Is long term exposure to new skins bad for your health?

General plastic products are harmless, when plastic products meet the following three conditions, it will cause harm to the human body: first, contain harmful ingredients; Second, harmful ingredients can escape from the plastic and enter your body; Third, this thing contains a lot of harmful ingredients.

Studies have found that PVC escapes from plastic, enters food, and eventually enters the human body. When heated, or when the material is placed in an acidic (alkaline) environment, the chemical bonds that bind BPA to the plastic break, and PVC escapes from the plastic and enters the plastic-coated food. After entering the body, PVC disrupts the endocrine system due to its similarity with sex hormones.

Extended Information: PVC (Polyvinyl Chloride) Chemical and Physical Properties Rigid PVC is one of the most widely used plastic materials. PVC material is an amorphous material.

PVC materials are often added with stabilizers, lubricants, auxiliary processing agents, pigments, reinforcing agents and other additives in practical use.

Polyvinyl chloride resin is a multi-component plastic, which can be added with different additives according to different uses, so with different compositions, its products can present different physical and mechanical properties, such as adding or not adding plasticizers to make it soft and hard products. In general, PVC products have the advantages of chemical stability, flame resistance, self-extinguishing, wear resistance, sound and shock absorption, high strength, good electrical insulation, low price, wide range of materials, and good air tightness. Its disadvantage is that the thermal stability is poor, and it is easy to age under the action of light, heat and oxygen.

Polyvinyl chloride resin itself is non-toxic, and if it is made of non-toxic plasticizers, stabilizers and other auxiliary materials, it is harmless to humans and animals. However, most of the plasticizers and stabilizers used in PVC products generally seen on the market are toxic, so they cannot be used to contain food except for products with non-toxic formulas.

Sort of, of course. The new skin is dyed, and there are toxins in the dyeing. So toxins hurt the body.

I think long-term exposure to new skins is harmful to health. The new skin has an unpleasant smell.

That's a complicated question! I'll tell you that the skins are processed with chemicals! There will definitely be residual medicine! Regular exposure is certainly bad for health! It's better to do some protection to be safe! You try it!

The skin is an erhu.

A very important process in the production process, if you want to cover the python skin well, it is not something that can be mastered overnight. Since the vibration of the erhu skin is very complex, it is not possible to deduce the formula of the skin vibration here, but can only refer to the formula of the "tensioned circle" vibration that has been deduced by physicists to qualitatively explain the influence of factors such as the thickness and tightness of the erhu skin on timbre, sound quality and noise.

How to avoid the noise of the erhu in the high position? In order to avoid the noise of the erhu in the high position, it is necessary to make the resonance frequency of the skin as high as possible, so that the resonance frequency is higher than the range of the erhu. How can this be done?

Let's analyze what factors are related to noise.

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Ad. First resonant frequency.

The average displacement amplitude of the membrane when the frequency of the forcing force of the membrane (i.e., the frequency at which the strings vibrate) is low enough (less than 50% of the first resonant frequency).

Regardless of frequency. This is the elastic control zone of the membrane. That is, the membrane does not resonate only when the vibration frequency of the string is within the elastic control region of the membrane.

As can be seen from the above equation, in order to increase the first resonance frequency of the skin as much as possible (the lowest resonance frequency, there is also a first resonance frequency above.

II. The third ......resonance frequency), you should choose a smaller diameter barrel and a thinner skin, and cover the skin a little tighter.

Of course, the diameter of the barrel should not be too small, otherwise the pronunciation will be too sharp; The skin should not be too thin, otherwise it will also be prone to noise; The skin should not be stretched too tightly, otherwise the pronunciation will be sharp. These are all well known.

Based on this conclusion, it can be seen that at least the following two practices are incorrect:

1. In order to eliminate the noise of the erhu, most people apply some grease and other things on the skin, but it is not appropriate to do so, because after the skin is coated with grease, its surface density increases, so that the resonance frequency of the skin becomes lower, and the result is more likely to produce noise.

2. In order to avoid the noise of the new piano, someone will put a little pressure on the skin to make the skin become a little looser, but it is also inappropriate to do so, because the more relaxed the skin, the lower its resonance frequency, and the result is more likely to produce noise.

The skin of the new piano is generally tight, so that the pronunciation is sharp and bright, like a high hu. As long as such a situation is not particularly serious and intolerable, it should be said to be normal. If the skin of the new instrument is loose, it will affect the service life of the instrument.

