Subject: The mechanism of changing hair shape during perm
Permanent wave products
The first patent in 1935 in the USA for cold permanent.
Permanent compositions must meet the following requirements:
Guarantee the preservation of the curl for a certain period of time;
Do not change the original hair color;
Rinse hair off with warm water;
Easy to wet hair;
Do not have an allergic or irritating effect on the skin;
Have a pleasant smell and have a marketable appearance. Do not change the color of natural hair.
Perm preparations:
the composition for perm is produced industrially. Available in ready-made form (cannot be diluted), it usually has four gradations: for difficult-to-manage hair, for normal hair, for colored hair, for bleached hair. It is a solution of thioglycolic acid with various technological additives.
fixer (fixative, neutralizer) is available both ready-to-use and concentrated (i.e., subject to dilution: 1:1) Contains alkali - H2O2 to neutralize the acid in the lotion.
Processes occurring inside the hair structure during chemical exposure.
1) When the hair is exposed to a chemical composition, a partial rupture of the disulfur bridges between the keratin chains occurs due to the deposition of hydrogen on the sulfur atoms. The hair swells, the scales rise. The hair loses its elasticity, becomes stringy and easily takes the shape of a curler. This process is calleddeoxidation .
2) During the curling process, the destroyed disulfur bridges are displaced: the hair takes the shape specified with the help of curlers. Under the influence of a neutralizing composition, disulfide bonds are restored again - a process calledoxidation . The action of the fixative is to restore the disulfur bridges. When the fixative is applied to the hair, oxygen penetrates into the hair and combines with hydrogen deposited on the sulfur atoms of cystine bonds, forming water H2O. The disulfur bonds are restored again, but in a displaced form, i.e. Due to the fact that the hair is in a twisted state, under the influence of normal tension, the free parts of the sulfur bridges are displaced, and at the moment of action of the fixator, these free parts are opposite the other halves, and not their own. This way the hair is secured in a curled form. The hair scales close and it takes on a curled shape.
Partial destruction of two-sulfur bridges means the destruction of part of all bridges. The optimal percentage of destroyed bridges is 30%. This percentage allows you to get an elastic curl and maintain the cosmetic qualities of the hair.
In this regard, it is necessary to choose the right chemical composition for the hair and strictly observe the recommended exposure time.
If the composition is too strong or the exposure time is increased with the correct composition, the hair will become loose, sensitive and will not hold curl well.
If a weak composition is chosen or the holding time is reduced with the correct composition chosen, the curl will turn out to be very weak and the curl will not last long.
Thus, the concept of “light curling” should mean choosing large curlers, and not reducing the time the chemical composition is left on the hair.
Alkalinity and acidity
The chemical indicator of the acidity and alkalinity of a solution is expressed through pH - a unit of measurement of the concentration of hydrogen ions in solutions, i.e. alkaline or acidic in nature. The pH scale includes values from 0 to 14, value 7 is the middle of the scale and means “neutral” (clean water level).NaturalStyling from Schwarzkopf– slightly alkaline perm, pH level 8.2-9. The higher the pH, the more persistent (obvious) the curl and its duration, but also the more aggressive effect on the hair. Accordingly, the lower the pH, the less stress for the hair - this is its natural environment, but the less long-lasting and elastic the curl.
Questions
1. Name the main structural elements of hair.
2. What is the hair cuticle? How do hair with different cuticles react to perms?
3. What types of chemical bonds exist inside the hair?
4. What is the cross section of the hair? And what is the importance of the hair section for performing a permanent?
5. What should lotions and fixatives be?
61 62 63 64 65 66 67 68 69 ..Hair perm technology by a hairdresser
Neutralization when perming hair by a hairdresser
The perm composition, the pH of which is 8.5-9.5, acts on the hair like an alkali. If you leave a small amount of it on your hair, it will gradually destroy it. Rinsing your hair with water will not completely remove the curling compound. Therefore, the next important hair treatment operation during perm is neutralization with a weak solution of acetic or citric acid.
