COATED AND VARNISHED MEMBRANE COMPRISING SILVER, METHOD FOR THE PRODUCTION THEREOF AND USE THEREOF AS A VIRUCIDE

Abstract

A coated and varnished membrane, the membrane including at least one fabric having at least one side coated with at least one layer of polyvinyl chloride, and at least one varnish film on the coated side of the membrane, the varnish film including a polymeric binder and silver in the form of a silver element less than 250 nm in size. A process for manufacturing a membrane according to the invention. A use of a membrane as a virucide.

Claims

1. A coated and varnished membrane, said membrane comprising at least one fabric having at least one side coated with at least one layer of polyvinyl chloride, and at least one varnish film on said coated side of the membrane, said varnish film comprising a polymeric binder and silver in a form of a silver element less than 250 nm in size, said membrane being such that the varnish film has an average thickness comprised in a range of 0.5 to 20 μm and that a mass content of the silver in the varnish film is in a range of 0.00001 to 3%.

2. The membrane according to claim 1, wherein the fabric is selected from wovens, nonwovens, gris, knits, and mixtures thereof.

3. The membrane according to claim 1, wherein the fabric is made from textile material and comprises yarns or fibers made from a material selected from the group comprising glass, polyesters, polyamides, polyacrylates, viscoses, nylons, cottons and polyvinyl acetates, polyvinyl alcohols, and mixtures thereof.

4. The membrane according to claim 1, wherein the layer of polyvinyl chloride comprises polyvinyl chloride, at least one plasticizer and at least one heat stabilizer.

5. The membrane according to claim 1, wherein the average thickness of the varnish film is in a range of 1 to 12 μm.

6. The membrane according to claim 1, wherein the mass content of the silver in the varnish film is in the range of 0.0005 to 2%.

7. The membrane according to claim 1, wherein the polymeric binder is selected from the group comprising polyester polyurethanes, polyether polyurethanes, polycarbonate polyurethanes, silicone-modified polyurethanes, acrylics, acrylates, acrylate copolymers, acrylic copolymers, acrylic styrenes and ethylene vinyl acetates and mixtures thereof.

8. The membrane according to claim 1, wherein the varnish film further comprises at least one additive such as an adhesion promoter; a spreading agent; an anti-foaming agent; and a slip agent.

9. A process for manufacturing a membrane according to claim 1, comprising the following steps: (a) providing a coated membrane comprising the at least one fabric coated on at least one side with the at least one layer of polyvinyl chloride; (b) providing a varnish comprising an aqueous medium, at least one polymeric binder, and silver; (c) depositing on the coated side from step (a) a film of the varnish from step (b), to a thickness in a range of 0.5 to 20 μm; and (d) drying the varnish film from step (c), leading to a production of the coated and varnished membrane.

10. The process according to claim 9, wherein the silver is present in the varnish in a form of a dispersion of colloidal silver of particles of nanometric size less than 250 nm.

11. The process according to claim 9, wherein the silver is present in the varnish in a form of Ag.sup.+ ions solubilized in the varnish.

12. The membrane according to claim 1, said membrane being configured for use as a virucide.

13. The membrane according to claim 1, wherein the average thickness of the varnish film is in a range of 2 to 10 μm.

14. The membrane according to claim 1, wherein the mass content of silver in the varnish film is in a range of 0.001 to 1%.

15. The process according to claim 9, wherein the silver is present in the varnish in a form of a dispersion of colloidal silver of particles of nanometric size less than 150 nm.

16. The process according to claim 9, wherein the silver is present in the varnish in a form of a dispersion of colloidal silver of particles of nanometric size less than 100 nm.

17. The process according to claim 9, wherein the silver is present in the varnish in a form of soluble complexes.

18. The process according to claim 9, wherein the silver is present in the varnish in a form of complexes soluble in water selected from the group comprising silver nitrates AgNO.sub.3, and silver chlorides AgCl, and mixtures thereof.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0082] The way to implement the invention, as well as the advantages which result therefrom, emerge from the following description of the embodiments, in support of the appended FIGS. 1 to 4 in which:

[0083] FIG. 1 is a schematic sectional view of a first embodiment of the membrane of the invention.

