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:
Oct. 11, 1994
Filed:
Dec. 08, 1992
Fidelis C Onwumere, Woodbury, MN (US);
Kurt C Frisch, Jr, Fridley, MN (US);
Minnesota Mining and Manufacturing Company, St. Paul, MN (US);
Abstract
Ungelled, aqueous dispersions of silane-terminated partially crosslinked polyurethane polymers are described which are the reaction product of A) an isocyanate-containing prepolymer formed from: (i) a molar excess of organic polyisocyanate sufficient to promote substantially equal access to isocyanate groups; (ii) active hydrogen-containing material; (iii) sterically hindered amines; (iv) emulsifying monomer; B) chain-extending monomer; C) an organic compound having a pKb of at most about 7; and D) a silane coupling agent represented by the general formula ASi(OR.sup.2).sub.3 and present in an amount sufficient to partially crosslink the polyurethane resin but insufficient to gel the dispersion, provide advantages over previously known polyurethanes used as surface coatings. The hindered amine allows surface coatings incorporating the polyurethanes to be easily removed by aqueous compositions having pH between about 2 and 5. Methods of making the prepolymers, polymers, and dispersions are also presented.