EP4138770A1

EP4138770A1 - Transparent shampoo bar and method for preparing the same

Info

Publication number: EP4138770A1
Application number: EP20931929.2A
Authority: EP
Inventors: Congying LIU; Zhengqiao DENG
Original assignee: Henkel AG and Co KGaA
Current assignee: Henkel AG and Co KGaA
Priority date: 2020-04-23
Filing date: 2020-04-23
Publication date: 2023-03-01
Also published as: CN115427007A; WO2021212404A1; EP4138770A4

Abstract

It relates to a method for producing a transparent shampoo bar, comprising: i) preparing a solution i) comprising at least one N-acyl amino acid and water, the solution i) having a temperature of 70 ℃ to 100 ℃, preferably 75 ℃ to 90 ℃, more preferably 80 ℃ to 88 ℃, ii) preparing a solution ii) comprising at least one alkali and water, the solution ii) having a temperature of 70 ℃ to 100 ℃, preferably 75 ℃ to 90 ℃, more preferably 80 ℃ to 88 ℃, iii) adding the solution ii) to the solution i) with stirring at a temperature of 70 ℃ to 100 ℃, preferably 75 ℃ to 90 ℃, more preferably 80 ℃ to 88 ℃, so as to obtain a homogeneous transparent solution iii); and iv) cooling the solution iii) to room temperature, wherein a) at least one alcohol is comprised in the solution i) and/or the solution ii) and/or the solution iii), b) the water is comprised in a total amount of no more than 40 wt%, preferably no more than 30 wt%, based on the total weight of the transparent shampoo bar, and c) optionally, a second surfactant and/or a hair conditioning compound is/are comprised in the solution i) and/or the solution ii) and/or the solution iii). It also relates to the transparent shampoo bar produced by the method thereof.

Description

Transparent shampoo bar and method for preparing the same

Technical field

The present invention relates to a transparent shampoo bar in solid form and to a method for preparing the same.

Background of the invention

Shampoo is a basic hair care product representing the largest segment of hair care cosmetics. The main function is to remove dirt, grime, and sebum from the hair and scalp. Nowadays, with the increasing consumer needs, in addition to cleansing function, some of the shampoos also have additional benefits, e.g. conditioning performance to hair and mildness to scalp.
Conventional shampoos are viscous liquid, filling in a bottle or sachet and can be directly applied on wet hair. However, shampoos in liquid form have greater tendency to leak out of their packaging, which can be very bothersome when they come into contact with clothing, for example, during moving. Moreover, in order to make a viscous liquid, more or less thickeners or gelling agents are needed in these products, which would have drawback of inhibiting foam development. In addition, it has been noted that thicker compositions often require a lot of rinsing water in order to remove the surplus product on the hair. Thus, the conventional shampoos in viscous liquid form need more water and thus are not environment-friendly either during the production or during the use.
With the increasing consciousness of sustainability, people turn to seek for products which is more sustainable and more environment friendly, such as the products containing less water, using less package and less social footprint.
Therefore, it may be advantageous to provide shampoo products in solid form, especially as a shampoo bar. A shampoo bar has advantages of less water, easy to carry, no leaking-out issue, and less package materials. In addition, from the perspective of aesthetics, there is a need in the field for a transparent shampoo bar, which is easy to produce and has good cleansing performance and optionally has good conditioning performance.
Summary of the invention
The present invention provides a method for producing a transparent shampoo bar, and the method is simple and easy to handle and low cost and can provide a shampoo bar having excellent transparency.
One aspect of the present invention is to provide a method for producing a transparent shampoo bar, comprising:
i) preparing a solution i) comprising at least one N-acyl amino acid and water, the solution i) having a temperature of 70 ℃ to 100 ℃, preferably 75 ℃ to 90 ℃, more preferably 80 ℃ to 88 ℃,
ii) preparing a solution ii) comprising at least one alkali and water, the solution ii) having a temperature of 70 ℃ to 100 ℃, preferably 75 ℃ to 90 ℃, more preferably 80 ℃ to 88 ℃,
iii) adding the solution ii) to the solution i) with stirring at a temperature of 70 ℃ to 100 ℃, preferably 75 ℃ to 90 ℃, more preferably 80 ℃ to 88 ℃, so as to obtain a homogeneous transparent solution iii) ; and
iv) cooling the solution iii) to room temperature,
wherein
a) at least one alcohol is comprised in the solution i) and/or the solution ii) and/or the solution iii) ,
b) the water is comprised in a total amount of no more than 40 wt%, preferably no more than 30 wt%, based on the total weight of the transparent shampoo bar, and
c) optionally, a second surfactant and/or a hair conditioning compound is/are comprised in the solution i) and/or the solution ii) and/or the solution iii) .
Another aspect of the present invention is the transparent shampoo bar obtained from the method of the present invention.
Still another aspect of the present invention is a transparent shampoo bar, comprising:
- a salt in situ formed from at least one N-acyl amino acid and at least one alkali,
- water,
- at least one alcohol,
- optionally, a second surfactant, and
- optionally, a hair conditioning compound.
Still another aspect of the present invention is a bi-layer shampoo and conditioning bar, comprising a transparent shampoo bar of the present invention on one side and a conditioning bar on the other side.
The transparent shampoo bar of the present invention has excellent transparent appearance, has good cleansing performance and optionally has good conditioning performance.
Brief introduction to the figures
Figure 1 is photos showing the transparency of the transparent shampoo bars of the present invention and of a commercially available LUSH shampoo bar.
Figure 2 shows wet combing test results using the transparent shampoo bar from Example 1 of the present invention and different shampoos of the prior art.
Figure 3 shows dry combing test results using the transparent shampoo bar from Example 1 of the present invention and different shampoos of the prior art.

