FR2557123A1 - Process for the production of vegetable dye extracts and their uses - Google Patents

Abstract

Process for the preparation of a composition for dyeing by means of natural dyes extracted from plants, characterised in that the dye extract in fine powder form is mixed with one or a number of inorganic compounds which are chemically inert towards this extract and insoluble in water and are taken in the form of fine powder, these inorganic compounds not giving any insoluble dyeing combination with the said extract.

Description

 The invention relates to a process for the preparation of compositions based on natural dyes; it also includes the compositions thus obtained.

These are applicable to the dyeing of various materials, in particular textile fibers, cellulose sheets, polymers, keratin materials, and others.

 The use of vegetable dyes has been known and practiced since Antiquity. The dyeing was done by bringing the material to be dyed into contact with an aqueous suspension of different parts of the plant rich in dye; this is how textiles were dyed, for example, by placing them in baths containing wood, bark, roots, leaves, fruits, flowers or seeds, plants containing the desired dye. . It is in such a way that the Chinese, then Greeks and Romans made the dyeing of the fabrics in red by madder directly using the crushed roots; this process is also still used today. Another way of operating is to make an extract of the dye from the chosen plant and use it immediately for dyeing, such as safflower, whose flowers are exhausted with alkaline water and the extract is immediately used for dyeing. These practices do not give reproducible results, because of the variations in the contents and qualities of the dye from one batch of plants to another; on the other hand, the heterogeneity of the bath leads to irregularities in coloring on the material treated.

 There are known plant extracts concentrated in the liquid form, in the form of blocks, in crystallized powder or in atomized powder, intended for the dyeing of textiles, leathers or inks. We find in this form there for example extracts of logwood, red wood or indigo. Such extracts give reproducible coloration only in operations involving large quantities of dyes and dyestuffs; use of these preparations is therefore suitable only for specialized industries, but not for users with small quantities of materials to be treated.

 However, given the non-toxicity of most natural dyes, as well as the very affordable price of some of them, these dyes still have many applications today. Natural, vegetable coloring preparations are known in the form of liquid concentrates such as oleoresins in solution or dispersion in oils or other fatty substances, in concentrated hydroalcoholic extracts, or in water-soluble extracts, optionally stabilized by antioxidants. Similarly, there are water-soluble powders, in particular oleoresins, alcoholic or aqueous extracts, atomized on maltodextrins, on potassium carbonate or on lactose, or else dried on mixtures of gelatin and sucrose. Such preparations are used in industries food and pharmaceutical, for coloring drinks, oils, dairy products, confectionery, cookies, ice cream, etc. The dry, powdered preparations are suitable for dehydrated drinks, flour, soups, sauces, coating of tablets, capsules, syrups and others. However, these extracts, even very concentrated, most often undergo more or less extensive degradation after a few months of storage. It should also be noted that the practically possible colors are limited to yellow, orange, red, green and brown.

 With regard to the specific application of vegetable dye extracts to hair coloring, the manufacturers generally do not give any information on the shelf life of the dye in the cosmetic product offered. Sometimes the color expected on the keratin fiber is mentioned. The use of these extracts is simple, but the coloration obtained is weak and the storage random.

 Other compositions for dyeing the hair include a coloring, vegetable, dry extract, a coloring plant powder, or the dye itself in powder form mixed with substances such as sugars, polyols, mineral or organic salts or powders. of exhausted plants. At the time of use, the whole is mixed with lukewarm milk or lukewarm water and placed on the hair for the purpose of obtaining reflections.These kinds of preparations are difficult to use, because they form a very thick paste or plaster; they require large quantities of dye and mechanical means for the preparation intended for the hair.

 There are also mixtures of coloring plant powders, all ready to be put in the form of poultices by adding water, for the coloring of a hair. These products present difficulties of use inherent in the formation of a poultice; in general, the coloration attained is weak and the application time long.

 Certain natural dyes are used in paints, coatings, varnishes, inks, plastic matins, etc. They are then found in the form of pigments or lacquers: the dye is adsorbed thereon on an insoluble powder or combined with it in the form of a metal complex. It is therefore made insoluble and is not released when the pigment or lacquer is dissolved in water. In the abovementioned uses, this product is found in dispersion in a medium containing a binder such as resin, gum or synthetic polymer; when this dispersion is applied to a support, the dye does not react with it; in other words, there is no question of dyeing of the support by the dye.

