Splicing of coated abrasive materials

Claim 2

A COATED ABRASIVE HAVING ITS ENDS JOINED TOGETHER BY DRY, HEAT-ACTIVATABLE, PREFORMED ADHESIVE FILM COMPRISNG THE REACTION PRODUCT OF A COMPOSITION COMPRISING IN ADMIXTURE A HYDROXYL TERMINATED POLYURETHANE-POLYESTER HAVING A HYDROXY NUMBER OF FROM ABOUT 2 TO ABOUT 15 AND A COMPONENT HAVING AVAILABLE FREE ISOCYANATE GROUPS, THE AVAILABLE ISOCYANATE GROUPS IN THE COMPOSITION BEING PRESENT IN THE AMOUNT OF FROM ABOUT 0.24 GRAMS TO ABOUT 8.5 GRAMS PER 100 GRAMS (SOLID) OF SAID POLYURETHANE-POLYESTER, SAID ADHESIVE FILM BEING ONLY PARTIALLY CURED SO THAT IT CAN BE SEQUENTLY TACKIFIED AND SOFTENED WITH APPLICATION OF HEAT IN THE RANGE OF FROM 175*F TO 350*F FOR FROM 5 TO 1 SECOND, RESPECTIVELY.

Claim 3

The coated abrasive according to claim 1 wherein the isocyanate component is triphenyl methane triisocyanate.

Claim 4

The coated abrasive according to claim 1 wherein the isocyanate component is diphenylmethane 4,4''-diisocyanate.

Claim 5

The coated abrasive according to claim 1 wherein the isocyanate component is an isocyanate terminated polyurethane reaction product of trimethylol propane and toluene diisocyanate.

Claim 6

The coated abrasive according to claim 1 wherein the thickness of the film is at least about 1.5 mils.

Claim 7

Method of joining abrasive material together comprising the following procedural steps: a. providing a dry, heat-activatable, preformed, at least partially cured adhesive film comprising the reaction product of a hydroxyl terminated polyurethane-polyester with a component having available free isocyanate-groups; b. preparing two free ends of coated abrasive material to be joined together in overlapped position; c. positioning the preformed adhesive film on the abrasive side of one of said ends of said abrasive material; d. heating said preformed adhesive film at a temperature of from 175* to 350*F for 5 to 1 second respectively, thereby to soften and tackify the film; e. overlapping the other free end of said abrasive material with said one end whereby said softened, tacky, partially cured, adhesive film is located between the ends to be joined; f. heating said overlapped ends and adhesive film from 175*F to 350*F for 30 to 5 seconds, respectively, while subjecting the same to pressure of from 1500 to 12,000 lbs/in.2, said heat and pressure being sufficient to cause said adhesive film to be further softened and flowed into intimate contact with the surfaces of the ends to be joined; and g. further curing said adhesive in a moist atmosphere at room temperature thereby to obtain maximum joInt strength.

Claim 8

Method of joining abrasive material together comprising the following procedural steps: a. providing a dry, heat-activatable, preformed, at least partially cured adhesive film comprising the reaction product of a hydroxyl terminated polyurethane-polyester with a component having available free isocyanate-groups; b. preparing two free ends of coated abrasive material to be joined together in overlapped position; c. positioning the preformed adhesive film on the abrasive side of one of said ends of said abrasive material; d. heating said preformed adhesive film at a temperature of from 175* to 350*F for 5 to 1 second respectively, thereby to soften and tackify the film; e. overlapping the other free end of said abrasive material with said one end whereby said softened, tacky, partially cured, adhesive film is located between the ends to be joined; f. heating said overlapped ends and adhesive film from 175*F to 350*F for 30 to 5 seconds, respectively, while subjecting the same to pressure of from 1500 to 12,000 lbs/in.2, said heat and pressure being sufficient to cause said adhesive film to be further softened and flowed into intimate contact with the surfaces of the ends to be joined; and g. further curing said adhesive in a moist atmosphere at room temperature thereby to obtain maximum joInt strength.

Claim 9

Method according to claim 6 wherein said partial curing of the adhesive film is obtained by heating the solvent free film for from 15 to 60 minutes at from about 300* F. to about 250* F.