Amorphous high performance polyamide

Abstract

The disclosure relates to an improved method of producing MPMD based amorphous, semi-aromatic polyamides in order to improve their mechanical properties. It also relates to improved formulations of these polyamides which have further improved mechanical properties by the incorporation of greater amounts of isophthalic acid. The disclosure relates to an improved method of producing MPMD based amorphous, semi-aromatic polyamides in order to improve their mechanical properties. It also relates to improved formulations of these polyamides which have further improved mechanical properties by the incorporation of greater amounts of isophthalic acid.

1 . A method of making a copolyamide comprising polycondensing 2-methyl-1,5-pentamethylene diamine (“MPMD”) with a mixture of isophthalic acid and terephthalic acid in the presence of a catalyst. 
     
     
         2 . The method of  claim 1 , wherein the catalyst is a phosphorus-based catalyst. 
     
     
         3 . The method of  claim 2 , wherein the catalyst is sodium hypophosphite, 
     
     
         4 . The method of  claim 1 , wherein MPMD is at least 6 mol % excess than the mixture of isophthalic acid and terephthalic acid. 
     
     
         5 . The method of  claim 1 , further comprising adding excess MPMD is to the copolyamide relative to the mixture of isophthalic acid and terephthalic acid. 
     
     
         6 . The method of  claim 1 , further comprising mixing MPMD with isophthalic acid and terephthalic acid in water to form an aqueous salt solution and further comprising:
 heating the salt solution at a constant first temperature of at least 130° C. and a constant first pressure to evaporate the salt solution to a concentration of about 70%;   heating the about 70% salt solution to a higher second temperature of at least 200° C. and second pressure of at least 200 psia under a closed system;   gradually distilling water from the solution while the second pressure is held constant and the temperature is increased to a third temperature of at least 230° C.;   gradually reducing pressure to atmospheric while the temperature is increased to a fourth temperature of at least 260° C.; and   reducing the pressure by vacuum for at least 15 minutes while the temperature is increased to a fifth temperature.   
     
     
         7 . The method of  claim 6 , wherein the fifth temperature is at least 280° C. 
     
     
         8 . The method of  claim 6 , wherein the first pressure is higher than atmospheric. 
     
     
         9 . The method of  claim 1 , wherein the MPMD, isophthalic acid, and terephthalic acid are present in an amount sufficient to produce a copolyamide containing about 40 to about 60 mol % 2-methyl-1,5-pentamethyleneterephthalamide (“MPMD-T”) units and about 40 to about 60 mol % 2-methyl-1,5-pentamethyleneisophthalamide (“MPMD-I”) units. 
     
     
         10 . The method of  claim 1 , wherein the MPMD, isophthalic acid, and terephthalic acid are present in an amount sufficient to produce a copolyamide containing about 50 to about 60 mol % MPMD-T units and about 40 to about 50 mol % MPMD-I units. 
     
     
         11 . A method of making a polyamide blend comprising blending an aliphatic polyamide with a copolyamide containing about 40 to about 60 mol % MPMD-T units and about 40 to about 60 mol % MPMD-I units. 
     
     
         12 . The method of  claim 11 , wherein the aliphatic polyamide is present in the polyamide blend in a ratio of from about 65 to about 95 wt. %, and the copolyamide is present in a ratio of from about 5 to about 35 wt. %. 
     
     
         13 . The method of  claim 11 , wherein the copolyamide is present from about 10 to about 30 wt. %. 
     
     
         14 . The method of  claim 11 , wherein the aliphatic polyamide is selected from polyhexamethlyeneadipamide (N66), polycaproamide (N6), polyenanthamide (nylon 7), polylaurolactamide (nylon 12), polyundecaneamide (nylon 11), polyhexamethylenedodecamide (nylon 612), and combinations thereof. 
     
     
         15 . The method  claim 11 , further comprising adding a reinforcing material selected from glass fiber, inorganic filler or a rubber component. 
     
     
         16 . A method of making a conditioned article comprising:
 providing a copolyamide containing about 40 to about 80 mol % MPMD-T units and about 20 to about 60 mol % MPMD-I units;   producing a dry as-molded article from the copolyamide;   conditioning the article; and   recovering the conditioned article.