Detailed description of the invention

It is to be understood by one of ordinary skill in the art that the present discussion is a description of exemplary embodiments only and is not intended as limiting the broader aspects of the present invention. Each aspect so described may be combined with any other aspect (s) unless clearly indicated to the contrary. In particular, any feature indicated as being preferred or advantageous may be combined with any other feature or features indicated as being preferred or advantageous.
Unless specified otherwise, in the context of the present invention, the terms used are to be construed in accordance with the following definitions.
Unless specified otherwise, all wt. %or %by weight values quoted herein are percentages by weight.
Unless specified otherwise, as used herein, the terms “a” , “an” and “the” include both singular and plural referents.
The terms “comprising” and “comprises” as used herein are synonymous with “including” , “includes” or “containing” , “contains” , and are inclusive or open-ended and do not exclude additional, non-recited members, elements or process steps.
The term “consisting essentially of” as used herein means that the listed components constitute main body of the composition, for example, at least 70%by weight of the composition, at least 80%by weight of the composition, at least 85%by weight of the composition, or at least 90%by weight of the composition.
The term “consisting of” as used herein is close-ended and exclude additional, non-recited members, elements or process steps.
The term “at least one” or “one or more” used herein to define a component refers to the type of the component, and not to the absolute number of molecules. For example, “one or more polyols” means one type of polyol or a mixture of a plurality of different polyols.
The terms “about” , “around” and the like used herein in connection with a numerical value refer to the numerical value ±10%, preferably ±5%. All numerical values herein should be interpreted as being modified by the term “about” .
The term “room temperature” used herein refers a temperature of about 20 ℃ to about 25 ℃.
The term “transparent shampoo bar” used herein can be interpreted as that a shampoo bar having a thickness of about 2.5 cm has a light transmittance of more than 70%, preferably more than 80%, more preferably more than 85%, still more preferably more than 90%.
Unless specified otherwise, the recitation of numerical end points includes all numbers and fractions subsumed within the respective ranges, as well as the recited end points.
All references cited in the present specification are hereby incorporated by reference in their entirety.
Unless otherwise defined, all terms used in the present invention, including technical and scientific terms, have the meaning as commonly understood by one of the ordinary skilled in the art to which this invention belongs.
The method of the present invention will be described in detail as below.
In one aspect of the present invention, a method for producing a transparent shampoo bar is provided, wherein the method comprises:
i) preparing a solution i) comprising at least one N-acyl amino acid and water, the solution i) having a temperature of 70 ℃ to 100 ℃, preferably 75 ℃ to 90 ℃, more preferably 80 ℃ to 88 ℃,
ii) preparing a solution ii) comprising at least one alkali and water, the solution ii) having a temperature of 70 ℃ to 100 ℃, preferably 75 ℃ to 90 ℃, more preferably 80 ℃ to 88 ℃,
iii) adding the solution ii) to the solution i) with stirring at a temperature of 70 ℃ to 100 ℃, preferably 75 ℃ to 90 ℃, more preferably 80 ℃ to 88 ℃, so as to obtain a homogeneous transparent solution iii) ; and
iv) cooling the solution iii) to room temperature,
wherein
a) at least one alcohol is comprised in the solution i) and/or the solution ii) and/or the solution iii) ,
b) the water is comprised in a total amount of no more than 40 wt%, preferably no more than 30 wt%, based on the total weight of the transparent shampoo bar, and
c) optionally, a second surfactant and/or a hair conditioning compound is/are comprised in the solution i) and/or the solution ii) and/or the solution iii) .
In step i) of the present invention, a solution i) is prepared by mixing and heating its components to a temperature of 70 ℃ to 100 ℃, preferably 75 ℃ to 90 ℃, more preferably 80 ℃ to 88 ℃. Preferably, the mixing and/or heating is/are done with stirring.
The components of the solution i) at least comprise at least one N-acyl amino acid and water. Further, the solution i) may also comprises at least one alcohol and/or optionally other ingredient (s) that do not react with the at least one N-acyl amino acid, such as a second surfactant, a conditioning compound, a preservative, a perfume, an antioxidant, and any combinations thereof.
For the preparation of the solution i) , the order of mixing the components of solution i) is not particularly limited, as long as a solution i) having a temperature of 70 ℃ to 100 ℃, preferably 75 ℃ to 90 ℃, more preferably 80 ℃ to 88 ℃, is obtained. Each component can be mixed with another one or more components and, optionally, preheated to a temperature within the above specified temperature range, and finally, all components, preheated or non-preheated, are mixed together at the temperature within the above specified temperature range, so as to obtain the solution i) . For example, the at least one N-acyl amino acid and water may be firstly mixed and heated to a temperature falling in the above specified temperature range, and the at least one alcohol (if present) and/or said other ingredient (s) (if present) , preheated or non-preheated, can be added to the heated mixture of at least one N-acyl amino acid and water while keeping the temperature within the specified range, so as to obtain the solution i) . Or, all components including the at least one N-acyl amino acid, water, the at least one alcohol (if present) and/or said other ingredient (s) (if present) can be mixed and heated together to a temperature of 70 ℃ to 100 ℃, preferably 75 ℃ to 90 ℃, more preferably 80 ℃ to 88 ℃, so as to obtain the solution i) . Or, the at least one N-acyl amino acid and water and the at least one alcohol (if present) may be firstly mixed and heated to a temperature falling in the above specified temperature range, and said other ingredient (s) (if present) , preheated or non-preheated, can be added to the heated mixture of at least one N-acyl amino acid and water and the at least one alcohol (if present) while keeping the temperature within the specified range, so as to obtain the solution i) . The mixing order of each component of the solution i) is not limited to the above examples.
The at least one N-acyl amino acid useful in the present invention can be selected from a group consisting of N-acyl glutamic acid, N-acyl alanine, N-acyl glycine, N-acyl lysine, N-acyl proline and N-acyl sarcosine. The acyl in the N-acyl amino acid may comprise an aliphatic acyl group having 6 to 22 carbon atoms. Specifically, the at least one N-acyl amino acid useful in the present invention can be selected from a group consisting of cocoyl glutamic acid, lauroyl glutamic acid, stearoyl glutamic acid, myristoryl glutamic acid, palmitoyl glutamic acid, oleoyl glutamic acid, cocoyl alanine, lauroyl alanine, stearoyl alanine, myristoryl alanine, palmitoyl alanine, oleoyl alanine, cocoyl glycine, lauroyl glycine, stearoyl glycine, myristoryl glycine, palmitoyl glycine, oleoyl glycine, cocoyl lysine, lauroyl lysine, stearoyl lysine, myristoryl lysine, palmitoyl lysine, oleoyl lysine, cocoyl proline, lauroyl proline, stearoyl proline, myristoryl proline, palmitoyl proline, oleoyl proline, cocoyl sarcosine, lauroyl sarcosine, stearoyl sarcosine, myristoryl sarcosine, palmitoyl sarcosine and oleoyl sarcosine.
In the solution i) of the present invention, the water content is not particularly limited, as long as the at least one N-acyl amino acid can be dissolved in the water at the temperature of 70 ℃ to 100 ℃ and the criteria that the total content of water in the transparent shampoo bar is not greater than 40 wt%, preferably no more than 30 wt%, based on the total weight of the transparent shampoo bar, can be satisfied. When the alcohol and/or said other ingredient (s) are contained in the solution i) , the water content is sufficient to dissolve these ingredients and form a homogeneous solution i) . For example, the water content in the solution i) can be no more than 40 wt%, based on the total weight of the solution i) . The water content in the solution i) can be adjusted by evaporating excess water or adding water if required.
