摘要:
A method for forming a balloon for a dilatation catheter involving the steps of extruding a segment of thermoplastic material, maintaining the center portion at a temperature below the glass transition of the thermoplastic material, drawing the segment to a predetermined length, wherein after the drawing the wall thickness of the center portion does not appreciably change, and expanding the segment in a mold to produce the balloon.
摘要:
A method for forming a balloon for a dilatation catheter involving the steps of extruding a segment of thermoplastic material, maintaining the center portion at a temperature below the glass transition of the thermoplastic material, drawing the segment to a predetermined length, wherein after the drawing the wall thickness of the center portion does not appreciably change, and expanding the segment in a mold to produce the balloon.
摘要:
A laminate balloon comprising at least two layers of separately oriented thermoplastic polymer material, which are coextensive over the body of the balloon. The two layers may be made of different polymer materials, including an underlying layer made of a low compliant, high strength polymer, such as PET, and an overlying layer of a softer and more flexible polymer material relative to the first polymer material, such as a polyester-polyether block copolymer. The balloon structures have an additive burst pressure, meaning that they are stronger than a single-layer reference balloon corresponding to the underlying polymer layer. The balloons are characterized by a combination of flexibility and surface softness which allows catheters to track down into lesions relatively easily, puncture resistance, abrasion resistance and refoldability, in addition to low compliance and high burst strength. The balloons may be prepared with generally linear or with stepped compliance profiles. Methods of preparation of such balloons are also disclosed.
摘要:
A laminate balloon comprising at least two layers of separately oriented thermoplastic polymer material, which are coextensive over the body of the balloon. The two layers may be made of different polymer materials, including an underlying layer made of a low compliant, high strength polymer, such as PET, and an overlying layer of a softer and more flexible polymer material relative to the first polymer material, such as a polyester-polyether block copolymer. The balloon structures have an additive burst pressure, meaning that they are stronger than a single-layer reference balloon corresponding to the underlying polymer layer. The balloons are characterized by a combination of flexibility and surface softness which allows catheters to track down into lesions relatively easily, puncture resistance, abrasion resistance and refoldability, in addition to low compliance and high burst strength. The balloons may be prepared with generally linear or with stepped compliance profiles. Methods of preparation of such balloons are also disclosed.
摘要:
A processing technique and a composition which allow compositions of PBT polymers or copolymers to be formed into blow molded articles, especially medical balloons such as dilatation or stent placement balloons, from extruded tubular parisons. The process includes a longitudinal stretch step run at a temperature below the Tg of the polymeric material and a radial expansion step run at a temperature above the Tg of the polymeric material. During the longitudinal stretch step, the tubing is subjected to high internal pressure. In the composition a small amount of boric acid is added to the polybutylene terephthalate in a melt blend to give a formulation which has reduced crystallinity after extrusion and which can more readily fashioned into high strength blow molded articles than PBT by itself. Articles, which may be formed using the invention include medical device balloon articles in which the polymer consists essentially of PBT optionally blended with boric acid.
摘要:
Balloons for medical devices, particularly balloon angioplasty catheters, which have hybrid compliance curves in which growth rate slows at higher pressures are made from block copolymer thermoplastic elastomers.
摘要:
Balloons for medical devices, particularly balloon angioplasty catheters, are made from particular block copolymer thermoplastic elastomers in which the block copolymer is made up of hard segments of a polyester or polyamide and soft segments of polyether; the polyester hard segments are polyesters of an aromatic dicarboxylic acid and a C2-C4 diol; the polyamide hard segments are polyamides of C6 or higher carboxylic acids and C6 or higher organic diamines or of C6 or higher aliphatic ω-amino-α-acids, and the polyether soft segments are polyethers of C2-C10, diols; the block copolymer has a low flexural modulus, namely less than 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%. The polymers provide high strength, thin wall, compliant and semi-compliant balloons, which leads to a low profile catheter. The low profile catheters have very good initial crossing, good trackability, good recrossing after first inflation.
摘要:
Balloons for medical devices, particularly balloon agioplasty catheters, which have hybrid compliance curves in which growth rate slows at higher pressures are made from block copolymer thermoplastic elastomers.
摘要:
Balloons for use on medical devices such as catheter balloons are formed from polymer blend products which include a liquid crystal polymer (LCP), a crystallizable thermoplastic polymer, especially thermoplastic polyesters such as PET, and a compatabilizer. The compatabilizer may be an ethylene-maleic anhydride copolymer, an ethylene-methyl acrylate copolymer, an ethylene-methyl acrylate copolymer, an ethylene-methyl acrylate-maleic anhydride terpolymer, an ethylene-methyl-methacrylic acid terpolymer, an acrylic rubber, an ethylene-ethyl acrylate-glycidyl methacrylate terpolymer or a mixture of two or more such polymers.
摘要:
A processing technique and a composition which allow compositions of PBT polymers or copolymers to be formed into blow molded articles, especially medical balloons such as dilatation or stent placement balloons, from extruded tubular parisons. The process includes a longitudinal stretch step run at a temperature below the Tg of the polymeric material and a radial expansion step run at a temperature above the Tg of the polymeric material. During the longitudinal stretch step, the tubing is subjected to high internal pressure. In the composition a small amount of boric acid is added to the polybutylene terephthalate in a melt blend to give a formulation which has reduced crystallinity after extrusion and which can more readily fashioned into high strength blow molded articles than PBT by itself. Articles, which may be formed using the invention include medical device balloon articles in which the polymer consists essentially of PBT optionally blended with boric acid.