 As can be seen, the prior art relating to the use of natural, vegetable dyes does not generally give very good results, except in certain specific cases. This technique exhibits operational inconvenience, lack of reproducibility, generally too low color intensity, and difficulties in preserving the coloring preparation.

 The present invention provides significant progress for this purpose: it makes it possible to obtain preparations of vegetable dyes, very stable, easily applicable to the dyeing of all kinds of materials, on a small or large scale. The invention also makes possible the preparation of compositions of any desired concentration, applicable to obtaining light shades as well as intense colorings. The colored extracts prepared according to the invention are characterized by very good stability, under current storage conditions, in particular at room temperature, in the dark, in a stoppered bottle without any particular precautions. These products are insensitive to humidity and do not require the addition of any preservative; the plant extract provides more effective protection than a preservative, in some cases.

 The process according to the invention consists in mixing a coloring extract, plant, in the solid state, with one or more mineral compounds, chemically inert with respect to this extract, these compounds, also solid, insoluble in water, having a low apparent density and a high specific surface. It is understood that both the coloring extract and the mineral compound are in the form of a fine powder.

 The inertness of the mineral compound vis-à-vis the plant extract means that placed in an aqueous medium, these products do not form any insoluble combination of the dye. In other words, when the composition according to the invention is diluted with water, the unchanged particles of the mineral compound and the particles or solution of the vegetable dye are found in the liquid. This is a fundamental difference between the compositions according to the invention and the pigments well known in the art, which contain particles formed by a mineral compound to which a dye is combined, these particles being insoluble in water. In addition, the mineral compound must not give rise to any reaction of oxidation, reduction or release of ions with respect to the dye used.

 The coloring powder, used according to the invention, is preferably constituted by an extract made, in the manner known per se, from one or more parts of a plant containing the dye, that is to say that the preferred form of the invention uses a powder of the coloring matter, vegetable, itself. However, the fact of adding the mineral compound, mentioned above, makes it possible to obtain good coloring products, even with powders obtained by the grinding of resins, leaves, petals, fruits, barks, wood, seeds, etc. a coloriferous plant; thanks to the fineness of the grinding and the presence of the mineral compound, the drawbacks, mentioned above about the old methods, are no longer felt here.

 In carrying out the invention, the fineness of the powders used must be such that the particles have only a size of approximately 1 to 50 microns and, preferably, from 2 to 30 microns. Particularly favorable results are obtained when the particles of the plant extract have sizes between 5 and 10 microns and those of the mineral material from 2 to 16 microns.

The first criterion, in the choice of the mineral compound, is - as indicated above - not to form a water-insoluble combination with the desired dye. The other two criteria preferably reside in an apparent density not exceeding 300 g / dm3 or better between 50 and 200 g / dm3 for the loose powder. The specific surface must be greater than 8 m2 / g and preferably
2 from 10 to 110, 2 / su
By way of nonlimiting example, mention may be made, as inorganic compounds, suitable for carrying out the invention, of oxides such as those of zinc, titanium, silicon, Al, natural silicates such as kaolin, bentonite or talc , certain carbonates, phosphates or fluorides such as those of calcium or magnesium for example, etc.

Apart from natural silicas, synthetic, microcrystalline, hydrophilic or hydrophobic silicas can be used by chemical treatment.

 It is understood that a mineral compound which, with certain dyes, gives a pigment and therefore does not form part of the invention for this dye there, can possibly be used, within the framework of the present invention - with another dye - with which it does not give insoluble pigment. This is for example the case of hydrated alumina which forms, with madder extract, a lacquer which is outside the present invention; on the other hand, the same hydrated alumina can form a mixture, according to the invention, with an extract of indigo leaves.

 The relative proportions of dye and mineral compound can vary within a wide range, in particular from 5 to 98% of one of them, in the mixture; practically, the preferred proportions are about 10 to 80%, by weight.

 It goes without saying that a composition according to the invention can comprise one or more coloring extracts with one or more mineral compounds defined above.

 The coloring extracts, put in the form of the compositions according to the invention, are particularly stable on storage for a fairly long time, exceeding, in most cases, 18 months, even when the content of coloring element is low. In addition, they are easily dispersed or redissolved, uniformly, without the formation of lumps, lumps or micelles, in the solvent usually used to carry out the actual dyeing, depending on the material to be dyed; this can be done by simple stirring, not requiring the use of any special apparatus, and this both at room temperature and at any temperature between 100C and the boiling point of the solvent, according to the process required by the nature of the material to be colored. The solvent can be water, another solvent, a mixture of solvents or a solution constituted by various chemical substances generally used for dyes.