As is known, alkali is characterized by an excess of OH ions in a solution. The greater their relative quantity, the higher the alkali concentration,
i.e., with a neutral reaction of the environment, the pH of the solution is 7 and the relative amount of hydrogen ions H+ and hydroxide ion OH- - is approximately equal. Some excess of some or other iodines is inevitable, but in hairdressing practice there is no need to accurately determine it. An increase in the alkalinity of the solution begins with an increase in pH, i.e., when it begins to exceed 7. As noted, the composition for perm is a low concentration alkali with pH “9.
Acidic solutions, which include, in particular, citric and acetic acids, are characterized by a predominant amount of hydrogen ions H+. The more of them in the solution, the lower the pH of the environment, i.e., an increase in the number of hydrogen ions entails a decrease in the pH of the environment, starting from 7.
What happens in the solution during the neutralization reaction? As is known, in a solution of any liquid in which water is present, there is a continuous decomposition and combination of water molecules according to the scheme HOH----->H+OH.
One water molecule breaks down into one hydrogen ion H+ and one hydroxide ion OH-, which, when combined, form a water molecule again. If the reaction of the medium is neutral, that is, the solution contains the same amount of one and the other ions, a continuous process of decomposition of water molecules and their combination occurs. If OH- ions predominate, some of them are not able to form water due to the lack of a sufficient number of hydrogen ions H+. By adding an acid in which hydrogen ions predominate to an alkaline solution, the following picture can be observed: as the number of hydrogen ions increases, the number of hydroxide ions will correspondingly decrease, which, when meeting each other, will form water. Thus, as soon as there is one hydrogen ion for each free hydroxide ion, the reaction of the medium will become neutral. If there are slightly more hydrogen ions, the reaction of the medium will be slightly acidic. In hairdressing practice, due to the inability to accurately control the pH of the medium before and after neutralization, it is necessary to use compositions that approximately ensure complete neutralization of the alkali. Typically, a weakly acidic solution of acetic or citric acid is used for these purposes.
For a composition of such a weak concentration, you can take 2.5 g of citric acid and dissolve it in 1 liter of warm water. To better neutralize alkali residues on your hair, you need to rinse it well with the prepared mixture. Rinsing alone is not enough - the alkali remains on some areas of the hair. The operation must be repeated several times. To completely wash out the alkali, the following is recommended: under the wing
(an adaptation to the chair for washing hair) place a bowl into which the composition flows after rinsing; from the bowl it is poured into a jug, from which it is again poured onto the hair. The operation should be repeated 4-5 times.
After neutralization, the hair is wrung out, dried with a towel and curled with curlers.
When perming heavily bleached hair that has been significantly loosened by hydrogen peroxide, you need to increase the amount of water in the neutralization solution to 2 liters, leaving the amount of acid 2.5 g unchanged, or, conversely, halve the content of citric acid without changing the amount of water.
Perms were invented in the mid-1930s. Its purpose is to give the hair volume, fluffiness, pliability, i.e. the ability to preserve hairstyles longer.
The chemical composition of hair is a complex compound, the main parts of which are keratin and pigment. Keratin is a water-insoluble protein with a high content of sulfur, nitrogen, and amino acids.
The most important amino acid is cystine, which stabilizes the protein structure, but under the influence of perm preparations it breaks down at the site of the cystine bond. In this case, cysteine is formed, thanks to which the hair becomes able to take the shape given to it. It becomes plastic, and its ability to withstand physical and chemical influences drops sharply.
When the bonds in this structure are broken, the hair becomes pliable. When perming, the hair is wound onto bobbins, changing the shape of the hair and its cross-section. If you look at the cross section of straight, curly and very curly hair, it will be different. Straight hair has a round cross-section, curly hair has an oval cross-section, and strongly curly hair has a flattened oval.
