Polymer film, waterproof sound-permeable membrane, waterproof sound-permeable member, electronic device, electronic device case, waterproof sound transmission structure, waterproof gas-permeable membrane, waterproof gas-permeable member, waterproof ventilation structure, suction sheet, method for holding workpiece by suction on suction unit, method for producing ceramic capacitor, optical film, optical member, and composition

Patent metadata

Field	Value
Publication number	US-2017292000-A1
Application number	US-201515513736-A
Country	US
Kind code	A1
Filing date	Sep 24, 2015
Priority date	Sep 24, 2014
Publication date	Oct 12, 2017
Grant date	—

Abstract

The polymer film of the present invention has through holes extending from one principal surface of the polymer film to the other principal surface of the polymer film. The through holes are straight holes having a central axis extending straight, and have a shape in which the area of a cross-section perpendicular to the direction of the central axis increases from the one principal surface of the polymer film toward the other principal surface. This polymer film has passages in its thickness direction, has an unconventional structure, and can be used in various applications, such as in a waterproof sound-permeable membrane, in a waterproof gas-permeable membrane, and in a suction sheet. The ratio a/b of the opening diameter a of the through holes at the one principal surface to the opening diameter b of the through holes at the other principal surface is 80% or is less than 80%.

First claim

1 . A polymer film having through holes extending from one principal surface of the polymer film to the other principal surface of the polymer film, wherein
the through holes are straight holes having a central axis extending straight, and the through holes have a shape in which the area of a cross-section perpendicular to the direction of the central axis increases from the one principal surface of the polymer film toward the other principal surface.

2 . The polymer film according to claim 1 , wherein the through holes have an opening diameter a at the one principal surface and an opening diameter b at the other principal surface, and a ratio a/b of the opening diameter a to the opening diameter b is 80% or is less than 80%.

3 . The polymer film according to claim 1 , the polymer film being composed of at least one selected from polyethylene terephthalate, polycarbonate, polyimide, polyethylene naphthalate, and polyvinylidene fluoride.

4 . A waterproof sound-permeable membrane comprising the polymer film according to claim 1 , wherein
the through holes have an opening diameter a of 12.0 μm or less at the one principal surface, and a gas permeability from the other principal surface to the one principal surface, as expressed in terms of Frazier number measured according to JIS L 1096, is 2.0 cm 3 /(cm 2 ·second) or more and 80 cm 3 /(cm 2 ·second) or less.

5 . The waterproof sound-permeable membrane according to claim 4 , wherein the through holes have an opening diameter a at the one principal surface and an opening diameter b at the other principal surface, and a ratio a/b of the opening diameter a to the opening diameter b is 80% or less.

6 . The waterproof sound-permeable membrane according to claim 4 , wherein
the polymer film has: the through holes having a central axis extending in a first oblique direction with respect to a perpendicular direction to the principal surfaces of the film; and the through holes having a central axis extending in a second oblique direction with respect to the perpendicular direction, and the first and second oblique directions are different from each other.

7 . The waterproof sound-permeable membrane according to claim 4 , wherein a water entry pressure as measured according to Method B (high hydraulic pressure method) of water penetration test specified in JIS L 1092 is 3 kPa or more.

8 . The waterproof sound-permeable membrane according to claim 4 , further comprising a sound-permeable supporting layer stacked with the polymer film.

9 . A waterproof sound-permeable member comprising:
the waterproof sound-permeable membrane according to claim 4 ; and a supporting member joined to the waterproof sound-permeable membrane.

10 . An electronic device comprising:
a housing enclosing an audio part and provided with an opening for transmission of sound between the audio part and the outside of the housing; and a waterproof sound-permeable membrane placed to cover the opening and adapted to permit transmission of sound between the audio part and the outside of the housing and prevent water from entering the housing from the outside through the opening, wherein the waterproof sound-permeable membrane is the waterproof sound-permeable membrane according to claim 4 .

