LT7084B - Sound absorbing composite panel - Google Patents

Abstract

Composite sound absorbing panel - designed for indoor use to reduce reverberation time and improve speech intelligibility index (STI). For the production of a composite panel, the main raw material - tire textile fiber - can be used, binding the particles with a binder. The composite panel has no worse sound-absorbing properties (α reaches 0.99 at some frequencies) than the widely used mineral wool, has good thermal conductivity properties (λ up to 0.045 W/m∙K), low bulk density of tire textile fiber, which provides lower loads in the structure. When comparing the material's CO2 emissions, they are lower than rock wool during production.

Description

TECHNICAL FIELD

The invention relates to sound-absorbing materials that are applied indoors by hanging on the ceiling.

STATE OF THE ART

The area of room acoustics in building design is an integral part that contributes to the improvement of acoustic comfort in rooms. An important parameter depends on the level of acoustic comfort - the speech intelligibility index, which determines how well speech is transmitted indoors from the source to the receiver. In the case of bad sound absorption, a long reverberation time will be heard in the room, which will worsen intelligibility, and in the opposite case, it will improve. Most often, the reverberation time indoors is controlled by using sound-absorbing materials, i.e. i.e. mineral wool, sound-absorbing panels, etc. However, such tools have drawbacks: they are produced from non-renewable sources, waste large amounts of energy, which leads to significant environmental pollution.

The closest analogues of the presented invention are Composite Sound-Absorbing Material, described in United States Patent No. US20230147834A1 published in 2023; Adjustable porous sound absorber, described in the patent of the Republic of Lithuania in 2021. No. LT6879B and Acoustical ceiling panels, described in the United States patent in 2005 no. US7798287B1.

The first mentioned analogue of the invention is applied to the improvement of acoustic comfort in cars by using it as a sound-absorbing material in body parts. This composite material consists of two or more layers made of non-woven fabrics with a melt-blown ultra-fine fiber layer and a synthetic long fiber layer, which are bonded together using a thermopress. This type of material has shown good sound absorption at medium and high frequencies, but at low frequencies the sound absorption is quite low. These materials, like any other composite sound-absorbing materials, are characterized by the conversion of mechanical energy into heat.

The second design mentioned is an adjustable porous sound absorber with a composite panel made from papermaking sludge. This structure differs from the previous one in that it is made from waste and the structure is used indoors to reduce the reverberation time, but the installation possibilities of the structure are limited as it can only be installed on the wall due to the high density of the composite board. Also, if it is necessary to reduce the reverberation time, especially at low frequencies, the useful area of the room will be greatly reduced, since it will be necessary to increase the width of the structure. The principle of operation of this material is based on the same way: part of the energy is absorbed by the plate, part is reflected and part passes through the material, where later the wave resonance takes place.

The third mentioned analogue of the invention, which is described in US patent no. US7798287B1 is acoustic ceiling panels. These panels are characterized and differ from other similar materials in that the possibility of sound wave reflection from the material is reduced. These panels are made by complex use of different layers, which complicates their production. Although the invention claims that quite high sound absorption (α^. = 0.70) is achieved, mineral wool and various foams are used as an absorbing material layer, the production of which contributes to environmental pollution.

ESSENCE OF THE INVENTION

The object of the invention is a composite sound-absorbing panel made from recycled materials and a binder. After applying the composite panel in the room, the sound would be effectively absorbed and the reverberation time would be reduced, the speech transmission index would be improved (Fig. 2 presents a visualization of the application in the room). Composite sound-absorbing panels will have a low density (bulk density of tire textile fibers - 40 kg/m ³ ), a sound absorption coefficient of up to 0.99 is achieved in the medium frequency range. Composite panels will be characterized by simple installation in the structure. It is suggested to use tire textile fiber (cleaned from rubber impurities) as absorbent porous material. Composite panels are made on the basis of tire textile fiber, which has no possibility of secondary use and is considered waste.

DESCRIPTION OF DRAWINGS

The images show images of a composite panel where:

Fig. Composite panel drawing: 1 - cover panel; 2 composite sound absorbing panel; 3 - falling sound wave into the material; 4 absorbed sound wave energy in the material; 5 - reflected sound wave energy from the material; 6 - sound wave energy passing through the material; d the thickness of the composite sound-absorbing panel.

Fig. Visualization of indoor application of composite panels.

A composite sound absorbing panel consists of the following components:

1. Tire textile fiber waste;

2. Binding material (polyurethane resin or polyvinyl acetate or starch).

DESCRIPTION OF IMPLEMENTATION OF THE INVENTION

The field of application of the invention is use in the indoor environment of buildings (premises). The intended composite sound-absorbing panel can be fixed to the internal elements of the building (overlay panels or roof structure). After assessing the reverberation time of the building room and determining non-compliance with the limit values given in the valid normative documents, the composite sound-absorbing panel is installed in the room on the building element. Also, with the use of composite panels, suspended ceilings can be created that can cover the engineering systems of the building without encumbering the building element.

PRINCIPLE OF OPERATION OF COMPOSITE SOUND ABSORBING PLATE

The operation of the composite sound-absorbing panel is based on the principle of sound absorption and reflection of the porous materials of the diffuse field. As the sound propagates in the room, the sound wave falls on the composite panel (2) suspended from the ceiling (1). When the sound wave collides with the element (3), mechanical energy is transformed into thermal energy, part of the energy is absorbed in the material (4), part of the energy is reflected from the surface of the material back into the room (5) and part of the energy passes through the material (6) (transmission occurs). . Since the sound absorption of acoustic materials depends on the thickness of the material (d), the sound absorption peak is reached at ¼ wavelength of the frequency of interest, so the thickness of the panel must be chosen according to the frequency range of interest to improve.

Claims (3)

DEFINITION OF THE INVENTION 1. Composite sound-absorbing panel, which consists of fibrous or granular or cellular material bound together using a binding material, but differs in that the composite material consists of secondary use of textile fiber waste (80-90%), which is obtained by recycling end-of-life tires. 2. A composite sound-absorbing board, consisting of two or more interconnected components, differs in that the binding material makes up 20-10% of the total mass of the board, and the binders can be polyurethane resin or polyvinyl acetate or starch. 3. The composite panel, which consists of sound-absorbing and binding materials, differs in that the peak of the sound absorption coefficient of the composite tire textile fiber panel in the medium frequency range (500-2000 Hz) reaches up to 0.99.