CA1109344A

CA1109344A - Coated substrate having a low coefficient of friction hydrophilic coating and a method of making the same

Info

Publication number: CA1109344A
Application number: CA303,351A
Authority: CA
Inventors: Michael J. Micklus; David T. Ou-Yang
Original assignee: Biosearch Medical Products Inc
Current assignee: Biosearch Medical Products Inc
Priority date: 1977-08-08
Filing date: 1978-05-15
Publication date: 1981-09-22
Also published as: NL188740B; AU3856878A; DE2828617A1; IT1109430B; CH634590A5; AR219763A1; CH639675A5; NL7808290A; IT7850558A0; FR2399879B1; AU512679B2; SE441064B; NL188740C; GB1600963A; MX151865A; SE7808442L; BR7805057A; DE2828617C2; FR2399879A1; BE869588A

Abstract

ABSTRACT OF THE DISCLOSURE
A substrate is coated with a polyvinylpyrollidone-polyurethane interpolymer. In the method, a polyisocyanate and a polyurethane in a solvent such as methyl ethyl ketone are applied to a substrate and the solvent evaporated. If the substrate is a polyurethane, only the polyisocyanate need be employed. Polyvinylpyrollidone in a solvent is then applied to the treated substrate and the solvent evaporated The invention is applied, for example, to a tube such as a catheter, a condom and a peristaltic pump tube.

Description

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For numerous applications such as contact lenses, catheters, peristaltic pump chamber6, condoms, lmplant materials, arteriovenous shunts, gastroenteric feed tubes and endotracheal tubes it is desired to have a material such as a polyurethane, acrylic polyester, or a vinyl resin or a rubber having a much lower coefficient of riction wllen wet than is possible with those materials per se. In the prior art polyvinylpyrollidone has been chemically grafted to a polymer substrate by irst activating the sub~trate by irradiation or chemically. The resultant coating does not have a very low coefficient of friction. Polyurethane coatings are well lcnown, but do not have a very low coeficient of friction. Heretofore, polymer subs~rates have been given a lower coefficient o riction by coating them with a non-permanent coating such as silicone or given a fluorocarbon coating neither of which is hydrophilic and which do not have as low a coefficient of friction as desired. Also fluorocarbon coatings are hard to handle because they have a low coeficient o riction at all times.
These problems have been solved surprisingly by this invention by providing a coating o polyvinylpyrollidone-polyurethane interpolymer. The hydrophilic coatings of this invention are advantageous since they have a very low coeficient of friction when wetted with a water base liquid or a lower aliphatic alcohol such as methanol or ethanol and yet are much less slippery when dry. This is an advantage, for example, in the handling of catheters since it is desirable to have them not slippery for handling but protecting the patlent by becoming slippery when contacting an aqueous fluid. This is an important advantage of the invention in view of the high degree of lubricity of the coatings. Further, the coating thickness is not limited to a few molecular monolayers as in the case of other methods such as chemlcal or radiation grafting and may be applied in thicknesses of several hundred micrometers. In addition the coatings are non-reactive with respect to living tissue and are non-thrombogenlc when in contact with blood. For each of these reasons, the product and method of the invention are unique and of great value.
The invention comprises a substrate, for example a tube, coated with a polyvinylpyrollidone-polyurethane interpolymer and the method of making the same by applying a polyisocyanate and usually a polyurethane in a solvent and then applying a polyvinylpyrollidone ln a solvent to form a polyvinylpyrollidone-polyurethane interpolymer.
The invention comprises a substrate coated with a polyvinylpyrollidone-polyurethane interpolymer. Any polyurethane may be used.
While the substrate may be any material to which conventional polyurethane coatings adhere, it i~ preferred to use polymer substrates such as a polyurethane resin, a vinyl resin such as polyvinylchloride, a polyacrylate such as polymethyl-methacrylate, a polycarbona~e, a polyester such as polyethylene terephthalate, polybutylene terephthalate, polytetramethylene terephthalate, or a rubber such as latex rubber or polyisoprene.
The method of the invention comprises applying a polyisocyanate and a polyurethane in a solvent to the surface of the substrate to be coated with the interpol~Jmer by dipping, spraying or the like and then evaporating the solvent preferably by air drying. This step forms a polyurethane coating with unreacted isocyanate groups on the substrate. Exemplary of the polyisocyanate are polymethylenepolyphenyl isocyanate, '~ f"D~

