Tokyo-based Mitsubishi said the plan, announced May 4, would boost its relatively small sales in engineering plastic parts outside of Japan, while Zurich-based Quadrant said it would gain improved access to Asia and would save money by delisting from the Swiss stock exchange.

The companies said the deal hinges on regulatory approval, which they said is expected, and on existing Quadrant shareholders voting for the privatization plan.

The Quadrant executives involved in the bid said they and Mitsubishi currently own about 32.7 percent of Quadrant, and need 66.67 percent for the deal to be completed.

The offer prices Quadrant at a 58 percent premium over the average stock price of the last 60 days, and is likely to be completed this summer, the companies said in a joint statement. Quadrant said its independent directors are supporting the offer.

Quadrant Chairman Adrian Niggli said that the deal would give his company better access to Mitsubishi research and development and raw materials, leading to more innovation.

Niggli said in an e-mail to Plastics News that the buyout is being funded by Mitsubishi, but he said Quadrant will operate independently and no management changes are planned. He said they do not expect any other bidders.

Quadrant board Vice President Marco Forster said having the backing of strong shareholders such as Mitsubishi is important in the current economic climate.

“An alliance with a prime industrial partner having a long-term view is a better option for Quadrant’s stakeholders than being raided by pure financial investors,” according to a statement from the management group and Mitsubishi.

Mitsubishi officials said Quadrant’s technology, research and distribution channels would help it achieve its goal of boosting overseas sales to 40 percent of its business by 2012.

Mitsubishi also said the two companies hope to expand their partnership in the injection molding business in Europe and the United States.

The two companies have a long-standing partnership in Japan making engineering plastic parts, Nippon Polypenco Ltd., and as part of the deal, Quadrant will increase its ownership in that joint venture to 55 percent.

Mitsubishi and the Quadrant executives formed a 50-50 partnership, Aquamit BV, to jointly run their alliance and complete the buyout, and said the venture company will become part of Mitsubishi if the privatization is complete.

Quadrant has a global network of 19 factories and 2,400 employees making semi-finished and finished plastic products from a wide range of materials.

Mitsubishi Plastics employs about 6,700 and is part of the much larger Mitsubishi Chemical Holdings Corp.