Process for preparing flowable amorphous poly-alpha olefin adhesive pellets

Abstract

The present invention relates to a process for producing free-flowing, agglomeration resistant amorphous poly-alpha-olefin based adhesive pellets. The process includes (a) extruding the adhesive through an orifice of a die plate immersed in a cooling fluid; (b) cutting the adhesive into a plurality of pellets in the cooling fluid; (c) solidifying the pellets at a temperature range of about 25° C. to about 40° C. for at least 30 minutes; and (d) separating the pellets from the recrystallization fluid and drying the pellets. The pellets harden at least three folds faster than conventionally formed pellets.

I/We claim: 
     
         1 . A plurality of adhesive pellets manufactured by the process comprising the steps of:
 a) extruding an adhesive through an orifice of a die plate immersed in a cooling fluid, which has a temperature T 1 ;   b) cutting the adhesive into a plurality of pellets in the cooling fluid;   c) solidifying the pellets in a recrystallization fluid at temperature T 2  for at least 30 minutes and up to 24 hours;   d) separating the pellets from the recrystallization fluid and drying the pellets;   wherein the T 1  is less than about 45° F. and the T 2  is higher than T 1  by at least 30° F.;   wherein the adhesive comprises an amorphous poly-alpha-olefin polymer having a cold crystallization temperature;   wherein the adhesive has a needle penetration number of (i) 8 to 50 dmm after 1 hour conditioning at 77° F., (ii) 10 to 45 dmm after 4 hour conditioning at 77° F., and (iii) 10 to 40 dmm after 24 hour conditioning at 77° F.; and   wherein the pellets have an average percent deformation, (d 0 -d 1 )/d 0 ×100%, less than 40%, where d 0  is an initial diameter and d 1  is a diameter measured after applying a weight of 70 g for one minute.   
     
     
         2 . The adhesive pellets of  claim 1  wherein the pellets are hot melt adhesive pellets. 
     
     
         3 . The adhesive pellets of  claim 1  wherein the amorphous poly-alpha-olefin polymer comprises a comonomer of ethylene, propylene, butene, pentene, hexane, heptene, octane, nonene, decene, undecene, dodecene, and mixtures thereof. 
     
     
         4 . The adhesive pellets of  claim 3  wherein the amorphous poly-alpha-olefin polymer comprises a comonomer of propylene and butene. 
     
     
         5 . The adhesive pellets of  claim 1  wherein the hot melt adhesive has a cold crystallization temperature of about 77 to about 105° F. 
     
     
         6 . The adhesive pellets of  claim 5  wherein the hot melt adhesive has a cold crystallization temperature of about 82 to about 104° F.