US 7,491,287 B2
Bonding method with flowable adhesive composition
Andrew Behr, Littleton, Colo. (US); Eumi Pyun, Austin, Tex. (US); Victoria A. Russell, Brooklyn Park, Minn. (US); William J. Schultz, North Oaks, Minn. (US); Terry L. Smith, Roseville, Minn. (US); Wendy L. Thompson, Roseville, Minn. (US); and Stephen Znameroski, Eagan, Minn. (US)
Assigned to 3M Innovative Properties Company, Saint Paul, Minn. (US)
Filed on Jun. 09, 2006, as Appl. No. 11/423,191.
Prior Publication US 2007/0295446 A1, Dec. 27, 2007
Int. Cl. B29C 65/00 (2006.01)
U.S. Cl. 156—272.2  [156/296; 156/330; 523/168] 20 Claims
 
1. A method of bonding comprising:
preparing a flowable adhesive composition, the preparing comprising
surface modifying silica nanoparticles, the surface modifying comprising
providing a surface modification mixture comprising (a) silica nanoparticles; (b) a silane surface modifying agent having hydrolysable groups; (c) water, wherein the number of moles of water present in the mixture is greater than the number of moles of hydrolysable groups; and (d) an optional water-miscible solvent;
heating the surface modification mixture to at least 50° C. to form non-aggregated, surface-modified silica nanoparticles having surface-modifier covalently attached to the silica nanoparticles;
forming a dispersion comprising the non-aggregated, surface-modified silica nanoparticles and an epoxy resin;
removing basic material from the surface-modified silica nanoparticles either before or after forming the dispersion;
removing at least most of the water and the optional water-miscible solvent; and
adding a cationic photoinitiator after the removing step;
positioning the adhesive composition between a first article and a second article; and
curing the adhesive composition in the presence of actinic radiation to bond the first article to the second article.