The County Cavan-headquartered company will fund the deal from its existing cash resources.
Of the $82m sum, $72m will be paid in cash on completion, while the remaining $10m will be made up of working capital.
Kingspan chief executive Gene Murtagh said: "This investment represents a new and exciting frontier for our insulation business in North America, giving us particular exposure to the residential sector.
"It is a tremendous opportunity for Kingspan to build upon the growing success of our existing Insulated Panel business throughout the region, and at a time when North America's focus on energy efficiency and security is at an all-time high."
Pactiv's building insulation division produces a range of products which it supplies throughout the US from its manufacturing base in Virginia.
The agreement is subject to local approval of licence and permit transfers.