After a year and a half of use, the skin of the new piano can gradually soften to the appropriate extent. To speed up the process, a cotton swab dipped in a small amount of vegetable oil can be applied to the back of the leather, then the barrel is laid flat, a 3 cm square piece of wood is placed on the leather, and then 10 to 15 kg of pressure is applied to the block, and then removed after 12 hours; If it is still tight, repeat it several times. It is also possible to set the strings two degrees higher than the second degree after playing the piano without unloading the piano horse, and so on.

One or two months. You can also lay the piano flat on the table, dip the thumbs of both hands in a small amount of vegetable oil, and press the piano skin vigorously in the direction of the scales, every day.

Once or twice, until the skin is moderately tight. However, artificially accelerating the process of fluffing the piano skin is always better than natural softness in terms of sound effect, and it may also cause some damage to the piano skin. Therefore, if it is not a last resort, it is better to let the leather change naturally during use.

No processing is required. The skin of the erhu, although the sound is very thin at the beginning, the vocal range is not wide enough, as long as you practice the piano at high power every day, so that the skin membrane fully vibrates, the tube will also be due to the drying of the heating air in summer or northern winter, the water will evaporate, and naturally shrink, so that the skin will relax a little, the timbre will also relax, and the bright and clean characteristics of the treble area will last for many years. In the southern region, although the humid climate has little impact on the wood, it has a greater impact on the skin, because the wet skin is easy to be damp and soft, so the new qin should be selected with a tight skin erhu.

It is better to deal with the erhu new qin skin if it is too tight, because the erhu skin is a very professional technique. It plays a key role in the tone of the erhu.

1. The bow hair is tightened by hand. Develop this habit to pull out a nice sound. In the absence of special skill, the bow rod is attached to the barrel.

2. It is good to be tight, it is easy to come out of the end when it is loose, and it is easy to hang to the bow hair, and the rosin foam is not easy to fly when rubbing rosin.

3. Pull the fast song, and tighten the bow; Slow tunes are looser.

4. Develop this habit to pull out a good sound. The bow of the erhu can be adjusted to the appropriate tightness according to the needs of the performance. However, it should not be adjusted too loose or too tight, because too loose makes the bow lose its due elasticity and is not easy to operate; If it is too tight, the pronunciation will be stiff, and it will lack subtle intrinsic ingredients, and it is easy to deform the bow shaft.

Therefore, the tightness of the skin is, of course, "not loose or tight" the best.

If the timbre of a new erhu is impeccable, it is because the skin is loose, and some mahogany erhu manufacturers, in order to cater to consumers, deliberately loosen the skin, so that customers can make a rich and transparent sound when they get it. A really good handmade erhu has a very tight skin, and the sound of a new erhu will appear bright and even sharp, and its sound will become more and more beautiful over a period of months to a year as the player opens the tone. According to your own habits, the sound can be perfectly matched with the player, play a more natural and beautiful music, and the service life will be longer.

If it feels very severe, you can remove the saddle, the silencer blanket, loosen the strings, rub some petroleum jelly on the skin, and if you don't have one, you can also rub it directly with walnuts until the skin has completely absorbed the oil. Let it sit for another week or so. The voice will be a little mellow.

But don't rub too much, too much will cause the skin to collapse.

It is normal for the skin of the new erhu qin to be too tight, and there is no need to use artificial methods to loosen it, no matter what method is used, it is actually a kind of damage to the new qin, similar to pulling seedlings to help grow, and quick desire is not reached.

As long as you use it every day, don't loosen the strings when you don't need to hang up, so that the skin is always under the pressure of the saddle, and after a period of time, the skin will loosen slightly.

The leather is an important part of the erhu, and it is also very important for the maintenance of the erhu skin and the maintenance of the erhu's timbre, and it is also the most important concern for every erhu player.

If the erhu leather is well maintained, it will have a long lifespan. Most of the erhu we see with damaged skin is caused by improper storage and infrequent use. If the erhu is used frequently, its skin will maintain a certain elasticity.

The skin of the erhu new qin is too tight, and there should be two ways to deal with it. The first is the physical method, which is to put a two-centimeter-wide wooden block under the skin, and press a large wooden block of 10 to 20 kilograms on top of it, and loosen the skin by pressing it. The second is to apply chicken fat to the skin by chemical methods, and after a period of time to soften the skin, the skin can be adjusted to a moderate tightness.

