Nylon composition having increased hydroylzability and method for increasing hydrolyzability of nylon

Abstract

The present invention provides a nylon composition having increased hydrolyzability which is obtained by physically mixing 100 parts by weight of a nylon with 1 to 50 parts by weight of at least one polymer selected from the group consisting of polylactic acid, polyglycolic acid and a copolymer containing 50 mol % or more of a lactic acid unit or a glycolic acid unit as a repeating unit in its chain; and a method for increasing the hydrolyzability of a nylon by preparing such a composition. High hydrolyzability can be imparted to the nylon inherently having extremely low hydrolyzability without impairing its original mechanical strength. Therefore, various molded articles made from the nylon can be hydrolyzed under natural circumstances, and thus the wastes are not stored.

What is claimed is: 
     
       1. A nylon composition having increased hydrolyzability which is obtained by physically mixing 100 parts by weight, of a nylon with 1 to 50 parts by weight of at least one polymer selected from the group consisting of polylactic acid, polyglycolic acid and a copolymer containing 50 mol % or more of a lactic acid unit or a glycolic acid unit as a repeating unit in its chain. 
     
     
       2. The nylon composition according to claim 1 wherein the weight average molecular weight of the polylactic acid or the copolymer containing 50 mol % or more of the lactic acid unit is from 150 to 700,000. 
     
     
       3. The nylon composition according to claim 1 wherein the weight average molecular weight of the polyglycolic acid or the copolymer containing 50 mol % or more of the glycolic acid unit is from 150 to 200,000. 
     
     
       4. The nylon composition according to claim 1 wherein the copolymer containing 50 mol % or more of the lactic acid unit or the glycolic acid unit is lactic acid-glycolic acid copolymer. 
     
     
       5. A method for increasing the hydrolyzability of a nylon which comprises the step of physically mixing 100 parts by weight, of a nylon with 1 to 50 parts by weight of at least one polymer selected from the group consisting of polylactic acid, polyglycolic acid and a copolymer containing 50 mol % or more of a lactic acid unit or a glycolic acid unit as a repeating unit in its chain. 
     
     
       6. The method for increasing the hydrolyzability of a nylon according to claim 5 wherein the weight average molecular weight of the polylactic acid or the copolymer containing 50 mol % or more of the lactic acid unit is from 150 to 700,000. 
     
     
       7. The method for increasing the hydrolyzability of a nylon according to claim 5 wherein the weight average molecular weight of the polyglycolic acid or the copolymer containing 50 mol % or more of the glycolic acid unit is from 150 to 200,000. 
     
     
       8. The method for increasing the hydrolyzability of a nylon according to claim 5 wherein the copolymer containing 50 mol % or more of the lactic acid unit or the glycolic acid unit is lactic acid-glycolic acid copolymer. 
     
     
       9. The method for increasing the hydrolyzability of a nylon according to claim 5 wherein the physical mixing is carried out in a temperature range of 170° to 300° C.