UPDATE 1-Huntsman CEO says bank commitments key to deal

* Huntsman CEO says wanted "certainty" in offer

* Huntsman CEO says banks cut secret deal with Apollo

* Huntsman shares close 1.9 pct lower (Adds additional comments from testimony)

By Anna Driver

CONROE, Texas June 16 (Reuters) - Peter Huntsman never would have agreed to sell the $4.5 billion chemical company founded by his father if he thought the banks funding the deal could wiggle out of their commitment, the executive told a Texas court on Tuesday.

"This is about certainty," Huntsman, president and chief executive officer of Huntsman Corp (HUN.N), told a jury in state district court located in a town about 40 miles north of Houston. "We're selling 40 years, two generations of life's work."

Huntsman is suing Credit Suisse Group AG (CSGN.VX) and Deutsche Bank AG (DBKGn.DE) for more than $4.6 billion in damages for their role in the failed $6.5 billion takeover of the company.

The banks were lenders in a 2007 buyout led by private equity firm Apollo Management LP [APOLO.UL] that fell apart after Apollo and the banks backed out of the deal, claiming it would create an insolvent company as the U.S. economy deteriorated.

Under questioning from company lawyers, Peter Huntsman said the company agreed to a higher offer price from Apollo's Hexion chemicals business even though the private equity firm had burned them in earlier negotiations.