The at least one N-acyl amino acid can be used in an amount of from 10 wt%to 50 wt%, preferably from 15 wt%to 40 wt%, based on the total weight of the transparent shampoo bar.
In one embodiment, the solution i) comprises or consists of the at least one N-acyl amino acid and water.
In another embodiment, the solution i) comprises or consists of the at least one N-acyl amino acid, water, the at least one alcohol, a conditioning compound, and a second surfactant.
In another embodiment, the solution i) comprises or consists of the at least one N-acyl amino acid, water, the at least one alcohol, a second surfactant, a conditioning compound, a preservative and an antioxidant.
In step ii) of the present invention, a solution ii) is prepared by mixing and heating its components to a temperature of 70 ℃ to 100 ℃, preferably 75 ℃ to 90 ℃, more preferably 80 ℃ to 88 ℃. Preferably, the mixing and/or heating is/are done with stirring.
The components of the solution ii) at least comprise at least one alkali and water. Further, the solution ii) may also comprises at least one alcohol and/or optionally other ingredient (s) that do not react with the at least one alkali, such as a second surfactant, a conditioning compound, a preservative, a perfume, an antioxidant, and any combinations thereof.
For the preparation of the solution ii) , the order of mixing the components of solution ii) is not particularly limited, as long as a solution ii) at a temperature of 70 ℃ to 100 ℃, preferably 75 ℃ to 90 ℃, more preferably 80 ℃ to 88 ℃, is obtained. Each component can be mixed with another one or more components and, optionally, preheated to a temperature within the above specified temperature range, and finally, all components, preheated or non-preheated, are mixed together at the temperature within the above specified temperature range, so as to obtain the solution ii) . For example, the at least one alkali and water may be firstly mixed and heated to a temperature falling in the above specified temperature range, and the at least one alcohol (if present) and/or said other ingredient (s) (if present) , preheated or non-preheated, can be added to the above heated mixture while keeping the temperature within the specified range, so as to obtain the solution ii) . Or, all components including the at least one alkali, water, the at least one alcohol (if present) and/or said other ingredient (s) (if present) can be mixed and heated together to a temperature of 70 ℃ to 100 ℃, preferably 75 ℃ to 90 ℃, more preferably 80 ℃ to 88 ℃, so as to obtain the solution ii) . Or, the at least one alkali and water and the at least one alcohol (if present) may be firstly mixed and heated to a temperature falling in the above specified temperature range, and said other ingredient (s) (if present) , preheated or non-preheated, can be added to the above heated mixture while keeping the temperature within the specified range, so as to obtain the solution ii) . The mixing order of each component of solution ii) is not limited to the above examples.
In the solution ii) of the present invention, the water content is not particularly limited, as long as the at least one alkali can be dissolved in the water at the temperature of 70 ℃ to 100 ℃ and the criteria that the total content of water in the transparent shampoo bar is no greater than 40 wt%, preferably no more than 30 wt%, based on the total weight of the transparent shampoo bar, can be satisfied. When the alcohol and/or said other ingredient (s) are contained in the solution ii) , the water content is sufficient to dissolve these ingredients and form a homogeneous solution ii) . For example, the water content in the solution ii) can be no more than 40 wt%, based on the total weight of the solution ii) . The water content in the solution ii) can be adjusted by evaporating excess water or adding water if required.
The alkali useful in the present invention can be those selected from the group consisting of aminomethyl propanol, aminoethyl propanol, triethanolamine, ethanolamine, diethanolamine, tetrahydroxypropyl ethylenediamine, potassium hydroxide, sodium hydroxide and sodium bicarbonate.
Preferably, the at least one alkali used in the present invention comprises triethanolamine. For example, the at least one alkali can be triethanolamine or a combination of triethanolamine and an alkali other than triethanolamine, such as a combination of triethanolamine and aminomethyl propanol, a combination of triethanolamine and aminoethyl propanol, a combination of triethanolamine and ethanolamine and/or diethanolamine and/or tetrahydroxypropyl ethylenediamine.
The at least one alkali can be used in a total amount of from 5 wt%to 30 wt%, preferably from 10 wt%to 25 wt%, based on the total weight of the transparent shampoo bar.
In one embodiment, the solution ii) comprises or consists of the at least one alkali and water.
In another embodiment, the solution ii) comprises or consists of the at least one alkali, water and the at least one alcohol.
In another embodiment, the solution ii) comprises or consists of the at least one alkali, water, the at least one alcohol, a conditioning compound, and a second surfactant.
In another embodiment, the solution ii) comprises or consists of the at least one alkali, water, the at least one alcohol, a second surfactant, a conditioning compound, a preservative and an antioxidant.
The at least one alcohol, the conditioning compound, the preservative or the antioxidant used in the solution ii) may be the same as those used in the solution i) , and/or may be different from those used in the solution i) , respectively.
To prepare solutions i) and ii) having a temperature of 70 ℃ to 100 ℃, any conventional heating means/methods can be used herein without any particular limitation. Preferably, heating is done with stirring so as to achieve a homogenous solutions i) and ii) .
In step iii) of the present invention, it is required to add the solution ii) to the solution i) , preferably slowly, with stirring, so as to ensure a homogeneous transparent solution iii) . In this step, reaction may take place. Without being bounded to the theory, it is believed that salt (s) may be formed from the reaction between the at least one N-acyl amino acid and the at least one alkali, and the salt (s) in situ formed herein function in different way in the solution iii) compared with the salt (s) added thereto directly. In practice, if the addition order is reversed, i.e., adding the solution i) to the solution ii) , a process for producing a shampoo bar with high transparency cannot be established (see Comparative Example 3) . Meanwhile, if the salt (s) of the at least one N-acyl amino acid and the at least one alkali is added directly into the system without reaction taking place, a shampoo bar with high transparency cannot be obtained (see Comparative Examples 1 and 2) .
In step iii) of the present invention, except for the operation of adding the solution ii) to the solution i) , at least one alcohol and/or said other ingredient (s) , preheated or non-preheated, can be incorporated during the operation or after the operation, so as to obtain the homogeneous transparent solution iii) .
The term “preheated” as used herein refers to that the indicated substance is preheated to the temperature falling in the range of 70 ℃ to 100 ℃, preferably 75 ℃ to 90 ℃, more preferably 80 ℃ to 88 ℃, or to a temperature lower than the above specified range, prior to mixing with other component (s) .
In order to obtain a transparent shampoo bar, an important point of the present invention is the addition of the solution ii) comprising at least one alkali to the solution i) comprising at least one N-acyl amino acid, and the addition order cannot be reversed. As for other components in the transparent shampoo bar, the addition order or timing of them is not particularly limited.
There are commercially available transparent liquid shampoos. However, the formation of a transparent shampoo bar is quite different from the formation of a transparent liquid shampoo. In the transparent liquid shampoo, a transparency appearance is present when all components are in dissolved state. When most of solvent is removed, some of the components will precipitate and a non-transparent solid phase will be formed. During the formation of a transparent shampoo bar, much less water (or solvent) is used during the manufacture. Under such a low content of solvent, a simple mixing of all components together, even under high temperature, would not give a transparent shampoo bar, because once the temperature is back to room temperature, some components would precipitate and thus form solid with non-transparent appearance.
