Hair coloring

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Hair coloring at the hairdresser's

A hair coloring is made to give the hair different shades, that is the natural hair color to change. Hair coloring is usually colourfast even after washing your hair several times with detergents containing surfactants .

Color changes of the hair can be achieved by bleaching agents or hair dyes. The hair color can be divided into temporary, semi-permanent and permanent colorations in relation to the number of hair washes after coloring and the respective durability of the color change. Temporary hair coloring will disappear after the first wash with a hair shampoo. It is based on the physical adhesion of a dye. Semi-permanent hair coloring lasts about two to ten washes. Permanent coloring can withstand more than ten washes. Cosmetic dyes are chemically coupled to certain amino acids in the hair or, during bleaching, the hair's pigments are oxidized.

The rock musician Kelly Osbourne with a purple-tinted " granny gray "

It is estimated that around half of adult women in developed countries use hair dyes. The colors are strongly dependent on fashion trends and vary from culture to culture.

history

Hair dyeing with the natural dyes henna , indigo , and later also with rastik was common as early as 3000–4000 years ago . The Romans colored their hair with lead combs that were dipped in vinegar. The reaction with the amino acid cysteine in the hair keratin gave rise to blonde to dark shades.

From 1900 on, the colorants often consisted of inorganic silver nitrate solutions or other metal salts mixed with pyrogallol solution. The silver ions reacted with the amino acid cysteine ​​in the hair. This enabled color tones to be set between blonde and black. The first permanent azo dye for hair was developed in 1883. A hair dye for human hair from 1895 consisted of 1,4- phenylenediamine , p- aminophenol and diaminophenol and was marketed under the name "Chenie's Haarfarbe Fo"; Even then, the possible risk of skin irritation during the dyeing process was emphasized.

Based on p-phenylenediamine, which Ernst Erdmann recognized as a hair dye at Agfa in 1888, Eugène Schueller's hair dye Aureole was also available in 1907 in Paris (the founder of L'Oreal). In 1947 Schwarzkopf brought out a hair dye series for end users (Polycolor).

Temporary hair coloring

The temporary hair coloring is used to slightly change the natural hair coloring. This color can be completely removed with a single hair wash. Azo, triphenylmethane or anthraquinone dyes are used for hair coloring . The temporary dyes are sold as aqueous, alcoholic solutions.

In connection with hair lacquer, very small golden or silver luster pigments or even fluorescent substances can be brought into the hair. Eyelash and eyebrow dyes are also temporary hair dyes. For example, soot and ocher are used as colorants.

Semi-permanent hair coloring

Semi-permanent dyes are used for shading. They have a high affinity for the keratin of the hair and the dyes are bound physically. Natural semi-permanent hair dyes are obtained from henna, rening, chamomile, wood, bark extracts and rastik.

Henna

Leaves and stems of the Lawsonia alba Lam plant . (or L. inermis L.) contain 2-oxy-1,4-naphthoquinone as a color component. The dye is obtained by drying leaves and stems, pulverizing them, dissolving the dye with hot water and then applying it to the hair. The henna dye gives dark hair a chestnut tint.

Tight

Found in the leaves of the indigo plant . It is used together with henna. With henna you can achieve shades between red-blonde and black depending on the mixing ratio.

chamomile

The flower pigment apigenin (5,7,4'-trioxoflavone) of chamomile causes the hair to turn yellow.

Rastik

Is a mixture of pyrogallol and iron and copper salts. Pyrogallol was obtained by roasting gall apples. The hair is colored deep black by Rastik.

Nitrophenyldiamines , azo and quinoneimine dyes in conjunction with organic solubilizers such as glycol ethers or polypropylene are used as synthetic hair dyes .

Permanent hair coloring

Hair and beard dyed blue

Permanent hair coloring is practically impossible to remove, but the hair grows about 1 cm per month, so that at least the roots have to be colored regularly if you want to keep your hair evenly colored.

Sensitive people can cause skin irritation with two-component hair coloring. Hair coloring, permanent waving or frequent washing can also damage the hair, which adversely affects the shine, combability and feel of the hair. The companies try to reduce these disadvantages by adding cationic surfactants and adding keratin . Recently, alkylguanidine compounds have also been recommended for treatment or post-treatment. Quite mild, one-component, enzyme-based hair colors have also been developed. However, such a hair dye must be well protected from atmospheric oxygen before it is applied to the hair. The advantage of these colorants is that they are milder than two-component colorants, but the disadvantage is that they are weaker in color.

