Method of increasing the tensile strength of a dilatation balloon

Claim 1

A method of making a thin wall dilatation balloon having a high percentage of the maximum tensile strength of the balloon material, the method comprising the steps of: heating a thin wall, tubular parison of a biaxially orientable polymer by flowing a heated fluid through the interior of the parison to achieve a radially decreasing temperature gradient across the sidewall of the parison going from the inner to the outer surface of the parison, the outer surface being heated to a temperature no less than the orientation temperature of the polymer and the parison having a wall thickness of no greater than about 25 mils; axially drawing and circumferentially expanding the parison while subject to said temperature gradient, said circumferential expansion being achieved by sealing one end of the parison and injecting a heated fluid to expand the parison; and wherein the temperature gradient is selected to compensate for differing degrees of stretch across the sidewall and produce the thin wall dilatation balloon having a substantially uniform and relatively high degree of orientation across the sidewall and thus a high average tensile strength.

Claim 2

A method of making a thin wall dilatation balloon having a high percentage of the maximum tensile strength of the balloon material, the method comprising the steps of: heating a thin wall, tubular parison of a biaxially orientable polymer by flowing a heated fluid through the interior of the parison to achieve a radially decreasing temperature gradient across the sidewall of the parison going from the inner to the outer surface of the parison, the outer surface being heated to a temperature no less than the orientation temperature of the polymer and the parison having a wall thickness of no greater than about 25 mils; axially drawing and circumferentially expanding the parison while subject to said temperature gradient, said circumferential expansion being achieved by sealing one end of the parison and injecting a heated fluid to expand the parison; and wherein the temperature gradient is selected to compensate for differing degrees of stretch across the sidewall and produce the thin wall dilatation balloon having a substantially uniform and relatively high degree of orientation across the sidewall and thus a high average tensile strength.

Claim 10

A method of making a thin wall dilatation balloon having a high percentage of the maximum tensile strength of the balloon material, the method comprising the steps of: heating a thin wall, tubular parison of a biaxially orientable semi-crystalline polymer to achieve a radially decreasing temperature gradient across the sidewall of the parison going from the inner to the outer surfaces of the parison, the outer surface being heated to a temperature no less than the orientation temperature of the polymer, and the parison having a wall thickness of no greater than about 25 mils; axially drawing and circumferentially expanding the parison while subject to said temperature gradient, said circumferential expansion being achieved by sealing one end of the parison and injecting a heated fluid to expand the parison; and wherein the temperature gradient is selected to compensate for differing degrees of stretch across the sidewall and produce the thin wall dilatation balloon having a substantially uniform and relatively high degree of orientation across the sidewall and thus a high average tensile strength.

Claim 11

A method of making a thin wall dilatation balloon having a high percentage of the maximum tensile strength of the balloon material, the method comprising the steps of: heating a thin wall, tubular parison of a biaxially orientable semi-crystalline polymer to achieve a radially decreasing temperature gradient across the sidewall of the parison going from the inner to the outer surfaces of the parison, the outer surface being heated to a temperature no less than the orientation temperature of the polymer, and the parison having a wall thickness of no greater than about 25 mils; axially drawing and circumferentially expanding the parison while subject to said temperature gradient, said circumferential expansion being achieved by sealing one end of the parison and injecting a heated fluid to expand the parison; and wherein the temperature gradient is selected to compensate for differing degrees of stretch across the sidewall and produce the thin wall dilatation balloon having a substantially uniform and relatively high degree of orientation across the sidewall and thus a high average tensile strength.