After step iii) , the transparent solution iii) may be optionally kept still at the temperature of 70 ℃ to 100 ℃, preferably 75 ℃ to 90 ℃, more preferably 80 ℃ to 88 ℃ without stirring for about 5 min to about 1 h, for example for about 15 min to 40 min. Then, the solution iii) can be poured into a mold and cooled to room temperature, and a transparent shampoo bar in solid form is obtained. The water content in the solution iii) can be adjusted by evaporating excess water or adding water if required, as long as the water content in the solution iii) is no more than 40 wt%, preferably no more than 30 wt%.
The term “solid form” used herein refers to a state that the bar does not flow under its own weight and does not change its shape under a force of holding it up.
The at least one alcohol useful in the present invention may be those alcohols having no more than 10 carbon atoms, preferably those aliphatic alcohols, preferably having 2 or 3 OH groups. Examples of the alcohol include ethanol (denatured or undenatured) , ethylene glycol, propylene glycols such as 1, 3-propanediol, butylene glycols such as 1, 2-butanediol, 2, 3-butanediol, 1, 4-butanediol, pentylene glycols such as 1, 2-pentanediol, isopentyldiol, 1, 5-pentanediol, hexylene glycols such as 1, 2-hexanediol, 1, 6-hexanediol, octanediols, nonanediols such as 1, 9-nonanediol, decylene glycols such as 1, 10-decanediol, glycerine, sorbitol, diethylene glycol, dipropylene glycol, and the like.
The at least one alcohol is an essential component of the present invention. The alcohol may be comprised in the solution i) and/or the solution ii) and/or solution iii) . In other words, it is not particularly limited in which step the at the at least one alcohol is added to the system, as long as the alcohol is present in the system. Also, it is feasible that the alcohol is present in each solution of the system or added in each step to the system. Moreover, the alcohol in each solution or added in each step may be the same or different from each other.
The expression “at least one alcohol is comprised in the solution i) and/or the solution ii) and/or the solution iii) ” can be interpreted as:
- at least one alcohol is only comprised in the solution iii) ,
- at least one alcohol is comprised in the solutions i) and iii) ,
- at least one alcohol is comprised in the solutions ii) and iii) , and
- at least one alcohol is comprised in the solutions i) , ii) and iii) .
In one embodiment of the present invention, the at least one alcohol may be present together with the N-acyl amino acid and water, and they may be heated together to a temperature falling in the range of 70 ℃ to 100 ℃, preferably 75 ℃ to 90 ℃, more preferably 80 ℃ to 88 ℃.
In one embodiment of the present invention, the solution i) may comprise propylene glycol and glycerine and ethanol, and the solution ii) does not comprise the alcohol, and no alcohol is incorporated during step iii) .
In another embodiment of the present invention, the solution i) may comprise propylene glycol and glycerine, and the solution ii) may comprise ethanol, and butylene glycol is incorporated during step iii) .
In still another embodiment of the present invention, the solution i) may comprise propylene glycol and glycerine and ethanol, the solution ii) may comprise propylene glycol and glycerine and ethanol, and no alcohol is incorporated during step iii) .
No matter in which solution the at least one alcohol is present, the at least one alcohol in total is comprised in an amount of from 5 wt%to 30%, preferably, from 10 wt%to 20 wt%, based on the total weight of the transparent shampoo bar.
Optionally, a second surfactant may be comprised in the solution i) and/or the solution ii) and/or the solution iii) . In other words, it is not particularly limited in which step the second surfactant is added to the system, as long as the second surfactant is present in the system. Also, it is feasible that the second surfactant is present in each solution of the system or added in each step to the system. Moreover, the second surfactant in each solution or added in each step may be the same or different from each other. From the perspective of better cleaning effect, it is preferred to comprise a second surfactant in the system in addition the N-acyl amino acid or its in situ formed salts.
The term “second surfactant” used herein refers to those surfactants that do not belong to N-acyl amino acids as defined in the present invention and salts in-situ formed from the N-acyl amino acids and the alkali as defined in the present invention. For example, if sodium lauryl sarcosinate is directly added to solution i) , the sodium lauryl sarcosinate serves as the second surfactant, but if lauryl sarcosine is added to solution i) and then reacts with the alkali in the solution ii) , the lauryl sarcosine does not serve as the second surfactant. In short, if the surfactant added to the system does not take part in the reaction to form a salt, the added surfactant serves as the second surfactant.
The second surfactant useful in the present invention may be selected from anionic surfactants, amphoteric surfactants, glucoside derivatives and the like.
Example of the anionic surfactants include Sodium Laureth-11 Carboxylate, Ammonium Laureth-12 Sulfate, Sodium Laureth-12 Sulfate, Sodium Laureth-13 Carboxylate, Sodium/MEA Laureth-2 Sulfosuccinate, Sodium Laureth-4 Phosphate, Sodium Laureth-4 Carboxylate, Sodium Laureth-40 Sulfate, Sodium Laureth-5 Carboxylate, Disodium Laureth-6 Sulfosuccinate, Laureth-6 Carboxylic Acid, Sodium Laureth-6 Carboxylate, Magnesium Laureth-8 Sulfate, Sodium Laureth-8 Sulfate, Sodium Laureth-8 Carboxylate, Potassium Laureth Phosphate, Ammonium Laureth Sulfate, Magnesium Laureth Sulfate, Sodium Laureth Sulfate, MEA-Laureth Sulfate, MIPA-Laureth Sulfate, TEA-Laureth Sulfate, TIPA-Laureth Sulfate, Disodium Laureth Sulfosuccinate, Disodium Lauryl Phosphate, Potassium Lauryl Phosphate, Sodium Lauryl Phosphate, Ammonium Lauryl Sulfate, Potassium Lauryl Sulfate, Magnesium Lauryl Sulfate, Sodium Lauryl Sulfate, MEA-Lauryl Sulfate, TEA-Lauryl Sulfate, Sodium Lauryl Sulfoacetate, Disodium Lauryl Sulfosuccinate, Sodium Lauryl Glycol Carboxylate, Sodium Lauryl Glucose Carboxylate, Magnesium Oleth Sulfate, Sodium Oleth Sulfate, TEA-Oleyl Sulfate, Sodium Oleyl Sulfate, Sodium Coceth-30 Sulfate, Sodium Coceth Sulfate, Sodium Coco-Sulfate, Sodium Cocoyl Isethionate, Sodium Cocoyl Isethionate, Sodium Cocoyl Isethionate, Sodium Cocoyl Isethionate, Sodium Cocoyl Isethionate, Disodium Oleamido MIPA Sulfosuccinate, Disodium Oleamido MIPA Sulfosuccinate, Sodium Stearyl Sulfate, Sodium Steareth-4 Phosphate, Sodium PEG-7 Olive Oil Carboxylate, Sodium Trideceth-3 Carboxylate, Sodium Trideceth-4 Carboxylate, Sodium Trideceth-7 Carboxylate, Sodium Trideceth Sulfate, Sodium C10-15 Pareth Sulfate, Sodium C10-16 Pareth-2 Sulfate, Potassium C12-13 Alkyl Phosphate, TEA-C12-13 Alkyl Sulfate, Sodium C12-13 Pareth Sulfate, Sodium C12-13 Alkyl Sulfate, Disodium C12-14 Pareth-2 Sulfosuccinate, Sodium C12-14 Pareth-3 Sulfate, Sodium C12-14 Olefin Sulfonate, Ammonium C12-15 Pareth Sulfate, Sodium C12-15 Pareth-3 Sulfate, Sodium C12-15 Pareth-7 Carboxylate, Sodium C12-15 Pareth Sulfate, Ammonium C12-15 Alkyl Sulfate, Sodium C12-15 Alkyl Sulfate, Sodium C12-18 Alkyl Sulfate, Sodium C14-16 Olefin Sulfonate, Sodium C14-17 Alkyl Sec Sulfonate, Sodium C14-18 Olefin Sulfonate, Sodium C16-18 Olefin Sulfonate, Sodium Methyl Cocoyl Taurate, Sodium Methyl Cocoyl Taurate, Sodium Methyl Cocoyl Taurate, Sodium Methyl Oleoyl Taurate, Sodium Methyl Oleoyl Taurate, Sodium Methyl Oleoyl Taurate, Disodium Ricinoleamido MEA-Sulfosuccinate, Disodium PEG-12 Dimethicone Sulfosuccinate, Trideceth-7 Carboxylic Acid, Disodium Coco-glucoside sulfosuccinate, Sodium Coco-glucoside tartrate, Disodium Coco-glucoside citrate, Sodium hydroxypropylsulfonate laurylglucoside crosspolymer, Sodium Lauryl Sarcosinate, Ammonium Lauroyl Sarcosinate, Potassium Lauroyl Sarcosinate, Sodium Palmitoyl Sarcosinate, Ammonium Cocoyl Sarcosinate, Sodium Cocoyl Sarcosinate, TEA-Cocoyl Sarcosinate, TEA-Lauroyl Glutamate, Disodium Lauroyl Glutamate, Potassium Lauroyl Glutamate, Sodium Lauroyl Glutamate, Sodium Palmoyl Glutamate, Potassium Myristoyl Glutamate, Sodium Myristoyl Glutamate, Disodium Cocoyl Glutamate, Potassium Cocoyl Glutamate, Sodium Cocoyl Glutamate, TEA-Cocoyl Glutamate, Disodium Stearoyl Glutamate, Sodium Stearoyl Glutamate, Sodium Cocoyl Glycinate, and Potassium Cocoyl Glycinate.
