EA011173B1 - Layered sound absorptive woven fabric - Google Patents

Abstract

The invention relates to the layered sound absorptive non-woven fabric containing the resonance membrane and at least one another layer (1, 3) of the fibrous material at which the resonance membrane is created by a layer (2) of nanofibres having diameter to 600 nanometers and of surface weight 0.1 to 5 g/m, at the same time the resonance membrane together with at least one layer (1, 3) of fibrous material is formed by cross laying to the required thickness and surface weight.

Description

Technical field

The invention relates to a layered sound-absorbing nonwoven material containing a resonant membrane and at least one next layer of fiber material.

Prior art

Sound-absorbing materials are widely used in the automotive, aviation, construction and engineering industries. They are designed to provide hygienic measures in terms of protection from the effects of unwanted and harmful sound. Consequently, the development of a suitable acoustic material is performed taking into account the frequency range of unwanted sound waves in a given environment.

For suppressing high sound frequencies, mainly porous materials are used, but they are not suitable for suppressing low-frequency sounds, and primarily because of the large material thickness required. Such materials include, for example, melamine, polyurethane and metal foam materials or nonwoven materials of mineral or polymeric fibers. To absorb the sound of lower frequencies, these materials are unsuitable, since this requires a large material thickness.

To suppress the low frequencies, first of all, constructions based on the phenomenon of resonance are used, when due to the resonance of some of the elements, the sound energy is converted into thermal energy. However, these structures are able to absorb sound energy only in a certain low frequency range, and at other frequencies their sound-suppressing ability is very small. Combinations of perforated sheet, sound-absorbing material and, in some cases, air gap are used. The characteristic properties of a perforated sheet are determined by the number, diameter and location of the holes.

Usually they strive to combine the above properties into one acoustic system, which would be able to suppress sounds of both low and high frequencies.

From DR 10251951 A, a layered sound-absorbing material is known, consisting of one or several identical layers of fibers with a diameter of 0.05-5 μm, obtained by splitting a polyvinyl alcohol film (RUA). These fibers usually have a wide variation in diameter, but only a very small fraction of these fibers can have a diameter of less than 1 micron. This is also answered by information about the magnitude of sound absorption at a low frequency, i.e. low 10% absorption capacity.

From 1P 2003049351 A, a layered sound-absorbing material is known, consisting of several layers of non-woven material and several layers of polyester fibers of usual diameters made by meltblown method (sh11Io ^ n), which allows to get the smallest diameter of fibers approx. 1 micron. The disadvantage of this material is that it is designed to absorb sound waves mainly at mid frequencies, i.e. from 1000 to 4000 Hz.

The purpose of the invention is to eliminate or at least minimize the disadvantages of the existing state of the art and create a material capable of absorbing sound energy at low thickness at both low and high frequencies.

DISCLOSURE OF INVENTION

The purpose of the invention is achieved by a layered sound-absorbing non-woven material containing a resonant membrane and at least one next layer of fiber material, the essence of which is that the resonant membrane is formed by a layer of nanofibers with a diameter up to 600 nm, surface density of 0.1-5 g / m ² , at the same time, the resonant membrane is molded together with the next at least one layer of fiber material by transverse overlapping to obtain the desired thickness and the required surface density.

It is advantageous if the layer of nanofibers is obtained by the method of electrostatic spinning of a fiber from a polymer solution, since such a layer of nanofibers can be applied to the backing layer of fiber material during fiber spinning, and then merged with this layer.

The lining layer of the fiber material according to claim 3 is advantageously formed by at least one layer of fiber wadding (combed material) formed by fibers with a diameter of 10-45 μm, weighing 5-100 g / m ² .

To increase the sound-absorbing ability of the layer of nanofibers is connected with a layer of combed fiber fleece, formed by fibers with a diameter of 10-45 μm, weighing 5-100 g / m ² , on each of its sides.

The sound absorbing material of the invention absorbs sound at low frequencies without losing absorption at higher sound frequencies. According to this property, based on the phenomenon of resonance of a layer of nanofibres, smoothly suppressed by the lining layer, which is formed with profit by combed fiber wadding, this material surpasses the materials known so far.

Brief Description of the Drawings

Exemplary embodiments of the invention are shown schematically in the attached drawings, where, according to the invention, FIG. 1 shows a section of a material from a layer of combed fiber wadding and a layer of nanofibers;

FIG. 2 - section of the material from the layer combed fiber fleece, a layer of nanofibers and the following

- 1,011,173 layers of combed fiber wadding;

FIG. 3 - section of a material from a layer of combed fiber wadding, a layer of nanofibers and two subsequent layers of combed fiber wadding;

FIG. 4 - section of a material from a layer of combed fiber wadding, a layer of nanofibers and the following three layers of combed fiber wadding;

FIG. 5-11 depict the dependence of sound absorption coefficient on the sound frequency and surface density of a separate layer of nanofibers in the examples 1-7.

