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 face coated with at least one layer of polyvinyl chloride, and at least one varnish film on the coated face of the membrane, the varnish film including a polymeric binder and a mineral matrix in powder form including silver particles. A method for producing a membrane according to the invention. A use of a membrane according to the invention as a virucide.

Claims

1. A coated and varnished membrane, said membrane comprising at least one fabric having at least one face coated with at least one layer of polyvinyl chloride, and at least one varnish film on said coated face of the membrane, said varnish film comprising a polymeric binder and a mineral matrix in powder form comprising silver.

2. The membrane according to claim 1, wherein the fabric is selected from wovens, nonwovens, grids, 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, 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 varnish film has an average thickness in range of 0.5 to 20 μm.

6. The membrane according to claim 1, wherein a mass content of the silver in the varnish film is in a range of 0.01 to 5%.

7. The membrane according to claim 1, wherein matrix particles comprising the silver have a size strictly less than 20 μm.

8. The membrane according to claim 1, wherein the polymeric binder comprises an acrylic or methacrylic (co)polymer or a polyurethane.

9. The membrane according to claim 1, wherein the varnish film further comprises at least one co-binder selected from the group comprising fluorinated (co)polymers and homopolymer and copolymer PVC resins.

10. The membrane according to claim 1, wherein the varnish film further comprises at least one additional additive selected from UV stabilizers, matting agents, heat stabilizers, and pigments.

11. A method 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 the at least one face with the at least one layer of polyvinyl chloride; (b) providing a varnish comprising at least one solvent, at least one polymeric binder, and at least one mineral matrix in the form of a powder comprising the silver; (c) depositing, on the coated face of 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), resulting in obtaining the coated and varnished membrane.

12. The method according to claim 11, wherein the solvent is selected from the group comprising ketones, alcohols, cyclic alcohols, acetates, ketone alcohols, cyclic ethers, aromatic solvents, hydrocarbon solvents, and mixtures thereof.

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

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

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

16. The membrane according to claim 1, wherein a mass content of the silver in the varnish film is in a range of 0.05 to 3% by weight.

17. The membrane according to claim 1, wherein a mass content of the silver in the varnish film is in a range of 0.05 to 2% by weight.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0078] 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 5 in which:

[0079] FIG. 1 is a schematic sectional view of a first embodiment of the membrane of the invention.

[0080] FIG. 2 is an enlargement of FIG. 1.

[0081] FIG. 3 is a schematic sectional view of a second embodiment of the membrane of the invention.

[0082] FIG. 4 is an enlargement of FIG. 3.

[0083] FIG. 5 is a photograph taken by transmission electron microscopy (TEM) of powder particles according to the invention. It shows the micrometric dimension of such particles.

[0084] 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

[0085] The coated and varnished membrane 1 of FIG. 1 comprising a core or textile reinforcement 2 consisting of a weave of high tenacity polyester yarns, formed of warp yarns 22 intersecting with weft yarns 21 and 23. The woven core 2 was coated on both faces, respectively 31 and 32, with a layer of PVC. According to the invention, two films of varnish, respectively 41 and 42, were deposited on each coated face, the film 42 being enlarged in FIG. 2. The film 42 comprises a matrix in the form of a powder 4 comprising silver, said powder being dispersed within the film 42.

[0086] 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 faces with two successive layers of PVC, respectively 34 then 36, on one face, and 33 then 35 on the other face. According to the invention, two films of varnish, 44 and 43 respectively, were deposited on each coated face, the film 43 being enlarged in FIG. 4. The film 43 comprises a matrix in the form of a powder 40 comprising silver, said powder being dispersed within the film 43.

EXAMPLES

[0087] Different tests were carried out on the same membrane coated with the same varnish film. To that end, a solvent-borne varnish was deposited on one face covered with a membrane made from high tenacity polyester fabric coated with PVC on each face.

[0088] The matrix comprising silver particles that was used was Sanitized® BCA 2141, phosphate glass from Sanitized, photographed by TEM in FIG. 5.

[0089] The varnish was manufactured 48 hours before its use and stored at a temperature above 5° C.

[0090] The varnish had the following composition (in parts by weight):

[0091] Composition of the solvent-based varnish (by weight)

[0092] The starting varnish is a commercial product, varnish Rowakryl® G34902 (dry extract 15.5%), from Rowa, at 99.15% by weight, to which 0.85% by weight of Sanitized® BCA2141 was added.

[0093] The final dry extract of the varnish was 16.25%.

[0094] The varnish includes the following components:

[0095] Ketone solvent: Methyl ethyl ketone

[0096] Ester solvent: Methoxypropyl acetate

[0097] Polymer binder: Polymethyl methacrylate

[0098] Polymer co-binder: PVC (homopolymer)

[0099] Ca/Zn heat stabilizer.

[0100] The thickness of the varnish once dried was on average 6.5 μm. It was checked by optical measurement on a microtome section of the slice of the membrane.

[0101] The matrix content in the varnish (dry extract) was 5.2%, the silver content in the matrix was 1.8%. Therefore, the silver content of the dry varnish was 0.09%.