Examples of the amphoteric surfactants include Cocamidopropyl Betaine, Lauramidopropyl Betaine, Palm Kernelamidopropyl Betaine, Palmitamidopropyl Betaine, Babassuamidopropyl Betaine, Soyamidopropyl Betaine, Methoxycinnamidopropyl Hydroxysultaine, Erucamidopropyl Hydroxysultaine, Cetyl Betaine, Myristyl Betaine, Behenyl Betaine, Shea Butteramidopropyl Betaine, Myristamidopropyl Betaine, Undecylenamidopropyl Betaine, Wheat Germamidopropyl Betaine, Capryl/Capramidopropyl Betaine, Coco-Hydroxysultaine, Coco-Betaine, Coco/Oleamidopropyl Betaine, Cocamidopropyl Hydroxysultaine, Cocamidopropyl Betainamide MEA Chloride, Cocamidoethyl Betaine, Isostearamidopropyl Betaine, Stearyl Betaine, Stearamidopropyl Betaine, Oleyl Betaine, Oleamidopropyl Betaine, Lauryl Hydroxysultaine, Lauryl Betaine, Lauramidopropyl Hydroxysultaine, Sodium Cocoamphopropionate, Disodium Cocoamphodipropionate, Disodium Cocoamphodiacetate, Sodium Cocoamphohydroxypropylsulfonate, and Sodium Cocoamphoacetate.
Examples of the glucoside derivatives include C12-16 Alkyl Glucoside, C12-18 Alkyl Glucoside, C12-20 Alkyl Glucoside, C8-14 Alkyl Glucoside, Decyl Glucoside, Arachidyl Glucoside, Cetearyl Glucoside, Myristyl Glucoside, Caprylyl/Capryl Glucoside, Caprylyl Dimethicone Ethoxy Glucoside, Caprylyl Glucoside, Coco-Glucoside, Ethyl Glucoside, Isostearyl Glucoside, and Lauryl Glucoside.
In one embodiment of the present invention, the second surfactant may be present together with the N-acyl amino acid and water, and they may be heated together to a temperature falling in the range of 70 ℃ to 100 ℃, preferably 75 ℃ to 90 ℃, more preferably 80 ℃ to 88 ℃.
The expression “a second surfactant and/or a hair conditioning compound is/are comprised in the solution i) and/or the solution ii) and/or the solution iii) ” can be interpreted as:
- a second surfactant or a hair conditioning compound is only comprised in the solution iii) ,
- a second surfactant or a hair conditioning compound is comprised in the solutions i) and iii) ,
- a second surfactant or a hair conditioning compound is comprised in the solutions ii) and iii) ,
- a second surfactant or a hair conditioning compound is comprised in the solutions i) , ii) and iii) ,
- a second surfactant and a hair conditioning compound are only comprised in the solution iii) ,
- a second surfactant and a hair conditioning compound are comprised in the solutions i) and iii) ,
- a second surfactant and a hair conditioning compound are comprised in the solutions ii) and iii) ,
- a second surfactant and a hair conditioning compound are comprised in the solutions i) , ii) and iii) .
The second surfactant can be comprised in the transparent shampoo bar in an amount of from 0 wt%to 25 wt%, preferably from 5 wt%to 20 wt%, based on the total weight of the transparent shampoo bar.
Optionally, a hair conditioning compound may be comprised in the solution i) and/or the solution ii) and/or be incorporated later into the solution iii) . In other words, it is not particularly limited in which step the conditioning compound is added to the system, as long as the conditioning compound is present in the system. Also, it is feasible that the conditioning compound is present in each solution of the system or added in each step to the system. Moreover, the conditioning compound in each solution or added in each step may be the same or different from each other. From the perspective of better conditioning effect, it is preferred to comprise a hair conditioning compound.
The term “conditioning compound” used herein refers to those compounds imparting additional characters, except for the cleansing effect, to the hair, for example, smooth, combability, elasticity, shining, softness, hair damage repairing, and the like.
The conditioning compound useful in the present invention may be selected from cationic polymers, fatty acid esters carrying hydrophilic groups, oils, plant extracts and the like.
Examples of the cationic polymers include Starch Hydroxypropyltrimonium Chloride, Guar Hydroxypropyltrimonium Chloride, Locust Bean Hydroxypropyltrimonium Chloride, Caesalpinia Spinosa Hydroxypropyltrimonium Chloride, Cassia Hydroxypropyltrimonium Chloride, Dextran Hydroxypropyltrimonium Chloride, Hydroxypropyl Guar Hydroxypropyltrimonium Chloride, Hydroxypropyl Oxidized Starch Pg-Trimonium Chloride, Hydrogenated Starch Hydrolysate Hydroxypropyltrimonium Chloride, Ginseng Hydroxypropyltrimonium Chloride, Lauryl Methyl Gluceth-10 Hydroxypropyldimonium Chloride, Acrylamidopropyltrimonium Chloride/Acrylamide Copolymer, Propyltrimoniumchloride Acrylamide/Dimethylacrylamide Copolymer, Dimethylacrylamide/Ethyltrimonium Chloride Methacrylate Copolymer, Polymethacrylamidopropyltrimonium Chloride, Acrylamidopropyltrimonium Chloride/Acrylates Copolymer, Acrylamidopropyltrimonium Chloride/Acrylamide Copolymer, Pg-Hydroxyethylcellulose Cocodimonium Chloride, Pg-Hydroxyethylcellulose Stearyldimonium Chloride, Soyamidopropalkonium Chloride, Distearoylethyl Dimonium Chloride, Dipalmitoylethyl Dimonium Chloride, Polyquaternium-1, Polyquaternium-10, Polyquaternium-104, Polyquaternium-11, Polyquaternium-15, Polyquaternium-16, Polyquaternium-18, Polyquaternium-19, Polyquaternium-2, Polyquaternium-22, Polyquaternium-24, Polyquaternium-28, Polyquaternium-30, Polyquaternium-32, Polyquaternium-33, Polyquaternium-35, Polyquaternium-37, Polyquaternium-39, Polyquaternium-4, Polyquaternium-43, Polyquaternium-44, Polyquaternium-46, Polyquaternium-47, Polyquaternium-49, Polyquaternium-50, Polyquaternium-51, Polyquaternium-52, Polyquaternium-53, Polyquaternium-55, Polyquaternium-56, Polyquaternium-57, Polyquaternium-6, Polyquaternium-61, Polyquaternium-62, Polyquaternium-63, Polyquaternium-64, Polyquaternium-65, Polyquaternium-67, Polyquaternium-68, Polyquaternium-69, Polyquaternium-7, Polyquaternium-73, Polyquaternium-74, Polyquaternium-75, Polyquaternium-76, Polyquaternium-78, and Polyquaternium-80.
Examples of the fatty acid esters carrying hydrophilic groups include PEG-7 Glyceryl Cocoate, PEG-7 Caprylic/Capric Glycerides, PEG-70 Mango Glycerides, and PPG-3 Caprylyl Ether.
Examples of the oils include plant oils, essential oils such as mint oil, silicone oils such as Dimethicone, and Bisamino PEG/PPG-41/3 Aminoethyl PG-Propyl Dimethicone.
The hair conditioning compound can be comprised in an amount of from 0 wt%to 30 wt%, preferably from 0.1 wt%to 20 wt%, more preferably 0.2 wt%to 10 wt%, based on the total weight of the transparent shampoo bar.
Moreover, additives such as a preservative, an antioxidant, a perfume can be optionally added at any step in the method of the present invention.
In another aspect of the present invention, a transparent shampoo bar produced by the method according to the present invention is provided.
In still another aspect of the present invention, a transparent shampoo bar is provided, wherein the bar comprises:
- a salt in situ formed from at least one N-acyl amino acid and at least one alkali,
- water,
- at least one alcohol,
- optionally, a second surfactant, and
- optionally, a hair conditioning compound.
In the transparent shampoo bar of the present invention, the expression “a salt in situ formed from at least one N-acyl amino acid and at least one alkali” should be interpreted as that the salt existing in the transparent shampoo bar is formed in place rather than added from outside. As shown in the examples, merely adding a salt of N-acyl amino acid directly to the system cannot form a transparent shampoo bar, and according to the examples, a salt of N-acyl amino acid can be added as a second surfactant, but in order to form a transparent bar, at least a part of the salt of N-acyl amino acid should be formed in situ. Thus, if a salt of N-acyl amino acid is detected in a commercial transparent shampoo bar which further comprises other components of the present invention, it can be determined that the salt of N-acyl amino acid is formed in situ, or at least a part of the salt of N-acyl amino acid is formed in situ, and hence the commercial transparent shampoo bar should be deemed as falling in the scope of the present invention.
The salt in situ formed from at least one N-acyl amino acid and at least one alkali is comprised in an amount of from 15 wt%to 80 wt%, preferably from 20 wt%to 55 wt%, based on the total weight of the transparent shampoo bar.