Due to the fact that the amino acid cystine is present in the hair, the hair has good elasticity; straight hair does not hold a curl well when styling the hair, as it quickly returns to its original state. When exposed to perm preparations, the hair becomes pliable, it can be wound onto any shape of bobbins, and it will take the shape that is given to it.
Perm preparations have restorative properties, i.e. the broken cystine bond of keratin can be restored. To restore hair elasticity, it is necessary to use compositions with oxidizing properties. Therefore, to secure the curl, use 3...5% hydrogen peroxide H 2 0 2 - fixer. When hair is exposed to hydrogen peroxide, the cystine bond is restored, cysteine is converted to cystine and the hair regains its original elasticity.
The hair perm process takes place at a pH of 9...11; The higher the pH of the composition, the stronger its effect on the hair, it swells faster, the S-S cystine bond breaks faster, but the hydrolysis of hair amino acids also occurs more actively. Therefore, the choice of drug concentration must be approached individually, depending on the hair, its structure, condition, and the effect of oxidative dyes on the hair.
Perm preparations are available for various hair types:
- for healthy people who are difficult to perm;
- for normal healthy people who have not been subjected to chemical treatment;
- for painted ones.
Each drug has its own type of fixative or one common one.
The basis of preparations for perm are organothio compounds and their derivatives. The hair perm formula contains thioglycolic acid CH 2 - S - HCOOH.
Compounds related to thioglycolic acid make it possible to influence the shape of the hair at the normal temperature of the human hair.
Disadvantages of thioglycolic acid:
- in the air it releases hydrogen sulfide and mercaptan, which have a strong unpleasant odor;
- is toxic, can cause painful phenomena - headache, general malaise, decrease in the content of white blood cells;
- When working with solutions of thioglycolic acid, skin diseases are observed: redness and dryness, cracks, dermatitis, blistering rash, itching, eczema, urticaria, nail damage.
As a protective means when applying the solution to the hair, it is recommended to work with rubber gloves and breathe in the fumes of the solution as little as possible.
The principle of perm hair. The strength of healthy hair is ensured by the presence of disulfur bridges, which create internal bonds in the keratin chains and give the hair its shape.
At the first stage of curling, a chemical deoxidation process occurs. The deoxidizing agent brings hydrogen into the hair, which destroys the disulfur bridges. At this stage, chemical exposure occurs.
At the second stage, hair curling is done. When winding hair with bobbins, the hair changes shape. Broken disulfur bridges in keratin chains are displaced, the hair takes the shape that is given to it. Hair can be twisted into any shape of bobbins, tied in knots, braided, etc. At this stage of perm, a mechanical effect occurs: the hair turns from a straight round section into a curly, ribbon-shaped one.
At the third stage of curling, the hair is fixed. Thanks to the oxidizing agent contained in the fixative, oxygen is released. By combining with hydrogen, it restores disulfur bridges. Under the influence of the fixative, the cystine bond of keratin is restored, and the hair acquires its original elasticity, but in a new form. At this stage, a chemical effect on the hair occurs. When hair is deoxidized, 30% of the disulfur bridges are destroyed, which allows you to get a good elastic curl and maintain hair quality. It follows from this that every third bridge must be broken. To maintain these indicators, it is important to choose the right chemical composition and accurately observe the duration of its exposure on the hair. If you use too strong a chemical composition or increase the length of time it is left on your hair, the curl will become sensitive and will not hold its shape well. If you choose a weak chemical composition or reduce the length of time it is left on your hair, the curl will be weak and the perm will last for a short time.
The chemical composition of the curl can be alkaline, acidic and neutral. Each group has its own advantages and disadvantages. Therefore, the master must be able to do various types of perm.
Alkaline perm. Ammonium thioglycolate, a chemical compound formed by the reaction of ammonia with glycolic acid, is the main active ingredient in hair perm formulations. The effect of the chemical alkaline composition on the hair is characterized by good opening of the cuticle scales and the composition freely penetrating into the hair. This explains the strong elasticity of the resulting curl and its long-lasting durability, which is a significant advantage of alkaline curling. This perm is suitable primarily for those who want their hairstyle to last as long as possible.