Since hydrogen peroxide, as an oxidizing agent, damages the hair fiber and can cause skin irritation, companies are trying to replace this compound with the use of dicarbonyl groups and amino compounds.

Two-component hair coloring

With permanent hair coloring (oxidation hair coloring), oxidation bases , i.e. easily oxidizable aromatic compounds (such as phenylenediamine , tolylenediamine, aminophenol ) are applied to the hair together with nuances (substances that change the color tone) in the presence of hydrogen peroxide, ammonia, emulsifiers and water . The dye particles then migrate into the inside of the hair - which has been swollen by the alkaline medium - and there are oxidized to complex dyes, where they chemically combine with the hair keratin. The dye is only created when the dye bases are oxidized by the hydrogen peroxide. A commercially available permanent hair dye consists of two components: a tube with the oxidation bases, nuances and a vial with hydrogen peroxide.

In addition to the dye bases, a hair dye also contains thickeners, for example fatty alcohols and lanolin , so that the mixture becomes creamier. So that the oxidation bases are not oxidized prematurely under the influence of air, a colorant also contains antioxidants, for example sodium sulfite or sodium formaldehyde sulfoxylate or ascorbic acid . The color paste also contains some ammonia solution (approx. 1% or monoethanolamine) and some surfactant .

Oxidation bases and nuancers

Oxidation bases can be p-, o- phenylenediamine , o-, p- dihydroxybenzene and o-, p- aminophenol or derivatives of these compounds. Depending on the composition of the aromatic compounds, different colors are obtained.

Common oxidation bases are, for example, 2,5-diaminotoluene , 2,3-diaminotoluene , 2-aminophenol and 4-aminophenol . The disubstituted aromatics in the m-position ( m-dihydroxybenzene , m-aminophenol , m-phenylenediamine ) serve as shading agents .

Prohibited ingredients

The German Cosmetics Ordinance of 1977 and 1982 banned 1,4-phenylenediamine , 2,4-toluenediamine and 2,4-diaminoanisole , as they are suspected of having carcinogenic effects. Carcinogenic effects have also been demonstrated with 2,4-diaminoanisole and 2,4-diaminotoluene. The following compounds are prohibited in hair dyes: 1,2-diaminobenzene, 1,4-diaminobenzene, 2,4-diaminoanisole, 2,5-diaminoanisole, 2,4-diaminotoluene, 2-amino-4-nitrophenol, 2-amino 5-nitrophenol. The permitted dyes may only be present in the dye in the permitted doses. Before 1990, bans on chemical ingredients in hair dyes were handled differently from country to country. For example, 1,4-phenylenediamine (a compound for producing black shades) was an important hair dye in many countries (for example in the United States); in Germany, the use of this compound was banned as early as 1906. The free oxidation bases must not be more than 6% in the hair dye. Hydroquinone may be used at 2%, resorcinol at 5% and α-naphthol at only 0.5%.

Physical color change

This method of color change is semi-permanent, it does not change the natural pigment, so-called substantive dyes are used. Since the color cannot penetrate the cortex of the hair, the colorants are only deposited on the cuticle . Therefore, this type of color change only lasts up to about a maximum of twelve washes. The pigments in the so-called "direct pullers" are cationic. Due to the electrically positive charge (cationic) of the color, it can attach itself to the negatively charged (anionic) hair. The more porous the hair, the more intensely the color is applied to this point and can penetrate further into the cortex. However, permanent or lightening results cannot be achieved with this method.

Furthermore, plant colors can be counted among the semi-permanent color changes. In the case of vegetable dyes, chemical additives are largely dispensed with, so the durability on the hair is also limited. Since it is not a “coloring” in the strict sense, lighter coloring is not possible. Adding permanent hair dyes to hair dyed with vegetable dyes is not advisable.

