ES2371725T3 - METHODS FOR MANUFACTURING A SUBSTRATE WITH ANTIMICROBIAL PROPERTIES. - Google Patents

Abstract

Process for the production of a glass-type substrate that has antimicrobial properties, characterized in that it comprises the following steps: (i) deposition of a non-gelling metal layer comprising an inorganic antimicrobial agent obtained at the beginning of a precursor, in the form of metal, chelate or ion, on at least one of the exposed surfaces of the substrate; (ii) diffusion of the agent under said at least one surface exposed to the substrate by heat treatment at a temperature greater than 200 and less than 380 ° C, for a period in the range of between 5 minutes and 40 minutes.

Description

Methods for manufacturing a substrate with antimicrobial properties

[0001] The present invention relates to a substrate, in particular a glass-type substrate or a metal substrate, in which at least one of its surfaces has antimicrobial properties, in particular antibacterial

or antifungal. The present invention also relates to a process for the production of said substrate.

[0002] In the field of ceramic substrates, EP 653 161, for example, describes the possibility of coating them with a glaze composed of silver to provide them with antibacterial properties.

[0003] In the field of glass type substrates, it is known that sol-gel processes provide an antimicrobial surface. These processes require a hardening phase of the sol-gel layer, which implies high temperatures of the order of 500 ° -600 ° C (sintering temperature). Processes that require the substrate to be immersed in a composition comprising a silver salt are also known. In this case, a layer of silver is not deposited, but an ion exchange takes place in the solution at an elevated temperature.

[0004] A process for producing a glass substrate having antimicrobial properties from EP 1449816 is also known. This process requires both a drying phase between 20 ° and 105 ° C and a heat treatment at 600 °-650 ° C. This heat treatment has some disadvantages, particularly with regard to the cost and the uniformity of the product. In addition, it makes the process very poorly reproducible, since it has been discovered that at these temperatures the diffusion of silver is very rapid and a slight variation in the duration of the heat treatment results in a significant variation in the diffusion depth of silver and, therefore, this causes a variation in the antibacterial properties of the substrate. It should be noted that said heat treatment causes an undesirable yellow coloration of a soda-lime glass substrate. In addition, with this procedure, after being treated, the product can no longer be cut to a particular size due to the necessary tempering process.

[0005] A process for obtaining antimicrobial substrates is also known from US 2002/0001604 A1. Example 1 describes a process in which a soda-lime glass substrate is coated with an aqueous colloidal silver dispersion and then heat treated or at a temperature of 500 ° C for 30 minutes.

[0006] Therefore, there is a need to provide a substrate, of glass or metal, with antimicrobial properties, which is easy to use and economical to produce.

[0007] According to one embodiment, the present invention relates to a process for the production of a substrate (in particular glass) having antimicrobial properties, characterized in that it comprises the following steps:

(i)

 deposition of a non-gelling layer comprising an inorganic antimicrobial agent in the form of metal, chelate or ion on at least one of the surfaces of the glass substrate;

(ii)

 diffusion of the agent on or under said at least one surface of the substrate by heat treatment at a temperature greater than 200 and less than 380 ° C, for a period in the range of 5 minutes to 40 minutes.

[0008] According to another embodiment in relation to a glass or metal substrate, the process is characterized in that it comprises the following sequential steps:

(i)

 deposition of a non-gelling metal layer comprising an inorganic antimicrobial agent, obtained at the beginning of a precursor, in the form of metal, colloid, chelate or ion, on at least one of the substrate surfaces;

(ii)

 deposition of a top coat;

(iii) diffusion of the agent in said topcoat by heat treatment at a temperature between 200 and 750 ° C for a period in the range of 2 minutes to 2 hours.

[0009] During the heat treatment, the antimicrobial agent may diffuse under the surface towards the center of the substrate if no coating is applied, or in a lower coating or in an upper coating in the event that those coatings are applied on the substrate .

[0010] If a lower coating is applied, it may advantageously comprise a first layer that has the function of blocking or slowing down the migration of the antimicrobial agent, and a second layer that serves as a reservoir for the antimicrobial agents. These functions can be determined in a product manufactured in accordance with the invention by comparing the antimicrobial effect of similar products with and without undercoating and / or analyzing diffusion profiles (see Figures 1 and 2).