[0102] All the tests were also carried out on a comparative coated and varnished membrane, i.e., a membrane prepared with the varnish Rowakryl® G34902 without silver, its formula being identical to the coated and varnished membrane according to the invention, except for the presence of silver.

[0103] Efficacy Test Against Viruses

[0104] Preliminary trials carried out to verify the feasibility of the test: [0105] cell cytotoxicity indicator [0106] membrane residual activity indicator

[0107] Controls made during the tests: [0108] cell cytotoxicity indicator [0109] membrane residual activity indicator [0110] positive controls on 304 stainless steel disc

[0111] The virological analyzes are carried out by determining the infectious titers on MRC5 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.

[0112] The test was carried out compared to a reference coated membrane, i.e., a membrane that did not contain silver.

[0113] The human coronavirus HCoV-229E, which is part of the enveloped alpha coronavirus family, was used in the test.

[0114] The contact time between the membrane (comparative or according to the invention) and the solution containing the virus is 60 min.

[0115] Two environmental conditions were tested: [0116] Cleanliness condition standardized in medical field: 0.3 g/l BSA [0117] Complex interference condition: saliva and respiratory mucus.

[0118] The solution comprising the virus was deposited in an amount of 50 to 100 μL and the amount 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).

[0119] The results for the coated and varnished membrane according to the invention compared to the comparative membrane (without silver) was a reduction of 99.78% in the viral load at 60 min, for the virus alone, and a 99.46% reduction in viral load at 60 min, for the virus with mucus and saliva.

[0120] Conformity was established for a value strictly greater than 90% after 1 hour of contact. Consequently, the tests demonstrated the antiviral function of the membrane according to the invention.

[0121] Test Demonstrating Weldability

[0122] Tests were carried out on an industrial high-frequency bench to verify that the varnish film did not form a barrier to 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.

[0123] The value found had to be equal to, or greater than, the value stated in the product datasheet, which is 6 daN over a width of 5 cm. The values measured were 7.9 daN/5 cm for the coated and varnished membrane according to the invention, against 7 daN/5 cm for the comparative membrane, which, therefore, validated the test for the two membranes.

[0124] Test Demonstrating Non-Irritation of the Skin

[0125] Tests were carried out according to the protocol described in the OEC TG 439 standard (In vitro skin irritation: reconstructed human epidermis test method. June 2019) to verify that the varnish film was not irritating when in contact with the skin.

[0126] Skin irritation was assessed after 35 min of exposure followed by 25 min of exposure at room temperature, cleaning of the product and 42 hours of post-exposure incubation. The viability of EpiDerm™ tissue was measured via the enzymatic conversion of the vital dye MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide, CAS No. 298-93-1) in comparison with tissues treated with a negative control substance (% viability). According to the MTT results (100%) and the predictive model, the product was classified (UN GHS classification) as “non-irritating to the skin”.

[0127] Virucidal Efficacy Test After Wear of the Varnish on the Coated Membrane

[0128] To verify the good virucidal efficacy of the varnish film on the coated membrane after wear, a virucidal activity test after 5000 Martindale cycles from the ISO 21 702 (2019) standard was used both on the coated membrane and on a non-active surface (test control surface), according to different contact times (5 min, 15 min and 60 min), the interfering substance being a mucus-saliva mixture and the virus being the human coronavirus HCoV-229E.

[0129] The results were as follows:

TABLE-US-00001 Contact Logarithmic Virucidal Interfering time reduction efficacy Product substance (min) (Log10) (%) Coated Mucus-saliva 5 2.17 99.32% membrane 10 3.37 99.96% after 5000 15 3.87 99.99% Martindale cycles

[0130] The tests thus show efficacy after wear.

[0131] Varnish Adhesion Test on the Coated Membrane

[0132] 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 for the comparative membrane.

[0133] Cleanability Tests of the Coated and Varnished Membrane According to the Invention

[0134] 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: [0135] measuring the initial color of the fabric and recording it [0136] taking a non-woven wipe as used in hospitals [0137] impregnating it with betadine or eosin and rubbing it on the fabric. Leaving to “dry” for 10 min. [0138] wiping with a clean dry wipe. [0139] cleaning with high surface disinfectant detergent Anios (didecyldimethylammonium chloride and polyhexamethylene biguanide hydrochloride). [0140] remeasuring the Delta E (CMC) after cleaning [0141] if Delta E (CMC) <2 excellent cleaning [0142] if Delta E (CMC) <5 good cleaning [0143] if Delta E (CMC) <7 average cleaning [0144] if Delta E (CMC) >7 poor cleaning

[0145] The membrane according to the invention made it possible to obtain results qualifying the cleaning as excellent, whether for betadine or for eosin. The comparative membrane gave the same result.

[0146] Test Results

TABLE-US-00002 Varnish Weld- adhesion ability Coating % Ag Anti- (after (greater resistance in the viral 2000 than 6 to varnish action cycles) daN/5 cm) cleaning Comparative   0% None OK 7 Excellent membrane Membrane 0.09% More OK 7.9 Excellent according than 90% to the reduction invention after 60 min

[0147] “OK” means that the test is considered conclusive: the coated and varnished membrane according to the invention is compliant: the property was validated.

[0148] 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.