In China, a traditional folk instrument player always has to adjust the shaft to adjust the tightness of the strings before playing, and the purpose of this is to change the optional "loudness" or "tone" of the erhu sound); The listener can close his eyes and tell that the erhu is being played and not any other instrument, and he is judging by the sound

1) The tone is related to the vibration frequency of the sound emitter, the tighter the string, the higher the vibration frequency, the higher the tone, the player always has to adjust the shaft to adjust the tightness of the string before playing, the purpose of his doing this is to change the tone of the sound; (2) Different musical instruments have different materials and structures to produce the timbre of the sound.

The first problem is easy to solve, get a little 502 glue and rub it on the piano shaft to dry it and put it back. If you send it very well, you can rub it on 1 layer after the glue is dry, the effect is very good, and my piano doesn't even need to be fine-tuned after using this method, hehe. The piano sounds like a gaohu, so congratulations on picking a good piano that may be promising.

After 1 or 2 years, you will find that the drink is getting more and more moist, and if the new piano sounds very moist, then after 2 years, the skin will collapse.

The loose piano shaft is not a big problem, there will be more or less encountered with the erhu, I bought the Zhengyintang erhu, but also a little loose in the back, ask their customer service on the Internet and they told me a way: sprinkle some chalk ash or rosin powder in the hole where the piano shaft is placed, I used it very good You can also try it You can also ask the person who sells your erhu

1 The skin of the erhu is most susceptible to changes due to air humidity. The manufacturers who make the erhu are all based on the pianos sold to different regions, and the tightness of the skin is different when making the erhu. The air humidity in the south is relatively high, and the skin is relatively tight when the erhu is skinned; The climate in the north is dry, and the skin is looser when skinning.

In the rainy season in the north, the air humidity is relatively high, and the skin will become soft, and the sound will be muffled when playing, and the depression under the saddle can be clearly seen.

2 Some erhu in the early days, the erhu skin at that time basically did not use imported python skin, the skin was thin and translucent, and the skin technology at that time was all manual, the six opposite sides of the barrel were divided into three groups and wrapped with a rope to wrap the symmetrical afterburner pulling, the rope was slightly relaxed and its traction was not enough, and the covered skin was soft and collapsed. Now, although the erhu production process is operated by hand, the skin is pulled by mechanical traction, and screws are added diagonally to generate tension, so there is basically no skin that is not tight.

3 Some people are accustomed to hanging the erhu on the wall and not playing it for a long time, and they do not loosen the strings and saddle for a long time, resulting in a soft skin or a depression in the center of the skin, and the skin is inelastic, and even the column is slightly deformed and bent sideways.

2] The skin becomes soft, which will have a great impact on the sound quality of the erhu, and it is basically impossible to play. When playing, the sound is muffled, not crisp and translucent, the treble does not go up, and it sounds soft and weak, not high-pitched.

3] The solution to the fluffy skin: To solve the fluffy skin, we must first distinguish the reason for its fluffiness.

1 If the fluffy skin is caused by moisture, put the piano in a ventilated place or put the piano in the piano case, put some desiccant in the piano case, and wait for 24 hours to take it out and use it.

2 If it's the reason for production, then you can only change the skin. Because the skin is already loose, this cannot be changed.

3 If you don't play the erhu on the wall for a long time, and the skin is soft due to not loosening the strings and removing the saddle, in this case, quickly loosen the strings and saddle, put the piano into the piano case, and then put a wet sponge in the piano case, wait for 24 hours to take out the piano and put it in a ventilated place to dry naturally, or put it in the piano case to take out the wet sponge, put more desiccant, and wait for 24 hours or more time. After this treatment, the soft and sunken skin can be alleviated, which also improves the sound quality of the erhu.

4] It is worth noting that to develop a good habit, the strings must be loosened after playing, and remember, the piano cannot be left overnight with the saddle! After playing, put the piano case in time, and put some desiccant in it, and it is not damp.

If the strings are not loosened for a long time, it will not only cause the skin to be soft and dented, but also cause the skin fibers to age and lose their elasticity, thus shortening the service life of the erhu.

The maintenance of the erhu is very important, especially the skin, which is the most vulnerable part of the erhu as a whole. In order to avoid unnecessary problems, when buying an erhu, you should use your fingernails to hit the skin, and there is a high-pitched resonance and crisp sound, which proves that its sound is crisp and translucent. Gently press the leather with your fingers** is not so firm, but it is rich in some elasticity, press the strings with your fingers, the skin will have a sense of undulation, you should choose this kind of skin.