AKRON (July 27)—Crain Communications Inc. has agreed to buy the plastics industry trade shows operated by Advanstar Communications Inc. of Cleveland. Crain—which publishes Plastics News—will assume control of the Plastics Fair Expos and the Western Plastics Expo, which includes the Western Powder Show. The three exhibitions are schedule to take place next year. Terms of the deal weren´t disclosed. Crain also publishes Rubber & Plastics News.