The following additional products fall under the category of "direct dyes":

Color fixers and hair dryer lotions
  • Carrier: alcohol;
Use: after washing your hair with a dampened cotton wool, apply in sections
Color foams
  • Carrier: alcohol foam;
Use: after washing your hair, squeeze the hair off, apply in sections to the sectioned hair with a brush
  • Carrier: PVP / VA copolymers, care substances;
Use: apply evenly in terms of quantity - rinse off after exposure time
Color rinse
  • Carrier: cationic care substances;
Use: after washing your hair, pour it diluted with water over the hair.
Color gel / color cream
  • Carrier: cationic gel based on care substances;
Use: apply evenly in quantity - let dry

Chemical color change

There are two different methods available to the hairdresser for permanent color changes: bleaching and oxidative coloring. A product that is required for both processes is hydrogen peroxide (formula: H 2 O 2 ). Due to the addition of H 2 O 2 , an oxidative process occurs in the hair, oxygen is deposited and changes the color effect of the pigments. Since the chemical color change is additive, except in the case of bleaching, i.e. dyes are deposited, targeted coloring of hair that has already been chemically colored is no longer possible. Due to the reactivity of oxygen, H 2 O 2 is used to dye hair. The following H 2 O 2 concentrations are available to the hairdresser :

concentration application
1.9-2.5% suitable for intensive tints
3-4% very well applicable for dyeing or intensive tints
6% Permanent color tone on tone or a tone lighter or darker (depending on the shade)
9% Permanent coloring 2 to 3 tones lighter
12% Permanent lightening of 3 to 4 tones, or more than four tones with a super lightener
18% neither useful nor necessary, must not get on the scalp and is not used in Europe

A peroxide strength of up to 6% is best for bleaching. A common misconception is that 1.9%, 3% or 4% would not lighten sufficiently. However, this has been refuted by various tests. A solution with 1.9% H 2 O 2 is also able to gently lighten a dark base. The only downside is that it takes a little longer. The result is a clear shade of blonde without a lot of gold.

ingredients

Color prepresses

These are undeveloped pigments which, due to their small molecular size, can penetrate the hair very well and thus achieve a uniform coloration of the cortex. The oxidative process is only triggered by the addition of H 2 O 2 . The active oxygen turns colorless color precursors into a visible pigment. Since these pigments combine with one another, a kind of “cage effect” is created and pigments can hold onto the cortex of the hair. Only when a hair color contains dye precursors can white hair be completely covered. Basically there are only two types of color precursors, but these are both contained in different amounts in each shade. The concentration of the dye precursors and couplers results in different, oxidative hair colors. Color precursors are mostly PPD, PTD or Recorsin. These have a brown design and give the hair color the depth of shade

  • Group 1 = color precursors
  • Group 2 = Nuanceure (color coupler)
    • Sometimes direct or temporary color pigments are also contained in oxidative colors
Nuanceure / color coupler

Nuanceurs are partially developed or partially oxidized color formers that give a color a certain color direction or nuance. All dyes are made from various basic chemical substances and made durable.

Alkalis

Ammonia water or similar substances are used as alkalizing agents in all hair colors ( toluene , diamines , resorcinol and many others). The amount and pH value are different. Alkalis have the property of volatilizing, which is why the concentration decreases with the length of the exposure time. Alkalis are indispensable for hair coloring, as they make the hair swell and thus make the hair more absorbent. Only then can the color penetrate the cortex.

Carrier masses

These include solvents such as isopropanol or ethanol, etc. Cream (so-called zero masses) or gels are the most common carrier masses in color cosmetics. They mostly consist of fat-like, cationically adjusted basic substances that have a caring effect.

Wetting agents

promote the penetration of all active ingredients, as they reduce the surface tension of the moisture, and ensure an even distribution on the hair.

Buffer substances

ensure that the active ingredients are broken down evenly, i.e. they ensure that the work process does not proceed explosively after the dye has been mixed together and keep the pH value constant.

Reducing agent

keep the color in the pack stable and reduce the dyes' sensitivity to oxidation. Although these cannot prevent Rite dyes, for example, from being only about 70% reactive after just six months.

Fragrances

overlay the strong odor, especially with alkalis.