4,4'-diphenylmethane diisocyanate and position iso~ers thereof,

2,4-tolylene diisocyanate and position isomerQ thereof,

3,4-dichlorophenyl diisocyanate and isoferrone isocyanate.
Adducts or prepolymers of isocyanates and polyols such as the adduct of trimethylolpropane and diphenylmethane diisocyanate or tolylene diisocyanate are suitable. For further examples Technology, H.F. Mark, ~.G. Gaylord and N.M. sikales (eds.), (1969). Exemplary of the polyurethane is the reaction product of 2~4-tolylene diisocyanate 10 polyurethane is the reaction product of 2,~-tolylene diisocyanate and position isomers thereof, 4,4'-diphenylmethane diisocyanate and position isomers thereof, polymethylenepolyphenyl isocyanate, or 1,5-napthylene diisocyanate with 1,2-polypropylene glycol, polytetramethylene ether glycol, 1,4-butanediol, 1,4-butylene glycol, 1,3-butylene glycol, poly(l,4-oxybutylene) glycol, caprolactone, adipic acid esters, phthalic anhydride, ethylene glycol, 1,3-butylene glycol, 1,4-butylene glycol or diethylene glycol. (For further examples see Encyclopedia of Polymer Science and Technolo~ cited above). Chain extenders with 20 hydrogen-containing difunctional compounds such as ~ater, diamines, or amino acids may be used. Chain extenders are exemplified by 1,4-butanediol, hexamethylene diamine,

4,4-methylene-bis~2-chloroaniline3 (MOCA), trimethylolpropane, and e~hanolamine. Other additives include accelerators, catalysts, stabilizers, plasticizers, or the like which improve or modify ~he properties of the urethane. Exemplary are dicumyl peroxide, benzothiazyldisulfide, mercapto benzothiazole, benzothiazole disulfide, polypropylene adipate, and metal salts such as potassium acetate, cobalt naphthenate, and zinc chloride.
The solvent is one which will no~ reac~ with the isocyanate, i.e. lt should b~ ree o reactive amino, hydroxyl and carboxyl groups. Preferred solvents are dichlorornethane, methyl ethyl ketone, acetone, ethyl lactate, chloroform, trichloroethylene and ethyl acetate. The hydroxyl of the ethyl lactate is not suficiently reactive to be detrimental Preferred polyurethanes are polytetramethylene ether glycol-diphenylmethane diisocyanate (~I), polytetramethylene ether glycol-tolylene diisocyanate (TDI), polytetramethylene ether glycol-isoferrone isocyanate, poly(l,4-oxybutylene) glycol-diphenylmethane diisocyanate (MDI), poly(l,4-oxybutylene) glycol-tolylene diisocyanate (TDI), poly(l,~-oxybutylene) glycol-isoferrone isocyanate, polyethylene glycol-diphenylmethane diisocyanate (MDI), polyethylene glycol-tolylene diisocyanate (TDI), polyethylene glycol-isoferrone isocyanate, polypropylene glycol-diphenylmethane diisocyanate (MDI), polypropylene glycol~tolylene diisocyanate (TDI), polypropylene glycol-isoferrone isocyanate, polycaprolactone-diphenylmethane diisocyanate (~I), polycapro-lactone-tolylene diisocyanate (TDI), polycaprolactone-isoferrone isocyanate, polyethylene adipate-diphenylmethane diisocyanate (MDI), polyethylene adipa~e~tolylene diisocyanate (TDI), poly-ethylene adipate-isoferrone isocyanate, polytetramethylene adipate-diphenylmethane diisocyanate (~I), polytetramethylene adipate-tolylene diisocyanate (TDI), polytetramethylene adipate-isoferrone isocyanate, polyethylene-propylene adipate-diphenyl-methane dlisocyanate tMDI), polyethylene-propylene adipate-tolylene diisocyanate (TDI), and polyethylene-propylene adipate-isoferrone isocyanate polyurethanes.
Advantageously the polyisocyanate in the solution will be from about 0.4% to about 5% (weight to volume - W/V), preferably from about 0.4% to about 3% (W/V) and the polyurethane advantageously will be rom about 0.3% to about 10% (weight to volume), preferably from about 0.3% to about ~/O (W/V).
While the substrate generally need be in contact with theolution only briefly, for example 1 to 4 minutes, ln the case of a rubber latex substrate a longer period of from about 15 to 120 minutes or more is desirable to achieve firm adherence of the final interpolymer coating to the rubber latex. Also with a rubber latex substrate a pretreatment step of soaking the rubber latex in a suitable solvent such as a chlorinated hydrocarbon solvent, for example, me~hylene chloride, chloroform, l,l,l-trichloroethane, and ethylene chlorlde, or example from 15 to 120 minutes or more, to swell the rubber i9 advantageoug.
The thus treated substrate is then coated with poly-vinylpyrollidone in a solvent to form a polyvinylpyrollidone-polyurethane interpolymer. The polyvinylpyrollidone advantageously has an average molecular weight of at least 120,000 with the preferred average molecular weight being about 360,000. Exemplary of suitable solvents are chloroform, trichlorethylene, ethylene dichloride, methylene chloride and ethyl lactate. The solvent selected will be unreactive with the substrate. The polyvinyl-pyrollidone in the solution advantageously will be from about 0.5% to about 10% and preferably from about 1% to about 4%
(weight to volume). While more than 10% of polyvinylpyrollidone can be used, no advantage ls gained. The polyvinylpyrollidone in the solvent is applied by dipping, straying or the like for a short period, for example rom about 1 to 4 minutes. After the polyvinylpyrollidone solution has been applied to the coated substrate, the solvent is evaporated preferably by air drying.
Advantageously the residual traces of solvent are removed by subjecting the coated substrate to a temperature of from about ~ 3~ ~