Examples of carrying out the invention

The layered sound-absorbing nonwoven fabric in FIG. 1 contains a resonant membrane formed by a layer of 2 nanofibres made by electrostatic molding, with a diameter of up to 600 nanometers, weighing 0.1-5 g / m ² , and layer 1 of carded material (fiber wadding), while in a favorable design layer 1 of carded fiber The fleece forms a carrier layer on which layer 2 of the resulting nanofibers is placed during electrostatic spinning of the fiber, and then both layers are joined in a known manner at a certain temperature in the heat / air chamber.

In the sound absorbing material of FIG. 2 to the material of FIG. 1, the next layer of 3 combed fiber wadding is applied from the originally uncovered side of the layer 2 of nanofibers. In other embodiments, the next layer 3 may be double - see FIG. 3, or triple - FIG. four.

To obtain the desired thickness and the required surface density of the final sound-absorbing nonwoven material, it is advantageous if, after the material has been formed from separate layers, according to FIG. 1-4, it is molded by transverse overlapping until the required thickness and required surface density are obtained.

Layer 2 nanofibers performs the function of an acoustic resonant membrane resonating at a low frequency. This nature of the membrane is due to the nano-size interfiber gaps. Sound waves incident on the acoustic resonant membrane cause forced oscillations of the membrane, the amplitude of which has a maximum value in the case of resonance, while adjacent layers 1, 3 of combed fiber wadding provide sufficient suppression of oscillations of the resonating membrane, thereby transforming the maximum amount of sound energy accumulated in the resonator in heat energy. At the same time, layer 1 and / or 3 of combed fiber wadding provides not only sufficient suppression of vibrations of the resonating membrane formed by layer 2 of nanofibers, but also absorbs sound energy at higher frequencies. The above-mentioned layers 1, 2, 3, moreover, are combined into one resonant system by superimposing separate layers 1, 2, 3 on each other and their subsequent connection, for example, in a heat-air bonding chamber. As a result of such layering of resonant elements, a material was obtained which, thanks to a resonant membrane formed by layer 2 of nanofibers, absorbs the sound of low frequencies and at the same time, layer 1 and / or 3 combed fiber wadding also absorbs sound of higher frequencies. The material according to the invention achieves high values of sound absorption at low and high frequencies, while providing the possibility of choosing the thickness of the material, as well as its surface density in accordance with various requirements.

Specific examples of the performance of sound-absorbing materials according to the invention are given below.

Example 1

The sound-absorbing material contains a layer of 1 combed fiber fleece with a surface density of 11 gm ^-2 , obtained on a combing car from a two-component fiber of the core-shell type, consisting of a polyester core and a copolyester sheath, with a tone of 5.3 dtex. A layer 2 of nanofibers with a surface density of 2 g / m ^{-2 was} deposited on this layer of fiber fleece 1 by electrostatic spinning. On the pair of layers 1, 2 prepared in this way, the next layer 3 of carded fiber wadding is applied on the side of layer 2 of nanofibers. Therefore, the structure of the base material is made according to FIG. 2, and then formed by transverse overlapping to obtain sound-absorbing material with a total thickness of 25 mm and a surface density of 630 gm ^-2 . The sound-absorbing material passes through the heat-air chamber at a circulating air temperature of 140 ° C, due to which the adjacent layers are mutually connected. This sound-absorbing material may contain a layer of 2 nanofibers weighing in the range from 2 gm ^-2 to 0.1 gm ^-2 .

FIG. 5 shows the dependence of sound absorption coefficient on sound frequency and surface density of a separate layer 2 of nanofibers for sound-absorbing material, shown in Example 1, where curve N1 shows this dependence for layer 2 of nanofibers with a surface density of 2 gm ^-2 , curve N2 - for layer 2 of nanofibers surface density of 1 g.m ^-2 , N3 curve - for layer 2 of nanofibers with a surface density of 0.5 gm ^-2 , curve N4 - for layer 2 of nanofibers with a surface density of 0.3 gm ^-2, and curve N5 - for a layer 2 nanofibers weighing 0.1 g m ^-2 . Curve P represents this relationship for a material containing only a layer of combed fiber fleece, without the use of a layer of 2 nanofibers. Using individual curves, you can choose the design

- 2,011,173 sound-absorbing material in accordance with the needs when solving a specific problem.

