Method for forming a balloon mold and the use of such mold

• US 5,163,989 A
• Filed: 08/27/1990
• Issued: 11/17/1992
• Est. Priority Date: 08/27/1990
• Status: Expired due to Term

• Current Assignee: Advanced Cardiovascular Systems Incorporated
• Original Assignee: Advanced Cardiovascular Systems Incorporated
• Inventors: Campbell, Peter F., Ryan, Timothy J.
• Primary Examiner(s): Woo, Jay H.
• Assistant Examiner(s): Davis, Robert B.
• Application Number:
  US07/573,534
• Time in Patent Office: 813 Days
• Field of Search: 264/225, 264/226, 264/227, 264/221, 264/219, 264/317, 264/510, 264/511, 264/512, 264/571, 264/573, 604/96, 65/110, 65/102, 65/108
• US Class Current: 65/110
• CPC Class Codes: A61M 2025/1004 Balloons with folds, e.g. folded or multifolded
• CPC Class Codes: A61M 25/1002 characterised by balloon shape A61M25/1006, A61M25/1009 take precedence
• CPC Class Codes: A61M 25/1029 Production methods of the balloon members, e.g. blow-moulding, extruding, deposition or by wrapping a plurality of layers of balloon material around a mandril
• CPC Class Codes: A61M 25/1038 Wrapping or folding devices for use with balloon catheters
• CPC Class Codes: B29C 49/00 Blow-moulding, i.e. blowing a preform or parison to a desired shape within a mould; Apparatus therefor
• CPC Class Codes: B29C 49/48 Moulds
• CPC Class Codes: B29K 2067/00 Use of polyesters or derivatives thereof, as moulding material
• CPC Class Codes: B29K 2909/08 Glass
• CPC Class Codes: B29L 2031/7542 Catheters
• CPC Class Codes: C03B 23/076 Shrinking the glass tube on to a mandrel

Abstract

A mold and method for forming a balloon for dilatation catheters, particularly balloons with a prismlike shape with a transverse polygonal cross section when the internal pressure is at atmospheric conditions. Upon inflation to higher internal pressures, the balloon assumes a normal circular cross section. The balloon shape is particularly suitable for balloons formed of polyethylene terephthalate and the like which are not readily heat settable. Reduced deflated profiles are obtained. The mold is formed by first making a preformed core member which has the shape and dimensions which are desired for the balloon. A heat-formable tubular member, preferably formed of borosilicate glass such as PYREX, is disposed about the core member, subjected to heat and an internal vacuum so as to be shaped onto the exterior of the core member. Once shaped, the tubular member is allowed to cool and set, the core member is dissolved away, leaving the shaped glass mold having an internal molding chamber with the desired shape and dimensions for the inflatable balloon.

Claims

1. A method of making a mold for forming small diameter inflatable members comprising:

a) forming a core member having a shape and dimensions which correspond to the shape and dimensions of inflatable members to be molded and having an inner passageway extending therein which is in fluid communication with an opening at an end of the core member;

b) inserting an end of an elongated holding member into the opening in an end of the core member;

c) disposing the core member with the elongated holding member inserted within an end thereof within the interior of a heat-formable tubular member having proximal and distal ends;

d) forming a mold by heating the heat-formable tubular member while applying a vacuum to the interior thereof to cause the heat-formable tubular member to be shaped about the core member and take the shape and dimensions of the exterior of the core member; and

e) passing a solution through the inner passageway of the core member to thereby dissolve the core member to remove the core member from the interior of the mold.

2. The method of claim 1 wherein the heat-formable tubular member is made from heat formable glass.

3. The method of claim 2 wherein the glass ia borosilicate glass.

4. The method of claim 1 wherein the inner passageway of the core member passes through the entire length of the core member.

5. The method of claim 4 wherein core member is made from stainless steel.

6. The method of claim 5 wherein the solution for dissolving the core member is an acidic aqueous solution containing iron chloride.

7. The method of claim 6 wherein the pH of the aqueous solution ranges from about 1 to about 2.

8. The method of claim 1 wherein the holding members are removed from the mold after the core member is dissolved.

9. A method of forming a small diameter inflatable member comprising:

a) forming a mold having an inner molding chamber with a continuous molding surface therein having the shape and dimensions of the desired inflatable member by the steps of,

forming a core member having a shape and dimensions which correspond to the shape and dimensions of inflatable members to be molded and having an inner passageway extending therein which is in fluid communication with an opening at an end of the core member,

inserting an end of an elongated holding member into the opening in an end of the core member,

disposing the core member with the elongated holding member inserted within an end thereof within the interior of a heat-formable tubular member having proximal and distal ends

forming a mold by heating the heat-formable tubular member while applying a vacuum to the interior thereof to cause the heat-formable tubular member to be shaped about the core member and take the shape and dimensions of the exterior of the core member, and

passing a solution through the inner passageway of the core member to thereby dissolve the core member to remove the core member from the interior of the mold;

b) inserting a tubular plastic member within the molding chamber;

c) subjecting the plastic tubular member to internal fluid pressure and heat so that the tubular plastic member inflates within the molding chamber, engages the continuous molding surface of the molding chamber and thereby takes on the shape and dimensions thereof; and

d) cooling the shaped plastic tubular member to retain the desired shape of the balloon therein.