50~ to about 100C., for example, ln an oven. There remains a polyvinylpyrollidone-polyurethane interpolymer coating ~ilm on the substrate which when wet has an extremely low coefficlent of friction and is hydrophilic.
If ~he substrate is of polyurethane, then ~he polyur~thane in the solution may be eliminated and only the polyisocyana~e need be used while carrying out the first step of the above described method.
All steps are carried out at room temperature except where otherwise specifled.
The following Examples more specifically illustrate the invention:

(1) A clean rubber latex urinary catheter is placed in dichloromethane and allowed to swell for 1 hour.
(2) The catheter is removed from the dichloromethane and dipped immediately into a methyl ethyl ke~one solution containing 2% (weight/volume) o equal weights of a 32% (weight/volume) solution of polycaprolactone-tolylene diisocyanate polyurethane in ethyl acetate (commercially available from Hughson Corporation B as Chemlockl~7000) and a 40% (weight/volume) solution of the adduct of trimethylolpropane-diphenylmethane diisocyanate in methyl ethyl ketone (Chemlock 7200). The catheter is allowed to remain in the solution or l hour.
(3) The catheter is removed and air dried for 3 minutes.
(4) Step 2 is repeated but only for 4 seconds.

(5) Step 3 is repeated.

(6) Steps 4 and 3 are repeated.

(7) The catheter is dipped into a 4% solution (weight to volume) of polyvinylpyrollidone (M,W. 360,000) dissolved in ~ T~ k .' - ~f~"~

ethyl lactate for 5 seconds.

(8) The catheter is removed and air dried. The dry catheter is cured in an oven at 65C. for 6 hours,

(9) The catheter is removed from the oven.
All steps carrled out at room temperature except where specifically stated otherwise.
E ~ ~LE 2 (1) A peristaltic pump tube of polytetramet~ylene ether glycol-diphenylmethane diisocyanate ~MDI)-polyurethane (available as Royla~E85 rom Uniroyal Chemical, Divlsion of Uniroyal, Inc., Maugatuck, Connecticut) is dipped into a 1% solution ~weight/
volume) of diphenylmethane diisocyanate (MDI), (available from Upjohn as Isonate 143 L) in methyl ethyl ketone for 1 minute.
(2) The polyurethane tubing is removed and air dried until the MEK solvent evaporates, (3) The polyurethane tubing is dipped into a 3% (W/V) solution o polyvinylpyrollidone in chloroorm for 1 minute.
(4~ The tubing i5 air dried and then oven cured for l hour at 75C.
All steps carried out at room tempera~ure ~mless specifically stated otherwise.
Figure 1 is a plan view of a condom in accordance with the invention;
Figure 2 is a fragmentary view of the condom of Figure l;
Figure 3 is a modified condom in accordance with the invention;
Figure 4 is a fragmentary view of the condom of Figure 3;
Figure 5 is a modified condom in accordance with the invention;
Figure 6 is a fragmentary view of the condom of Figur~ 5;
~ T~

~ 3.~3~

Figure 7 i8 a plan view oE a cardiovascular ca~heter partially broken away;
Figure 8 is a plan v-iew of a peristaltic pump tube partially broken away; and Figure 9 is a plan view of a urethral catheter partially broken away.
A condom 2 in accordance with the -Lnvention is shown in Figure 1. As best seen in Figure 2, condom 2 has a base material or substrate 4 of polyisoprene the exterior of which i6 coated with a coating 8 of polyvinylpyrollidone-polyurethane interpolymer.
The base material is secured to the conventional rubber band 10 at the inner end of condom 2.
A condom 12 shown in Figure 13 has, as best seen in Figure ~, a base material or subs~rate 1~ of polyurethane provided with an outer layer of polyvinylpyrollidone-polyurethane inter-polymer 16.
The condom 20 shown in Figure 5 has, as best seen in Figure 6, a base layer or substrate 22 of rubber latex to which is secured a film 26 of polyvinylpyrollidone-polyurethane inter-polymer.
As shown in Figure 7, a cardiovascular catheter 30 isformed from a tubular member 32 of polyvinylchloride having a reduced tip end 34 coa~ed with a layer 36 of polyvinylpyrollidone interpolymer.
As shown in Figure 8 a peristaltic pump tube 40 of polyvinylchloride is coated with a layer 42 of polyvinylpyrollidone-polyurethane interpolymer.
Aæ shown in Figure 9, a urethral catheter 46 has a tip 48, a balloon portion 50, a drain connector 54 and a valve branch 56 formed from a branched tu~e 58 of rubber latex coated with a ~ O~l.r~

polyvinylpyrollidone-polyurethane interpolymer 60. An in~lation valve 62 is secured to valve branch 56.
It will be understood ~hat the above de~cribed embodi-ments are illustrative and are not in.tended to be limiting,

