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US 4,181,548 AGranted
Laminated plastic packaging material
OwnerJoseph L. Weingarteninventor
Life of this patent
Estimating the term…
Abstract
A three layer laminated plastic cushioning material having a substantially flat central layer with sealed air pockets formed on both sides of the central layer between the central layer and layers positioned on opposite sides of the central layer.
Claims1
In a method for the continuous fabrication of laminated cushioning material including the steps of heating a first layer of thermoplastic material above the softening temperature of the thermoplastic;
- passing the softened material over a first forming roller including a plurality of depressions in the outer surface;
- supplying a vacuum to the depressions to draw portions of the softened thermoplastic layer into the depressions;
- passing a second layer of thermoplastic over the roller in contact with the first layer to form air pockets between the first layer and second layer;
- heating the first layer and second layer to a fusing temperature prior to application of the second layer;
- passing the first and second layer past a heated pressure roller adjacent the first roller;
- removing the fused layer from the first roller;
- forming a plurality of air pockets on the side of said first layer remote from said second layer with the additional steps comprising:
- heating a third layer of thermoplastic material above the softening temperature of the thermoplastic;
- passing the softened material over a second forming roller including a plurality of depressions in the outer surface;
- supplying a vacuum to the depressions to draw portions of the softened thermoplastic layer into the depressions;
- passing the fused layers and the third layer between a second pressure roller and the second forming roller;
- said second pressure roller including a plurality of depressions adapted to receive the air pockets on said fused layers;
- supplying a pressure to the depressions of the second roller adjacent the second forming roller to supply a pressure to the fused layer equal to the pressure between the second pressure roller and the second forming roller;
- heating the fused layer and the third layer to a fusing temperature prior to passing between the second pressure roller and the second forming roller;
- removing the three fused layers from the second forming roller.
12 more elements
Dependencies are inferred from the claim text.