Dip-molded polymeric medical devices with reverse thickness gradient, and methood of making same
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Abstract
An expandable polymeric medical article is formed by a novel dip-molding process, involving multiple dipping and rotational drying of liquid polymeric material layer at different pivotal positions. Preferably, the rotational drying is conducted so as to form an expandable polymeric medical article having a reverse thickness gradient in relation to the thickness gradient of conventional dip-molded polymeric medical articles. Specifically, the expandable polymeric medical article of the present invention has an expandable body member and a neck member, wherein such neck member has a wall thickness that is greater than that of the expandable body member, before any significant expansion of such body member.
88 Citations
56 Claims
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1-29. -29. (canceled)
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30. A method for forming an expandable polymeric medical article, comprising the steps of:
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(a) providing a liquid dip-molding composition comprising at least one polymeric material;
(b) providing a rotatory mandrel capable of axial rotation at an adjustable rotational speed, wherein said rotatory mandrel is capable of being pivotally rotated in at least one additional direction;
(c) dipping said rotatory mandrel into the liquid dip-molding composition so as to apply a layer of said polymeric material onto said rotatory mandrel;
(d) removing said rotatory mandrel from the liquid dip-molding composition;
(e) repeating steps (c) to (d) for one or more times, wherein between each dipping, said layer of polymeric material is partially dried on said rotatory mandrel at a substantially vertical position, with the rotatory mandrel axially rotating during such drying;
(f) pivotally rotating said rotatory mandrel in said additional direction to a substantially inverted position, and partially drying said layer of polymeric material thereat with said rotatory mandrel axially rotating during the drying;
(g) optionally, pivotally rotating said rotatory mandrel in said additional direction to a substantially horizontal position, and partially drying said layer of polymeric material thereat with said rotatory mandrel axially rotating during the drying;
(h) optionally, repeating steps (c) to (g) until said layer of polymeric material achieves a predetermined average thickness;
(i) curing said layer of polymeric material on said rotatory mandrel; and
(j) removing said layer of polymeric material from the rotatory mandrel to form said expandable polymeric medical article. - View Dependent Claims (31, 32, 33, 34, 35, 36, 37, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56)
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38. The method of clam 37, wherein said dimethyl siloxane dispersion comprises xylene solvent.
Specification