Claims

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:

1. The method of placing on a substrate a hydrophilic coating which has a low coefficient of friction when wetted with a water based liquid comprising:
applying to the substrate a solution having from about 0.4% to about 5% (weight to volume) polyisocyanate and from about 0.3% to about 10% (weight to volume) polyurethane, evaporating the solvent, applying a solution having about 0.5% to about 10% (weight to volume) polyvinylpyrollidone to the thus treated substrate and then evaporating the solvent of the last mentioned solution to form a polyvinyl pyrollidone-polyurethane interpolymer.

2. The method in accordance with claim 1 in which the substrate is a polyurethane resin.

3. The method of claim 1 in which the polyiscoyanate and polyurethane are in solution in methyl ethyl ketone.

4. The method of claim 1 in which the polyvinyl-pyrollidone is in solution in ethyl lacate.

5. The method of claim 1 in which the polyvinyl-pyrollidone is in solution in chloroform.

6. The method of claim 1 in which the polyisocyanate is from about 0.4% to about 3% and the polyurethane is from about 0.3% to about 4% (weight to volume) of first mentioned solution and the polyvinylpyrollidone is from about 1% to about 4% (weight to volume) of the second mentioned solution.

7. The method of placing on a polyurethane substrate a hydrophilic coating which has a low coefficient of friction when wetted with a water based liquid comprising:
applying to the substrate a solution having from about 0.4% to about 5% (weight to volume) polyisocyanate, evaporating the solvent, applying a solution having from about 0.5% to about 10%

(weight to volume) polyvinylpyrollidone to the thus treated substrate and then evaporating the solvent to form a polyvinyl-pyrollidone polyurethane interpolymer.

8. The method of claim 7 in which the polyisocyanate is from about 0.4% to about 3% (weight to volume) of the first mentioned solution and the polyvinylpyrollidone is from about 1% to about 4% (weight to volume) of the second mentioned solution.

9. An article having a very low coefficient of friction when wetting with a water base liquid or a lower aliphatic alcohol comprising:
a substrate to which conventional polyurethanes adhere, and a cured polyvinylpyrollidone-polyurethane interpolymer coating on said substrate.

10. An article in accordance with claim 9 in which the substrate is of polyurethane.

11. An article in accordance with claim 9 in which the substrate is of a material other than polyurethane coated with a film of polyurethane.

12. An article in accordance with claim 9 having a polyvinylchloride substrate.

13. An article in accordance with claim 9 having a rubber latex substrate.

14. An article in accordance with claim 9 having a polyisoprene substrate.

15. An article in accordance with claim 9 having a polyester resin substrate.

16. A condom having a base material of polyurethane, and a cured coating of a polyvinylpyrollidone-polyurethane interpolymer on the outside of said base material wherein said coated condom has a very low coefficient of friction when wetted with a water base liquid or a lower aliphatic alcohol.

17. A resilient tube to which conventional polyurethanes adhere coated with a cured polyvinylpyrollidonepolyurethane interpolymer to provide the tube with a surface having a very low coefficient of friction when wetted with a water base liquid.

18. A device in accordance with claim 9 in which the tube is of rubber latex.

19. A catheter having a tubular body to which conventional polyurethanes adhere, and a cured coating of polyvinyl-pyrollidone-polyurethane interpolymer on the outside of said body providing the outer surface of said body with a coating having a very low coefficient of friction when wetted with a water base liquid or a lower aliphatic alcohol.

20. The method of placing on a substrate a hydrophilic coating which has a low coefficient of friction when wetted with a water based liquid, comprising:
applying, in the case where there is a non-polyurethane substrate, a solution having from about 0.4% to about 5% (weight to volume) polyisocyanate and from about 0.3%
to about 10% (weight to volume) polyurethane or, in the case where the substrate is of polyurethane, applying thereto a solution having from 0.4% to about 5% (weight to volume) polyisocyanate;
evaporating the solvent, and applying a solution having about 0.5% to about 10% (weight to volume) polyvinylpyrollidone to the thus treated substrate and then evaporating the solvent of the last mentioned solution to form a polyvinyl pyrollidone-polyurethane interpolymer.