Individual ingredients can cause allergic reactions. For this reason, it is important to test the product on a small area of ​​skin before use and to check the list of ingredients in the case of known allergies.

procedure

After mixing the paint with H 2 O 2 , the following sequence results:

Alkalizing agents (ammonia, MEA with mostly high pH between 9 and 11) make the hair swell and neutralize the stabilization of the H 2 O 2 . This releases active oxygen. Depending on the concentration, this brightens the natural pigment. The carrier compound ensures that the hair color sticks. The wetting agents improve the hair's absorption capacity, buffer substances (such as deer horn salt ) regulate the entire process. When at least 6% H 2 O 2 is added, the natural pigment is first lightened and at the same time the color precursors and couplers are brought into the hair. These now overlay the lightened natural pigment, which leads to the desired result after a certain exposure time, depending on the concentration of H 2 O 2 .

concentration Exposure time
1.9-2.5% 20 min
3-4% 30 min
6% 30-35 min
9% 35-40 min
12% 40-60 min

The exact determination of the customer's natural tone is essential for the hairdresser in order to determine the correct H 2 O 2 concentration. The mixing ratio of the components (color / H 2 O 2 ) also plays a role in achieving the desired color target. It is important to note that when lightening natural hair, an undertone / bleaching table for the hair becomes visible. This must be neutralized or reinforced as required.

Undertone table:

  1. Extra light blonde - very light gold,
  2. Light-light blonde - light gold,
  3. Light blonde - gold,
  4. Medium blonde - copper,
  5. Dark blonde - copper red,
  6. Light brown - red copper,
  7. Medium brown - natural red,
  8. Dark brown - brown red,
  9. Black - brown black,

This table is visible with: lightening, bleaching and coloring with 6%, 9% and 12%. This also explains why self-bleached or self-dyed hair usually has an orange or gold edge, because there was usually wrong, with too high an oxidant or too short a time. Only a specialist can add corresponding “counter colors” to the coloration and determine the correct exposure time. Complementary colors are:

  1. Orange - blue
  2. Gold - purple
  3. Red Green

Failure to take into account the bleaching table or undertone table also leads to a green cast in the hair. This happens when the bleached hair is dyed dark again. "Reverse pigmentation" must take place in advance. This means that the hair gets pigments that were broken down during lightening. Usually a copper-gold or copper-red tint is used in advance.

In summary, if you decide to dye your hair yourself, the most common sources of error lie in the following areas:

  • The color is not only applied to the regrown roots, resulting in an uneven color result.
  • The wrong hair color is used - depending on which color was used last time, unpleasant results can be achieved.
  • The paint is applied unevenly: it can lead to blotchy hair
  • The hair is often not acidified, so that allergies or intolerances arise. Color residues remain in the hair and also on the scalp. If the cuticle is still open, the color pigments can quickly fall out.
  • Improper care after dyeing is a big problem, causing the paint to lose its shine.

Bleaching

Woman with bleached hair

For a permanent color change, the hairdresser can still use the bleaching function. When bleaching, hydrogen peroxide is used in concentrations of 1.9 to a maximum of 12%; the hair structure changes at higher hydrogen peroxide concentrations. More than 6% oxidants must not be applied to the skin.

The hair consists of several peptide chains, the basic building blocks of which are individual amino acids. The amino acids in peptides contain functional groups which, through interactions ( hydrogen bonds ) with other amino acids and their functional groups and salts, give the hair its specific strength and elasticity. When bleaching the color pigment melanin is dissolved and many hydrogen bonds lose their hold. There are two different melanins:

  1. Eumelanin is brown-black (granular, solid structure)
  2. Pheomelanin is gold-red (small, diffuse structure)

The pigments that give the hair its color are destroyed by oxidation, and the hair becomes blond.

Since bleaching not only destroys color pigments, but also a lot of the “putty” of the cortex, bleaching should be carried out with appropriate caution. Otherwise, damage to the hair and even hair loss can result. A hairdresser can be liable for damages if the bleaching is carried out incorrectly.

The bleaching powder contains ammonia (opens the cuticle) and persulfates (lightening accelerator), which make the hair swell and thus allow the H 2 O 2 to have an effect on the pigments. The differences in the speed of the lightening are exclusively in the exposure time or in the supply of heat using Climazon or the like. The addition of heat is not recommended, however, as heat can cause more hair and scalp damage. Two factors are much more important for maximum whitening results:

  1. Amount of bleaching (apply product generously)
  2. Time (lower oxidant with longer exposure time)

As a rule, the bleaching is washed out with an acidic shampoo in order to restore the natural pH value of the hair. After lightening with bleaching preparations, a hair treatment or hair mask should be applied. Protein-containing or ceramide-containing products, which can partially repair the damage to the hair, are best suited.

