초록 ▼

A profound improvement in the properties and capabilities of elastomeric polyurethane joint sealing compositions is achieved by incorporating a fibrillated polyolefin of high surface area which is rendered compatible by combining it with effective stabilizing cofillers, such as titanium dioxide, cal

A profound improvement in the properties and capabilities of elastomeric polyurethane joint sealing compositions is achieved by incorporating a fibrillated polyolefin of high surface area which is rendered compatible by combining it with effective stabilizing cofillers, such as titanium dioxide, calcium carbonate, carbon black, fibrous talc, serpentine, kaolin, or various other metal silicate fillers. Such cofillers are capable of improving compatibility and stabilizing the sealant mixture so that unacceptable sweat out or exudation of liquid is prevented and so that the outer surface of the applied sealant has an acceptable surface quality after curing. When 2 to 8 percent by weight of fibrillated polyolefin of macrofibrillar structure, preferably containing macrofibrils with diameters from 1 to 10 microns, is incorporated in a polyurethane joint sealant together with 8 to 30 percent of stabilizing cofillers, it becomes possible to provide revolutionary new joint sealants with remarkable properties, such as Boeing sag values of 0.1 and below for caulking compositions applied to extremely wide joints. These unique non-sag joint sealants can be compounded to form strong soft low-modulus elastomers ideally suited for vertical joints subject to extreme cyclical movement as is common in modern building construction.

대표청구항 ▼

In a non-sag elastomeric-type joint sealing composition containing a curable polyfunctional polyurethane prepolymer with terminal reactive groups and an average molecular weight of at least 1000 mixed with fillers and other compounding ingredients and having a PFER value of at least 2 and a Boeing s

In a non-sag elastomeric-type joint sealing composition containing a curable polyfunctional polyurethane prepolymer with terminal reactive groups and an average molecular weight of at least 1000 mixed with fillers and other compounding ingredients and having a PFER value of at least 2 and a Boeing sag value below one, said composition being curable at ambient temperatures from 10°to 40°C. to provide a strong elastomeric polyurethane sealant with an elongation in excess of 100 percent, the improvement wherein said composition incorporates 2 to 8 percent by weight of a fibrillated polyolefin with a surface area (BET) of at least 5 square meters per gram comprising macrofibrils having an average diameter below 20 microns and an average aspect ratio of at least 30 to 1; wherein said composition incorporates 8 to 30 percent by weight of a compatible cofiller that stabilizes the composition to prevent substantial sweat out; and wherein the amounts of the fibrillated polyolefin and the cofiller are selected to provide a non-sag joint sealing composition which can be applied by extrusion and cured under ambient conditions to provide a strong soft low-modulus elastomeric sealant with a Shore A durometer hardness below 45.