TPU acoustic film and preparation method thereof

Abstract

The invention provides a TPU acoustic film. The TPU acoustic film is prepared from modified TPU particles, polylactic acid, an antioxidant and a coupling agent A; and the modified TPU particles are prepared from oligomeric diol, isophorone diisocyanate, a chain initiator, a chain terminator, nanometer calcium carbonate, polyformaldehyde and a composite coupling agent B. The acoustic film preparedthrough the method has smooth and stable surface, the diameter is 1.55-2.72 mm, and the thickness is 2.5-7.2 [mu]m; and the ratio of the diameter to the thickness of the acoustic film is very large, the acoustic film has excellent acoustic characteristics and has excellent responsivity within the acoustic frequency range of 0.025-25000 Hz, the sensitivity can reach 50-100 mv / pa, and the static pressure sensitivity reaches up to 9 [mu]m / pa.

Description

technical field [0001] The invention relates to the technical field of acoustic thin films, in particular to a TPU acoustic thin film and a preparation method thereof. Background technique [0002] Sound wave is a kind of mechanical wave generated by the vibration of sound source. The space of sound wave propagation is sound field. When sound propagates in gas and liquid medium, it is a longitudinal wave, but it may be mixed with transverse wave when it propagates in solid medium. The frequency of sound waves that can be heard by the human ear is generally between 20 Hz and 20,000 Hz. Below 20Hz is infrasound, above 20kHz is ultrasound. Sound waves in different frequency bands have different uses in practical applications. Infrasound is used in geoacoustic exploration, and ultrasound is used in nondestructive testing and ultrasonic imaging. When the sound wave propagates in the air, it will cause the density of the air to change, causing the air pressure to change periodic...

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Problems solved by technology

FP microphone film does not require it to be piezoelectric or capacitive, and various materials can be used to prepare acoustic films, such as silver film, silicon film, graphene film, polymer film, sugar-based film, etc.; the sensitivity of the acoustic film and the thickness of the film It is inversely proportional to the cube of the film radius and proportional to the fourth power of the film radius; considering the size of the sensor, the thickness of the acoustic film is often relatively small. At the micron or even nanometer level, it is difficult to increase the radius of the film, and the preparation process of the film is also complicated. High cost, low response to low frequency, the preparation of acoustic film is a difficult point in the development of acoustic sensors

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