[0011] Each layer of the lower coating may in particular have a thickness between 5 and 1000 nm, preferably between 8 and 800 nm, more preferably between 10 and 600 nm.

[0012] The substrate can be a flat glass sheet, particularly soda-lime glass that can be float glass. It can be transparent glass. The glass may have a thickness in the range of 2.5 to 12 mm. It can be transparent glass or colored glass. It may comprise a reflective layer (to form a mirror) or a layer of enamel or paint (for wall covering), generally on the surface opposite the antimicrobial surface.

[0013] The substrate may have a surface area greater than 0.8 m to 0.8 m; It can be adapted to be cut in a finishing size by a subsequent cutting operation.

[0014] When the substrate is a transparent soda-lime glass, according to a preferred embodiment, the maximum temperature of the heat treatment is preferably lower than 350 ° C and, advantageously higher than 200 ° C, preferably higher than 220 ° C, and particularly higher than 240 ° C.

[0015] The duration of the heat treatment must be adjusted according to the selected temperature. In particular for the second embodiment, it is found that a duration in the range of preferably between 5 minutes and 1 hour, and between 7 and 40 minutes is particularly preferred.

[0016] A particularly advantageous temperature-duration combination has proven to be a temperature in the range of between 200 ° and 350 ° C over a period ranging from 10 to 30 minutes.

[0017] The antimicrobial agent can be selected from various inorganic agents known for their antimicrobial properties, in particular silver, copper and zinc. Advantageously, the antimicrobial agent is in metallic form.

[0018] The process according to the invention advantageously comprises an additional step (iii) that consists in removing any excess of antimicrobial agent that remains on the surface, that is, that has not diffused during the heat treatment stage (ii) . This removal can be achieved by washing. In particular, solutions based on HNO3, FeCl3 or Fe (NO3) 3 are suitable for said washing process. This washing can prevent any antimicrobial agent from remaining on the surface in metallic form in an amount such that it could cause the treated surface to be too reflective. For some applications, it is preferred that the substrate treated according to the invention does not show any significant increase in light reflection (RL) or any significant reduction in light transmission (TL) in relation to the untreated substrate.

[0019] It has been discovered that with the process according to the invention, a very small amount of the antimicrobial agent can be deposited on said at least one surface of the substrate. In some cases, an amount of more than 5 mg / m2, preferably more than 20 mg / m2 may be appropriate and more than 35 mg / m2 of surface to be treated is particularly preferred. However, the use of much higher concentrations (800 or 900 mg / m2) does not hamper the result, instead these concentrations have proved to be simply unnecessary and may require that excess be eliminated on a much more significant scale.

[0020] Various methods known per se may be suitable for depositing the layer comprising the antimicrobial agent. In particular, deposition is possible by pyrolytic spraying, by ionic bombardment or by a method similar to the method used for the production of mirrors, which comprises spraying a salt of an antimicrobial agent such as AgNO3 and precipitation by reduction of the antimicrobial agent in the form of metal.

[0021] Various types of glass substrate can be considered depending on the applications sought. In addition to the traditional transparent soda-lime float glass, a glass that is colored, frosted or stamped can also be used. The glass sheets can be treated on one or both sides. The face opposite the treated face can undergo any desired type of surface treatment. For example, a paint or enamel coating or a reflective layer can be applied thereon, for example, for applications such as wall coverings or mirrors.

[0022] The invention also relates to a glass substrate comprising an antimicrobial agent present in or diffused at or below at least one of its exposed surfaces, such that the ratio I (CsAg) / I (CsSi) on the surface (measured according to the dynamic SIMS method) is greater than 0.015, preferably greater than 0.020 and particularly greater than 0.025 is preferred. The amount of antimicrobial agents present or diffused on at least one of its surfaces is advantageously greater than 0.1 mg / m2, preferably greater than 1 mg / m2, and more than 10 mg / m2 of antimicrobial surface is particularly preferred.

