Polyether block amide catheter balloons

Abstract

An inflatable member such as a balloon which is formed at least in part of a polyamide/polyether block copolymer thermoplastic elastomer, commonly referred to as polyether block amide (PEBA). The presently preferred PEBA copolymer is polyamide/polyether polyester copolymer, such as PEBAX®. The balloon of the invention exhibits high tensile strength, high elongation, and low flexural moduli. The balloon may be formed as a single layer of PEBA, or as a multilayer coextrudate having at least one PEBA layer. The balloon may be 100% PEBA or a blend of PEBA with another polymer, such as nylon.

What is claimed is:  
     
         1 . A balloon for a medical device formed from a length of tubing of a polymer material by radial expansion of the tubing under pressure, the polymer material comprising a block copolymer thermoplastic elastomer characterized as follows: 
 the block copolymer is represented by the formula:                          in which PA is a polyamide hard segment of molecular weight in the range of 500-8,000;    PE is a polyether soft segment of molecular weight in the range of 500-2,500 and the repeating number n is between 5 and 10, the polyamide hard segments are polyamides of C 6  or higher carboxylic acids and C6 or higher organic diamines or of C 6  or higher aliphatic ω-amino-α-acids, and the polyether soft segments are polyethers of C 2 -C 10  diols;    the block copolymer has a flexural modulus of less than about 150,000 psi;    the block copolymer has a hardness, Shore D scale, of greater than 60; and    the percentage by weight of the block polymer attributable to the hard segments is between about 50% and about 95%.    
     
     
         2 . A balloon as in  claim 1  wherein the block copolymer segment, PA, is an aliphatic polyamide of one or more C 10 -C 12  aliphatic acids and one or more C 10 -C 12  aliphatic diamines or of a C 10 -C 12  aliphatic ω-amino-α-acid.  
     
     
         3 . A balloon as in  claim 1  wherein the polyamide segment, PA, is selected from the group consisting of nylon 12, nylon 11, nylon 9, nylon 6, nylon 6/12, nylon 6/11, nylon 6/9 and nylon 6/6.  
     
     
         4 . A balloon as in  claim 1  wherein the polyamide segment, PA, is nylon 12 of a molecular weight of 3,000-5,000, and the polyether segment, PE, is poly(tetramethylene ether) of molecular weight between 500 and 1250.  
     
     
         5 . A balloon as in  claim 1  wherein the polyamide segments, PA, comprise between 80 and 90% by weight of the polyamide/polyether polyester.  
     
     
         6 . A balloon as in  claim 1  wherein said polyether segment, is selected from the group consisting of poly(tetramethylene ether), poly(pentamethylene ether) and poly(hexamethylene ether).  
     
     
         7 . A balloon as in  claim 1  wherein the wall strength of the balloon is at least 15,000 psi.  
     
     
         8 . A balloon as in  claim 7  wherein the wall thickness, single wall basis, is no more than 0.0015 inches and said wall strength is greater than 18,000 psi.  
     
     
         9 . A balloon as in  claim 8  wherein said wail thickness is no more than 0.0009 inches.  
     
     
         10 . A balloon as in  claim 7  wherein said wall strength is greater than 20,000 psi.  
     
     
         11 . A balloon as in  claim 1  wherein the polymer material forming the tubing further comprises a second polymer blended with the block copolymer thermoplastic elastomer.  
     
     
         12 . The balloon as in  claim 11  wherein the second polymer is nylon.  
     
     
         13 . The balloon as in  claim 12  wherein the nylon is selected from the group consisting of nylon 11 and nylon 12.  
     
     
         14 . The balloon as in  claim 13  wherein the percentage by weight of the nylon is about 30% to about 95%.  
     
     
         15 . The balloon as in  claim 13  wherein the block copolymer thermoplastic elastomer has a hardness of Shore D durometer of about 60D to about 72 D.  
     
     
         16 . A balloon for a medical device, comprising 
 a) a first polymeric layer; and    b) at least a second polymeric layer coextruded with the first layer, comprising a block copolymer thermoplastic elastomer represented by the formula:                          in which PA is a polyamide hard segment of molecular weight in the range of 500-8,000;    PE is a polyether soft segment of molecular weight in the range of 500-2,500 and the repeating number n is between 5 and 10, the polyamide hard segments are polyamides of C 6  or higher carboxylic acids and C6 or higher organic diamines or of C 6  or higher aliphatic ω-amino-α-acids, and the polyether soft segments are polyethers of C 2 -C 10  diols;    the block copolymer has a flexural modulus of less than about 150,000 psi;    the block copolymer has a hardness, Shore D scale, of greater than 30; and    the percentage by weight of the block polymer attributable to the hard segments is between about 50% and about 95%.    
     
     
         17 . The balloon as in  claim 16  wherein the first polymeric layer comprises nylon.  
     
     
         18 . The balloon as in  claim 17  wherein the nylon is selected from the group consisting of nylon 11 and nylon 12.  
     
     
         19 . The balloon as in  claim 18  wherein the block copolymer thermoplastic elastomer has a hardness of Shore D durometer of about 35D to about 72 D.  
     
     
         20 . An intravascular catheter, comprising: 
 a) an elongated catheter shaft having a proximal end, a distal end, and a lumen extending therein; and    b) an inflatable member on the distal end of the catheter shaft having an interior in fluid communication with the lumen of the catheter shaft, and being formed from a polyether/polyamide polyester block copolymer having a flexural modulus of less than about 150,000 psi.    
     
     
         21 . The intravascular catheter of claim  20  further including a stent disposed about the inflatable member.