Acoustically active materials

Patent metadata

Field	Value
Publication number	US-2020095392-A1
Application number	US-201816616157-A
Country	US
Kind code	A1
Filing date	Jun 11, 2018
Priority date	Jun 14, 2017
Publication date	Mar 26, 2020
Grant date	—

Abstract

A polymer matrix composite includes a porous polymeric network structure; and a plurality of acoustically active particles distributed within the polymeric network structure. The weight fraction of acoustically active particles is between 0.80 and 0.99, based on the total weight of the polymer matrix composite. The polymer matrix composite has an air flow resistance of less than 100 seconds/50 mL/500 μm.

First claim

What is claimed:

1 . A polymer matrix composite comprising:
a porous polymeric network structure; and a plurality of acoustically active particles distributed within the polymeric network structure; wherein the weight fraction of the acoustically active particles is between 0.80 and 0.99, based on the total weight of the polymer matrix composite; and wherein the polymer matrix composite has an air flow resistance of less than 100 seconds/50 mL/500 μm.

2 . The polymer matrix composite of claim 1 , wherein the polymer matrix composite has a density of between 0.05 to 1 g/cm 3 .

3 . The polymer matrix composite of claim 1 , wherein the polymer matrix composite has a porosity of at least 50%.

4 . The polymer matrix composite of claim 1 , wherein the acoustically active particles comprise acoustically active metal oxide particles.

5 . The polymer matrix composite of claim 4 , wherein the acoustically active metal oxide particles have an average particle size of 100 nm to 20 μm.

6 . The polymer matrix composite of claim 4 , wherein the acoustically active metal oxide particles have a specific surface area of at least 50 m 2 /g.

7 . The polymer matrix composite of claim 4 , wherein the acoustically active metal oxide particles are hydrophobic.

8 . The polymer matrix composite of claim 1 , wherein the porous polymeric network structure comprises polyurethane, polyester, polyamide, polyether, polycarbonate, polyimide, polysulfone, polyphenylene oxide, polyacrylate, polymethacrylate, polyolefin, styrene or styrene-based random and block copolymer, chlorinated polymer, fluorinated polymer, or copolymers of ethylene and chlorotrifluoroethylene.

9 . The polymer matrix composite of claim 1 , wherein the porous polymeric network structure comprises a plurality of interconnected fibrils.

10 . The polymer matrix composite of claim 1 , wherein the porous polymeric network structure comprises a polymer having a number average molecular weight of 5×10 4 g/mol to 1×10 7 g/mol.

11 . The polymer matrix composite of claim 1 , wherein the polymer matrix composite is in the form of a sheet having a thickness of between 50 micrometers and 5000 micrometers.

12 . The polymer matrix composite of claim 1 , wherein the porous polymeric network structure is produced by an induced phase separation of a miscible thermoplastic polymer-solvent solution and, optionally, wherein the induced phase separation is at least one of thermally induced phase separation and solvent induced phase separation.

13 . A method of making polymer matrix composite, the method comprising:
mixing a thermoplastic polymer, a solvent the thermoplastic polymer is soluble in, and a plurality of acoustically active particles to form a miscible thermoplastic polymer-solvent solution; inducing phase separation of the thermoplastic polymer from the solvent; and removing at least a portion of the solvent, thereby forming a polymer matrix composite, wherein the polymer matrix composite has an air flow resistance of less than 100 seconds/50 mL/500 μm.

14 . The method of claim 13 , wherein the inducing phase separation step includes at least one of thermally induced phase separation and solvent induced phase separation.

15 . The method of claim 13 , wherein the mixing step is conducted at temperature between 20° C. to 350° C.

16 . The method of claim 13 , wherein the inducing phase separation step is conducted at a temperature that is between 5° C. to 300° C. below the mixing step temperature.

17 . The method of claim 13 , further comprising stretching or compressing the polymer matrix composite.

18 . The method of claim 13 , wherein the solvent comprises a paraffin oil or paraffin wax.

19 . An electronic device comprising an acoustic device, the acoustic device comprising the polymer matrix composite of claim 4 .

Assignees

• 3M Innovative Properties Co

Inventors

• Acharya Bharat R
• Dehn Derek J
• Stolzenburg Fabian
• Shanti Noah O

Classifications

• C08J9/0066 Primary

  Use of inorganic compounding ingredients · CPC title

• C08J2377/00

  Characterised by the use of polyamides obtained by reactions forming a carboxylic amide link in the main chain; Derivatives of such polymers · CPC title

• C08J2327/02

  not modified by chemical after-treatment · CPC title

• C08J2205/044

  Micropores, i.e. average diameter being between 0,1 micrometer and 0,1 millimeter · CPC title

• C08K2201/005

  Additives being defined by their particle size in general · CPC title