TGWU general secretary Tony Woodley said the vote indicated many workers wanted to take redundancy, but added the vote did not signal the end of the TGWU campaign.
The decision to close the Ryton plant in Coventry was made in April.
The plant will be brought to a close in two stages. It currently operates two shifts, which will be moved to a single shift in July. Production will not continue beyond July next year. The company said it will work with trade unions and the Government to provide support packages for its staff.