 Thanks to the coloring preparation, produced according to the invention, the dyeing of fibers or other materials can be done in a completely homogeneous manner; it is very simple and the reproducibility of the colors is facilitated, because the method of the invention makes it easy to handle very small quantities of coloring substances, precisely, without complicated or elaborate weighing equipment. Indeed, it suffices to take a composition according to the invention with a low dye content so that the quantity of dyestuff is low for a relatively large volume. In addition, thanks to the compounds according to the invention, the dye molecules can react uniformly with the metal salts, the oxidizing substances or other reagents present in the dye solution: a material dyed homogeneously in all points is thus obtained. .Therefore, the user can easily have several shades for the same shade, and this without varying his dyeing process for the same material to be dyed: the intensity of the coloring is determined by the actual manufacture of the coloring composition. . In addition, the different colors, which can be proposed, can be mixed without drawback, when there is no reactivity between the coloring extracts used, before the dyeing proper, the different dyes are then distributed uniformly over the material to be dyed. and the user can obtain a wide variety of colors.

 Another advantage of the compositions according to the invention is that the time required to obtain the dye of a given material is extremely reduced. For example, in the case of wool, the dyes, for which two days or more were needed, can be done in just 2 to 3 hours.

 The process according to the invention applies to a large number of coloring plants, and allows a wide range of basic colors to be obtained, in particular yellow, brown, orange, blue, red, black and, by mixing, intermediate colors. By way of nonlimiting example, a table is given below of some of the plants which can be used for obtaining the coloring extracts used in the process according to the invention.

Plant name Parts used
Dyers' Chamomile,
german, roman flower heads
Gaude-Réséda Plant
Saffron flower stigmata
Bois d'Arc Bois
Quercitron Bark and wood
Sophora japonica Flower buds
Dyers' mulberries Wood
Sea buckthorn Fruit
Buckthorn Bark
Chinese Rhubarb Rhizome
Marigold Flowers
Kesu Flowers
Turmeric Rhizome
Fustet Bark and wood
Acacia catechu, cachou, gambir,
areca nut
Walnut Fruit
Rocou Seed
Henna Leaf
Indigo Leaf
Garance Racine
Morinda Racine
Orcanette Root
Red sandalwood Wood
Pernambuco Wood
Lichens Plant
Dragonblood Fruit secretion
Logwood log
The nonlimiting examples which follow illustrate the invention.

EXAMPLE 1
Paper coloring
0.08 parts of crystallized aluminum sulphate, previously dissolved in 0.8 parts of water, are added to 100 parts of a suspension of 2.5 parts of bisulphited wood pulp bleached in water.

0.25 g of a composition comprising, according to the invention, is added to this preparation, with stirring.
10% of log extract
85% talc in particles of 2 to 5 microns
5% microcrystalline silica, 2 to 4 microns.

After 15 minutes, the whole is filtered on canvas, pressed and then dried. The sheet of paper, thus produced, is colored in the mass in a beautiful uniform purple; moreover, the coloring resists water well.

If simple coloring extracts are used, this results in a sheet of paper with an irregularly speckled blue-violet background of darker purple spots.

EXAMPLE 2
Paper coloring
The operations are the same as in Example 1, but the coloring composition is replaced by the following
4% log extract
6% Sophora japonica extract,
85% talc
5% microcrystalline silica.

The sheet of paper obtained is uniformly green.

EXAMPLE 3
Dyeing of furs
On a fleece of sheep, washed and tanned, is applied using a soft brush, on the top of the hairs, a solution of ferrous acetate. After drying, the following solution is applied
100 parts of lime water (water saturated in hy
calcium hydroxide)
2 parts of double aluminum sulphate and
ammonium
2 parts of iron sulfate
10 parts, added just at the time of use
ploi, of a composition constituted according to the in
vention by
27% kaolin in particles from 3 to 10 microns
3% microcrystalline silica
25% log extract
45% pernambuco extract.

 All of this solution, also applied with a brush, is used to evenly color the fleece in brown, if the latter is completely covered. If it is distributed in spots, one obtains an imitation of the fur of certain animals.

 This process has also been tested on other types of fleeces or furs.

 When one wants to carry out a similar dyeing of furs by the old method, using a plant powder, one encounters difficulties. It is the same when one wants to use a plant extract not prepared according to the invention; in fact, the dye solution is not homogeneous, it forms a suspension with clusters of dye particles, due to poor solubi ration, especially at 200C. The coloring of the fur is irregular, unacceptable, unless you use very long and powerful agitation.