The definition and selections for the at least one N-acyl amino acid and the at least one alkali useful in the transparent shampoo bar of the present invention are the same as those mentioned above in the method according to the present invention.
The water is comprised in a total amount of no more than 40 wt%, preferably no more than 30 wt%, based on the total weight of the transparent shampoo bar.
The at least one alcohol is an essential component for the transparent shampoo bar of the present invention. The definition and selections for the at least one alcohol useful in the transparent shampoo bar of the present invention are the same as those mentioned above in the method according to the present invention. The at least one alcohol is comprised in an amount of from 5 wt%to 30%, preferably, from 10 wt%to 20 wt%, based on the total weight of the transparent shampoo bar.
Optionally, a second surfactant may be comprised in the transparent shampoo bar. From the perspective of better cleansing effect, it is preferred to comprise a second surfactant in the system in addition the N-acyl amino acid or its in situ formed salts. The definition and selections for the second surfactant useful in the transparent shampoo bar of the present invention are the same as those mentioned above in the method according to the present invention. The second surfactant can be comprised in the transparent shampoo bar in an amount of from 0 wt%to 25 wt%, preferably from 5 wt%to 20 wt%, based on the total weight of the transparent shampoo bar.
Optionally, a hair conditioning compound may be comprised in the transparent shampoo bar. From the perspective of better conditioning effect, it is preferred to comprise a hair conditioning compound. The definition and selections for the hair conditioning compound useful in the transparent shampoo bar of the present invention are the same as those mentioned above in the method according to the present invention. The hair conditioning compound can be comprised in the transparent shampoo bar in an amount of from 0 wt%to 30 wt%, preferably from 0.1 wt%to 20 wt%, more preferably 0.2 wt%to 10 wt%, based on the total weight of the transparent shampoo bar.
Moreover, additives such as a preservative, an antioxidant, a perfume can be optionally comprised in the transparent shampoo bar of the present invention.
The transparent shampoo bar of the present invention can be in any shape, like any usual shapes of soaps, and can be in any size like any usual sizes of soaps, for example, a size for using a few times such as only one to five times of shampooing, or a size for using in a relatively long time of shampooing.
In addition, the present invention also provides a bi-layer shampoo and conditioning bar, comprising a transparent shampoo bar of the present invention on one side and a conditioning bar on the other side. The conditioning bar useful in the present invention can be any color as required, for example, a white conditioning bar.
As for the conditioning bar useful in the present invention, all contents of the patent application with the application No. PCT/CN2018/124871 is incorporated herein by reference.
Examples
The invention will now be described by way of the following examples. The following examples are intended to assist one skilled in the art to better understand and practice the present invention. The scope of the invention is not limited by the examples but is defined in the appended claims. All parts and percentages are based on weight unless otherwise stated.
Raw Materials
Example 1:
Table 1: Components used for preparing the transparent shampoo bar
Method:
1. Mixing components No. 1 to 6 together and heating them to a temperature of about 85 ℃;
2. Adding components No. 7 to the heated components No. 1 to 6 with stirring while keeping the temperature of about 85 ℃;
3. Mixing components No. 8 to 11 together and adding them to the heated components No. 1 to 7 with stirring, so as to obtain the solution i) having a temperature of about 85 ℃;
4. Mixing components No. 12 to 13 and heating them to a temperature of about 85 ℃, so as to obtain the solution ii) ;
5. Adding the solution ii) slowly to the solution i) with stirring for about 2 to 5 min while keeping the temperature of about 85 ℃;
6. Then adding components No. 14 to 16 with stirring, so as to obtain the solution iii) .
7. Stop stirring and maintain the temperature at about 85 ℃ for about 20 min;
8. Pouring the solution iii) into a mold and naturally cooling down to room temperature, a uniform transparent shampoo bar was obtained.
The obtained shampoo bar has excellent transparency, see Figure 1, in which a shampoo bar according to Example 1 with a thickness of 2.5 cm is shown, and the letters under the bar can be clearly seen visually through the bar. By comparison, the commercially available LUSH shampoo bar is completely non-transparent.
Example 2: Bi-layer shampoo and conditioning bar
Table 2: Components used for preparing the bi-layer shampoo and conditioning bar
Components No. 1 to 11 were used to prepare the conditioning layer; and components No. 12 to 22 were used to prepare the transparent shampoo layer.
White conditioning layer preparation:
1. Mixing components No. 5 to 11 and heating them to a temperature of about 85 ℃;
2. Adding components No. 1 to 4 to the heated components No. 5 to 11 with stirring at a temperature of about 85 ℃;
3. Cooling down to a temperature of 60 -65 ℃; and
4. Pouring the mixture into a mold, and fully curing the mixture.
Transparent shampoo layer preparation:
1. Mixing components No. 12 to 17 together and heating them to a temperature of about 85 ℃, so as to obtain the solution i) ;
2. Mixing components No. 18 to 19 and heating them to a temperature of about 85 ℃, so as to obtain the solution ii) ;
3. Adding the solution ii) slowly to the solution i) with stirring for about 2 to 5 min while keeping the temperature of about 85 ℃;
4. Adding components No. 20 to 22 with stirring, so as to obtain the solution iii) .
5. Stop stirring and maintain the temperature at about 85 ℃ for about 20 min;
Bi-layer preparation:
Pouring the above obtained solution iii) into the same mold of the conditioning layer, naturally cooling down to room temperature so as to form a bi-layer shampoo and conditioning bar with one side being the transparent shampoo bare and the other side being the white conditioning bar.
Example 3:
Table 3: Components used for preparing the transparent shampoo bar
Method:
1. Mixing components No. 1 to 6 together and heating them to a temperature of about 85 ℃, so as to obtain the solution i) ;
2. Mixing components No. 7 to 9 together and heating them to a temperature of about 85 ℃, so as to obtain the solution ii) ;
3. Adding the solution ii) slowly to the solution i) with stirring for about 2 to 5 min while keeping the temperature of about 85 ℃, so as to obtain the solution iii) ;
4. Stop stirring and maintain the temperature at about 85 ℃ for about 20 min;
5. Pouring the solution iii) into a mold and naturally cooling down to room temperature, a uniform transparent shampoo bar was obtained.
The obtained shampoo bar has excellent transparency, see Figure 1, in which a shampoo bar of Example 3 with a thickness of 2.5 cm is shown, and the letters under the bar can be clearly seen visually through the bar.
Example 4:
Table 4: Components used for preparing the transparent shampoo bar
Method:
1. Mixing components No. 1 to 6 together and heating them to a temperature of about 85 ℃;
2. Mixing components No. 7 to 11 together and adding them to the heated components No. 1 to 6 with stirring, so as to obtain the solution i) having a temperature of about 85 ℃;
3. Mixing components No. 12 to 13 and heating them to a temperature of about 85 ℃, so as to obtain the solution ii) ;
4. Adding the solution ii) slowly to the solution i) with stirring for about 2 to 5 min while keeping the temperature of about 85 ℃;
5. Then adding components No. 14 to 16 with stirring, so as to obtain the solution iii) .
6. Stop stirring and maintain the temperature at about 85 ℃ for about 20 min;
7. Pouring the solution iii) into a mold and naturally cooling down to room temperature, a uniform transparent shampoo bar was obtained.
The obtained shampoo bar has excellent transparency, see Figure 1, in which a shampoo bar of Example 4 with a thickness of 2.5 cm is shown, and the letters under the bar can be clearly seen visually through the bar.
Example 5:
Table5: Components used for preparing the transparent shampoo bar
Method:
1. Mixing components No. 1 to 5 together and heating them to a temperature of about 85 ℃;