[0023] The ratio of I (CsAg) / I (CsSi) is measured using a Cameca ims-4f apparatus. I (CsAg) is the maximum intensity obtained for CsAg + ions and I (CsSi) is the maximum intensity obtained for CsSi + ions after bombardment of the substrate surface by a beam of Cs + ions that progressively decap the surface of the sample. The energy of the Cs + ion beam reaching the substrate is 5.5 keV. The angle of incidence of the beam is 42º with respect to the normal substrate. The surface values indicate that the values are taken for as little depth as possible as long as the value obtained is significant. Depending on the erosion index used, the first significant values may correspond to maximum depths of approximately 1 to 5 nm. In the present case, the surface values correspond to a maximum depth of 2 nm. To ensure that the values obtained are significant, the ratio of Ag107 / Ag109 isotopes must in particular be close to the theoretical value (1.0722), in particular it will be in the range of 1.01 to 1.13.

[0024] In some embodiments of the invention, a substrate having antimicrobial agents present on at least one exposed surface may be an annealed glass sheet. The term "annealed glass sheet" is used herein to mean that the glass can be cut in size without breaking in the way that a tempered or hardened glass sheet would break when cut. Said annealed glass sheet preferably has a surface compression of less than 5 MPa.

[0025] The invention also relates to metal or other substrates comprising antimicrobial agents present in or diffused at or below at least one of its exposed surfaces at an atomic% preferably greater than 1% or more, preferably greater than 1, 5%, more preferably greater than 2%.

[0026] The substrate according to the invention has an antibacterial effect on a large number of bacteria, whether gram positive or gram negative bacteria, in particular on at least one of the following bacteria: Escherichia coli, Staphylococcus aureus, Pseudomonas aeruginosa, Enterococcus hirae. The antibacterial effect measured in accordance with JIS Z 2801 is in particular, at least on any one of these bacteria, greater than log 1, preferably greater than log 2, and particularly greater than log 2.5 is preferred. The substrate will be considered bactericidal in accordance with JIS Z 2801 if it has an effect greater than log 2. However, the invention also relates to substrates that have a minor effect (for example, a bacteriostatic effect, which means that bacteria they are not necessarily destroyed but can no longer develop).

[0027] The substrate according to the invention advantageously has an antifungal effect (fungicide or fungistatic) on any fungus, in particular Candida albicans or Aspergillus niger.

[0028] When the glass substrate used is a transparent glass, it can advantageously have antimicrobial properties, as well as a neutral reflection color. In particular, the colorimetric indices (CIELAB system) in reflection at * and b * (Illumiant C, 10 ° observer) are in the range between -10 and 6, preferably between -5 and 3 and particularly preferred between -2 and 0, and the purity may be less than 15%, preferably less than 10% and particularly less than 5% is preferred.

[0029] If the substrate is a colored glass, it can be considered that antimicrobial properties can be obtained without greatly changing the initial color of the substrate. The change in color is usually expressed with the colorimetric index by Delta E *; DeltaE * = [(1 * 1 - 1 * 2) 2 + (a * 1 - a * 2) 2 + (b * 1 - b * 2) 2] 1/2. A DeltaE * of less than 3, preferably less than 2, can be obtained for an antimicrobial substrate according to the invention.

[0030] When the glass substrate used is a transparent glass, it can advantageously have both antimicrobial properties and a visible light absorption of less than 1.5%, preferably less than 1.4%, and particularly less than 1.3 is preferred %. It can have a visible light transmission within the range of 80 to 91%, preferably 84 to 90%. And the visible light reflection may be less than 15%, preferably less than 12%, more preferably less than 10%.

[0031] The substrate according to the invention preferably has in particular an antimicrobial effect after any one of the following accelerated aging tests: wet spray test (test for 20 days in a chamber with a humidity of more than 95% at 40 ° C) after 500 hours of UV irradiation (4 340A ATLAS lamps, chamber at 60 ° C), after 24 hours immersed in a solution of H2SO4 (0.1 N), after 24 hours immersed in a NaOH solution (0.1 N).

[0032] Preferred or alternative embodiments of the present invention are described in the appended claims.

[0033] The present invention will be described in more detail below in a non-restrictive manner with respect to the accompanying drawings:

Figures 1a to 1e show the diffusion profiles of silver towards the surface of the substrate for samples obtained using the procedure of Example 1 (deposition of the silver layer by spraying); Figure 2 shows a diffusion profile of silver into the substrate surface for a sample obtained using the procedure of Example 2 (precipitation deposition of a silver layer by reduction of the corresponding salt).

