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Low density paperboard articles

  • US 7,740,740 B2
  • Filed: 09/27/2007
  • Issued: 06/22/2010
  • Est. Priority Date: 01/26/2000
  • Status: Expired due to Fees
First Claim
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1. A method for making a paperboard material comprisingproviding a papermaking furnish containing cellulosic fibers and from about 0.25 to about 10% by weight dry basis expandable microspheres;

  • forming a paperboard web from the papermaking furnish;

    drying the web;

    calendaring the web to a caliper of from about 24 to about 35 mils and an apparent density ranging from about 6.0 to about 10 lb/3 MSF/mil; and

    applying from about 0.5 to about 3.5 mil of a barrier coating on at least one of the surfaces of the calendered web, wherein the paperboard material has an average internal bond of at least about 80×

    10

    3
    ft-lbf and a Sheffield smoothness of at least about 300 SU.

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