total weight of the thermochromic material.

5. The container according to any one of the preceding claims, where the upper temperature limit at which the first pigment changes color completely and reaches the maximum level of said change, producing a homogeneous color in the container, coincides with the lower limit of temperature at which the second pigment begins to change color.

6. The package according to any one of the preceding claims, wherein the first pigment changes color at a temperature between 40 ° C and 65 ° C, while the second pigment changes color at a temperature between 45 ° C and 70 ° C.

7. The container according to any one of the preceding claims, having color purple at room temperature; pink color when the color of the first pigment disappears; and white, when the color of the second pigment begins to fade.