36results about How to "Improve low-frequency sound absorption performance" patented technology

The invention relates to low-frequency sound absorption needling non-woven composite materials and a preparation method of the low-frequency sound absorption needling non-woven composite materials and application of the low-frequency sound absorption needling non-woven composite materials. The composite materials comprise kapok fibers or hollow Dacron non-woven fabric and polyethylene films. The preparation method comprises: mixing, opening, carding and meshing are conducted to 60%-90% kapok fibers and 40%-10% hollow Dacron non-woven fabric according to mass percent; a fiber mesh is inputted in a needling machine so as to conduct needling reinforcement, the fiber mesh is reeled and cut off so as to obtain kapok or hollow Dacron needle non-woven fabric; the polyethylene films in 0.06mm-0.10mm are smoothly placed on one side of the needle non-woven fiber mesh, and are composited, taken out and cooled, and then the low-frequency sound absorption needling non-woven composite materials are obtained. The composite materials can be applied to the field of automotive trim, construction, high-speed rail and the like. The sound absorption materials have the advantages of being light in weight, simple in operation of the preparation method, good in economic benefit and suitable for industrial production.

The invention discloses a continuously and gradually enlarging gradient punching double-porosity sound absorbing device and application thereof. A porous material is adopted as a substrate of a perforated porous material plate, gradient holes are periodically formed in the perforated porous material plate, the punching direction is perpendicular to the perforated porous material plate, the punching pore diameter continuously become larger or smaller in the thickness direction, and according to actual requirements, the gradient double-porosity sound absorbing plate can be directly placed on rigid backing, or a hollow cavity is reserved between the sound absorbing plate and the rigid backing to further improve the sound absorbing property. The continuously and gradually enlarging gradient punching double-porosity sound absorbing device is simple and practical in structure, has a superior sound absorbing property and a flexible sound absorbing adjusting function in a low frequency band, amedium frequency band and a high frequency band, and has good and wide application prospects.

The invention belongs to the technical field of material processing, and particularly relates to a rare earth rubber-polyurethane foam composite layered material used for low frequency sound absorption and a preparation method thereof. The method comprises the following steps: pretreating rare earth oxide powder; sequentially adding nitrile rubber, zinc oxide, stearic acid, zinc stearate, an anti-aging agent, an accelerator, carbon black, rare earth oxide powder, sulfur and a softener into an internal mixer or an open mill for mixing and vulcanization treatment to obtain a rare earth oxide-nitrile rubber composite material for low frequency sound absorption; using a binder to compound the rare earth oxide-nitrile rubber composite material and polyurethane foam according to the structure with the rare earth oxide-nitrile rubber composite material on one side facing the sound wave and the polyurethane foam on the other side to obtain the rare earth oxide / butyronitrile rubber-polyurethanefoam double layered composite material. The rare earth oxide / butyronitrile rubber-polyurethane foam double layered composite material has a plurality of energy dissipation mechanisms such as magneticacoustic conversion, damping dissipation and interface resonance, has an excellent mid-low frequency sound absorption effect, is light in quality and small in thickness, and has broad application prospects in the field of sound absorption.

The invention discloses a gradient slitting double-porosity sound absorbing device and application thereof. The gradient slitting double-porosity sound absorbing device comprises a seamed porous material plate and rigid backing; the seamed porous material plate is arranged on the rigid backing, a plurality of gradient slits are formed in the seamed porous material plate periodically at intervals,and the slitting direction of the gradient slits is perpendicular to the seamed porous material plate. The gradient slitting double-porosity sound absorbing device is simple and practical in structure, has a superior sound absorbing property and a flexible sound absorbing adjusting function in a low frequency band, a medium frequency band and a high frequency band, and has good and wide application prospects.