* Simmons sees bankruptcy exit within 60 days

* Joins several mattress companies to file bankruptcy

* Buyers Ares, Teachers' Private Capital own rival Serta

* Canada and Puerto Rico operations not part of filing (New throughout, adds dateline and bylines)

By Jonathan Stempel and Ajay Kamalakaran

NEW YORK, Nov 16 (Reuters) - Simmons Co, maker of the Beautyrest mattress and other bedding products, has filed for bankruptcy protection and expects to be sold to two buyers in a transaction valued at roughly $760 million.

Private equity firm Ares Management LLC and the Teachers' Private Capital unit of the Ontario Teachers' Pension Plan, which together own rival mattress maker Serta, will buy Atlanta-based Simmons in a prepackaged reorganization plan.

Simmons filed for Chapter 11 protection on Monday with the U.S. bankruptcy court in Delaware, and expects to emerge within 60 days. It said the filing did not include its Canadian and Puerto Rican businesses, and would not affect daily operations.

The 139-year-old company is now owned by private equity firm Thomas H Lee Partners LP [THL.UL], which acquired it in 2003 in a $1.1 billion transaction. Ares and Teachers' Private Capital would become Simmons' seventh owner in 24 years.