Polyurethane-adhesive for masonry construction

Abstract

A structural adhesive for masonry of a polyurethane adhesive base with dispersed thermal stabilizer particulate additive of a mean particle size sufficient for providing, after application and curing, cured structural adhesive thermal stability in favorable accordance to a predefined threshold. The polyurethane base provides at least 85 weight percent of the structural adhesive at a viscosity sufficient for room temperature bead application of the structural adhesive.

1 . Masonry, comprising:
 (a) a plurality of masonry units, each masonry unit comprising stone, brick, concrete or ceramic and having at least one bonding surface, and   (b) cured adhesive positioned to join a bonding surface from one said masonry unit to a bonding surface of another said masonry unit, said cured adhesive cured from an applied adhesive comprising:
 (i) a single component moisture-cured polyurethane adhesive base, said base providing at least 85 weight percent of said structural adhesive; and 
 (ii) at least 0.5 weight percent of a particulate thermal stabilizer dispersed throughout said adhesive base, the thermal stabilizer comprising particles of fumed silica or particles comprising calcium carbonate. 
   
     
     
         2 . The masonry of  claim 1 , wherein the polyurethane is an isocyanate-polyol reaction product prepolymer having a free NCO percent of from about 10.5 to about 19.6 and formed from about 35 to about 70 weight percent of isocyanate precursor, based on the weight of said prepolymer, and a remainder of hydroxy terminated polyol precursor, wherein said isocyanate precursor is selected from the group consisting of isomeric methylenebis(phenyl isocyanate), polymethylene polyphenylisocyanate having an isocyanate functionality of between 2.1 and 3, and combinations thereof, and wherein said hydroxy terminated polyol precursor is selected from the group consisting of hydroxy terminated poly(oxyalkylene)polyol having a hydroxyl functionality of between 2 and 4, polyester polyol having a hydroxyl functionality of between 2 and 3, and combinations thereof. 
     
     
         3 . The masonry of  claim 1 , wherein the surface treated fumed silica particulate has a mean particle size of about 7 to about 16 nm and the calcium carbonate particulate has a mean particle size of about 0.07 to about 0.7 microns. 
     
     
         4 . The masonry of  claim 3 , wherein the combined amount of the fumed silica and the calcium carbonate in the applied adhesive is in the range from 2.5 to 9.9 weight percent. 
     
     
         5 . The masonry of  claim 1 , wherein the combined amount of the fumed silica and the calcium carbonate in the applied adhesive is in the range from 2.5 to 9.9 weight percent. 
     
     
         6 . The masonry of  claim 4 , wherein the applied adhesive comprises at least 0.5 weight percent of the fumed silica and at least 0.5 weight percent of the calcium carbonate. 
     
     
         7 . The masonry of  claim 5 , wherein the applied adhesive comprises at least 0.5 weight percent of the fumed silica and at least 0.5 weight percent of the calcium carbonate. 
     
     
         8 . The masonry of  claim 1 , wherein the applied adhesive further comprises:
 (iii) from about 0.05 to about 0.4 weight percent of polydimethylsiloxane defoamer;   (iv) a tertiary amine catalyst selected from the group consisting of 4,4′-dimorpholinodiethylether, bis(2-dimethylaminoethyl)ether, and combinations thereof;   (v) less than 3.4 weight percent of surface treated fumed silica particulate having a mean particle size of about 7 to about 16 nm; and   (vi) less than 6.5 weight percent of calcium carbonate particulate having a mean particle size of about 0.07 to about 0.7 microns.   
     
     
         9 . The masonry of  claim 8 , wherein said applied adhesive further comprises from about 1.3 to about 10 weight percent of plasticizer selected from the group consisting of adipates, pthalates, benzoates, cyclic carbonates, and combinations thereof. 
     
     
         10 . The masonry of  claim 8 , wherein from about 0.5 to about 1.5 weight percent of 4,4′-dimorpholinodiethylether is in said adhesive when said tertiary amine catalyst is 4,4′-dimorpholinodiethylether, and from about 0.05 to about 0.5 weight percent of bis(2-dimethylaminoethyl)ether is in said adhesive when said tertiary amine catalyst is bis(2-dimethylaminoethyl)ether. 
     
     
         11 . The masonry of  claim 7 , wherein, the weight percent of said calcium carbonate particulate is zero. 
     
     
         12 . The masonry of  claim 7 , wherein the weight percent of said fumed silica particulate is zero. 
     
     
         13 . The masonry of  claim 7 , wherein said applied adhesive has a viscosity of from about 5,000 to about 200,000 centipoises at 72 degrees Fahrenheit. 
     
     
         14 . A method for constructing masonry, the method comprising:
 (a) providing a plurality of masonry units, each masonry unit each masonry unit comprising stone, brick, concrete or ceramic and having at least one bonding surface;   (b) adhering said masonry units together by joining the bonding surfaces together with an adhesive comprising:
 (i) a single component moisture-cured polyurethane adhesive base, said base providing at least 85 weight percent of said structural adhesive; and 
 (ii) at least 0.5 weight percent of a particulate thermal stabilizer dispersed throughout said adhesive base, the thermal stabilizer comprising particles of fumed silica or particles comprising calcium carbonate; and 
   (c) curing the adhesive.   
     
     
         15 . The method of  claim 15 , wherein said adhering comprises applying a daubing of from about 0.065 to about 0.75 inches in thickness of said adhesive to at least one bonding surface.