Sound-transmitting waterproof film and method for producing same

Patent metadata

Field	Value
Publication number	US-2016337737-A1
Application number	US-201515111417-A
Country	US
Kind code	A1
Filing date	Jan 8, 2015
Priority date	Jan 13, 2014
Publication date	Nov 17, 2016
Grant date	—

Abstract

Provided is a sound-transmitting waterproof film having waterproof performance and stable sound-transmitting performance in a wide tonal range. The sound-transmitting waterproof film includes a porous film of a synthetic resin, and has a water pressure resistance of 10 to 400 kPa in accordance with a JIS L 1092 method B (a high water pressure method) and has an acoustic loss of less than 10 dB at a frequency of 1 kHz, an acoustic loss of less than 5 dB at a frequency of 2 kHz, and an acoustic loss of less than 5 dB at a frequency of 5 kHz in sound-transmitting performance tests.

First claim

1 . A sound-transmitting waterproof film comprising a porous film of a synthetic resin, wherein the sound-transmitting waterproof film has a water pressure resistance of 10 to 400 kPa in accordance with a JIS L 1092 method B (a high water pressure method) and has an acoustic loss of less than 10 dB at a frequency of 1 kHz, an acoustic loss of less than 5 dB at a frequency of 2 kHz, and an acoustic loss of less than 5 dB at a frequency of 5 kHz in the following sound-transmitting performance tests;
(Sound-Transmitting Performance Test) A speaker, a sound-transmitting waterproof film, and a microphone are arranged in this order, a distance between the speaker and the sound-transmitting waterproof film and a distance between the sound-transmitting waterproof film and the microphone are all set to 10+1 mm, a diameter of a sound-transmitting opening of the sound-transmitting waterproof film is set to 3.5 mm, sweep signal sound at each frequency is output from the speaker a sound pressure of which is set to 80 dB at a frequency of 1 kHz, and a sound pressure detected by the microphone is measured. A difference in sound pressure between absence of the sound-transmitting waterproof film and presence of the sound-transmitting waterproof film is defined as an acoustic loss.

2 . The sound-transmitting waterproof film according to claim 1 , wherein the synthetic resin is a polyurethane resin.

3 . The sound-transmitting waterproof film according to claim 1 , wherein the porous film of the synthetic resin is a porous film formed by coagulating a synthetic resin solution containing a synthetic resin and a polar organic solvent in water.

4 . The sound-transmitting waterproof film according to claim 3 , wherein the synthetic resin solution contains the synthetic resin, 1 to 75 mass % of inorganic fine particles based on a total solid content, and the polar organic solvent.

5 . The sound-transmitting waterproof film according to claim 4 , wherein the inorganic fine particles are inorganic fine particles of which surfaces are hydrophobized.

6 . The sound-transmitting waterproof film according to claim 1 , wherein the sound-transmitting waterproof film satisfies IPX5 and IPX7 protection degrees against infiltration of water defined in JIS C 0920.

7 . The sound-transmitting waterproof film according to claim 1 , wherein the sound-transmitting waterproof film has a 10% modulus of 0.3 to 2.0 N/25 mm and a 100% modulus of 0.5 to 5.0 N/25 mm.

8 . The sound-transmitting waterproof film according to claim 1 , wherein the sound-transmitting waterproof film has an elongation of 100 to 500%.

9 . The sound-transmitting waterproof film according to claim 1 , wherein the sound-transmitting waterproof film has an air permeability of 3 to 500 sec/100 mL in accordance with a Gurley method of JIS L 1096.

10 . An electrical product comprising a housing which comprises an opening for a sound reception part or a sound production part, and the sound-transmitting waterproof film according to claim 1 , which is attached to the opening.

11 . A method for producing the sound-transmitting waterproof film according to claim 1 , the method comprising:
applying a synthetic resin solution containing a synthetic resin and a polar organic solvent on a releasable substrate, and immersing and coagulating the applied synthetic resin solution in water.

Assignees

• Seiren Co Ltd

Inventors

• Kato Yoshiharu
• Sakamoto Katsumi
• Yamada Yoshiyuki
• Kishimoto Naoya

Classifications

• H04R1/023 Primary

  Screens for loudspeakers · CPC title

• G01H15/00

  Measuring mechanical or acoustic impedance · CPC title

• H04M1/03

  Constructional features of telephone transmitters or receivers, e.g. telephone hand-sets · CPC title

• H04R1/086 Primary

  Protective screens, e.g. all weather or wind screens · CPC title

• H04R1/44

  Special adaptations for subaqueous use, e.g. for hydrophone · CPC title