Noise-proof earplugs (sound-proof earplugs) are generally made of silica gel or low-pressure foam materials and high-elastic polyester materials. After being inserted into the ear canal, it is in close contact with the external auditory canal, so as to isolate the sound from entering the middle ear and the inner ear (eardrum) and achieve the purpose of sound insulation, thus enabling people to have a quiet rest or working environment.
history
The earliest earplug products were invented in Europe. Legend has it that Scottish fishermen used a wax earplug to resist the decadent voice of the sea witch. The earliest earplug products also originated in Europe, and wax earplugs are the most traditional materials. It can be softened by hand and made into a shape suitable for the ear canal. However, the disadvantage is that it is not hygienic enough, and earwax may remain in the ear canal, which is not easy to clean. And wearing it for a long time will hurt your ears. Later, due to the continuous research and development of new materials, an elastic material gradually became the mainstream of making sound-proof earplugs, which is polyvinyl chloride (PVC) foam sound-proof earplugs with slow resilience. After the slow-rebound earplugs are rubbed into thin strips by hand, they will slowly expand after a few minutes and gradually return to their original shapes. Earplugs with different specifications and shapes can be molded according to different people, which is convenient to wear. However, the EU later gave a new definition to PVC products. They found that PVC compounds contain toxins [1], which is not suitable for making products close to human body, and completely banned the use of this material. Therefore, the materials for making anti-noise earplugs abroad are now replaced by PU materials.
classify
1. Classification by material
Silicone earplugs: Generally speaking, silicone earplugs are reusable, but because of the low softness of silicone, long-term wear often causes discomfort or even pain in the ear canal. Because silica gel is not as soft as sponge and cannot be attached to the ear canal wall, the sound insulation effect is often not as ideal as sponge earplugs. Sponge earplug: anti-noise earplug made of low-pressure foam material and high-elastic polyester material, with smooth surface, slow rebound, no ear swelling pain when used, and sound insulation effect between 25 dB and 40 dB. This kind of earplug is very suitable for sleeping every night, but it can't be reused because the slow rebound effect will be weakened after cleaning. Generally speaking, sponge earplugs are disposable. However, with the development of science, there are some sponge earplugs on the market that can be reused for more than half a year and can be scrubbed. Wax: wax is the originator of anti-noise earplugs, which can be softened by hand and made into a shape suitable for the ear canal. However, the disadvantage is that it is not hygienic enough, and earwax may remain in the ear canal, which is not easy to clean. And if you wear it for a long time, your ears will feel swollen and painful.
Classify according to shape
The most common shape of anti-noise earplugs is bullet type. There are also rocket-shaped (T-shaped), trumpet-shaped, cylindrical and tripod patented by Bagu. Bullet shape is widely used. The rocket-shaped sponge earplug, which is recognized as comfortable and has good sound insulation effect, is easy to pull out, but it is easy to cause cracks in the ear canal, resulting in unsatisfactory sound insulation effect. The center of the horn is hard, which is convenient for earplug insertion. Christmas trees are generally made of silicone, which brings a slight sense of expansion. The derivative of the pyramid bullet shape used for labor protection earplugs and swimming earplugs is the earplug shape independently developed by 3M Company. Cylindrical earplugs are very soft and can be easily kneaded into a shape suitable for the ear canal. However, compared with the bullet type and the rocket type, because the width of both ends is the same, the end entering the ear canal is not easy to be kneaded to fit the size of the ear canal.
3. Classification by function
Labor earplugs are also made of silica gel, which can prevent the sound from the machine from causing eardrum discomfort, and have good anti-manufacturing performance, but they are hard and have obvious swelling pain when worn, so they are not suitable for sleeping. Generally, labor-saving earplugs are equipped with ropes for easy removal at any time. Sleep earplugs are generally made of soft, slow-rebound materials. At present, the anti-manufacturing performance of sleeping earplugs on the market can basically reach the level of silica gel. However, because this material is not as waterproof as silica gel, it is not easy to clean, so it is not widely used in production workshops and is generally used for daily sleep. I do, but I often feel a foreign body in my neck when I sleep, and I feel uncomfortable. Swimming earplugs (waterproof earplugs) prevent water from entering the ear canal, and generally use materials with good waterproof performance, such as silica gel. But bringing it into the ear can cause swelling and pain. Not suitable for sleeping and daily use.
Application mode
Fine rubbing: rub the earplugs into strips, and the finer the rubbing, the easier it is to wear. Stuffing: Pull up the upper ear corner and stuff two-thirds of the earplug into the ear canal. Press and hold: Press and hold the earplug for about 20 seconds until the earplug expands and blocks the ear canal. Pull out: When taking out the earplug after use, gently rotate the earplug and pull it out.
Distinguish between good and bad.
1. Slow rebound effect
The elasticity is too large, and the anti-noise earplug compresses the skin of the external auditory canal when it expands, which can cause discomfort such as ear swelling and earache; If the elasticity is too small, it can not be in close contact with the external auditory canal, and the sound insulation effect is reduced. So be sure to observe the rebound speed of earplugs. The longer the rebound time, the better the quality.
Step 2 be gentle
Softness directly affects the comfort of earplugs.
3. Surface characteristics
Some earplugs are sticky to the touch and stick to the skin of the ear canal when worn in the ear. Try to avoid buying them. The best identification method is to stick two earplugs tightly together and then separate them, depending on the time when they are separated, the sooner the better.
Potential health hazards of long-term use of earplugs
Using earplugs may cause earwax to be pushed into the middle ear when the earplugs are inserted into the ear canal, which may lead to tinnitus, hearing loss, pain or bacterial infection. Users with excessive earwax should use earplugs more carefully and often wash them with water and mild soap. However, foam earplugs are usually discarded after use, and may lose their slow rebound characteristics after soaking in water to dry. In addition, anti-noise earplugs may also be a stimulating factor of otitis media, because many bacteria will multiply more vigorously in warm and humid environment. However, it is usually safe to use anti-noise earplugs, but some potential dangers that may occur after long-term use must be prevented: when earplugs are inserted, the air pressure in the middle ear will rise and push the eardrum, causing pain because the earplugs are inserted too deeply. To avoid this danger, please carefully rub the earplug and insert it into the preset ideal position. When the earplug is completely expanded, it is best not to push it in. On the other hand, in order to avoid squeezing the eardrum when pulling out the earplug, the earplug should be turned out slowly, and no force can be exerted.
Precautions for use
Wash your hands before use. Gently press the earplug for 30 seconds until the earplug is completely expanded and fixed. Replace or clean earplugs in time.
I hope the answer will satisfy you, but I suggest you stay in normal schools or library schools, where the environment is better.