Santa Monica-based private equity firm Sole Source Capital has agreed to buy Hi-De Liners Inc., a Massachusetts-based manufacturer of high-strength polyethylene film used in packaging in medical, food and industrial markets.

Terms of the transaction were not disclosed.

Orange, Mass.-based Hi-De Liners will be absorbed by Dallas Plastics, a Mesquite, Texas-based plastics company Sole Source acquired last fall.

“This is the first add-on for Dallas Plastics, and our second in the flexible packaging space,” said Sumil Menon, managing director with Sole Source.

“We’re trying to become a larger player in a fragmented industry and broaden our geographic reach and expand our product offerings,” he added.

Plastic film is used in everything from baby food pouches to sterile plastic bags filled with dentist tools. The film also is suitable for packaging applications under U.S. Food and Drug Administration regulations.

High-density polyethylene film uses less material and has been made thinner in recent years without sacrificing its tensile strength.  

Through this transaction, Dallas Plastics will add a fourth manufacturing facility to its operations in the United States.