Contract Heat Sealing


Heat Sealing is the process in which at least two thermoplastic sheets are joined. This joining occurs when heat and pressure are applied to an area of contact between the two materials. The sheets are fused to each other when the sealant layer melts and the molecular segments move across the interface to form entanglements. This produces a very strong seal. We can apply heat sealing to many materials to create a custom product to meet your needs. We can heat seal virtually any flexible product made of a thermoplastic material.

There are different methods of heat sealing including thermal sealing, impulse sealing, radio frequency sealing, and ultrasonic sealing. Radio Frequency (RF) heat sealing is accomplished by sending a high frequency (heating) current through two or more layers of thermoplastic material placed between two sealing electrodes or dies. One die is shaped in the image of the required seal. The other die may have the same shape or may be a flat plate. The dies are usually mounted on a pneumatic or hydraulic press to provide pressure for fusing the materials.

The high frequency energy produces localized heating by exciting the molecules of the materials to 27.12 MHz causing them to melt. This allows their molecules to intermingle and the pressure exerted on the material brings about a thorough fusion. When the current is shut off, the material will solidify during a brief cooling period and the materials become joined together at the point of the seal. The resulting seal can be stronger than the original work piece materials. These seals are especially useful for stitchless bonding of thermoplastic materials and watertight or airtight applications.


  • Produces and air tight and water tight product
  • Stitchless bonding of thermoplastic materials
  • Welded seams act as strong as base material