EXAMPLE 4
Dyeing of woolen threads
100 parts of wool in skeins are treated in a solution containing
10 parts of double aluminum sulphate and
potassium
3 parts of potassium hydrogen tartrate
3000 parts of water for one hour at 90oC.

After cooling, rinsing and draining, the dyeing is carried out in
3000 parts of water to which are added
10 parts of the following composition, pre
adorned according to the invention
70 parts of a dye broom extract
27 parts of talc
3 parts of microcrystalline silica.

After 45 minutes at 900C, the threads are colored in a beautiful lemon yellow, uniform and resistant.

In the case where the plants or the plant powder are used, 2 days are necessary to carry out the dyeing and this requires the laborious operating mode, according to 500 parts of young twigs of broom of the dyers, crushed, are put to macerate a overnight in 3000 parts of non-calcareous water, then brought to the boil for 45 minutes.

After cooling, the solution is filtered on fine canvas and the plant residues enclosed in a canvas bag, then returned to the dye bath. The skeins of wool, etched as before and still wet, are then placed in this solution and the whole brought to 900C for 45 minutes. After drying, the threads are colored in lemon yellow. However, if the dye solution is not properly filtered, the dye is not uniform and numerous rinses, after cooling, are necessary in order to completely remove the vegetable powder.

EXAMPLE 5
Hair dye
According to the technique described in French patent application No. 83 12458, the hair is first treated with a preparation (A) containing
5% nonylphenol to 10 moles of ethylene oxide,
0.8% diethanolamide from coconut oil
3% aluminum lactate qs per 100 deionized water brought to pH 3.5 with lactic acid.

After 5 minutes of this treatment, the hair is rinsed and then the following preparation is applied to them (B)
3.5 parts of nonylphenol to 6 moles of oxide
ethylene
1 part sorbitan monooleate
1.5 parts of isopropanol
2 parts of stearic acid
0.3 part soda
1 part of sodium alginate to which are added 3 parts of a composition containing according to the invention
30% kaolin
3% microcrystalline silica
30% red sandalwood extract
20% annatto extract
17% log extract
Applied for 30 minutes on blond hair, this composition makes it possible to obtain intense auburn-brown hair, after a simple rinsing and drying.

The use only of plant extracts leads to a non-homogeneous solution (B); there is an agglomeration of dyes in packages in the preparation, and, as a result, the coloring is not uniform.

The direct use of powders of these plants, for its part, leads to a solution (B) of difficult application, forming a plaster and allows obtaining only very pale reflections, not homogeneous from the point of view of coloring and distribution. In addition, abundant rinses of the hair are necessary for the elimination of vegetable powders.

Claims (9)

Claims  1. Process for the preparation of a composition for dyeing, by means of natural dyes, plant extracts, characterized in that the dye extract in fine powder is mixed with one or more mineral compounds, chemically inert with respect to this extract, insoluble in water, taken in the form of a fine powder, these mineral compounds not giving an insoluble coloring combination with said extract.  2. Method according to claim 1, characterized in that the powders of coloring extracts and those of mineral compounds are in particles of about 1 to 50 microns, and preferably from 2 to 30 microns.  3. Method according to claim 1 or 2, characterized in that the mineral compound is in powder whose particle size is from 2 to 16 microns.  4. Method according to one of claims 1 to 3, characterized in that the particles of the plant extract, dye, have sizes between 5 and 10 microns.  5. Method according to one of claims 1 to 4, characterized in that the powder of the mineral compound has an apparent density not exceeding 300 g / dm3 and preferably 3 between 50 and 200 g / dm3 in the non-packed state.  6. Method according to one of the preceding claims, characterized in that the mineral compound powder has a specific surface greater than 8 m2 / g and preferably from 10 to 110 m2 / g.  7. Method according to one of the preceding claims, characterized in that the mineral compound is an oxide or silicate of a metal, in particular zinc, titanium or silicon, aluminum, in particular a natural silicate of the kaolin, bentonite, talc and silica type .  8. Method according to one of claims 1 to 6, characterized in that the mineral compound is a microcrystalline silica, hydrophilic or made hydrophobic.  9. Composition, obtained by the process according to one of claims 1 to 8, characterized in that it contains 5 to 98% by weight of dry coloring extract, and preferably 10 to 80%.