EXAMPLE 1:

Production of antimicrobial samples

[0034] Transparent soda-lime glass samples were coated with a silver layer using the vacuum deposition method, also called magnetron ion bombardment, in a manner known per se using a silver metal target in a argon atmosphere. The amount of silver deposited was 40 mg / m2 of treated surface for sample 1.a (4 mm thick glass) and 100 mg / m2 of treated surface for samples 1.ba 1.e (2 mm glass of thickness).

[0035] To cause the silver to diffuse to the surface, the samples were then subjected to a heat treatment under the conditions (duration and temperature) specified in Table 1.

[0036] The treated samples were then washed in acid to remove any excess silver remaining in the

15 surface that therefore would not have diffused during the heat treatment. The objective is to eliminate any trace of silver on the surface (mainly metallic Ag) and therefore obtain a transparent glass without removing the silver that has diffused slightly towards the surface. Solutions of HNO3, FeCl3 or Fe (NO3) 3 are suitable for said washing process.

[0037] Figures 1.a to 1.e show the amount of silver diffused towards the surface of the substrate as a function of the depth (d) in the substrate. The amount of silver is estimated by measuring the ratio I (CsAg) / I (CsSi) obtained by dynamic SIMS. I (CsAg) is the maximum intensity obtained for CsAg + ions and I (CsSi) is the maximum intensity obtained for CsSi + ions after bombardment of the substrate surface by means of a Cs + ion beam using a Cameca apparatus ims-4f (beam of 5.5 keV and angle of incidence of 42º with respect to

25 the normal substrate).

Measurement of the antimicrobial effect

[0038] The bactericidal and fungicidal properties of some samples were analyzed according to JIS 30 Z 2801. The results are checked in Table 1 below.

[0039] A level of log 1 indicates that 90% of the bacteria inoculated on the glass surface were destroyed within 24 hours under the conditions of the standard; log 2 indicates that 99% of the bacteria were destroyed; Log 3 indicates that 99.9% of the deposited bacteria were destroyed, etc.

Table 1

Examples

Temperature ºC Duration (minutes) Broadcast profile I (Cs / Ag) / I (Cs / Si) Bacteria or fungus tested Antimicrobial effect

1st

250 fifteen Fig. 1.a 0.200 E. coli > log 4

1 B

250 30 Fig. 1.b 0.037 E. coli > log 4

1 C

300 fifteen Fig. 1.c 0.027 E. coli S. aureus P. aeruginosa E. hirae C. albicans log 3.6 log 3.4 log 4.1 log 1.0 log 1.2

1.d

350 fifteen Fig. 1.d 0.027

Comparative Example 1.e

400 fifteen Fig. 1.e 0.021 E. coli log 1.6

[0040] Sample 1.a has an aspect that is neutral in reflection. Colorimetric indices are a * = -0.2 and b * = -0.9 and the purity is 1.9%. Sample 1.c also has an aspect that is neutral in reflection. Indices

40 colorimetrics are a * = -0.2 and b * = - 0.7 and the purity is 1.5% (measured with Illuminant D, 10º angle).

[0041] Accelerated aging tests were performed on sample 1.c that demonstrated that the antimicrobial effect was preserved. An antibacterial effect was measured with respect to E. coli greater than or equal to log 4 after the following artificial aging tests:

-

wet spraying (test for 20 days in a chamber with a humidity of more than 95% and at 40 ° C);

-

after 500 hours of UV irradiation (4 340A ATLAS lamps, chamber at 60 ° C),

-

after 24 hours immersed in a solution of H2SO4 (0.1 N),

-

after 24 hours immersed in a solution of NaOH (0.1 N).

Example 2

[0042] 4 mm thick samples of clear soda-lime glass were coated with a silver layer by chemical deposition using a method similar to that used to produce mirrors.

[0043] The samples were first subjected to a sensitization step using a tin chloride solution. Then, an aqueous solution of AgNO3 was sprayed on the surface of the glass at a flow rate of 200 ml / min along with a reducing agent to reduce the silver salt in metal salt. Then, the excess was removed by rinsing. Amounts of 100 to 800 mg of Ag / m2 were deposited on one side of the glass substrates.

