Lubricious thermoplastic compounds and thermoplastic articles made therefrom
Lubricious thermoplastic articles are formed from thermoplastic compounds including (a) thermoplastic elastomer selected from thermoplastic polyurethane, polyether block amide, and combinations thereof; and (b) from about 5 to about 20 weight percent, by weight of the compound, of hydrophilic water-insoluble polymer selected from polyolefin-polyoxyalkylene block copolymer, crosslinked polyvinylpyrrolidone, and combinations thereof. The thermoplastic compounds are capable of providing enhanced lubricity in the thermoplastic articles without significant degradation in mechanical properties such as elongation and tensile strength, as compared to thermoplastic articles formed from the neat thermoplastic elastomer and subjected to the same heat processing history.
1. A lubricious thermoplastic article formed from a thermoplastic compound comprising:
(a) thermoplastic elastomer that is thermoplastic polyurethane; and
(b) from about 5 to about 20 weight percent, by weight of the compound, of hydrophilic water-insoluble polymer that is crosslinked polyvinylpyrrolidone;
wherein the crosslinked polyvinylpyrrolidone is a powder having a particle size distribution wherein at least 95% of particles have a particle size of less than 250 micrometers; and
the crosslinked polyvinylpyrrolidone is crosslinked prior to inclusion into the thermoplastic compound.
2. The article of claim 1 , wherein the hydrophilic water-insoluble polymer consists of crosslinked polyvinylpyrrolidone.
3. The article of claim 1 , wherein the article has a Relative Dynamic COF of less than about 0.9.
4. The article of claim 3 , wherein the article has at least one of a Relative Tensile Strength at Break of greater than about 0.8 and a Relative Elongation at Break of greater than about 0.8.
5. The article of claim 1 , wherein the article has a Relative Dynamic COF of less than about 0.6, and wherein the article has at least one of a Relative Tensile Strength at Break of greater than about 1 and a Relative Elongation at Break of greater than about 1.
6. The article of claim 1 , wherein the article has a Relative Dynamic COF (Wet) of less than about 0.5, and wherein the article has both a Relative Tensile Strength at Break of greater than about 1 and a Relative Elongation at Break of greater than about 1.
7. The article of claim 1 , wherein the thermoplastic compound further comprises one or more additives selected from the group consisting of antimicrobial agents; antioxidants and stabilizers; colorants; radiopaque agents; and combinations thereof.
8. The article of claim 1 , wherein the article is a catheter.
9. A method of making the article of claim 1 , the method comprising the steps of:
(a) providing ingredients comprising the thermoplastic elastomer and the hydrophilic water-insoluble polymer;
(b) melt mixing the ingredients to provide the thermoplastic elastomer compound; and
(c) forming the thermoplastic elastomer compound to provide the article for the intended use without a subsequent step of applying a lubricity enhancing agent to the article prior to the intended use.
10. The method of claim 9 , wherein the step of forming comprises extruding the thermoplastic elastomer compound.
11. The method of claim 9 , further comprising the step of inserting the article into a human body.