Polyamide molding compositions

Abstract

A thermoplastic molding composition comprising polyamide is disclosed. The composition that contains vinyl (co)polymer and an optional solvent is useful in application where inhibited crystallization of polyamide is desirable, including laser-welding.

1 . A method of laser-welding, comprising: 
 producing a molding composition comprising, 
 A) 90-99.995 wt % polyamide,  
 B) 0.005-5 wt % vinyl (co)polymer, and  
 C) 0-5 wt % solvent;  
   wherein the wt % are relative to the total weight of the composition;    providing at least a first joining partner and a second joining partner having a contact zone there between, wherein at least one joining partner is made of the molding composition;    applying radiation from a transmission laser to the contact zone; and    forming a weld bond between at least the first joining partner and the second joining partner to form an article.    
     
     
         2 . The method of  claim 1 , wherein A) is present in an amount of 95-99.994 wt %, B) is present in an amount of 0.005-1 wt % and C) is present in an amount of 0.001-1 wt %.  
     
     
         3 . The method of  claim 1 , wherein A) is present in an amount of 99-99.965 wt %, B) is present in an amount of 0.005-0.8 wt % and C) is present in an amount of 0.03-0.4 wt %.  
     
     
         4 . The method of  claim 1 , wherein the molding composition further comprises at least one member selected from the group consisting of fillers, reinforcing fillers, conventional additives, colorants and combinations thereof.  
     
     
         5 . The method of  claim 1 , wherein component B) is selected from the group consisting of poly-N-vinyllactam, poly-N-vinylpyrrolidone copolymers of vinyllactam, copolymers of vinylpyrrolidone, and combinations thereof.  
     
     
         6 . The method of  claim 1 , wherein the polyamide of A) is selected from the groups consisting of polyamide 6, polyamide 66, polyamide 11, polyamide 12, polyamide 610, polyamide 6I, polyamide 612, polyamide 6/66, polyamide 6I/6T, polyamide MXD6, polyamide 6/61, polyamide 6/6T, polyamide 6/IPDI and copolymers of these polyamides and combinations of these polyamides.  
     
     
         7 . The method of  claim 1 , wherein the polyamide of A) is polyamide 66.  
     
     
         8 . The method of  claim 1 , wherein the solvent is selected from the group consisting of water, alcohol, ketone, glacial acetic acid, chlorinated hydrocarbon, phenol and combinations thereof.  
     
     
         9 . The method of  claim 1 , wherein the radiation emitted by the laser is at a wavelength of 800-1060 nm.  
     
     
         10 . The method of  claim 1 , wherein the first joining partner comprises the molding composition.  
     
     
         11 . The method of  claim 1 , wherein the article is hollow.  
     
     
         12 . The method of  claim 1 , wherein the article is of multi-layer construction.  
     
     
         13 . The method of  claim 1 , wherein the molding composition is produced by a continuous process.  
     
     
         14 . The method of  claim 13 , wherein components B) and C) are added as a homogenous solution directly onto granules of the polyamide of component A).  
     
     
         15 . The method of  claim 13 , wherein components B) and C) are added as a solid to the polyamide of component A) during compounding.  
     
     
         16 . The method of  claim 13 , wherein components B) and C) are added as a liquid to the polyamide of component A) during compounding.  
     
     
         17 . The method of  claim 1 , wherein the molding composition is produced by a discontinuous process.  
     
     
         18 . The method of  claim 1 , wherein component B) is added directly to the polyamide of component A) prior to welding.  
     
     
         19 . The method of  claim 1 , wherein component B) is homogenously distributed throughout the molding composition.  
     
     
         20 . The method of  claim 1 , wherein the molding composition comprises less than 500 ppm of component B).