[0084] FIG. 2 is an enlargement of FIG. 1.

[0085] FIG. 3 is a schematic sectional view of a second embodiment of the membrane of the invention.

[0086] FIG. 4 is an enlargement of FIG. 3.

[0087] Obviously, the dimensions and proportions of the elements illustrated in FIGS. 1 to 4 may have been exaggerated in relation to reality, and were given only for the purpose of making it easier to understand the invention.

DETAILED DESCRIPTION OF THE INVENTION

[0088] The coated and varnished membrane 1 of FIG. 1 comprises a core or textile reinforcement 2 consisting of a weaving in high tenacity polyethylene yarns, formed of warp yarns 22 intersecting with weft yarns 21 and 23. The woven core 2 was coated on both sides, 31 and 32, respectively, with a layer of PVC. According to the invention, two films of varnish, 41 and 42, respectively, were deposited on each coated side, the film 42 being enlarged in FIG. 2. The film 42 comprises silver 4, dispersed within the film 42.

[0089] The coated and varnished membrane 10 of FIG. 3 comprises the same core or textile reinforcement 2. The woven core 2 was coated on both sides with two successive layers of PVC, 34 then 36, respectively, on one side, and 33 then 35 on the other side. According to the invention, two films of varnish, 44 and 43, respectively, were deposited on each coated side, the film 43 being enlarged in FIG. 4. The film 43 comprises silver 40 of nanometric size, dispersed within the film 43.

EXAMPLES

[0090] Different tests were carried out on a same membrane coated with the same varnish film. To that end, an aqueous-phase varnish was deposited on a coated side of a membrane made from high tenacity polyester fabric coated with PVC on each side.

[0091] The silver used was a colloidal dispersion, the commercial product Viroblock® NR103 from HEIQ.

[0092] The varnish was manufactured 48 hours before its use and stored at a temperature above 5° C.

[0093] The varnish had the following composition (in parts by weight): [0094] Binder: 63; Rolflex® C1 which is a cationic polyurethane polyester from Lamberti [0095] Adhesion promoter: 1; Deolink® TE 100 which is a 3-(2,3-Epoxypropoxy)propyl]-triethoxysilane from DOG [0096] Spreading agent: 1; TEGO Glide® 482 which is a dimethylpolysiloxane from TEGO Evonik [0097] Antifoaming agent: 0.5; Bye 022 which is a polysiloxane from BYK [0098] Slip agent: 0.1; TEGO Glide® 440 which is a siloxane and polyether copolymer from TEGO Evonik [0099] Silver particles: 34.3; Viroblock® from HEIQ (6% dry extract in the film)

[0100] The preparation of the varnish was carried out as follows:

[0101] Stirring with a butterfly-shaped blade at low speed: 100-300 rpm;

[0102] Depositing the varnish by squeegee on a mat on the plastisol described above

[0103] Progressive drying with a temperature ramp of 110° C., then 130° C., then 150° C.; then Calendering at 150° C.

[0104] The thickness of the varnish once dried was on average 5 to 7 μm. It was checked by optical measurement on a microtome section of the slice of the membrane.

[0105] Action Test Against Viruses

[0106] Preliminary trials carried out to verify the feasibility of the test: [0107] cell cytotoxicity indicator [0108] membrane residual activity indicator

[0109] Controls made during the tests: [0110] cell cytotoxicity indicator [0111] membrane residual activity indicator [0112] positive controls on 304 stainless steel disc

[0113] The virological analyzes are carried out by determining the infectious titers on MRCS cells (ATCC CCL-171) in limiting dilution. Cytopathogenic effects (CPE) readings are taken after 6 days of incubation at 37° C. and 5% CO.sub.2.

[0114] The test was carried out compared to a reference coated membrane, i.e., a membrane that did not contain silver.