11 . An electronic device case for enclosing an electronic device having an audio part, the electronic device case comprising:
an opening provided for transmission of sound between the audio part of the electronic device and the outside of the case; and a waterproof sound-permeable membrane placed to cover the opening and adapted to permit transmission of sound between the audio part of the electronic device and the outside of the case and prevent water from entering the case from the outside through the opening, wherein the waterproof sound-permeable membrane is the waterproof sound-permeable membrane according to claim 4 .

12 . A waterproof sound transmission structure comprising:
a housing provided with an opening for transmission of sound between the inside and outside of the housing; and a waterproof sound-permeable membrane placed to cover the opening and adapted to permit transmission of sound between the inside and outside of the housing and prevent water from entering the housing from the outside through the opening, wherein the waterproof sound-permeable membrane is the waterproof sound-permeable membrane according to claim 4 .

13 . A waterproof gas-permeable membrane comprising the polymer film according to claim 1 , wherein the through holes have an opening diameter a at the one principal surface and an opening diameter b at the other principal surface, and a ratio a/b of the opening diameter a to the opening diameter b is 80% or less.

14 . The waterproof gas-permeable membrane according to claim 13 , wherein the opening diameter a is 12 μm or less.

15 . The waterproof gas-permeable membrane according to claim 13 , wherein the density of distribution of the through holes in the polymer film is 1×10 3 holes/cm 2 or more and 1×10 9 holes/cm 2 or less.

16 . The waterproof gas-permeable membrane according to claim 13 , wherein an opening area ratio of the one principal surface is 50% or less.

17 . The waterproof gas-permeable membrane according to claim 13 , wherein
the polymer film has: the through holes having a central axis extending in a first oblique direction with respect to a perpendicular direction to the principal surfaces of the film; and the through holes having a central axis extending in a second oblique direction with respect to the perpendicular direction, and the first and second oblique directions are different from each other.

18 . The waterproof gas-permeable membrane according to claim 13 , having a gas permeability in a thickness direction thereof, the gas permeability being 0.5 seconds/100 mL or more as expressed in terms of Gurley number measured according to JIS L 1096.

19 . The waterproof gas-permeable membrane according to claim 13 , wherein a water entry pressure as measured according to Method B (high hydraulic pressure method) of water penetration test specified in JIS L 1092 is 5 kPa or more.

20 . The waterproof gas-permeable membrane according to claim 13 , further comprising a gas-permeable supporting layer stacked with the polymer film.

21 . A waterproof gas-permeable member comprising:
the waterproof gas-permeable membrane according to claim 13 ; and a supporting member joined to the waterproof gas-permeable membrane.

22 . A waterproof ventilation structure comprising:
a housing having an opening; and a waterproof gas-permeable membrane placed to cover the opening and adapted to permit permeation of gas between the inside and outside of the housing and prevent water from entering the housing from the outside through the opening, wherein the waterproof gas-permeable membrane is the waterproof gas-permeable membrane according to claim 13 .

23 . A suction sheet to be placed on a suction face of a suction unit that holds a workpiece by suction, the suction sheet comprising the polymer film according to claim 1 , wherein
the through holes have an opening diameter a at the one principal surface and an opening diameter b at the other principal surface, a ratio a/b of the opening diameter a to the opening diameter b is 80% or less, and the opening diameter a is 10 μm or less.

24 . The suction sheet according to claim 23 , wherein
one princ

Assignees

• Nitto Denko Corp

Inventors

• Furuyama Satoru
• Mori Masaaki
• Nagai Yozo
• Muraki Yuuzou
• Tachibana Toshimitsu
• Yamamoto Hajime

Classifications

• C08J7/123

  Treatment by wave energy or particle radiation (C08J7/18 takes precedence) · CPC title

• H01G4/12

  Ceramic dielectrics {(H01G4/085 takes precedence)} · CPC title

• B01D2325/022

  Asymmetric membranes · CPC title

• C08J2367/02

  Polyesters derived from dicarboxylic acids and dihydroxy compounds; (C08J2367/06 takes precedence) · CPC title

• C08J7/12

  Chemical modification · CPC title