Method of making a dry bonded paperboard structure
AssigneeSonoco Development, Inc.
InventorsJeremy E. Morin, Krishnaraju Varadarajan
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Abstract
A method of making a spirally wound dry bonded paperboard structure. The method includes adding a radio frequency active adhesive to the paperboard pulp stock during the paperboard fabrication process to first produce an RF active adhesive impregnated paperboard. The impregnated paperboard is then exposed to an RF energy field prior to or during winding, which activates the adhesive. The invention eliminates the need to apply a water-based adhesive to the paperboard prior to forming the structure, thereby reducing water migration into the paperboard.
Claims8
A method of producing a paperboard structure, the method comprising the steps of:
- adding a radio frequency active adhesive to paperboard pulp stock;
- forming a sheet from the pulp stock;
- exposing the sheet to RF energy to generate heat sufficient to cause the adhesive in the sheet to soften;
- arranging one or more of the sheets into at least partially overlapping relationship;
- and
- allowing the adhesive to harden, thereby affixing the overlapped sheets together.
A method of producing a multiple-ply paperboard sheet for dry bonding, the method comprising the steps of:
- providing a first batch of paperboard pulp stock;
- adding a radio frequency active adhesive to a second batch of paperboard pulp stock;
- forming a first sheet from the first batch of pulp stock;
- forming an RF adhesive impregnated sheet from the second batch of pulp stock;
- and
- affixing one sheet to the other by arranging the sheets into an overlapping relationship and exposing the RF adhesive impregnated sheet to RF energy.
Dependencies are inferred from the claim text.