If you want to act on the hair so that the form attributed to long-stay, you must perform the classic “permanent”. As mentioned, acts on the permanent covalent bonds allowing long-term maintenance of the new form. The permanent can be done in two ways:
- Permanent Hot (obsolete method);
- Permanent Cold (a method still used).
Wash the hair with water and remains basic throughout the course of a high temperature. In these conditions is the breaking of covalent bonds of the SS cystine, resulting amino acid solfenico and cystine. At this point we must act on the hair giving it a new shape with the rollers, and then proceed with drying using a hair dryer.
The reaction between cystine and basic water at high temperature is reversible, so the induced dehydration from dry hair will reform the original structure, restoring the SS bonds of cystine. The same reaction, however, may become irreversible formation of sulfur and thioethers, resulting in severe damage to the hair.
This method is the most widely used because it reduces the risk of damaging your hair seriously. The permanent cold running water, rinsing the hair with basic (pH 9 to 9.5). Act with the water leaving a reducing agent, in order to break the bond between two cysteine sulfurs by generating cystine. The first treatment lasts approximately 15-30 minutes. At this point, it imposes a new form to the hair, always with the use of curlers.
The next step in the oxidation to reconstitute the disulfide bond. If the oxidation is much pressure may be the formation of cysteic acid, which degrades the hair in an irreversible manner. The oxidation is done with the use of hydrogen peroxide at acidic pH with a maximum volume of 10 otherwise you risk stripping the hair. The cold does not permanently exclude a possible damage to the hair, however less frequent than permanent hot.
Standing in the cold there has been talk of reducing agents and oxidizing agents. Among the reducing agents include:
- Thioglycolic acid or acid 2-mercaptoetanoico. is a colorless liquid smelling, its molecular structure is similar to acetic acid, in which a hydrogen atom is replaced by a group-SH. is toxic and corrosive, so the concentrations used are very low. It ‘the most used.
- Cystine (an irritant);
- Tiolattico acid (used in Japan and not in Italy);
- Monotioglicerina (an irritant);
- Tioglicolammide (is thioglycolic acid amide and is irritating).
The oxidizing agents are:
- Hydrogen peroxide (H 2 O 2). To avoid irreversible damage to the hair you use it in an acid;
- More urea hydrogen peroxide;
- 2S 2 O 8 Na 2 also known as sodium per sulfate, little used;
- NABO 2 2H 2 O 2 H 2 O or hydrated sodium Meta borate.
All of the above substances used to oxidize and reform the link broken as a result of the reduction reaction. The re-oxidation can also occur naturally by exposing the hair to air but it is a long process (about 5-6 hours) and a lack of effectiveness in forming SS bonds.
From Hair to Smooth Wavy Hair
5 are the operations that serve to give the hair a wavy appearance:
- very wet the hair with a reducing lotion;
- leave the lotion about 15-30 minutes;
- wash the hair by reducing lotion;
- give the form;
- apply the oxidant lotion
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