Claim 16

A method of making a thin wall dilatation balloon from a tubular parison, wherein although the parison is expanded at substantially different inner and outer diameter stretch ratios, the resulting expanded article has a high percentage of the maximum tensile strength of the parison material, the method comprising the steps of: heating a thin wall, tubular parison of a biaxially orientable polymer by flowing a heated fluid through the interior of the parison to achieve a radially decreasing temperature gradient across the sidewall of the parison going from the inner to the outer surfaces of the parison, the outer surface being heated to a temperature no less than the orientation temperature of the polymer and the parison having a wall thickness of no greater than about 25 mils; axially drawing and circumferentially expanding the parison while subject to said temperature gradient, said circumferential expansion being achieved by sealing one end of the parison and injecting a heated fluid to expand the parison, and wherein the inner and outer diameter stretch ratios differ by at least about 25%; and wherein the temperature gradient across the sidewall is selected to compensate for the differing degrees of stretch across the sidewall and produce the thin wall dilation balloon having a substantially uniform and relatively high degree of orientation across the sidewall and thus a high average tensile strength.

Claim 17

A method of making a thin wall dilatation balloon from a tubular parison, wherein although the parison is expanded at substantially different inner and outer diameter stretch ratios, the resulting expanded article has a high percentage of the maximum tensile strength of the parison material, the method comprising the steps of: heating a thin wall, tubular parison of a biaxially orientable polymer by flowing a heated fluid through the interior of the parison to achieve a radially decreasing temperature gradient across the sidewall of the parison going from the inner to the outer surfaces of the parison, the outer surface being heated to a temperature no less than the orientation temperature of the polymer and the parison having a wall thickness of no greater than about 25 mils; axially drawing and circumferentially expanding the parison while subject to said temperature gradient, said circumferential expansion being achieved by sealing one end of the parison and injecting a heated fluid to expand the parison, and wherein the inner and outer diameter stretch ratios differ by at least about 25%; and wherein the temperature gradient across the sidewall is selected to compensate for the differing degrees of stretch across the sidewall and produce the thin wall dilation balloon having a substantially uniform and relatively high degree of orientation across the sidewall and thus a high average tensile strength.

Claim 23

A method of making a thin wall dilatation balloon having a high percentage of the maximum tensile strength of the balloon material, the method comprising the steps of: heating a thin wall, tubular parison of a biaxially orientable, semi-crystalline polymer to achieve a radially decreasing temperature gradient across the sidewall of the parison going from the inner to the outer surfaces of the parison, the outer surface being heated to a temperature no less than the orientation temperature of the polymer and the parison having a wall thickness of no greater than about 25 mils; axially drawing and circumferentially expanding the parison while subject to said temperature gradient, said circumferential expansion being achieved by sealing one end of the parison and injecting a heated fluid to expand the parison, and wherein the temperature gradient is selected to compensate for differing degrees of stretch across the sidewall to produce the thin wall dilatation balloon having a substantially unmiform and relatively high degree of orientation across the sidewall and thus a high average tensile strength, and heat setting the drawn and circumferentially expanded parison by elevating the temperature of the formed balloon and maintaining the temperature for a period of time sufficient for heat setting the balloon and ensuring the dimensional stability of the balloon.

Claim 24

A method of making a thin wall dilatation balloon having a high percentage of the maximum tensile strength of the balloon material, the method comprising the steps of: heating a thin wall, tubular parison of a biaxially orientable, semi-crystalline polymer to achieve a radially decreasing temperature gradient across the sidewall of the parison going from the inner to the outer surfaces of the parison, the outer surface being heated to a temperature no less than the orientation temperature of the polymer and the parison having a wall thickness of no greater than about 25 mils; axially drawing and circumferentially expanding the parison while subject to said temperature gradient, said circumferential expansion being achieved by sealing one end of the parison and injecting a heated fluid to expand the parison, and wherein the temperature gradient is selected to compensate for differing degrees of stretch across the sidewall to produce the thin wall dilatation balloon having a substantially unmiform and relatively high degree of orientation across the sidewall and thus a high average tensile strength, and heat setting the drawn and circumferentially expanded parison by elevating the temperature of the formed balloon and maintaining the temperature for a period of time sufficient for heat setting the balloon and ensuring the dimensional stability of the balloon.