Air Products turned down a counter-proposal from Wrexham staff
Unions for 200 factory staff facing redundancy say they are "disgusted" that the UK government has not offered financial aid.
Up to 60 Air Products staff at Acrefair, Wrexham are expected to leave next month, with the remainder gone by December, as work moves to China.
The Wales Office said Secretary of State Peter Hain had asked his minister Wayne David to meet the Unite union.
It said it was "committed to helping Welsh businesses".
Workers say they cannot understand why a rescue package was offered to Anglesey Aluminium but not to them.
American-owned Air Products announced earlier this year that the plant - which opened in 1950 - would close when production moves to China.
The Unite union said many of those facing redundancy had trained workers in China, and it would seek help from the government to try and maintain a manufacturing base at Wrexham.
Ken Morris, chairman of the works' shop stewards committee said there was anger that Anglesey Aluminium had been offered a £48m rescue package, while Air Products had received nothing.
Anglesey Aluminium rejected the four-year aid offer because it was "not enough to break even".
Smelting operations at the Holyhead plant will come to an end in September, leading to 390 job losses.
Mr Morris said: "It seems strange that they could come up with an offer of £48m to Anglesey Aluminium, but we get nothing.
Anglesey Aluminium was offered a £48m package, which was rejected
"If they'd offered only part of this, it might have been enough to keep us going.
"If this was the French or German governments, they would have stepped in by now."
Mr Morris, who has worked at the plant for 35 years, said the union tried to arrange a meeting with Welsh Secretary Peter Hain but "couldn't get anywhere near him".
He added: "We're disgusted and disappointed.
"The government is doing absolutely nothing to look after the manufacturing industry in this country.
"I have voted Labour all my life but this is not the Labour Party that we knew anymore."
As part of their campaign to save the factory, workers posted a petition on the 10 Downing Street website calling on the Prime Minister to intervene.
The petition attracted nearly 800 names.
In response to the petition, the government said it was "saddened" by the news.
But it added: "The decision by the Air Products management is, however, a commercial decision taken in difficult times to protect the company's long-term future and the government is unable to intervene."
It said the rapid response to redundancy team was in regular contact with the workforce to try and assist them.
It added that the Welsh Assembly Government and local authority were "doing everything possible" to help.
A Wales Office spokesperson said: "The secretary of state is aware of the request for a meeting and has asked his minister, Wayne David to meet with Unite at a mutually convenient time.
"We are committed to helping Welsh businesses through the current difficult economic climate."