[0044] To cause the silver to diffuse to the surface, the different samples were then subjected to different heat treatments over a period of 10 to 30 minutes at temperatures ranging from 250 ° to 350 ° C (see Table 2).

[0045] The treated samples were then washed in acid to remove excess silver left on the surface as in Example 1.

[0046] The diffusion profile of sample 2.d is shown in Figure 2.

[0047] The antimicrobial effect was analyzed using the same method as in Example 1 and the results are checked in Table 2 below.

Table 2:

Examples

Ag concentration deposited (mg / m2) Temperature and duration of heat treatment I (CsAg) / I (CsSi) Bacterium Antimicrobial effect

2nd

100 250 ° C, 15 min 0.15 E. coli > log 4.8

2.b

100 300 ° C, 15 min 0.14 E. coli > log 4.8

2 C

100 350 ° C, 10 min 0.075 E. coli > log 4.8

2.d

250 300 ° C, 15 min 0.021 E. coli > log 3.6

2.e

300 250 ° C, 15 min 0.22 E. coli log 4.8

2.f

300 300 ° C, 15 min 0.23 E. coli log 4.8

2 g

300 350 ° C, 10 min 0.13 E. coli > log 4.8

25 Example 3

[0048] 6 mm thick samples of transparent soda-lime glass were coated with a silver layer by means of pyrolytic spraying. A solution of AgNO3 was sprayed for 5 seconds on preheated samples at temperatures of 300 ° to 400 ° C. The solution was pyrolyzed in contact with the hot substrate and formed

30 a metallic silver film.

[0049] In this case, the two stages of deposition of the antimicrobial agent and their diffusion towards the surface were practically simultaneous since the substrate was preheated. In this case, the process could be used during the continuous production of float glass. Silver spraying could be arranged after the tin bath and

35 could be performed before the glass tape enters the annealing oven or the actual annealing oven.

[0050] The treated glass was then washed as in Examples 1 and 2.

Example 4 (outside the scope of the present invention)

[0051] Transparent soda-lime glass samples were coated with one or two layers of different metal oxides or oxycarbons with a thickness ranging between 13 and 500 nm, using pyrolytic deposition. The nature and thickness of the layers are checked in Table 3 below.

[0052] A layer of silver (100 to 500 mg / m2) was deposited on the last layer of the substrate and a tempering heat treatment was applied (temperature: 680 ° C, duration 6 minutes).

Table 3:

Substratum

Concentration of Ag deposited (mg / m2) Bacterium Antibacterial effect (log)

Glass / TiO2 (45 nm)

100 E. coli 1.6

300

E. coli 2.2

Glass / SiOxCy (70 nm)

100 E. coli 4.8

500

E. coli 4.8

Glass / SnO2: F (500 nm)

100 E. coli 1.1

Glass / SiOxCy (75 nm) / SnO2: F (300 nm)

100 E. coli > 4.8

500

E. coli > 4.8

Glass / SiO2 (25 nm) / TiO2 (13 nm)

100 E. coli 3.5

500

E. coli 4.3

[0053] The bactericidal properties of the samples were analyzed in accordance with JIS Z 2801. The results are checked in Table 3 above.

[0054] It is noted that, as a result of the layer or layers that are first deposited on the substrate, the antimicrobial effect is preserved despite high temperature heat treatment. Therefore, a product is obtained that has both the advantages of a tempered glass and an antimicrobial glass.

[0055] The presence of the coating layer can reduce the variability of the antimicrobial effect of the finished product to variations in the heat treatment process. In addition, it can provide a surface

or material that is better suited to contain the antimicrobial agent than the surface of the substrate.

[0056] For simplicity, it is also possible to perform the tempering stage at a later stage. To

15 to keep the substrates before tempering, it is therefore recommended that a first heat treatment be carried out at low temperature and for a short period (for example, from 250º to 400ºC for 5 to 30 minutes) to cause the antimicrobial agent to diffuse towards the layer or layers. The result is a sheet of glass that can be cut to a desired size and then tempered in a subsequent process.

