Process for preparation of slippery, tenaciously adhering, hydrophilic polyurethane hydrogel coating, coated polymer and metal substrate materials, and coated medical devices

• US 6,080,488 A
• Filed: 03/24/1998
• Issued: 06/27/2000
• Est. Priority Date: 02/01/1995
• Status: Expired due to Fees

• Current Assignee: Boston Scientific Scimed (Boston Scientific Corporation)
• Original Assignee: Schneider Electric SE
• Inventors: Helmus, Michael N., Ding, Ni, Forman, Michael R., Hostettler, Fritz, Rhum, David
• Primary Examiner(s): CAMERON, ERMA C
• Application Number:
  US09/126,376
• Time in Patent Office: 826 Days
• Field of Search: 428/423.3, 428/423.5, 428/423.7, 428/423.9, 428/424.8
• US Class Current: 428/423.3
• CPC Class Codes: A61L 29/085 Macromolecular materials
• CPC Class Codes: A61L 29/145 Hydrogels or hydrocolloids
• CPC Class Codes: A61L 31/10 Macromolecular materials
• CPC Class Codes: A61L 31/145 Hydrogels or hydrocolloids
• CPC Class Codes: C08G 18/10 Prepolymer processes involving reaction of isocyanates or isothiocyanates with compounds having active hydrogen in a first reaction step
• CPC Class Codes: C08G 18/283 Compounds containing ether groups, e.g. oxyalkylated monohydroxy compounds
• CPC Class Codes: C08G 18/307 Atmospheric humidity
• CPC Class Codes: C08G 18/3225 Polyamines
• CPC Class Codes: C08G 2230/00 Compositions for preparing biodegradable polymers
• CPC Class Codes: C08J 2475/00 Characterised by the use of polyureas or polyurethanes; Derivatives of such polymers
• CPC Class Codes: C08J 7/0427 with only one layer of a composition containing a polymer binder with more layers C08J7/042
• CPC Class Codes: C08J 7/043 Improving the adhesiveness of the coatings per se, e.g. forming primers adhesives in the form of films or foils characterised by the primer layers between the polymer carriers and the adhesives C09J7/50
• CPC Class Codes: C08J 7/046 Forming abrasion-resistant coatings; Forming surface-hardening coatings
• CPC Class Codes: C08J 7/056 Forming hydrophilic coatings
• CPC Class Codes: C08L 75/04 Polyurethanes
• CPC Class Codes: Y10T 428/31554 Next to second layer of polyamidoester
• CPC Class Codes: Y10T 428/31562 Next to polyamide [nylon, etc.]
• CPC Class Codes: Y10T 428/31565 Next to polyester [polyethylene terephthalate, etc.]
• CPC Class Codes: Y10T 428/31569 Next to natural rubber
• CPC Class Codes: Y10T 428/31587 Hydrocarbon polymer [polyethylene, polybutadiene, etc.]
• CPC Class Codes: Y10T 428/31678 : Of metal

Abstract

A process for the preparation of slippery, hydrophilic polyurethane hydrogel coating compositions, and materials composed of a polymeric plastic or rubber substrate or a metal substrate with a coating of a slippery, hydrophilic polyurethane hydrogel thereon, such that the coating composition tenaciously adheres to the substrate, are disclosed. The coating compositions and coated materials are non-toxic and biocompatible, and are ideally suited for use on medical devices, particularly, catheters, catheter balloons and stents. The coating compositions, coated materials and coated devices demonstrate low coefficients of friction in contact with body fluids, especially blood, as well as a high degree of wear permanence over prolonged use of the device. The hydrogel coating compositions are capable of being dried to facilitate storage of the devices to which they have been applied, and can be instantly reactivated for later use by exposure to water.

