Co-extruded plastic tubing

1 . Two-layer tubing for housing an insert, comprising an extremely lubricious tubular inner layer and a tubular outer layer disposed radially outward of and surrounding the inner layer, wherein:

the co-efficient of friction of the inner layer is less than the co-efficient of friction of the outer layer;

the outer layer consists essentially of a thermoplastic elastomer; and

the inner layer consists essentially of an organosilicon compound.

2 . The tubing of claim 1 , wherein the thermoplastic elastomer is a polyolefin-based material.

3 . The tubing of claim 1 , wherein the thermoplastic elastomer has a specific gravity averaging between about 0.91 g/cm3 and about 0.97 g/cm3 and an MFI of 0.20-2.00 g/10 min, as defined by ASTM D-1238; and

wherein the organosilicon compound has the empirical formula R 2 SiO, where R is an organic group.

4 . The tubing of claim 1 , wherein the inner layer is a copolymer consisting essentially of a polyethylene-based material with a silicone-based additive to decrease the coefficient of friction to a point below that of the outer layer.

5 . The tubing of claim 2 , wherein the polyolefin-based material is a polyethylene-based material.

6 . The tubing of claim 2 , wherein the polyolefin-based material is a polypropylene-based material.

7 . The tubing of claim 1 , wherein the total material volume ratio of the outside layer to the inner layer is approximately 4:1.

8 . The tubing of claim 1 , wherein the outer layer consists essentially of medical-grade high-density polyethylene and the inner layer consists essentially of a medical grade silicone co-polymer.

9 . A dispenser assembly comprising the tubing of claim 1 and an insert housed inside the inner layer.

10 . The dispenser assembly of claim 8 , wherein the outer layer consists essentially of medical-grade high-density polyethylene, the inner layer consists essentially of a medical grade silicone co-polymer, and the insert comprises a guidewire suitable for use in vascular procedures.

11 . The dispenser assembly of claim 8 , wherein the insert comprises a moving component of a machine.

12 . Two-layer tubing for housing an insert, comprising an extremely lubricious tubular inner layer and a tubular outer layer disposed radially outward of and surrounding the inner layer, the total material volume ratio of the outside layer to the inner layer being approximately 4:1, wherein:

the co-efficient of friction of the inner layer is less than the co-efficient of friction of the outer layer;

the outer layer consists essentially of a thermoplastic elastomer having a specific gravity averaging between about 0.91 g/cm3 and about 0.97 g/cm3 and an MFI of 0.20-2.00 g/10 min, as defined by ASTM D-1238;

the inner layer consists essentially of an organosilicon compound and an additive to decrease the coefficient of friction to a point below that of the outer layer, the organosilicon compound having the empirical formula R 2 SiO, where R is an organic group.

13 . The tubing of claim 12 , wherein the thermoplastic elastomer is a polyolefin-based material.

14 . Two-layer tubing for housing an insert, comprising an extremely lubricious tubular inner layer and a tubular outer layer disposed radially outward of and surrounding the inner layer, wherein:

the co-efficient of friction of the inner layer is less than the co-efficient of friction of the outer layer;

the outer layer consists essentially of medical-grade high-density polyethylene; and

the inner layer consists essentially of a medical grade silicone co-polymer and an additive to decrease the coefficient of friction to a point below that of the outer layer.