Example 5 (outside the scope of the present invention)

[0057] A sample of pyrolytic transparent soda-lime glass coated with a first layer of SiOx (75 nm) and a second layer of fluorinated doped SnO2 (320 nm) was used. A 100 mg / m2 silver layer was deposited by the vacuum deposition method as in Example 1 using a silver target in an atmosphere of

25 argon

[0058] The coated samples were subjected to a tempering process (670 ° C for 10 minutes).

[0059] The bactericidal properties of the sample were analyzed in accordance with JIS Z 2801. A log 2.58 was obtained. This indicates that good bactericidal properties were obtained simultaneously with the tempering characteristics.

Example 6

[0060] A sample of transparent soda-lime glass coated by vacuum ionic bombardment with the following layer stacking: Glass / ZnSnOx (10 nm) / NiCr (80-20) (1.8 nm) / Ag (2 , 2 nm or about 20 mg / m2) / ZnSnOx (10 nm).

[0061] The coated sample was subjected to a tempering process (670 ° C for 10 minutes).

[0062] The bactericidal properties of the sample were analyzed according to JIS Z 2801. A log 2.63 was obtained. This indicates that good bactericidal properties were obtained simultaneously with the tempering characteristics. This suggests that a certain amount of silver migrated during the tempering stage in the upper coating and that the NiCr layer played a barrier function for the migration of Ag to the substrate.

Example 7 (outside the scope of the present invention)

[0063] Steel samples were coated with a silver layer using the vacuum deposition method as in Example 1. A first sample was a galvanized steel of the commercial type "ST37" with a thickness of 1.5 mm. The second was a sample of rolled steel in cold and oil-free conditions of a thickness of 0.2 mm.

[0064] After being properly washed, the samples were coated using a silver metal target in an argon atmosphere. The amount of silver deposited was 100 mg / m2 of the treated surface.

[0065] The samples were subjected to a thermal diffusion process at 320 ° C for 10 min.

[0066] The bactericidal properties of both samples were analyzed as above and a 3.53 log was obtained for both samples.

[0067] When the substrate is a metal, particularly sheet metal, and particularly steel, a coating layer may be provided on the surface to receive or contain the antimicrobial agent. Particularly suitable coating layers of one or more of a titanium oxide, a titanium nitride and a zirconium oxide may be particularly suitable.

[0068] When the substrate is a flat glass substrate, the use of selected coating layers of one or more of silicon oxide, a silicon nitride, a tin oxide, a zinc oxide, a zirconium oxide can be employed. , a titanium oxide, a titanium nitride and an aluminum nitride.

[0069] A double coating layer may be used, for example, zirconium oxide / substrate / titanium oxide.

Claims (22)

1. Process for the production of a glass-type substrate that has antimicrobial properties, characterized in that it comprises the following steps:

(i)

 deposition of a non-gelling metal layer comprising an inorganic antimicrobial agent obtained at the beginning of a precursor, in the form of metal, chelate or ion, on at least one of the exposed surfaces of the substrate;

(ii)

 diffusion of the agent under said at least one surface exposed to the substrate by heat treatment at a temperature greater than 200 and less than 380 ° C, for a period in the range of 5 minutes to 40 minutes.

2.

 Process according to claim 1, characterized in that the temperature of the heat treatment is below 350 ° C.

3.

 Process according to any one of the preceding claims, characterized in that the temperature of the heat treatment is greater than 220 ° C, and particularly greater than 240 ° C is preferred.

Four.

 Process according to any one of the preceding claims, characterized in that the heat treatment is carried out during a period in the range of between 8 and 40 minutes.

5.

 Process according to any one of the preceding claims, characterized in that the heat treatment is carried out at a temperature in the range of between 200 ° and 350 ° C for a period ranging from 10 to 30 minutes.

6.

 Process according to any one of the preceding claims, characterized in that the precursor used in step (i) is in a metallic or ionic form, in particular in an ionic form and dissolved in an aqueous solution.

7.

 Process according to claim 6, characterized in that the layer comprising the antimicrobial agent is deposited by vacuum ionic bombardment or by a method that involves the precipitation of metal antimicrobial agents by reduction of a corresponding salt.

8.

