Seeing that the experts were so calm, Qingxiang finally took her eyes off his terrifying hand and sat down.

"If shampoo is a chemical product, perming agent is completely chemical agent. It destroys the original structure and pigment of the hair, reshapes the shape and color. So it is very corrosive."

Qin Kong said: "Now many perm and dye products that claim not to hurt hair or even hair care are completely nonsense! There are currently no perm and dye products that do not hurt hair, just like hair washing and care products that do not prevent hair loss!

These are all gimmicks of merchants' promotion, which take advantage of consumers' psychology. For example, the popular silicone-free shampoo is a concept that is hyped. Silicone oil is a smoothing agent, which makes hair smooth and shiny."

A female expert said: "So should we use shampoos containing silicone oil or without silicone oil?"

Qin Kong looked at her perm-dyed hair, "Generally, perm-dyed hair, scalp, and hair are damaged and dry, and are suitable for silicone oil shampoo.

It can reduce hair friction, and you will also reduce static electricity when combing your hair, making it easier to comb. In fact, it contains very little content in shampoo.

It is a macromolecule and cannot be absorbed by hair follicles. Moreover, the cleanser is the main ingredient in shampoo. How much silicone oil can remain on the scalp after rinsing the hair clean?

Therefore, silicone oil causes hair follicles blockage, hair loss, etc., and there is no scientific basis at all. It is a relatively safe and stable chemical ingredient."

Everyone nodded.

"On the contrary, if you use silicone-free oil for dry hair, the more you use it, the more you use it, the dryer you will be. Then you will use hair care products. You said you don't use silicone oil, but you still use it when you are doing hair care.

Conditioner and hair mask, the main ingredient is silicone oil, which is much higher than in shampoo. Otherwise, how will the smoothness and gloss of hair come out? This is a question of changing concepts."

Everyone nodded.

"And if you say you don't use silicone oil, then don't use cosmetics. Silicone oil is the basic ingredient in cosmetics and has been in cosmetics for nearly a hundred years! It is a moisturizing effect. Consumers are very stupid."

"Hahaha..." Everyone laughed.

"What about oily hair? Do you use silicone-free oil?" asked an expert again.

"If you use silicone-free oil on scalp oil, if you use it for a long time, your scalp will dry, which will stimulate the secretion of oil in your hair and cause the hair to become oilier."

"Oh." Everyone nodded.

"So it's not that the merchant promotes anything, you believe in whatever you want."

"Everyone pursues beauty and health, so the merchants target this psychology. But in fact, he used other ingredients instead.

If you want to keep your hair smooth, you cannot do without silicone oil. It is added to the conditioner if it is not added to the shampoo. Because other ingredients do not have such good results.”

Everyone nodded.

"Let's talk about perming and dyeing products. Shampoo promotes no silicone oil, so what is advertised as perming and dyeing agent is now advertised as ammonia-free. This is another hype concept.

Just as silicone oil is an important ingredient in skin care products, ammonia is also the main ingredient in perming and dyeing agents.

Perming agents are generally divided into one dose and two doses, namely softeners and shaping agents.

Ammonia, thio, and cysteine ​​are several common main ingredients in softeners.

Their working principle is to use ammonia to expand hair and open hair scales. The sulfhydryl disassembles the cortical layer and medulla layer, cuts off the disulfide bonds of the hair. Cysteine ​​permeates at the same time.

The main component of the styling agent is an oxidant, which promotes the re-joining of keratin cysteines into new disulfide bonds, and finally achieves the effect of changing the shape of the hair."

The experts listened very seriously and wrote chemical reactions on their notebooks. Qing Xiang and Liang Ange turned the pen in their hands, but they couldn't understand them, and they couldn't understand them even more when they looked at their notes.

"The proportion of these ingredients depends on what kind of hair function, such as resisting hair or healthy hair, and using ammonia as the main and sulfide as the auxiliary.

If the hair is mildly damaged or moderately damaged, use thio as the main ammonia as the supplement. If it is highly damaged, use cysteine ​​as the main one."

Qingxiang and Liang Ange held their cheeks, their eyes dazed.

Qin Kong looked at them, "Perming is a chemical reaction process, adding physical assistance from the bar tool to form a biological structure change and reshaping."

Qingxiang looked at Liang Ange, "Why don't we go out for a while?"

The experts laughed and said, "Teacher Qin teaches, how dare you skip class?"

Liang Ange rubbed his head, "I really don't know that perming my hair involves chemistry, physics, and biology! Teacher Kong, what kind of barber do you do, why not do research!"

The experts all laughed. Teacher Qin is really professional!

"Aren't I doing research now?" Qin Kong said, "Generally, barbers just memorize rotely, and there are methods for packaging perming and dyeing products.

But you need to understand this principle, from the protein molecules in the hair to the hair scales on the surface of the hair, how do you react when you encounter these products?

You must understand this to be able to easily deal with your perming and dyed hair. It will produce the best results with the lowest damage.”

