Stock material or miscellaneous articles – Composite – Of polyamidoester
Reexamination Certificate
1997-02-07
2001-05-29
Reddick, Judy M. (Department: 1713)
Stock material or miscellaneous articles
Composite
Of polyamidoester
C428S034300, C428S036500, C428S411100, C428S424200, C428S425100, C428S423500, C521S057000, C524S500000, C524S503000, C524S507000, C604S265000
Reexamination Certificate
active
06238799
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to hydrophilic coatings and coated articles derived therefrom. Further, the invention relates to coating composition which can be delivered from an aqueous based formulation.
BACKGROUND OF THE INVENTION
Devices used in the medical and dental industry are prepared from metals, ceramics, or synthetic or natural plastics and are often hydrophobic and non-slippery. Catheters and guide wires which are used for insertion through blood vessels, urethra or other body conduits require low-friction surfaces for preventing injury or inflammation of mucous membranes and for facilitating surgical procedures. To render the device more slippery, the device surfaces are often coated with low-friction materials, such as ptfe, Teflon®, silicone oil, glycerin or silicone fluid. This low-friction coating may result in the loss of maneuverability of the device from outside the body because they are slippery even when dry. Surface modification of hydrophobic, non-biocompatible or non-slippery surfaces by coating with a hydrophilic polymer is known; however, hydrophilic polymer coatings, when hydrated, possesses little in the way of physical integrity because of the high water content.
Prior art references have chemically linked a hydrophilic polymer to a more durable undercoat to improve the physical integrity of the hydrophilic coating. See, Gould in U.S. Pat. No. 4,810,543 and Kliment in U.S. Pat. No. 4,729,914. Baker (U.S. Pat. No. 4,980,231) and Markel (U.S. Pat. No. 4,943,460) describe the coupling of a polyvinylpyrrolidone polymer with an undercoating of an acid functional or anhydride functional material.
The prior art also has attempted to improve wet strength and coating durability while retaining slip by physically blending or co-extruding the hydrophilic polymer with a co-material having greater physical integrity. See, Creasy in U.S. Pat. Nos. 4,642,267 and 4,847,324, in which a polyurethane or a polyvinyl butyral is blended with a poly(N-vinyl lactam). Other references disclose the preparation of interpolymers. See, Micklus (U.S. Pat. Nos. 4,100,309 and 4,119,094) which report an association between polyurethane and polyvinylpyrrolidone polymers. Whitborne in U.S. Pat. No. 5,001,009 describes hydrophilic coatings including a polyolefin such as polyvinylpyrrolidone and a water-insoluble stabilizing polymer, such as cellulose ester. The two polymers may be applied in separate layers or may be premixed and applied in a single step.
Other attempts in the prior art to improve the performance of hydrophilic coatings include use of modified polyurethanes, which possess short hydrophilic segments. See, Teffenhart in U.S. Pat. No. 4,789,720, in which a hydrophilic polyurethane is prepared having polyethylene glycol and polypropylene glycol segments. Stoy et al. in U.S. Pat. Nos. 4,370,451, 4,379,874, 4,420,589, 4,331,783, 4,369,294, 4,337,327 and 4,026,296 describe a series of hydrophilic block copolymers including acrylamides and modified acrylonitriles which have found some use as coatings. These polymers possess limited physical strength when hydrated and are delivered from organic solvents.
Elton in U.S. Pat. No. 5,077,352 describes a cross-linked polyurethane-poly(ethylene oxide) composition which is derived by polymerization of an isocyanate and a polyol in a poly(ethylene oxide) containing solution. The solvent used must not contain any active hydrogens and hence the system may not be applied from aqueous media.