Example 2

The sound absorbing material shown in FIG. 1, contains a layer 1 of combed fiber fleece with a surface density of 11 g / m ^-2 , obtained on a core-sheath bicomponent combing machine consisting of a polyester core and a copolyester sheath, with a fineness of 5.3 dtex. The layer 2 of nanofibers with surface density from 2 to 0.1 gm ^-2 in the same way as in Example 1 was applied onto the layer 1 of a fiber batt using the method of electrostatic spinning. After that, the material from these two layers 1, 2 is formed by transverse overlaying obtain sound-absorbing material with a total thickness of 35 mm, weighing 630 gm ^-2 , and then exposed to heat in the same way as in example 1, as a result of which adjacent layers are joined.

The dependence of sound absorption coefficient on the sound frequency and surface density of an individual layer 2 of nanofibers for the material in Example 2 is shown in FIG. 6, where curve 13 expresses this dependence for layer 2 of nanofibers with a surface density of 0.5 gm ^-2 , curve 14 for layer 2 of nanofibers with a surface density of 0.3 gm ^-2 , curve 15 for layer 2 of nanofibers with a surface density 0.1 gm ^-2 .

Example 3

The sound-absorbing material has the same construction as in example 1, i.e. A layer of 2 nanofibers with a surface density from 2 to 0.1 gm ^{-2 is} applied on the main layer of combed fiber cotton wool by the method of electrostatic spinning. On the pair of layers 1 prepared in this way, the next layer 3 of combed fiber fleece is applied on the side of layer 2 of nanofibers. Consequently, the construction of the material is made according to FIG. 2, and then the material is formed by transverse overlapping to obtain a sound-absorbing material with a total thickness of 35 mm and a surface density of 630 gm ^-2 and is subjected to heat treatment in the same way as in example 1.

The dependence of the sound absorption coefficient on the sound frequency and surface density of a separate layer 2 of nanofibers for sound-absorbing material in Example 3 is shown in FIG. 7, where curve N1 expresses this dependence for layer 2 of nanofibers with a surface density of 2 g / m ^-2 , curve N2 for layer 2 of nanofibers with a surface density of 1 g / m ^-2 , curve N3 for layer 2 of nanofibers with a surface density of 0.5 g -m ^-2 , N4 curve - for layer 2 of nanofibers with a surface density of 0.3 g / m ^-2 , curve N5 - for layer 2 of nanofibers with a surface density of 0.1 g / m ^-2 . Curve P represents this relationship for a material containing only a layer of combed fiber fleece, without the use of a layer of 2 nanofibers.

Example 4

The sound-absorbing material was made in the same way as in Example 1, i.e., layer 2 of nanofibers with a surface density of 2 to 0.1 gm ^{-2 was} applied on the main layer 1 of combed fiber fleece. On the pair of layers 1, 2 prepared in this way, two next layers 3 of carded fiber wadding are applied on the side of layer 2 of nanofibers. Consequently, the construction of the material is made according to FIG. 3. After that, the material is formed by transverse overlapping to obtain a sound-absorbing material with a total thickness of 35 mm and a surface density of 630 gm ^-2 , and then subjected to heat treatment in the same way as in the example

one.

The dependence of the sound absorption coefficient on the sound frequency and surface density of an individual layer 2 of nanofibers for sound-absorbing material in Example 4 is shown in FIG. 8, where the PP1 curve expresses this dependence for layer 2 of nanofibers with a surface density of 2 g / m ^-2 , curve PP2 for a layer of 2 nanofibers with a surface density of 1 g / m ^-2 , and the curve РР3 for a layer of 2 nanofibers with a surface density of 0.5 g -m ^-2 , PP4 curve - for layer 2 of nanofibers with a surface density of 0.3 gm ^-2 , curve PP5 - for layer 2 of nanofibers with a surface density of 0.1 gm ^-2 .

Example 5

The sound-absorbing material was made in the same way as in Example 1, i.e. on the base layer 1 of combed fiber wool is applied by electrostatic spinning a layer of 2 nanofibers with a surface density from 2 to 0.1 gm ^-2 . On the pair of layers 1, 2 prepared in this way, three layers 3 of combed fiber wadding are applied on the side of layer 2 of nanofibers. Consequently, the construction of the material is made according to FIG. 4. After that, the material thus obtained is formed by transverse overlapping to obtain a sound-absorbing material with a total thickness of 35 mm and a surface density of 630 gm ^-2 , and then subjected to heat treatment in the same way as in example 1.

The dependence of sound absorption coefficient on the sound frequency and surface density of a separate layer 2 of nanofibers for the material in Example 5 is shown in FIG. 9, where the PPP2 curve expresses this dependence for layer 2 of nanofibers with a surface density of 1 gm ^-2 , the PPP3 curve is for layer 2 of nanofibers with a surface density of 0.5 gm ^-2 , and the PPP4 curve for layer 2 of nanofibers with a surface density of 0, 3 gm ^-2 .

