Thermal curing may be done at high pressure - at GTT, we have used up to 35 Bar (500 psi = 3.4 MPa) to pressurize coated roll goods or footwear before polymerization.
For this, the fabric or footwear is first coated, then it is placed into the pressure "Pod", shown left, where it is pressurized at room temperature. The pressure causes the chemical formulation to be squeezed into the twisted yarn, providing a highly uniform, thin coating of monomer + crosslinkers. Then, the Pressure Pod is heated, resulting in polymerization and crosslinking. The polymeric film retains its position inside the twisted yarn and fibers once cured and returned to atmospheric pressure.
For footwear, the pressure pushes the chemical into the sewn seams and deep within the shoe material. This provides a better water-proofing treatment and better abrasion resistance than be obtained by wet or dry means at atmospheric pressure.