Claims

1. A material bearing thereon a coating of a lubricious, hydrated hydrophilic polyurethane-polyurea hydrogel, said material being produced by a process comprising the steps of:

a) making a surface of a hydrophilic or hydrophilicized hydrophobic polymer substrate reactive by affixing reactive chemical functional groups thereto, at least a portion of which are amine-containing groups;

b) coating a reactive polymer substrate surface which results from step (a) with a first coating comprising a hydrophilic polyurethane prepolymer intermediate, containing terminal isocyanate groups, such that at least a portion of said terminal isocyanate groups are reacted with and are covalently bonded to said reactive chemical functional groups on said substrate surface, forming covalent polyurea bonds therewith, resulting in the formation of a tie coat of a polyurethane-polyurea hydrogel-forming polymer, on said substrate surface, that adheres to said substrate surface, and wherein at least a portion of said terminal isocyanate groups of said polyurethane prepolymer intermediate are present in said polyurethane-polyurea hydrogel-forming polymer such that they remain free to react with other species; and

c) coating a tie coat of the first-coated substrate surface which results from step (b) with a second coating comprising a moisture-containing, hydrogel-forming compound or mixture, which contains isocyanate-reactive functional groups, such that a barrier coat of a lubricious, hydrated hydrogel is formed upon the application of said second coating to said tie coat;

wherein said moisture of said hydrogel-forming compound or mixture is bound with said polyurethane-polyurea hydrogel-forming polymer of said tie coat to form a hydrogel of said barrier coat, on said tie coat, such that said hydrogel is a polyurethane-polyurea polymer hydrogel; and

wherein said isocyanate-reactive functional groups of said hydrogel-forming compound or mixture are reacted with and are covalently bonded to at least a portion of said terminal isocyanate groups of said polyurethane-polyurea hydrogel-forming polymer that remain free to react with other species, thereby directly attaching said polyurethane-polyurea polymer hydrogel to said tie coat and thus also indirectly attaching it to said substrate surface.

2. The material according to claim 1 wherein said polymer substrate is a plastic or a rubber.

3. The material according to claim 2 wherein said polymer substrate is selected from the group consisting of thermoplastic polyurethanes (TPU'"'"'s), polyesters, nylon polymers, block copolymers of a polyether polymer and a polyester polymer, and block copolymers of a polyether polymer and a compound selected from the group consisting of polyamides, polyimides, polyolefins, synthetic hydrocarbon elastomers, and natural rubber.

4. The material according to claim 3 wherein said polyester is polyethylene terephthalate (PET).

5. The material according to claim 3 wherein said nylon polymers include nylon-11 and nylon-12.

6. The material according to claim 3 wherein said polyolefins include polyethylenes (PE) and polypropylenes (PP).

7. The material according to claim 3 wherein said polyether polymer is aliphatic and said polyester polymer is aromatic.

8. The material according to claim 1 wherein when said substrate is a polymer, said reactive chemical functional groups are selected from the group consisting of amine-containing groups, hydroxyl groups, carboxyl groups, carbonyl groups, and combinations thereof.

9. The material according to claim 8 wherein said amine-containing groups are selected from the group consisting of amino groups, amido groups, urethane groups, urea groups, and combinations thereof.

10. The material according to claim 1 wherein when said substrate is a hydrophilic polymer or a hydrophilicized hydrophobic polymer, said reactive chemical functional groups are affixed to said surface of said substrate by plasma-treating said substrate with a plasma gas containing said reactive chemical functional groups.

11. The material according to claim 10 wherein when said reactive chemical functional groups are amine-containing groups, said plasma gas is a nitrogen-containing gas selected from the group consisting of ammonia, organic amines, nitrous oxide, nitrogen and combinations thereof.

12. The material according to claim 11 wherein said organic amines include primary and secondary organic amines, and combinations thereof.

13. The material according to claim 12 wherein said organic amines are selected from the group consisting of methylamine, dimethylamine, ethylamine, diethylamine, n-propylamine, allylamine, isopropylamine, n-butylamine, n-butylmethylamine, n-amylamine, n-hexylamine, 2-ethylhexylamine, ethylenediamine, 1,4-butanediamine, 1,6-hexanediamine, cyclohexylamine, N-methylcyclohexylamine, and ethyleneimine.

14. The material according to claim 12 wherein said organic amines are low boiling primary and secondary organic amines having a structure selected from the group (I-IV) consisting of:

##STR2## wherein R₁ and R₂ are monovalent hydrocarbon radicals having from 1 to about 8 carbon atoms;

R₃ is a divalent hydrocarbon radical having from 2 to about 8 carbon atoms; and

R₄ is hydrogen or lower alkyl.