Alkaline perm is used to style hair that is difficult to process, as well as to get a cool curl if the client’s perm was weak before.
Acid perm. The active ingredient in acid perms is glyceryl monothioglycolate, which has a lower pH compared to alkaline perms. The advantages of acid perm are explained by the fact that the composition passes directly through the scales without opening them. In physics, this process is called osmosis. The advantages of such a curl are obvious. However, hair that has become too soft and silky easily stretches at the root, which means it does not hold volume. If a client prefers soft, silky curls to volume, then it is difficult to find an alternative to acid perm. This type of curl does not last long on the hair, 4-6 weeks at most.
Neutral perm. The pH value of neutral curling is 7.4. When developing compositions for neutral curling, hydrophobic zones (water-repellent) were taken into account, which easily absorb excess liquid, unlike hydrophobic zones. Neutral perm smoothes out these differences. As a result, the hair does not experience additional stress, as it does not swell too much. With the help of a neutral perm, a very durable curl is obtained, but in appearance and tone it will differ from an alkaline one. The advantages of a neutral perm are, first of all, a natural, long-lasting, fairly elastic curl on soft hair.
What happens to hair when hair is dyed?
The hair structure consists of three layers. The core of the hair, the medula, is a soft, spongy substance that is covered with a hard shell (cortex). The outer part of the hair is the cuticle; it is formed by keratin scales that overlap each other. Good and healthy hair is characterized by a dense and even arrangement of these scales to the hair shaft. When using chemical dyes, the outer layer of hair is damaged - the cuticle is damaged. Chemical components penetrate inside the hair, destroying the natural pigment and filling the hair with artificial pigment. The hair structure is destroyed; in addition, chemicals negatively affect the hair follicles and scalp. Hair becomes dehydrated and degreased, becoming brittle and dull. The most traumatic type of coloring is hair bleaching, in which the natural pigment is completely destroyed.
What happens to hair during perm?
Perming has a very strong effect on the hair and causes trauma. The cuticle is the outer layer of the hair, which protects it from various types of damage, opens under the influence of a chemical composition, allowing the chemical composition to pass into the next layer - the cortex (the inner layer of hair, consisting of keratin fibers). It is in the cortex that the main reactions occur during the perm process. Basically, hair perms are alkaline. Hair scales are destroyed under the influence of an alkaline environment, which significantly weakens protection from environmental influences. Unfavorable factors destroy the biological membrane of the hair, which in turn leads to disruption of its functions. As a result, the hair becomes damaged, dull and weak. The substances contained in the chemical solution partially break the S-bonds (disulfide bonds that are responsible for the strength of the hair) and when fixing the curl, they create these bonds anew. If you have been perming for many years, the hair becomes dehydrated, becomes hollow, there is almost no keratin protein left in it, which is responsible for the growth, development, elasticity of the hair, and the cestin bonds are destroyed. Every day the hair becomes even thinner, even more brittle and “lifeless” - apparently it’s time to go to the hairdresser and get a short “hedgehog”.
Classification of drugs that change hair color?
All professional hair dyes are divided into 4 groups.
1. Lightening and bleaching. Capable of lightening hair by 3-7 tones. They are used both to obtain a lighter shade of hair, and to “wash off” the previous dye and prepare the hair for subsequent dyeing in a lighter tone.
2. Hair dyes that act by oxidation - begin to appear only when interacting with an oxidizing agent, entering into a chemical reaction with it, due to the content of a certain percentage of hydrogen peroxide. These are durable, indelible paints that can cover gray hair. Permanent dyes can lighten the natural hair color by 1-3 tones.