2. Mixing components No. 6 to 10 and 13 to 15 together and adding them to the heated components No. 1 to 5 with stirring, so as to obtain the solution i) having a temperature of about 85 ℃;
3. Mixing components No. 11 to 12 and heating them to a temperature of about 85 ℃, so as to obtain the solution ii) ;
4. Adding the solution ii) slowly to the solution i) with stirring for about 20 min while keeping the temperature of about 85 ℃, so as to obtain the solution iii) ;
5. Stop stirring and maintain the temperature at about 85 ℃ for about 20 min;
6. Pouring the solution iii) into a mold and naturally cooling down to room temperature, a uniform transparent shampoo bar was obtained.
The obtained shampoo bar has excellent transparency, see Figure 1, in which a shampoo bar of Example 5 with a thickness of 2.5 cm is shown, and the letters under the bar can be clearly seen visually through the bar.
Comparative Example 1:
Table 6: Components used for preparing the shampoo
Method:
1. Mixing components No. 1 to 6 together and heating them to a temperature of about 85 ℃;
2. Adding component No. 7 to the heated components No. 1 to 6 with stirring while keeping the temperature of about 85 ℃;
3. Mixing components No. 8 to 11 together and adding them to the heated components No. 1 to 7 with stirring, so as to obtain a first solution having a temperature of about 85 ℃; the first solution being a non-transparent solution as components cannot be completely dissolved;
4. Heating component No. 12 to a temperature of about 85 ℃, so as to obtain a second solution;
5. Adding the second solution slowly to the first solution with stirring for about 20 min while keeping the temperature of about 85 ℃, so as to obtain a third solution; the third solution being a non-transparent solution;
6. Stop stirring and maintain the temperature at about 85 ℃ for about 20 min;
7. Pouring the third solution into a mold and cooling down to room temperature, a non-uniform white shampoo bar with a brittle texture was obtained.
Comparative Example 2:
Table 7: Components used for preparing the shampoo
Method:
1. Mixing components No. 1 to 6 together and heating them to a temperature of about 85 ℃;
2. Adding components No. 7-10 to the heated components No. 1 to 6 with stirring while keeping the temperature of about 85 ℃;
3. Evaporating about 82.7g of the excess water to obtain a solution,
4. Pouring the solution to a mold and naturally cooling down to room temperature, a double-phase product was obtained in which the upper phase was a soft film and the lower phase was a flowable viscous liquid, and a bar in solid form was not be formed.
Comparative Example 3
Table 8: Components used for preparing the shampoo
Method:
1. Mixing components No. 1 to 6 together and heating them to a temperature of about 85 ℃;
2. Adding components No. 7 to the heated components No. 1 to 6 with stirring while keeping the temperature of about 85 ℃;
3. Mixing components No. 8 to 11 and 14-16 together and adding them to the heated components No. 1 to 7 with stirring, so as to obtain the solution i) having a temperature of about 85 ℃;
4. Mixing components No. 12 to 13 and heating them to a temperature of about 85 ℃, so as to obtain the solution ii) ;
5. Adding the solution i) slowly to the solution ii) with stirring while keeping the temperature of about 85 ℃; along with addition of solution i) , solid substance was immediately formed and aggregated in the solution ii) ; after addition of solution i) was completed, a non-uniform partially transparent solid shampoo piece was formed in the vessel and cannot be discharged into the mold.
Conditioning performance
A. Wet combability
Materials:
● The shampoo bar produced according to the Example 1,
● SK EC Hydro force shampoo, liquid,
● SK beology aqua shampoo, liquid,
● Hair swatches: Kerling International (Backnang, Germany) , China natural hair, lot #04/2016, N142, length 12 cm, weight 1 +/-0.05 g,
● Combs: Hercules (Hamburg, Germany) , hard rubber comb, fine-toothed
● Device: Customized machine for automated combing.
Test procedure:
● Pre-treatment of the hair strands: 10 hair strands were used for the reference and another 10 hair strands were used for product application. The hair was medium-bleached and stored at 25 ℃ and 25 %RH for at least 48 hours. The strands for the reference were soaked in water for 5 minutes shortly before the combing forces were determined.
● Application of shampoo
Shampoo bar: 0.17 g /g hair of the shampoo was dissolved in water (3.4 g in 10 ml) , then applied on damp hair and worked in thoroughly. After 2 min the strands were rinsed under standard conditions (tap water at 32 ℃, 0.5 L per min) for 18 sec while being combed automatically. The shampoo bar was applied twice.
Liquid shampoos: 0.25 g/g hair of the shampoo was applied on damp hair. After 2 min the strands were rinsed under standard conditions (tap water at 32 ℃, 0.5 L per min) for 18 sec while being combed automatically. The shampoo was applied twice.
● Measurement of wet combing work
Each strand was combed and moistened for 2 seconds before the measurement started.
After three pre-combing strokes, 10 combings were carried out on each strand while the strand rotated slowly. The mean value of the combing work was determined (see Figure 2) .
The less the work value is, the better the wet combability is. As shown in Figure 2, the transparent shampoo bar shows better wet combability than other two liquid shampoos of the prior art.
B. Dry combability
The materials and the pre-treatment of the hair strands and the application of shampoos are the same as those stated in the wet combability except for SK beology aqua shampoo.
Before the measurement, the hair strands were stored at 25 ℃ and 25 %RH for at least 24 hours. Each strand was discharged before the measurement.
After three pre-combing strokes, 10 combings were carried out on each strand while the strand rotated slowly. The median value of the combing work was determined (see Figure 3) . It can be seen that the transparent shampoo bar of the present invention has comparable dry combability to the liquid shampoo of the prior art.
C. Smooth of hair
Raw Materials:
● The shampoo bar produced according to the Example 1,
● The LUSH shampoo bar,
● Hair strands, from Hai chuan jin rong fa zhi pin, Shandong China.
Two hair strands (length: 25cm, weight: 4g) were bleached once, towel dried and blow dried, then leave at least for 48 hours at room temperature. 0.5 g shampoo bar was applied on damp hair directly and worked in thoroughly. Then the strands were rinsed under same conditions (tap water at 32 ℃, 0.5 L per min) for 1 minute. The shampoo bar was applied twice.
10 volunteers assessed the two wet hair strands treated by different shampoo bars through their fingers and comb, and chose the better one (more smooth or softer) , every volunteer evaluated three times.
All 10 people thought the hair treated by the shampoo bar according to Example 1 is more smooth than Lush shampoo bar on wet hair.
D. Detergency power
Raw materials:
● The shampoo bars produced according to the Examples 1 and 3 to 5,
● LUSH shampoo Bar,
● SK beology aqua shampoo, liquid,
● Hair strands, from Hai chuan jin rong fa zhi pin, Shandong China.
Hair strand’s weight was weighted and recorded (M1) , then 0.5g (M2) of artificial sebum were applied on dry hair evenly , and then the hair strand was wetted with the same amount of water, and 0.3g of shampoo (M3) was applied on the damp hair, softly washing hair for 30 sec, then rinsed under same conditions for 1 minute. The treated strands were stored at 25 ℃ and 25 %RH for at least 48 hours and weighted the weight (M4) .
The amount of sebum removed was calculated by using the following equation:
DP= (M1+M2-M4) /M3
In which,
- DP is the detergency power, meaning the amount of sebum that can be washed out per gram of shampoo,
- M1 is the weight of hair strand,
- M2 is the weight of artificial sebum actually applied,
- M3 is the weight of shampoo actually used,
- M4 is the weight of hair strand after drying.
The test results are shown as below.
As shown in the table, detergency power of each shampoo bar of the present invention is good and is comparable to the shampoos of the prior art.
Although some preferred embodiments have been described, many modifications and variations may be made thereto in light of the above teachings. It is therefore to be understood that the invention may be practiced otherwise than as specifically described without departing from the scope of the appended claims.