[0115] The human coronavirus HCoV-229E, which is part of the enveloped alpha coronas virus family, was used in the test.

[0116] The contact time between the membrane (comparative or according to the invention) and the solution containing the virus is 60 min.

[0117] Two environmental conditions were tested: [0118] Cleanliness condition standardized in medical field: 0.3 g/l BSA [0119] Complex interference condition: saliva and respiratory mucus.

[0120] 50 to 100 μL of solution comprising the virus was deposited and the quantity of virus deposited was 10.sup.5 TCID50 (for 50% Tissue Culture Infectious Dose: titer required to cause infection in 50% of the inoculated cell cultures).

[0121] By comparison with the comparative membrane (without silver), the results were, for the coated and varnished membrane according to the invention, a reduction in the viral load of 99.9% at 60 min of contact, whether for the virus alone or for the virus with mucus and saliva.

[0122] Compliance was established for a value strictly greater than 90% after 1 hour of contact without mucus or saliva. Consequently, the tests demonstrated the antiviral function of the membrane according to the invention.

[0123] Test Demonstrating Weldability

[0124] Tests were carried out on an industrial high-frequency bench to verify that the varnish film did not prevent the fusion of two layers of PVC and did not interfere with their interpenetration during the welding of two membranes according to the invention. After this assembly by high frequency, the force required to open the weld was measured, according to the protocol described in the EN 15619 standard Appendix C.

[0125] The resulting value had to be equal to, or greater than, the value stated in the product datasheet, which is 9 daN over a width of 5 cm. The values measured were 11 daN/5 cm for the coated and varnished membrane according to the invention, against 10 daN/5 cm for the comparative membrane, thus validating the test for the two membranes.

[0126] Varnish Adhesion Test on the Coated Membrane

[0127] To check the good adhesion of the varnish film on the coated membrane, an ISO 5981 standard scrub fluxmeter test was carried out. This test applies strong movements to the membrane, capable of causing the varnish to peel off if the adhesion is too weak. After 2000 cycles of movement, scotch tape was applied to the coated and varnished membrane to verify that the varnish did not come off: the varnish remained on the membrane and did not come off at the same time as the tape. Adhesion was thus considered to be compliant for the membrane according to the invention, as well as for the comparative membrane.

[0128] Cleanability Tests of the Coated and Varnished Membrane According to the Invention.

[0129] The resistance to betadine and eosin stains of a coated and varnished membrane according to the invention was tested in accordance with the following procedure: [0130] measuring the initial color of the fabric and recording it [0131] taking a non-woven wipe as used in hospitals [0132] impregnating it with betadine or eosin and rubbing it on the fabric. Leaving to “dry” for 10 min. [0133] wiping with a clean dry wipe [0134] measuring the Delta E (CMC) which quantifies the color evolution on the 2 types of stains [0135] cleaning with high surface disinfectant detergent Anios (didecyldimethylammonium chloride and polyhexamethylene biguanide hydrochloride). [0136] remeasuring the Delta E (CMC) after cleaning [0137] if Delta E (CMC) <2 excellent cleaning [0138] if Delta E (CMC) <5 good cleaning [0139] if Delta E (CMC) <7 average cleaning [0140] if Delta E (CMC) >7 poor cleaning

[0141] The membrane according to the invention made it possible to obtain results qualifying the cleaning as good, whether for betadine or for eosin.

[0142] Comparative Test Results

TABLE-US-00001 Weldability Coating % Ag Anti- (greater resistance in the viral Varnish than 6 daN/ to varnish action adhesion 5 cm) cleaning Comparative   0% None OK 10 daN/5 cm Good membrane Membrane 0.01% >90% OK 11 daN/5 cm Good according reduction to the after 60 invention min of contact “NOK” means that the test is not considered conclusive and OK means that the test is considered conclusive: the coated and varnished membrane according to the invention is compliant: the property was validated.

[0143] In conclusion, it was demonstrated that the coated and varnished membrane according to the invention has an antiviral action while retaining the desired properties of varnish adhesion, weldability and resistance to cleaning.