Surgical device with tack-free gel and method of manufacture

Abstract

A process of making a tack-free gel is disclosed comprising the steps of providing a mold defining a mold cavity, the mold cavity comprising a plastic material; pouring or injecting a molten gel having a high molding temperature into the mold cavity; and forming the tack-free gel as a thin layer of plastic of the mold cavity is melted over the gel. The forming step further comprises cooling the gel from the molten state to a solidified state. The melting temperature of the plastic material is lower than the molding temperature of the gel; and the higher the temperature differential, the greater the melting of the plastic material and the thicker the layer of the plastic material on the surface of the gel. The mold may be formed of low-density polyethylene (LDPE). With the process of the invention, the heat of the molten gel at its molding temperature is transferred to the surface of the LDPE mold so as to melt a thin layer of the LDPE. The mold may comprise a mold base having a plurality of mold holes forming a plurality of mold cavities, each of the mold holes comprising an axial pin to mold an axial hole through a center of the gel, an LDPE cylinder providing a predetermined inside diameter for the mold, and an LDPE disc mounted on the axial pin and disposed at the bottom of each mold cavity in the mold base. The process may further comprise the step of dabbing the gel in a low-friction powder such as polytetrafluoroethylene (PTFE) and a lubricant. The mold may further comprise a mold top disposed axially of the mold base and comprises a plurality of holes forming a plurality of cavities, each of the mold top holes is adapted to receive the LDPE cylinder, and a second LDPE disc disposed at the top of each mold cavity of the mold top.

Description

[0001] This is a continuation-in-part application claiming the priority of provisional application Ser. No. 60 / 492,949, filed on Aug. 6, 2003, entitled “Surgical Device With Tack-Free Gel and Method of Manufacture,” and of U.S. application Ser. No. 10 / 776,387, filed on Feb. 10, 2004, entitled “Access Sealing Apparatus and Method,” which claims priority to PCT application Serial No. PCT / US02 / 15696, filed on May 14, 2002, entitled “Access Sealing Apparatus and Method,” and to provisional application Ser. No. 60 / 312,683, filed on Aug. 14, 2001, entitled “Access Sealing Apparatus and Method,” all of which are fully incorporated herein by reference.BACKGROUND OF THE INVENTION [0002] 1. Field of the Invention [0003] This invention generally relates to gels having tacky surfaces and, more specifically, to surface treatments which will render the gel tack-free. [0004] 2. Discussion of Related Art [0005] A “gel” is often defined as a semisolid condition of a precipitated or coagulated colloi...

AI Technical Summary

Benefits of technology

[0013] In accordance with the present invention, a gel material having all of the advantageous properties previously discussed is further blessed with a non-tacky surface that can be provided at the earliest possible opportunity, during the molding step of the manufacturing process. From the time when the molten gel material first achieves its solid characteristics, it is provided with a non-tacky surface. In the case of a trocar seal, significant drag forces are avoided during the process of instrument insertion. Moreover, the advantages of high compliance, significant tear strength, and exceptional elongation are maintained without any of the disadvantages associated with a tacky device.

Problems solved by technology

While the advantageous properties of gels have made them candidates for many applications, one disadvantage has seriously limited their use.

Most gels are extremely tacky.

This characteristic alone makes them difficult to manufacture and aggravating to use.

But such attempts unfortunately have resulted in an intolerable sacrifice of the advantageous properties.

This has also tended to mask the advantageous properties and to significantly increase manufacturing costs.

Powders and lubricants have been applied to the tacky surfaces with results limited in both duration and effect.

As noted, however, the best gel materials tend to exhibit surfaces that are very tacky.

The use of a tacky gel can make the processes of manufacturing and using the gel seals extremely difficult.

The disadvantages are increasing in this application, where a tacky gel also produces significant drag forces during instrument insertion.

Furthermore, the tacky surfaces tend to draw and retain particulate matter during the manufacturing and handling processes.

Unfortunately, these lubricants tend to dry out over time leaving the gel in its natural tacky state.

The non-tacky gels, however, are not particularly heat tolerant, as low amounts of heat can rapidly cause the materials to take a set and distort particularly under compressive loads.

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