BOSTON – On a warm summer day in July 2006, Robin Aleo climbed to the top of a 6-foot inflatable pool slide and slid down head first. As she neared the bottom, the slide partially collapsed and Aleo slammed her head on the concrete pool deck, causing fatal injuries.

Five years later, a jury awarded Aleo’s family more than $20 million, finding that the slide sold by Toys R Us did not comply with federal safety standards for swimming pool slides.

Toys R Us will go before the highest court in Massachusetts on Monday to ask that the award be overturned.

The national chain argues that the 1976 Consumer Product Safety Commission regulation cited by Aleo’s family does not apply to inflatable in-ground pool slides, but only to rigid pool slides. Toys R Us also says the trial judge allowed lawyers for Aleo’s family to inflame the jury by accusing Toys R Us of importing an “illegal” product when it had relied on a certification that the slide met all safety regulations.

Aleo, 29, of Louisville, Colo., was visiting relatives in Andover when she went down a “Banzai” pool slide. Her husband, Michael, and 15-month-old daughter were watching as her head hit the pool deck. She suffered a broken neck and died the next day at a Boston hospital.

A jury in Salem Superior Court awarded Aleo’s estate $20.6 million in 2011, including $2.5 million in anticipated lost income from Aleo’s career in advertising and marketing, $100,000 for pain and suffering before her death and $18 million in punitive damages. Toys R Us argues that the $18 million in punitive damages was “grossly excessive.”

Lawyers for Aleo’s husband say pool slides have been subject to a federal safety standard since 1976. The standard applies to all pool slides, no matter what they are made of, said Benjamin Zimmermann, a Boston attorney who represents Michael Aleo.

Toys R Us, however, says the standard was only meant to apply to rigid slides, not the flexible, inflatable slides that have become popular in recent years.

“Inflatable slides did not exist (when the regulation was put in place),” Toys R Us lawyers argue in a legal brief filed in its appeal.

The company said the regulation “established performance standards that were designed for rigid slides and that could not be met by an air-filled slide made of fabric like the Inflatable Slide.”

But Aleo’s family says the regulation applies to all swimming pool slides “regardless of the materials of manufacture or structural characteristics.”

The slide had an instruction manual and small warning label near the climbing footholds that said the weight limit was 200 pounds, but the safety standard required that slides should be able to support up to 350 pounds. Aleo weighed 148 pounds, according to testimony at the trial.

A spokeswoman for Toys R Us said the Wayne, N.J.-based company has a policy of not commenting on pending litigation.

In its appeal brief, Toys R Us said the trial judge refused to allow testimony that Aleo had misused the slide and that some witnesses said she had “jumped” or “dived” off the slide head first.

Zimmermann, however, said that witnesses who testified during the trial said Aleo had slid down the slide.