Latex Bladders

Hi I make carbon prepreg gimbles which are one pice molder in a aluminium for pice mould. I need to make inflatible bladders that can handile 120 degress C for one hour. I have tride liquid latex with some sucess but it cant handile the heat .Silicon can do it but it’s two pot and goes off quick .It would be good to be able to dip in a mandrill or por in por out of a mould .What do they use?Thanks