Apparatus for bonding layers of resinous material

Apparatus for bonding portions of first and second films of polyester resinous material to one another, the polyester resinous material being of a type which is not bondable by application of conductively transferred heat and pressure directly to only the two films by reason of deterioration of the two films about the periphery of the seal zone when the heat and pressure are applied, the apparatus comprising:

• a. means for providing at least first and second films of polyester resinous material to be bonded to one another and at least one direct-heat isolating film of polyester resinous material;
• b. means for disposing a portion of one surface of the first film of polyester resinous material contiguous with a portion of one surface of the second film of polyester material for forming an interface between the contiguous portions;
• c. means for placing one surface of the isolating film of polyester resinous material adjacent the other surface of the portion of at least one of the first and second films of polyester resinous material disposed contiguous with the portion of the other film of polyester resinous material, the one surface of the direct-heat isolating film of polyester resinous material being exposed;
• d. means for compressing the contiguous portions of the first and second films of polyester resinous material against one another along the interface thereof by pressure applied to the exposed other surface of the direct-heat isolating film of polyester resinous material;
• e. means for applying energy for conductively heating the contiguous portions of the first and second films of polyester resinous material while the first and second films are being compressed by the compressing means, the energy being applied along their interface to raise the temperature thereof to at least the bonding temperature of the polyester resinous material of the first and second films of polyester resinous material and to cause a bond to be formed between the contiguous portions of the first and second films of polyester resinous material, the energy being applied by a member having a face portion which is moved directly into contact with the other surface of the direct-heat isolating film of polyester resinous material for conductively transmitting energy for heating by conduction through the exposed other surface of the direct-heat isolating film of polyester resinous material, the applied energy being sufficient to fuse the direct-heat isolating film of polyester resinous material against the other surface of the one of the first and second films of polyester resinous material to enhance the transfer of energy for heating the contiguous portions of the first and second films to the bonding temperature while causing the direct-heat isolating layer preventing the region of the first and second films adjacent the bond formed therein from being raised to a temperature which would cause degraduation thereof;
• and
• f. means for discharging the bonded first and second films of polyester resinous material and the bonded direct-heat isolating film of polyester resinous material through which the energy has been applied from the location at which the bond is formed.