June 13 (Reuters) - Instant Brands, the maker of Pyrex glassware and Instant Pot pressure cookers, has filed for bankruptcy, saying high interest rates, tighter credit conditions and falling consumer demand made its debt load unsustainable.

The company, controlled by private equity firm Cornell Capital LLC, and 14 affiliates filed for Chapter 11 protection from creditors on Monday with the federal bankruptcy court in Houston, with as much as $1 billion in liabilities.

Instant Brands, whose products also include Corningware, said it plans to keep operating while it restructures, and toward that end has lined up $132.5 million in financing.

The Downers Grove, Illinois-based company has more than 1,800 employees, over half of whom are unionized. Entities located outside the United States and Canada are not seeking court protection.

In a Tuesday court filing, Chief Restructuring Officer Adam Hollerbach said Instant Brands has seen sales fall as consumers weary of the COVID-19 pandemic started going out and traveling more last year, while spending less on goods for the home.

He said Instant Brands underwent several rounds of price hikes and operating cost reductions but it wasn't enough, and still faces "severely" tightened credit terms from suppliers.

Those and other factors "strained Instant Brands' liquidity and made its capital structure untenable," Hollerbach said.

S&P Global downgraded Instant Brands' rating last week, saying first-quarter net sales had fallen 21.9% from a year earlier.

In January, Instant Brands agreed to pay a fine and change its marketing practices to settle U.S. Federal Trade Commission claims that it falsely advertised Pyrex glass measuring cups as "Made in USA" while importing some of them from China.

Davis Polk & Wardwell is Instant Brands' law firm, and AlixPartners is its restructuring adviser.

The case is In re: Instant Brands Acquisition Holdings Inc, U.S. Bankruptcy Court, Southern District of Texas, No. 23-bk-90716.

Reporting by Jonathan Stempel in New York; Editing by Bill Berkrot and Lisa Shumaker

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