The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Feb. 26, 2013
Filed:
Aug. 28, 2009
Yaoliang Hong, Mason, OH (US);
Kosaraju Krishna Mohan, Mason, OH (US);
Peter M. Froass, Mason, OH (US);
Mark Fagan, Loveland, OH (US);
Christopher D. Anderson, Wescosville, PA (US);
Brian Boyars, Las Vegas, NV (US);
Eric Scott Daniels, Bethlehem, PA (US);
Victoria Laurentia Dimonie, Bethlehem, PA (US);
Edward David Sudol, Bethlehem, PA (US);
Andrew Klein, Somerville, NJ (US);
Yaoliang Hong, Mason, OH (US);
Kosaraju Krishna Mohan, Mason, OH (US);
Peter M. Froass, Mason, OH (US);
Mark Fagan, Loveland, OH (US);
Christopher D. Anderson, Wescosville, PA (US);
Brian Boyars, Las Vegas, NV (US);
Eric Scott Daniels, Bethlehem, PA (US);
Victoria Laurentia Dimonie, Bethlehem, PA (US);
Edward David Sudol, Bethlehem, PA (US);
Andrew Klein, Somerville, NJ (US);
International Paper Company, Memphis, TN (US);
Abstract
Expandable microspheres formed by suspension polymerization using a shot growth method are provided. The microspheres are formed of a continuous, gas impermeable shell surrounding a blowing agent. The shell includes a first polymer layer formed from primary monomers and a second layer that includes a chemically reactive monomer or a high Tg monomer. To form the microspheres, the primary monomers are polymerized in a reaction vessel to an approximate 90% polymerization, at which time a secondary monomer that is either a monomer having a Tg of at least 85° C. or a chemically reactive monomer, is added to the reaction vessel to drive the polymerization reaction to completion. The outer layer thus contains either a larger amount of the high Tg monomer or a chemically reactive monomer that possesses the ability to covalently bond a cationic species. The microspheres may be used in papermaking processes to increase the paper bulk.