- 3 011173

Example 6

The sound-absorbing material was made in the same way as in Example 1, i.e. on the base layer 1 of combed fiber wool is applied by electrostatic spinning a layer of 2 nanofibers with a surface density from 2 to 0.1 gm ^-2 . On the pair of layers 1, 2 prepared in this way, two next layers 3 of carded fiber wadding are applied on the side of layer 2 of nanofibers. Consequently, the construction of the material is made according to FIG. 3. The material obtained in this way is molded by transverse overlapping to obtain a sound-absorbing material with a total thickness of 35 mm and a surface density of 450 gm ^-2 and is subjected to heat treatment in the same way as in Example 1.

The dependence of the sound absorption coefficient on the sound frequency and surface density of an individual layer 2 of nanofibers for sound-absorbing material in Example 6 is shown in FIG. 10, where the PP1 curve expresses this dependence for layer 2 of nanofibers with a surface density of 2 g / m ^-2 , curve PP2 for a layer of 2 nanofibers with a surface density of 1 g / m ^-2 , and the curve РР3 for a layer of 2 nanofibers with a surface density of 0.5 g -m ^-2 , PP4 curve - for layer 2 of nanofibers with a surface density of 0.3 gm ^-2 , curve PP5 - for layer 2 of nanofibers with a surface density of 0.1 gm ^-2 .

Example 7

The sound-absorbing material was made in the same way as in Example 1, i.e. on the base layer 1 of combed fiber wool is applied by electrostatic spinning a layer of 2 nanofibers with a surface density from 2 to 0.1 gm ^-2 . On the pair of layers 1, 2 prepared in this way, three layers 3 of combed fiber wadding are applied on the side of layer 2 of nanofibers. Consequently, the construction of the material is made according to FIG. 4. The material obtained in this way is molded by transverse overlapping to obtain a sound-absorbing material with a total thickness of 35 mm and a surface density of 450 gm ^-2 and is subjected to heat treatment in the same way as in Example 1.

The dependence of the sound absorption coefficient on the sound frequency and surface density of an individual layer 2 of nanofibers for sound-absorbing material in Example 7 is shown in FIG. 11, where the PPP1 curve expresses this dependence for layer 2 of nanofibers with a surface density of 2 g / m ^-2 , the PPP2 curve for layer 2 of nanofibers with a surface density of 1 g / m ^-2 , and the PPP3 curve for a layer of 2 nanofibers with a surface density of 0.5 g m ^-2 , PPP4 curve - for layer 2 of nanofibers with surface density of 0.3 gm ^-2 .

The above embodiments of the invention are illustrative only. The invention also extends to sound-absorbing materials containing layers of combed fiber fleece, having different values of surface density, and / or composed of other fibers, as well as layers of nanofibers with other values of surface density selected as necessary. The invention is in no way limited to the number of layers of sound-absorbing material given in the description. The shown dependences of sound absorption coefficient on the sound frequency and surface density of a separate layer of nanofibers are evidence of the high sound absorption capacity of the material according to the invention, and especially in the frequency range of 500 to 6000 Hz, when the sound absorption coefficient is from 0.8 to almost 1.

Industrial Applicability

The invention is applicable mainly in the production of soundproofing cladding materials and components for the automotive, aviation, construction and engineering industries, and in comparison with the current state of technology contributes to a significant improvement in hygienic conditions in terms of protection from unwanted sound.

Claims (5)

CLAIM 1. Layered sound-absorbing non-woven material containing a resonant membrane and at least one next layer of fiber material, characterized in that the resonant membrane is formed by a layer (2) of nanofibers with a diameter of 600 nm and a surface density of 0.1-5 gm ^-2 . 2. Layered sound-absorbing material according to claim 1, characterized in that the layer (2) of nano fibers is formed by the method of electrostatic spinning of a fiber from a polymer solution. 3. Layered sound-absorbing material according to claim 2, characterized in that the layer (2) of nanofibers is connected to at least one layer (1) of combed fiber wadding formed by fibers with a diameter of 10-45 μm, weighing 5-100 gm ^{- 2} 4. Layered sound-absorbing material according to claim 3, characterized in that the layer (2) of the nanofibres is connected by its sides with two layers (1, 3) of carded fiber wadding formed by fibers with a diameter of 10-45 μm, weighing 5-100 gm ^-2 5. Layered sound-absorbing non-woven material according to any one of the preceding paragraphs, characterized in that the resonant membrane is formed together with the next at least one layer of fiber material by transverse overlaying into the system of layers having the desired - 4,011,173 thickness and / or required surface density.