Solo Cup Co. will begin laying off some Owings Mills-based corporate workers June 30 as it prepares to shut the Baltimore County manufacturing plant at the end of September, sooner than the company had anticipated, a company spokeswoman said Tuesday.

The Illinois-based maker of paper and plastic cups, lids and straws announced last June that it planned to close the plant in two years and eliminate 540 manufacturing jobs. The closing date has been moved up as the company has proceeded faster than expected to consolidate some operations, said Angie Gorman, the spokeswoman.

"The last few years have been difficult for us," she said. "Volume has been improving as the economy has improved, but generally speaking the economy has been difficult on the restaurant industry and the hospitality industry, and we serve those industries."

In addition to the already announced manufacturing layoffs, the company will eliminate or relocate 101 corporate positions in an office attached to the Reisterstown Road plant. The company notified Maryland's Department of Labor, Licensing and Regulation that it would begin corporate layoffs June 30, when three corporate employees are to be let go.

The remaining 98 corporate workers, in specialties such as information technology, human resources and graphics, will likely remain, possibly until the 1.4 million-square-foot facility is sold. At that point, some positions will be relocated to the company's Lake Forest, Ill., headquarters, while others could go to an as yet undetermined location in the Baltimore area, Gorman said.

As many as 50 of the corporate workers might be able to relocate, she added.

Solo Cup acquired the Baltimore County plant in a 2004 purchase of Sweetheart Cup Co., which had roots in the county going back more than eight decades. Last June, Solo Cup announced the closings of three of its 13 North American plants, in Owings Mills, Springfield, Mo., and Andover, Mass., which will eliminate a total of 1,240 jobs.