Rotary impulse sealer

A rotary impulse sealer for forming a series of discrete bonds in a bondable material, the rotary impulse sealer comprising:

• a roller rotatable about an axis, the roller having a roller body and a plurality of seal bars extending radially outwardly from the roller and spaced apart around the roller body, at least one of the seal bars having a body and a selectively heatable heating element extending along at least a part of a length of the seal bar body;
• a tensioned belt for introducing the bondable material to the roller;
• wherein the roller is rotatable through a pre-heating pressure application region of the rotary impulse sealer in which the at least one seal bar is adapted to apply pressure to a bond area of the bondable material, followed by a heating region of the rotary impulse sealer in which the at least one seal bar is adapted to heat the bond area and apply more pressure in the heating region than the pressure applied during the pre-heating pressure application region, the regions being stationary with respect to the rotation of the roller;
• wherein the speed of rotation of the roller is adjustable relative to the bondable material such that the at least one seal bar moves at substantially the same speed as the bondable material while the seal bar applies pressure to the bond area.