15. The material according to claim 10 wherein a radio frequency of 13.56 MHz, and a generating power of from about 0.1 to about 0.5 watts per square centimeter of plasma apparatus electrode surface, is utilized in said plasma treating of said substrate.

16. The material according to claim 10 wherein said plasma treatment is performed at a pressure of about 10^-2 Torr, at a temperature of up to about 60°

C., at a reactive chemical functional group-containing gas flow rate of from about 50 to about 2000 standard ml./min., and at a reactive chemical functional group-containing gas pressure of from about 0.01 to about 10 torr, for a period of time of at least 30 seconds.

17. The material according to claim 10 wherein said plasma treating of said substrate is performed in a mode selected from the group consisting of batch mode and continuous mode.

18. The material according claim 1 wherein said substrate is pre-treated, prior to making a surface thereof reactive, to clean said substrate.

19. The material according to claim 18 wherein said pre-treatment of said substrate is by a method comprising:

at least one of;

washing said substrate with at least one organic solvent; and

washing said substrate with an aqueous solution of at least one of neutral, anionic and cationic surfactants, and combinations thereof;

followed by washing said substrate with water, and drying.

20. The material according to claim 19 wherein said organic solvent is selected from the group consisting of alcohols, ketones, hydrocarbons, chlorinated hydrocarbons, ethers, petroleum ethers, cleaning spirits, and combinations thereof.

21. The material according to claim 20 wherein said alcohols include methanol, ethanol, and isopropanol;

said ketones include acetone and methylethyl ketone;

said hydrocarbons include pentanes and n-hexane;

said chlorinated hydrocarbons include methylene chloride and 1,1,1-trichlorethane; and

said ethers include diisopropyl ether, dioxane, and tetrahydrofuran.

22. The material according to claim 19 wherein said pre-treatment is performed for a period of time of from about 10 seconds to about 10 minutes.

23. The material according to claim 1 wherein when said substrate is a nonpolar hydrophobic polymer, said surface of said nonpolar hydrophobic polymer substrate is first made polar and hydrophilic before making said surface reactive according to step (a), by affixing reactive chemical functional groups selected from the group consisting of hydroxyl groups, carboxyl groups, carbonyl groups, and combinations thereof, to said surface of said nonpolar hydrophobic polymer substrate.

24. The material according to claim 1 wherein said hydrophilic polyurethane prepolymer intermediate is formed by the reaction of a water-soluble polyether polyol, or copolyether polyol, and an organic polyisocyanate.

25. The material according to claim 24 wherein said organic polyisocyanate is selected from the group consisting of aliphatic, cycloaliphatic, araliphatic, aromatic, and heterocyclic polyisocyanates.

26. The material according to claim 25 wherein said aliphatic, cycloaliphatic, araliphatic, aromatic, or heterocyclic polyisocyanate is a diisocyanate or a derivative thereof.

27. The material according to claim 26 wherein said hydrophilic polyurethane prepolymer intermediate is formed by reacting said polyether polyol or copolyether polyol with an excess of organic polyisocyanate.

28. The material according to claim 24 wherein said reaction which leads to the formation of hydrophilic polyurethane polymer is performed at temperature of up to about 90°

C.

29. The material according to claim 28 wherein the temperature is from about 50°

C. to about 70°

C.

30. The material according to claim 24 wherein the hydrophilic polyurethane polymer formation reaction is performed in a non-aqueous solution containing a total solids content of from about 20% to about 80%, by weight.

31. The material according to claim 30 wherein a non-aqueous solvent of said solution is selected from the group consisting of aromatic hydrocarbons, ketones, ethers, esters, chlorinated alkanes, and mixtures thereof.

32. The material according to claim 31 wherein said aromatic hydrocarbons include benzene, toluene and xylenes;

said ketones include methylethyl ketone;

said ethers include methyl tert. butyl ether, tetrahydrofurane and dioxane;

said esters include methylethoxy acetate, methylisopropoxy acetate, ethyl acetate, butyl acetate, and ethyl formate; and

said chlorinated alkanes include 1,1,1-trichloroethane.