Claims

A method for producing a transparent shampoo bar, comprising:

i) preparing a solution i) comprising at least one N-acyl amino acid and water, the solution i) having a temperature of 70 ℃ to 100 ℃, preferably 75 ℃ to 90 ℃, more preferably 80 ℃ to 88 ℃,

ii) preparing a solution ii) comprising at least one alkali and water, the solution ii) having a temperature of 70 ℃ to 100 ℃, preferably 75 ℃ to 90 ℃, more preferably 80 ℃ to 88 ℃,

iii) adding the solution ii) to the solution i) with stirring at a temperature of 70 ℃ to 100 ℃, preferably 75 ℃ to 90 ℃, more preferably 80 ℃ to 88 ℃, so as to obtain a homogeneous transparent solution iii) ; and

iv) cooling the solution iii) to room temperature,

wherein

a) at least one alcohol is comprised in the solution i) and/or the solution ii) and/or the solution iii) ,

b) the water is comprised in a total amount of no more than 40 wt%, preferably no more than 30 wt%, based on the total weight of the transparent shampoo bar, and

c) optionally, a second surfactant and/or a hair conditioning compound is/are comprised in the solution i) and/or the solution ii) and/or the solution iii) .
A transparent shampoo bar, comprising:

- a salt in situ formed from at least one N-acyl amino acid and at least one alkali,

- water,

- at least one alcohol,

- optionally, a second surfactant, and

- optionally, a hair conditioning compound.
The method according to claim 1 or the transparent shampoo bar according to claim 2, wherein the at least one N-acyl amino acid is selected from a group consisting of N-acyl glutamic acid, N-acyl alanine, N-acyl glycine, N-acyl lysine, N-acyl proline and N-acyl sarcosine.
The method according to claim 1 or 3 or the transparent shampoo bar according to claim 2 or 3 , wherein the acyl in the N-acyl amino acid is an aliphatic acyl group having 6 to 22 carbon atoms.
The method according to any one of claims 1 and 3 to 4 or the transparent shampoo bar according to any one of claim 2 to 4, wherein the at least one N-acyl amino acid is selected from a group consisting of cocoyl glutamic acid, lauroyl glutamic acid, stearoyl glutamic acid, myristoryl glutamic acid, palmitoyl glutamic acid, oleoyl glutamic acid, cocoyl alanine, lauroyl alanine, stearoyl alanine, myristoryl alanine, palmitoyl alanine, oleoyl alanine, cocoyl glycine, lauroyl glycine, stearoyl glycine, myristoryl glycine, palmitoyl glycine, oleoyl glycine, cocoyl lysine, lauroyl lysine, stearoyl lysine, myristoryl lysine, palmitoyl lysine, oleoyl lysine, cocoyl proline, lauroyl proline, stearoyl proline, myristoryl proline, palmitoyl proline, oleoyl proline, cocoyl sarcosine, lauroyl sarcosine, stearoyl sarcosine, myristoryl sarcosine, palmitoyl sarcosine and oleoyl sarcosine.
The method according to any one of claims 1 and 3 to 5 or the transparent shampoo bar according to any one of claim 2 to 5, wherein the at least one alkali is selected from a group consisting of aminomethyl propanol, aminoethyl propanol, triethanolamine, ethanolamine, diethanolamine, tetrahydroxypropyl ethylenediamine, potassium hydroxide, sodium hydroxide and sodium bicarbonate.
The method according to any one of claims 1 and 3 to 6 or the transparent shampoo bar according to any one of claim 2 to 6, wherein the at least one alcohol is selected from aliphatic alcohols having no more than 10 carbon atoms.
The method according to any one of claims 1 and 3 to 7 or the transparent shampoo bar according to any one of claim 2 to 7, wherein the at least one alcohol is selected from a group consisting of ethanol (denatured) , ethylene glycol, propylene glycols such as 1, 3-propanediol, butylene glycols such as 1, 2-butanediol, 2, 3-butanediol, 1, 4-butanediol, pentylene glycols such as 1, 2-pentanediol, isopentyldiol, 1, 5-pentanediol, hexylene glycols such as 1, 2-hexanediol, 1, 6-hexanediol, octanediols, nonanediols such as 1, 9-nonanediol, decylene glycols such as 1, 10-decanediol, glycerine, sorbitol, diethylene glycol, and dipropylene glycol.
The method according to any one of claims 1 and 3 to 8 or the transparent shampoo bar according to any one of claim 2 to 8, wherein the at least one alcohol is comprised in an amount of from 5 wt%to 30%, preferably, from 10 wt%to 20 wt%, based on the total weight of the transparent shampoo bar.
The method according to any one of claims 1 and 3 to 9 or the transparent shampoo bar according to any one of claim 2 to 9, wherein the hair conditioning compound is selected from cationic polymers, fatty acid esters carrying hydrophilic groups, oils, and plant extracts.
The method according to any one of claims 1 and 3 to 10 or the transparent shampoo bar according to any one of claim 2 to 10, wherein the second surfactant is selected from anionic surfactants, amphoteric surfactants, and glucoside derivatives.
The method according to any one of claims 1 and 3 to 11 or the transparent shampoo bar according to any one of claim 2 to 11, wherein the hair conditioning compound is comprised in an amount of 0 wt%to 30 wt%, preferably from 0.1 wt%to 20 wt%, more preferably 0.2 wt%to 10 wt%, based on the total weight of the transparent shampoo bar.
The method according to any one of claims 1 and 3 to 12 or the transparent shampoo bar according to any one of claim 2 to 12, wherein the second surfactant is comprised in an amount of 0 wt%to 25 wt%, preferably from 5 wt%to 20 wt%, based on the total weight of the transparent shampoo bar.
The method according to any one of claims 1 and 3 to 13 or the transparent shampoo bar according to any one of claim 2 to 13, wherein the at least one alkali comprises triethanolamine.
The method according to any one of claims 1 and 3 to 14 or the transparent shampoo bar according to any one of claim 2 to 14, wherein the at least one alkali is triethanolamine or a combination of triethanolamine and an alkali other than triethanolamine, such as a combination of triethanolamine and aminomethyl propanol, a combination of triethanolamine and aminoethyl propanol, or a combination of triethanolamine and ethanolamine and/or diethanolamine and/or tetrahydroxypropyl ethylenediamine.
The method according to any one of claims 1 and 3 to 15, wherein the at least one alkali is used in a total amount of from 5 wt%to 30 wt%, preferably from 10 wt%to 25 wt%, based on the total weight of the transparent shampoo bar.
The method according to any one of claims 1 and 3 to 16, wherein the at least one N-acyl amino acid is used in an amount of from 10 wt%to 50 wt%, preferably from 15 wt%to 40 wt%, based on the total weight of the transparent shampoo bar.
The transparent shampoo bar according to any one of claim 2 to 15, wherein the salt in situ formed from at least one N-acyl amino acid and at least one alkali is comprised in an amount of from 15 wt%to 80 wt%, preferably from 20 wt%to 55 wt%, based on the total weight of the transparent shampoo bar.
A transparent shampoo bar produced by the method according to any one of claims 1 and 3 to 17.
A bi-layer shampoo and conditioning bar, comprising a transparent shampoo bar according to any one of claims 2 to 15 and 18 to 19 or produced according to the method of any one of claims 1 and 3-17 on one side and a hair conditioning bar on the other side.