Kiezulas in U.S. Pat. Nos. 5,026,607 and Opolski in 5,272,012 describe water-based, lubricous coatings having domains of a siloxane slip additive within a crosslinked urethane. The slip additives is maintained in distinct domains which replenish the surface of the slip additive as it is removed during use. While retaining good slip, the lubricous surface is non-robust and abrades easily due to the poor compatibility of the siloxane slip additive with the polyurethane and low crosslink density of the urethane. Further, there are health concerns with the retention of siloxane in the body.
In all the above examples, the coatings are either fragile and loosely bound to the substrate or demonstrate limited wet strength. In addition, most of the coating procedures require use of organic solvents, which is discouraged from environmental, cost and worker/patient safety standpoints. Thus, many technical problems directed to providing a durable, low-cost and safe hydrophilic coating remain unresolved.
It is an object of the present invention to provide a coating which is hydrophilic, containing water for anti-adhesion, slip and electrical and ion transport, yet durable—particularly in the water-swollen phase.
It is yet a further object of the invention to provide a coating which is a poor growth medium for microbes.
It is another object of the invention to provide a coating which may be applied from aqueous-based solutions.
These and other objects are provided by the present invention which is described hereinbelow.
SUMMARY OF THE INVENTION
In one aspect of the invention, a water-based coating composition is provided including a supporting polymer comprising a plurality of functional moieties capable of undergoing crosslinking reactions, said supporting polymer soluble in or emulsified in an aqueous based medium; and a hydrophilic polymer, said hydrophilic polymer associated with the supporting polymer. The composition is characterized in that, when crosslinked at the functional moieties, the supporting polymer forms a three-dimensional network which minimizes disassociation of the hydrophilic polymer and maintains the slip of the composition.
The functional moiety may be selected from the group consisting of amino, hydroxyl, amido, carboxylic acid and derivatives thereof, sulfhydryl (SH), unsaturated carbon bond and heteroatom bonds, N—COOH, N(C═O)H S(OR), alkyd/dry resins, formaldehyde condensates, methylol acrylamides and allylic groups. The supporting polymer may be selected from the group consisting of polyacrylates, polymethacrylates, polyurethanes, polyethylene and polypropylene co-difunctional polymers, polyvinyl chlorides, epoxides, polyamides, polyesters and alkyd copolymers. The hydrophilic polymer may be selected from the group consisting of poly(N-vinyl lactams, poly(vinylpyrrolidone), poly(ethylene oxide) polypropylene oxide) polyacrylamides, cellulosics, methyl cellulose, polyanhydrides, polyacrylic acids, polyvinyl alcohols, and polyvinyl ethers.
In one embodiment of the invention, the supporting polymer has a molecular weight in the range of 5,000 to 10,000,000, and preferably has a molecular weight in the range of 30,000 to 100,000. The functional moiety of the supporting polymer has an equivalent weight in the range of about 115 to about 8700. In one embodiment of the invention, the supporting polymer comprises polyacrylate and the equivalent weight of the functional moiety is in the range of about 200 to about 1000. The supporting polymer may comprise polyurethane and the equivalent weight of the functional moiety is in the range of about 1000 to about 8700. The supporting polymer may comprise polyamine epoxide and the equivalent weight of the functional moiety is in the range of about 100 to about 2000.
In other preferred embodiments, the coating composition further comprises a crosslink agent. The crosslink agent may be selected from the group consisting of aziridines, polyfunctional carbodiimides, polyfunctional epoxides, unsaturated carbon and heteroatom bonds, melamine/urea condensates and ionic complexing agents. In other preferred embodiments, the coating composition further comprises one or more additives selected from the group consisting of co-solvents, plasticizers, antifoaming agents, anticrater agents, coalescing solvents, bioactive agents, antimicrobial agents, antithrombogenic agents, antibiotics, pigments, paint additives, radiopacifiers and ion conductors.
In another aspect of the invention, a coated article is provided having a surface coated with a hydrophilic coating. The hydrophilic coating
Clark & Elbing LLP
Reddick Judy M.
Scozzafava Mary Rose
Surface Solutions Laboratories, Inc.
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