Everyone nodded in admiration. Teacher Qin was really serious and responsible! The two students who were preparing to skip class also tried to continue listening.

"Why is it now that there is no ammonia?" Qin Kong continued, "because ammonia is strongly irritating and corrosive. Everyone should remember that in the past, the hair would have a pungent smell. That is the smell of ammonia."

Everyone nodded.

"There are no more unpleasant nowadays, and it has added flavors to suppress this smell, but it cannot change its irritating and corrosive effects.

Because it does not have this function, you can't finish it. It just reduces the taste a little, makes everyone feel more comfortable and more acceptable. It's purely psychological comfort."

"Now some big brands promote ammonia-free dyeing agents, which actually use alternative alkalizing agents such as ethanolamine and ammoniamethylpropanol.

These alternative ingredients can reduce the pungent odor of ammonia in the perming agent, but at the same time, its alkalization effect is also weakened. The result is that it cannot achieve the effect of ammonia.

For example, if the perming agent containing ammonia can achieve the effect at one time, you need to use ethanolamine repeatedly or increase the time. This will cause more damage to the hair and scalp.

Moreover, alternative ingredients such as ethanolamine are also alkalizing agents, which play the same role in hair and are not better than ammonia in terms of safety.”

The experts all nodded.

"You all know that hair was very bad after perming and dyeing, but it will be better after a while. Because ammonia can evaporate on its own and is easy to clean.

Like the most common ethanolamine in ammonia-free perming agents, it is odorless and cannot evaporate on its own, but it is toxic for inhalation and contact with the skin. So its toxic side effects are greater than ammonia."

Everyone nodded.

"In addition to promoting ammonia-free, we also like to claim pure plant hair dyeing, but in fact there is no pure plant-extracted hair dye, only hair dyes containing plant ingredients.

Hair dyes containing plant ingredients may use some plant dyes such as purpura. However, the extraction process of plant dyes is relatively complicated and the dyeing effect is not ideal.

In order to make the hair dye look longer, the hair dyes on the market have basically added para-phenylenediamine or other benzene derivatives.

Moreover, plant ingredients are also sensitized, and those who make essential oils know that. For example, Haina powder, which was once popular for a while, is said to be a pure plant, non-toxic and has no side effects, but its plant ingredients are actually sensitized.

In order to enhance the hair dyeing effect, p-phenylenediamine and heavy metals are also added. P-phenylenediamine is strongly sensitized, and heavy metals are the commonly used raw materials for the first generation of hair dyes. They are easy to enter the body and are not easy to metabolize. They have basically been eliminated now.

Those fast hair dyeing products such as washing black on the market have basically added an excess of para-phenylenediamine. This time I was allergic to it, probably because I was exposed to a large amount of para-phenylenediamine."

Liang Ange looked at him, "Do you know there is a tiger in the mountain, but you tend to go to Tiger Mountain?"

Everyone laughed again. Qin Kong was helpless.

"There are also some so-called nutrients that make your hair not so dry after perming and dyeing, and it is very smooth and bright. Most of them are added with smoothing agents and fluorescent agents. There is no nutrition, just to make your hair look better."

"Permanent hair dyes are now mainly oxidative hair dyes. Changing hair color mainly involves three chemical steps - oxidation, alkalinization, and color development.

Therefore, these products include three main ingredients: oxidizing agent, alkalizing agent, and dyeing agent.

Oxidants are the hydrogen peroxide milk we often call. Its function is to break down the natural melanin in the hair, make the hair fade and make the new colors appear. The higher the concentration, the stronger the effect.

Therefore, bleaching is also the most harmful to hair. High concentration of hydrogen peroxide is required to bleach all the original pigments of the hair.

Alkalinizers are ammonia and other substitutes. Their function is to expand the hair, open the hair scales, loosen the hair, and allow dye to enter the hair dry.

Dyeing agents are dyes. For different hair types, this product needs to be prepared by a barber.”

Qin Kong took a sip of water and said, "What kind of hair color is suitable for a person? It is related to his personal image and temperament and the workplace. Everyone likes to dye his hair so much because colors can greatly change his image and temperament."

Qingxiang said, "Wait! Are you going to talk about color?"

Qin Kong looked at her in a daze, Qingxiang picked up her cell phone and called the young people from the advertising department to come and listen to the class.

Then he looked at Qin Kong, "Teacher Qin, take a break during class, you should drink a little water first."

Everyone leaned on the back of the chair and laughed.

After a while, a group of young young people rushed in, holding their notebooks, "Teacher Qin!"

"Ah! What's wrong with your hand?"

"It seems like the eyes of a strange beast!"

"Right?" an expert also said excitedly.

Qin Kong was speechless again, not expecting that his hand could give them so many associations, nodding and said, "Very good, very good, you all have good imagination!"

Everyone sat down with a smile.

"Teacher Qin just talked about science, and now he talked about liberal arts, so I asked you to come and listen." Qingxiang said.
Chapter completed!