UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

FORM 8-K

CURRENT REPORT PURSUANT

TO SECTION 13 OR 15(d) OF THE

SECURITIES EXCHANGE ACT OF 1934

Date of Report (Date of earliest event reported): February 25, 2013

POLYPORE INTERNATIONAL, INC.

(Exact name of Registrant as specified in its charter)

Delaware

(State or Other  Jurisdiction of Incorporation)

(704) 587-8409
(Registrant’s Telephone Number Including Area Code)

Not Applicable
(Former Name and Former Address, if Changed Since Last Report)

Check the appropriate box below if the Form 8-K filing is intended to simultaneously satisfy the filing obligation of the registrant under any of the following provisions:

o            Written communications pursuant to Rule 425 under the Securities Act (17 CFR 230.425)

o            Soliciting material pursuant to Rule 14a-12 under the Exchange Act (17 CFR 240.14a-12)

o            Pre-commencement communications pursuant to Rule 14d-2(b) under the Exchange Act (17 CFR 240.14d-2(b))

o            Pre-commencement communications pursuant to Rule 13e-4(c) under the Exchange Act (17 CFR 240.13e-4(c))

Item 8.01.  Other Events.

On February 25, 2013, Polypore International, Inc. (the “Company”) announced that Celgard, LLC (“Celgard”), a subsidiary of the Company, filed a complaint in the U.S. District Court of the Western District of North Carolina against Sumitomo Chemical Company, Limited. The complaint alleges that Sumitomo Chemical has infringed Celgard’s United States Patent No. 6,432,586 issued for an invention entitled, “Separator for a High Energy Rechargeable Lithium Battery.”  The patent in the lawsuit covers ceramic composite layer lithium-ion battery separators first developed by Celgard for high-energy rechargeable lithium-ion batteries.  This lawsuit has been filed after a period in which Celgard attempted to resolve its concerns with Sumitomo Chemical over infringement of Celgard’s patent.

A copy of the press release is furnished as Exhibit 99.1 to this Current Report on Form 8-K.

Item 9.01.  Financial Statements and Exhibits.

(d) Exhibits.

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SIGNATURES

Pursuant to the requirements of the Securities Exchange Act of 1934, the registrant has duly caused this report to be signed on its behalf by the undersigned hereunto duly authorized.

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