JPS5839535B2 - Earplug - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to soundproof earplugs that can select any sound insulation effect depending on the nature or size of the noise source.

Traditionally, soundproof earplugs have been made by punching out a synthetic resin sponge body into a cylindrical shape, or for use in particularly noisy areas, the surface of the sponge body has been covered with a film, etc.
Earplugs coated with an adhesive sheet are used, but the sound insulation effect is limited, and they do not necessarily provide earplugs suitable for working in special noisy environments. These earplugs had the disadvantage that their surfaces and ends were hard, making it difficult for them to fit into the ear canal, and that they did not fit sufficiently into the ear.

By the way, the optimal sound insulation effect for earplugs used for work in factories, etc. should be determined empirically based on the frequency of the sound waves emitted from the noise source and the ventilation resistance value of the earplugs. Although it naturally differs depending on the noise environment, it has been practically difficult to change the material of the earplugs or the material of the adhesive coating, etc., depending on each noise environment.

In view of the above points, the present invention makes it possible to easily obtain earplugs having any sound insulation effect depending on the nature of the noise source, and at the same time, it is easy to attach to the ear canal, and the manufacturing cost is low. The aim is to provide earplugs for both children and children.

The present invention will be described in detail below with reference to the drawings.The gist thereof is that the surface of the earplug body 10 made of a foamed synthetic resin with an open cell structure, at least the surfaces 10a of both ends.
, 10b, an optional dense layer 12 having high ventilation resistance is formed integrally with the foamed synthetic resin 13.

That is, the main body 10, which is made of a synthetic resin foam with an open cell structure such as flexible polyurethane foam or flexible vinyl chloride foam, is formed by punching or the like and has a shape such as a cylinder, a truncated cone, or a two-stage cylinder to fit into the ear canal. It has the following.

Synthetic resin foams with an open cell structure, such as flexible polyurethane foam or flexible vinyl chloride foam, are flexible and easy to wear with earplugs, and polyurethane foam etc. have low sound absorption properties due to their sound absorption properties. They are ideal as soundproof earplugs for work use, as they allow easy passage of human speech and absorb high-pitched sounds (for example, motor noise).

The main body 10 having these shapes is inserted into the ear canal with its longitudinal direction, but in the present invention, a dense layer 12 with high ventilation resistance is formed at least on both ends 10a and 10b by heating and melting. It has its characteristics in that it has done so.

The dense layer 12 is formed by the foamed synthetic resin 1 that constitutes the main body 10.
Any desired dense layer can be easily formed by contacting the surface with a roll or press plate heated to the melting temperature of No. 3 or above, or by subjecting it to a heating melting process such as exposing it to flame.

In other words, the ventilation resistance value of the dense layer formed changes depending on the heating temperature, heating time, and the magnitude of the compressive force on the surface, and it is possible to continuously and freely form the desired dense layer until the state is completely impermeable. It can be done.

In addition, in order to obtain earplugs with a higher sound insulation effect, the entire surface of the main body 10 may be subjected to this heat-melting treatment to form a dense layer.

It is also preferable to mix a high-density inorganic filler into the foamed synthetic resin (especially polyurethane foam) used to enhance the sound insulation effect.

Furthermore, selecting a so-called "boundless type" foam with low rebound resilience as the foamed synthetic resin for the main body 1 not only enhances the sound insulation effect but also makes it easier and more complete to fit into the ear canal. This is also desirable.

That is, the rebound modulus is 0 to 15% (J I 5K-64
The foamed synthetic resin (according to Reference Test 2) has extremely low elasticity, which not only improves its own sound absorption performance and enhances the sound insulation effect, but also has a small restoring force after compression deformation, making it difficult to insert earplugs into the ear canal. When worn, if the earplug is compressed to make it smaller and inserted into the ear canal, the earplug gradually expands and eventually completely shields the ear canal, further enhancing the sound insulation effect of the earplug according to the present invention. I can do it.

For reference, the physical properties of flexible polyurethane foam as an example of a synthetic resin with low impact resilience are shown below.

(All according to the test method of JISK-6401.

) Specific gravity o, i 2 i Impact resilience 6 Hardness 25% - 21.9 Compression residual strain hook 3.3 In the earplugs according to the present invention having the above-mentioned structure, foaming with an open-cell structure is used. At least both ends of the main body made of resin, that is, the surface of the ventilation part, are heated and melted to form a dense layer with high ventilation resistance, which not only improves the sound insulation effect, but also increases the ventilation resistance depending on the degree of heating and melting. Since the earplugs can be selected, it is possible to easily provide earplugs with a sound insulating effect according to the noisy environment.

In addition, since a dense layer can be formed by simply heating the surface of the body, the manufacturing process is much easier than with conventional earplugs that are adhesively coated with sheets, films, etc., and the manufacturing cost is also low. can do.

Furthermore, since the main body is made of foamed resin with an open-cell structure, it is easy to fit into the ear canal and there is no risk of hurting the ear.

As mentioned above, this effect can be further improved by selecting a foamed synthetic resin with low impact resilience.

[Brief explanation of the drawing]

Fig. 1A is a perspective view of a cylindrical earplug showing an example in which a dense layer is formed on both ends, the mouth is a longitudinal sectional view thereof, and Fig. 2A is an example in which a dense layer is formed on the entire surface. Fig. 3A is a perspective view of a two-stage cylindrical earplug showing an embodiment in which a dense layer is formed on the entire surface;
The opening is a longitudinal sectional view thereof. 10... Main body, 10a, 'IOb...
Both ends, 12... Dense layer, 13... Foamed synthetic resin.

Claims (1)

[Scope of Claims] 1. An earplug made of a foamed synthetic resin having an open cell structure, characterized in that at least the surfaces of both ends thereof are heated and melted to form a dense layer with a high ventilation resistance. plug. 2 The foamed synthetic resin with an open cell structure has a rebound modulus of O~1
5% (according to JISK-6401 reference test 2) soft heat-softening synthetic resin foam
Earplugs as described in section.