3. Tinting hair dyes and tone-on-tone dyes are soft dyes that do not contain ammonia; therefore, they do not have the ability to lighten natural pigment. Such dyes help to make the natural hair color more saturated, give an interesting color nuance and shine to the hair. Tinting hair dyes penetrate only into the cuticle, while tone-on-tone dyes also envelop the natural pigment of the hair, making them quite durable. These dyes are washed off after about 20 hair washes, and their advantage is that in this case the problem of regrown roots does not arise: by the time the hair grows back, the color will gradually approach its natural color.
4. Tinted hair dyes. As a rule, they are produced on a gel basis, as well as in the form of foam or shampoo. They envelop the hair without penetrating its structure, so they are quickly washed off. The advantage of these preparations, firstly, is that they are almost harmless to hair, since they do not contain ammonia or peroxide, and secondly, they provide the opportunity to safely experiment with new shades. Can be used almost immediately after perm.
5. The technology creates a thin breathable film on each hair from natural ingredients, supplementing it with nourishing, moisturizing and protective substances. Does not damage hair at all! Creates a deep shade, revitalizes natural hair color, and adds crystal shine. Can be used if the use of alkaline dyes is contraindicated. It is the safest and even useful way to change the color of your hair!
What care is needed for colored hair?
To restore hair damaged by coloring to a healthy, radiant appearance, it is necessary to restore the protective layer of the hair. It’s not difficult – for this you should follow a few special recommendations:
1. Use products that support the color of dyed hair. The fact is that after coloring, the ph of your hair changes and what made your hair lush and shiny just yesterday is no longer suitable for it. Choose a series of heat-protective styling products.
Japanese MoltoBene hair delicacies are designed specifically for the care of colored hair. When developing them, all the nuances of caring for damaged hair structure were taken into account. With regular use, our products will help restore your colored hair to its former healthy appearance, noble shine and silkiness.
The chemical composition of hair is a complex compound. One of the main parts is keratin.
Keratin is a protein consisting of nineteen amino acids that are in a bound state and form polypeptide chains of the protein. One of the most important amino acids is cystine, which contains a lot of sulfur and is cross-linked with a disulfide. Disulfide bonds provide strength to the hair shape.
When exposed to a perm composition, cystine breaks down at the site of the S–S cystine bond.
Disulfide bonds are destroyed by thioglycolic acid, polypeptide chains of amino acids by ammonia. The cystine bond is broken and cysteine is formed. Protein fibers are damaged, and the hair loses its elasticity, the scales open.
At this moment, the hair becomes an almost arbitrarily formed mass, which, under the influence of winding on bobbins of different configurations, can be given any new shape.
The broken down molecules are moved into a new form that is given to them.
To make this shape stable, it must be fixed. To do this, use a weak solution of hydrogen peroxide. Remains of alkali in the hair are neutralized and stop their effects. At this moment, the swelling of the hair stops and it begins to return to its original state.
At the moment of fixation in the new form of hair, the cystine bond is restored and cysteine is converted into cystine, which gives the hair keratin its original strength and elasticity, the scales close.
Hair loses some of its weight during the curling process. This happens as a result of hydrolysis of keratin amino acids, when a small part of the hair goes into solution and is washed away.
The chemical process occurs at pH 9 – 11; The higher the pH of the composition, the stronger its effect on the hair. Hair swells faster, cystine bonds are broken faster, but the hydrolysis of hair keratin amino acids is more active. Therefore, the exposure time and concentration of the drug should be individual depending on the hair, its structure, condition (dry, oily, normal), and the effect of oxidative dyes on the hair.
Table 2.