33. The material according to claim 24 performed in the presence of a catalyst to promote reaction between said polyether polyol or said copolyether polyol and said organic polyisocyanate.

34. The material according to claim 33 wherein said catalyst is a tin-containing compound selected from the group consisting of stannous acylates, dialkytin dicarboxylates, and dialkytin oxides.

35. The material according to claim 34 wherein said tin-containing compound is selected from the group consisting of stannous octoate, stannous oleate, dibutyltin dilaurate, dimethyltin dilaurate, and dioctyltin oxide.

36. The material according to claim 34 wherein catalyst is at a concentration of from about 5 ppm to about 300 ppm.

37. The material according to claim 1 wherein said first coating is applied to said reactive surface of said substrate as a first coating solution containing from about 1% to about 25% by weight of prepolymer intermediate solids in a nonaqueous solvent selected from the group consisting of aromatic hydrocarbons, ketones, ethers, tetrahydrofurane, dioxane, esters, chloroalkanes, C₅ and C₆ alkanes, methylene dichloride, acetone and mixtures thereof.

38. The material according to claim 37 wherein said prepolymer intermediate solids are from about 1.5% to about 8%, by weight.

39. The material according to claim 37 wherein said first coating solution is applied to said reactive surface of said substrate by a method selected from the group consisting of dip-coating, continuous coating and spray coating.

40. The material according to claim 37 further comprising removing the solvent from said first coating solution after application of said first coating solution to said substrate.

41. The material according to claim 40 wherein solvent removal is by evaporation thereof.

42. The material according to claim 1 wherein said moisture-containing, hydrogel-forming compound or mixture of said second coating is selected from the group consisting of liquid water, saline solution, water vapor, and a high moisture content air or gas stream.

43. The material according to claim 42 wherein said moisture-containing, hydrogel-forming compound of said second coating is water.

44. The material according to claim 1 wherein said coating of a lubricious, hydrated hydrophilic polyurethane-polyurea polymer hydrogel has a thickness of from about 1 mil to about 5 mils.

45. The material according to claim 1 wherein steps (a) and (b) are completed within a period of time of two months from one another.

46. The material according to claim 1 wherein said process for producing said material further comprises heating said first-coated substrate, bearing said tie coat resulting from said first coating, to a temperature of from about 40°

C. to about 75°

C. to further promote covalent bond formation between terminal isocyanate groups and terminal reactive groups on said substrate surface, before application of said second coating.

47. The material according to claim 1 further comprising a slip additive added to said hydrophilic polyurethane prepolymer intermediate.

48. The material according to claim 1 wherein said hydrogel barrier coat of a hydrophilic polyurethane-polyurea hydrogel has a water content of at least about 70% by weight.

49. The material according to claim 48 wherein said water content is from about 85% to about 90% by weight.

50. The material according to claim 1 wherein the formation of said hydrogel barrier coat in step (c) is performed in the presence of a hydrogel formation promoting catalyst.

51. The material according to claim 50 wherein said hydrogel formation promoting catalyst is a tertiary amine.

52. The material according to claim 51 wherein said tertiary amine is selected from the group consisting of trimethylamine, triethylamine, tripropylamine, and triisopropylamine.

53. The material according to claim 50 wherein said catalyst is in aqueous solution.

54. The material according to claim 53 wherein said aqueous solution contains from about 0.03% to about 0.3% by weight of catalyst.

55. The material according to claim 1 wherein the formation of said hydrogel barrier coat in step (c) is performed in the presence of a compound selected from the group consisting of aliphatic, cycloaliphatic, araliphatic, and heterocyclic diamines, and inorganic diamines, to form a chain-extended hydrogel.

56. The material according to claim 55 wherein said inorganic diamine is selected from the group consisting of hydrazine and substituted hydrazine.

57. The material according to claim 1 wherein the formation of said hydrogel barrier coat in step (c) is performed in the presence of a dual catalytic and chain-extending compound containing an isocyanate reactant group and a catalytic moiety.

58. The material according to claim 57 wherein said dual compound containing an isocyanate reactant group and a catalytic moiety is an organic amine containing a tertiary amine group and at least one of a primary and a secondary amine group.