 Process according to any one of the preceding claims, characterized in that the antimicrobial agent is selected from silver, copper and zinc.

9.

 Process according to any one of the preceding claims, characterized in that the amount of antimicrobial agents deposited on said at least one surface the substrate is greater than 5 mg / m2, preferably greater than 10 mg / m2, and is particularly preferred greater than 20 mg / m2

10.

 Process according to any one of the preceding claims, characterized in that the substrate is coated with a lower coating before the deposition of stage (i), and that the diffusion of stage (ii) occurs mainly within the coating .

eleven.

 Process according to the preceding claim, characterized in that the lower coating comprises a first lower layer, which has the function of blocking or slowing down the migration of the antimicrobial agent, and a second lower layer, which serves as a reservoir for antimicrobial agents.

12.

 Process according to the preceding claim, characterized in that the lower blocking layer is selected from pyrolytic layers and obtained by ionic bombardment, in particular layers comprising a metal oxide, metal or metal alloy compound, such as Pd, NiCr , TiOx, NiCrOx, Nb, Ta, Al, Zr or ZnAl, or mixture thereof.

13.

 Process according to claim 10, characterized in that the lower layer comprises a first layer based on ZrO2 and a second layer based on TiO2, in particular the crystallized form of anatase.

14.

 Process according to any one of the preceding claims, characterized in that the substrate is a glass-type substrate, in particular a transparent soda-lime glass.

fifteen.

Process for the production of a glass or metal substrate that has antimicrobial properties, characterized in that it comprises the following steps:

to.

 deposition of a non-gelling metal layer comprising an inorganic antimicrobial agent, obtained at the beginning of a precursor, in the form of metal, colloid, chelate or ion, on at least one of the substrate surfaces;

b.

 deposition of a top coat

C.

 diffusion of the agent in said topcoat by heat treatment at a temperature between 200 and 750 ° C for a period in the range of 2 minutes to 2 hours.

16.

 Process according to any one of claims 1 to 15, characterized in that the total amount of antimicrobial agents comprising the substrate is greater than 0.1 mg / m2, preferably greater than 1 mg / m2, and is particularly preferred greater than 10 mg / m2 of antimicrobial surface.

17.

 Process according to any one of the preceding claims, characterized in that in at least one of the following bacteria: E. coli, S. aureus, P. aeruginosa (measured according to JIS Z 2801), the substrate has a bactericidal effect greater than log 2, and particularly superior to log 2.5 is preferred.

18.

 Process according to any one of the preceding claims, characterized in that the substrate has an antimicrobial effect after any of the following accelerated aging tests: wet spraying (test for 20 days in a chamber with a humidity of more than 95% and at 40 ° C), 500 hours of UV irradiation (lamps 4 340A ATLAS, chamber at 60 ° C), after 24 hours immersed in a solution of H2SO4 (0.1 N), after 24 hours immersed in a solution of NaOH ( 0.1 N).

19.

 Process according to any one of the preceding claims, characterized in that the substrate comprises antimicrobial agents that diffuse towards at least one of its exposed surfaces, so that the ratio I (CsAg) / I (CsSi) (average on the surface using the dynamic SIMS method) is greater than 0.020, and particularly greater than 0.025 is preferred.

twenty.

 Process according to any one of the preceding claims, characterized in that the substrate has a neutral color in reflection, that is, the colorimetric indices a * and b * are in the range of -10 to 6, preferably between -5 and 3 , and is particularly preferred between -2 and 0, and the purity is less than 15%, preferably less than 10%, and particularly less than 5% is preferred.

twenty-one.

 Process according to any one of the preceding claims, characterized in that the substrate has an integrated visible light absorption of less than 1.5%, preferably less than 1.4% and less than 1.3% is particularly preferred .

22

 Process according to any of the preceding claims, characterized in that the substrate is annealed.

 REFERENCES CITED IN THE DESCRIPTION This list of references cited by the applicant is only for the convenience of the reader. It is not part of the European patent document. Although special care has been taken in the compilation of references, errors or omissions cannot be excluded and the EPO rejects any responsibility in this regard.  Patent documents cited in the description • EP 653161 A [0002] 10 • EP 1449816 A [0004] • US 20020001604 A1 [0005]