Types of Perm
| Types of Perm | Active Ingredient | Chemical process | Recommended Hair Type | The result is you | Advantages | Flaws |
| Alkaline “cold” permanent pH 9.0 – 9.6 | Ammonium thioglycollate (TGA) | At room temperature | Tough, dense or highly resistant | Tight, durable curls | Fast chemical processing at room temperature | Unpleasant ammonia odor, possible damage to delicate hair |
| Exothermic permanent pH 9.0 – 9.6 | Same | Exothermic reaction | Same | Same | An exothermic chemical reaction causes a solution to heat up | Same |
| Truly acidic permanent pH 4.5 – 7.0 | Glycerol monothio-glycolate (MTGG) | Endothermic reaction | Extremely porous or severely damaged | Soft, unstable curls | Low pH causes minimal cuticle swelling | Requires additional heat; does not give tight, long-lasting curls |
| Permanent with balanced acidity pH 7.8 – 8.2 | Same | At room temperature | Porous or damaged | Soft curls | Minimal cuticle swelling; processing at room temperature | Repeated exposure may cause allergic reactions |
| Ammonia-free permanent pH 7.0 – 9.6 | Monoethanolamine/aminomethylpropanol | Same | From porous to normal | Medium curls, small curls | No unpleasant ammonia odor | The total concentration of the solution may vary depending on the manufacturer |
| Permanent without the use of TGA pH 7.0 – 9.6 | Mercaptan/cysteamine | » | Same | Same | May have a milder effect depending on the composition | Same |
| Permanent with pH 6.5 – 7.0 | Ammonium sulfite/disulfite | Enodothermic reaction | Normal, thin or damaged | Weak curls or the so-called “natural wave” | Minimal swelling of the cuticle layer | Requires additional heat, produces weak curls |
Preparations used in hairdressing salons for perms. “Lokon” is a transparent, colorless liquid, which is an aqueous solution of thioglycolate, alizarin oil, sodium hydrosulfite and beneficial additives.
Currently, new generation perm preparations are widely used.
« Ondaform» from Belita - an effective, gentle product. Contains special softening, moisturizing and skin-soothing additives (allantoin and lanolin). Designed for normal, weakened and difficult-to-curl hair. In addition to the main product, a perm fixative is available for all types of hair, neutralizing thioglycollate and fixing the resulting curl. "Onadaform-neutral" contains softening and conditioning additives, maximally protecting hair.
« Perform» from Bella, providing uniform natural perm with maximum hair care. The product contains perm regulators that control the intensity at the roots and ends of the hair: care sensors that layer on the damaged ends of the hair and restore their structure; shine enhancer, providing additional protection at the roots and ends of the hair; thioglycolic acid, which provides changes in hair shape.
Currently, many cosmetic brands produce perm products with the “bio” label. The "bio" formula simply means that the traditional active ingredients in curling products, such as thioglycolic acid or ammonia, are replaced with sulfide or natural urea.
Another type of permanent means is chemical hair straighteners.they cause the process of restructuring the basic structure of very curly hair into a straight form. The same chemical processes are used in chemical straightening and permanent waving procedures using thio-compounds. Although the chemical composition of hydroxide straighteners and permanent solutions may differ, all straighteners and all types of permanent solutions change the shape of hair by breaking its disulfide bonds.
The two most common types of chemical rectifiers are thio-(THA) and hydroxide rectifiers.
Each company, as a rule, produces several types of preparations for different hair groups:
I – for healthy, stubborn hair (the most powerful drug);
II – for normal hair;
III – for weakened hair (before perm, such hair is treated with a protective preparation);
IV – for blond hair.
According to consistency, the compositions are:
a) liquid (applied with a sponge or applicator);
b) gel-like (squeezed out of a tube or applied with a brush; convenient for curling individual strands);
c) foamy (the most harmless, gives volume with virtually no curls).
Retainers. All fixatives contain H2O2. Ready-made fixatives can be concentrated, non-concentrated, foam or non-foam.
Concentrated - diluted with water (1:1; 1:4, etc.)
Unconcentrated - ready to use.
Foam - foam with a sponge and apply to hair (it’s good to foam, because the foam “works” during fixation).
Not foamy - applied using an applicator.
The fixer can be prepared from 30% H2O2 (applied as foam).
Hair dyes
In hairdressing practice, all available dyes are divided into 4 groups:
1. brightening or bleaching;
2. oxidative or chemical (permanent);
3. tint or physical (semi-permanent);
4. herbal or natural (permanent).