59. The material according to claim 57 wherein said dual compound is ethylenediamine.

60. The material according to claim 1 wherein the formation of said hydrogel barrier coat in step (c) is performed in the presence of a basic inorganic salt selected from the group consisting of sodium carbonate, sodium bicarbonate, sodium borate, and sodium acetate, to cure said hydrogel.

61. The material according to claim 60 wherein said basic inorganic salt is in an aqueous solution having a salt concentration of from about 0.05% to about 0.2% by weight.

62. The material according to claim 61 further including a step of rinsing the resulting hydrogel coating with water to remove said inorganic salt.

63. A material bearing thereon a dried coating of a hydrophilic polyurethane-urea hydrogel, said material being produced by a process comprising:

performing the steps of the process according to claim 1; and

d) further performing a step of drying said lubricious, hydrated hydrophilic polyurethane-polyurea polymer hydrogel, to form a dried coating thereof.

64. The material according to claim 63 wherein said step of drying said second coating is performed by vacuum evaporation.

65. The material according to claim 64 wherein said vacuum evaporation is performed at a pressure in the range of from about 3 Torr to about 250 Torr.

66. The material according to claim 65 wherein said vacuum evaporation is performed at a temperature in the range of from about 20°

C. to about 60°

C.

67. A material bearing thereon a coating of a lubricious, hydrated hydrophilic, water-containing polyurethane-polyurea hydrogel, wherein said coating is formed by the reactivation of a dried hydrogel coating thereof, said coating being reactivated from a dried state, said material being produced by a process comprising:

performing the steps of the process according to claim 63; and

e) further performing a step of re-exposing said dried hydrogel coating formed in step (d) to an aqueous fluid to reactivate said dried hydrogel coating to a lubricious, hydrated hydrogel coating.

68. The material according to claim 67 wherein said aqueous fluid is selected from the group consisting of liquid water, saline solution, water vapor, and a high moisture content air or gas stream.

69. A sterilized coating of a reactivatable, dried, hydrophilic polyurethane-polyurea hydrogel, on the surface of a medical device fabricated from a polymeric substrate, said sterilized coating being produced by a process comprising:

a) making at least a portion of an outer surface of said polymeric substrate from which said medical device is fabricated, chemically reactive by affixing reactive chemical functional groups thereto;

b) coating the resulting reactive outer surface of said substrate with a first coating comprising a hydrophilic polyurethane-urea prepolymer intermediate, which is capable of forming a polyurethane-polyurea hydrogel-forming polymer, and which contains terminal isocyanate groups, such that at least a portion of said terminal isocyanate groups are reacted with and are covalently bonded to said reactive chemical functional groups on said surface of said substrate, forming covalent polyurea bonds therewith, resulting in the formation of a tie coat of a polyurethane-polyurea hydrogel-forming polymer, that adheres to said reactive outer surface of said substrate, and wherein at least a portion of said terminal isocyanate groups of said polyurethane-urea prepolymer intermediate are present in said polyurethane-polyurea hydrogel-forming polymer, such that they remain free to react with other species;

c) coating said tie coat with a second coating comprising a moisture-containing hydrogel-forming compound, further containing isocyanate-reactive chemical functional groups, such that a barrier coat of a lubricious, hydrated hydrogel is formed upon the application of said second coating to said tie coat of said first coated substrate;

wherein said isocyanate-reactive functional groups of said moisture-containing hydrogel-forming compound are reacted with and are covalently bonded to at least a portion of said terminal isocyanate groups of said polyurethane-polyurea hydrogel-forming polymer that remain free to react with other species, to form a hydrated, hydrophilic polyurethane-polyurea polymer hydrogel, that is directly adhering to said tie coat, and thus also indirectly adhering to said substrate surface;

d) drying said hydrated, hydrophilic polyurethane-polyurea hydrogel coating formed in step (c) to form a dried hydrogel coating thereof; and

e) sterilizing the resulting coated medical device, bearing said dried hydrogel coating of step (d).

70. The material according to claim 69 wherein said step of sterilization is performed by means of exposing said dried hydrogel-coated medical device to gamma-radiation.