Acid trigger

The acidic deduction or the reductive color deduction is a variant for correcting an oxidative color result in freshly dyed hair. This applies to colorations, intensive tints and permanent colorations. Here, by means of an acidic preparation, unsolidified and solidified color molecules are released from the hair, or the oxidized color molecules are chemically reduced by splitting off oxygen. There are several ways to carry out the reductive process in the hair. The simplest home remedy is to use ascorbic acid . To do this, vitamin C powder is dissolved in water and remains in the hair for up to 30 minutes. The artificial pigments are released from the hair. Long, thorough rinsing is very important. This application also helps against "green" hair after swimming in chlorinated water.

In an industrial color print, an alkaline reducing agent is usually developed by means of an acidic solution. The pH of the finished mixture is strongly acidic. The acidic color removal has no effect on the direct pigments (foam tints, henna colors, herbal hair colors). The acidic color print is used as an alternative to the alkaline print (bleaching), as it is gentler, for example to weaken an undesired shade or a color result that is too dark. However, this is best done shortly after dyeing the hair, as the dye molecules are then partly not fully consolidated and easier to loosen.

criticism

Chemical hair dyes are powerful chemicals that can cause side effects such as skin irritation. If the dye gets into the eye during application, it can be damaged. In order to reduce risks to humans to a minimum and to avert possible claims for damages against manufacturers, animal experiments are still carried out. The production process also pollutes the environment. Natural dyes are often a more compatible alternative.

See also

literature

  • Wilfried Umbach: Cosmetics, development, manufacture and use of cosmetic products. Georg Thieme Verlag, Stuttgart 1995, ISBN 3-13-712602-9 , p. 287 ff.
  • Claus Garbe with the collaboration of Babette Budczies, Ursula von Maltzan and Hans-Ulrich Melchert: Risk of cancer from hair dyes: Epidemiological research status and results of an investigation among Berlin hairdressers. (SozEp reports. 1/1983). Dietrich Reimer Verlag, Berlin 1983, ISBN 3-496-02211-6 .
  • Günter Vollmer , Manfred Franz: Chemical products in everyday life. dtv-Verlag, Stuttgart 1985, ISBN 3-423-03276-6 , pp. 185 ff.
  • Ullmann's Encyclopedia of Industrial Chemistry. 3. Edition. Volume 10, keyword: Cosmetics, p. 734 ff.
  • Ullmann's Encyclopedia of Industrial Chemistry. 4th edition. Volume 12, keyword: Hair treatment agents, p. 435 ff.
  • Ullmann's Encyclopedia of Industrial Chemistry. 5th edition. Vol A12, keyword: Hair Preparations, p. 583 ff.
  • Kerrin Riewerts: About hair dyes and rashes. In: Chemistry in our time 40, 2006, pp. 378–382.
  • Wilfried Umbach: Cosmetics and hygiene. 3. Edition. WILEY-VCH Verlag, Weinheim 2004, ISBN 3-527-30996-9 , pp. 293-315.

Individual evidence

  1. ↑ a b Wilfried Umbach: Cosmetics - Development, manufacture and use of cosmetic products. 2nd Edition. Georg Thieme Verlag, Stuttgart 1995.
  2. ↑ a b c Wilfried Umbach: Cosmetics - development, manufacture and use of cosmetic products. 2nd Edition. Georg Thieme Verlag, Stuttgart 1995, p. 287.
  3. ↑ Ullmann's Encyclopedia of Technical Chemistry. 3. Edition. Volume 10, p. 734.
  4. ↑ Chemisches Zentralblatt. 1898, p. 131.
  5. ↑ a b Ullmann's Encyclopedia of Technical Chemistry. 4th edition. Volume 12, p. 439.
  6. ↑ a b Ullmann's Encyclopedia of Technical Chemistry. 3. Edition. Volume 10, p. 736.
  7. ↑ Recent developments in hair cosmetics. In: SÖFW-Journal. 11-2006, p. 56.
  8. ↑ Ullmann's Encyclopedia of Technical Chemistry. 5th edition. Vol. A12, p. 584.
  9. ↑ 5,000 euros due to permanently bald head end: hairdresser is liable for incorrect bleaching. - District Court Coburg, judgment of July 29, 2009, 21 O 205/09, free-urteile.de
  10. ↑ Customer is entitled to compensation after unsuccessful hair coloring at the hairdresser's. - Mönchengladbach Regional Court, judgment of October 9, 2009, 5 S 59/09, free-urteile.de

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