Zotefoams, which has operated in the area for more than 90 years, makes foam used by brands including Nike.
The GMB union says the company increased profits by 34% last year and is calling for the plans to be reconsidered.
Workers now face redundancy, with the union urging the Government and politicians to intervene to protect jobs in Croydon.
Zotefoams has declined to comment, saying it has nothing further to add beyond what was set out in its latest financial statement.
