Polypore International Inc. agreed to sell itself to industrial conglomerate 3M Co. and Japan's Asahi Kasei Corp. in a two-part deal that values the filtration company at about $2.7 billion.

Including debt, the deal is valued at about $3.2 billion. Asahi Kasei will buy Charlotte, N.C.-based Polypore's energy storage business for $2.2 billion, while 3M will pay $1 billion for the company's separations media business.

The deals are contingent on each other and require approvals from regulators and Polypore shareholders.

Asahi Kasei, a Tokyo-based maker of fibers and textiles, said it would pay $60.50 a share, a 28.4% premium to the 30-day average of Polypore's share price. Monday's deal is the latest in a wave of acquisitions for Japanese companies over the past month despite the weaker yen.

3M, meanwhile, will boost its purification business through the deal. 3M, which is best-known for products like Scotch tape and Post-it Notes, also has benefited from stronger sales of water-filtration products in China and other developing countries where pollution fears are growing in recent quarters. 3M said the purchase would broaden its array of technology used for filtering out very tiny particles in such fields as pharmaceuticals and water treatment.

Polypore's separations business is a provider of microporous membranes and modules for filtration with sales of about $210 million in the 12 months ended in September.

3M, which posted $31.8 billion in sales in 2014, expects the deal to hurt earnings by three cents in the first year after closing.

James R. Hagerty contributed to this article.

Write to Chelsey Dulaney at Chelsey.Dulaney@wsj.com and Atsuko Fukase at atsuko.fukase@wsj.com

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