Federal Way-based Weyerhaeuser said it agreed to sell its liquid packaging board business to Nippon Paper Industries for $285 million in cash.
The transaction, expected to close in the third quarter, includes one mill in Longview with an annual capacity of 280,000 tons of the packaging material, used for products like milk cartons.
Weyerhaeuser said it expects to use a substantial portion of the proceeds to repay debt.
The company said it was reviewing the future of some operations when it announced in November 2015 its $8.4 billion acquisition of Plum Creek Timber. Weyerhaeuser announced in May that it would sell five pulp mills in the South and Canada to International Paper for $2.2 billion.
Weyerhaeuser is continuing to review its printing papers joint venture.