RU2791214C1 - Method for increasing antibacterial properties to door handles - Google Patents

Abstract

FIELD: medicine.

SUBSTANCE: invention relates to medicine, namely to a method for imparting antibacterial properties to door handles. The method consists in using a surface coating. Door handles are coated with a 10 nm thick alumina substrate and then a 25 nm or more thick titanium and vanadium oxide nanofilm using atomic layer deposition technology. The coating is applied at a temperature of 150 degrees Celsius.

EFFECT: providing door handles of any design and shape: durable, wear-resistant, uniform and non-toxic nanofilm of adjustable thickness with antibacterial properties, reducing the cost of coating using inexpensive, non-toxic, sufficiently strong and affordable materials (vanadium and titanium oxides).

1 cl, 7 dwg

Description

The invention relates to medicine, namely to preventive medicine or hygiene, can be used on door handles and other common items in medical institutions and organizations with a large flow of people (student dormitories, kindergartens, public transport handrails, buttons of bank POS terminals and elevators, etc.).

Common items, such as door handles in institutions and organizations with a large flow of people, buttons for elevators and bank POS terminals, handrails in the subway and public transport, and other objects that people constantly touch, can accumulate various infections. Therefore, all objects of common use that can potentially be in contact with people must have antibacterial properties to prevent the spread of pathogenic microorganisms. In addition, antibacterial properties must be combined with aesthetic quality, hardness, UV resistance, high color fastness and scratch resistance, etc.

The issue has become more relevant recently, when new infectious agents appear, including viruses that cause epidemics and pandemics.

Liquid and gel disinfectants, which are constantly treated with common objects, especially during pandemics, although they have good antiseptic properties, their action is limited in time, so they have to be treated repeatedly. In addition, many of them, especially potent ones, most often have a pungent unpleasant odor or cause allergic reactions in people.

Currently, various innovative technologies and nanotechnologies are used in the world, which are recommended, among other things, for the treatment of door handles in order to give them antibacterial properties.

Analogues.

And so, concerned about the consequences of the SARS virus, Chinese students Sum Min Won and Kin Pong Lee created a "self-sterilizing doorknob" . The lamps are powered by current, which is stored with the help of kinetic energy after each opening and closing of the door. The project is undergoing laboratory tests and is going to release ultraviolet pens for sale and, with the support of public and private organizations, equip public places with them. The creators hope that their invention will reduce the risk of infection in the city and reduce the spread of viruses in the future.

disadvantage is that the design of the handle is of the same type and not entirely successful. In addition, if the doors have not been opened for a long time, then, accordingly, there is no kinetic energy and the handles lose their self-sterilizing ability.

To give door handles antibacterial properties, British manufacturers have created an antibacterial pad (manufacturer: Purehold, UK) that has been laboratory tested and the results showed that 99.9% of bacteria were killed using silver technology embedded in the surface of the handle (independently tested by ISO 22196). The products do not use chemicals - only harmless silver ions, which will help improve hygiene and reduce illness and disruption of staff.

The term of use is 6 months. There is a timeline indicator for quick replacement when needed.

The disadvantages are: short period of use, the need to keep track of the time indicator, the use of an overlay with expensive silver, the shape of the handle (only cylindrical) and the limited diameter of the door handle (19 mm, 20 mm or 22 mm).

Door and window handles are also available with SecuSan antibacterial coating (leading European manufacturers HOPPE and dormakaba, recommended for installation in medical and educational institutions, enterprises and other crowded places. The wear-resistant PVD coating does not contain chemical additives and is not toxic. Method PVD is used for processing various materials, including brass and zinc alloys, the operation warranty is 5 years.

disadvantage is that if the door handle is made of brass, then it is pre-nickel-plated, then chrome-plated and only then PVD-coated. The PVD method itself is also inferior to the ACO antibacterial coating method offered by us.

To combat the spread of nosocomial infection Matt Roberts (Matt Roberts) came up withspecial design antibacterial door handledesigned specifically for use in medical settings. There are 23 holes on the surface of the Hygiene Handle. When someone grasps this handle to open the door, disinfectant gel is released under pressure through these holes. The handle also has a gel-free zone so that hospital staff who, for example, carry documents to another department, do not accidentally get them dirty. However, the author of the idea himself is sure that few people use these gels.

A team of British scientists and designers spent seven years creating antibacterial door handles. Surfaceskins offers antibacterial plates to the market, which are mounted on the front door at the level where a person usually presses his hand when entering the room. Inside the device is a reservoir with an alcohol-containing gel. A membrane with tiny valves for the distribution of the gel comes to the surface. Whenever a person presses on the device when the door is opened, pressure is applied to the tank. The gel is released onto the surface and thus disinfects the plate. This is about the same as if you used a regular hand gel after entering the building.

To study and confirm the effectiveness of Surfaceskins technology, the authors of the development conducted tests using bacteria that were found on the hands of medical clinic staff. To do this, they placed "malicious babies" on Surfaceskins door plates and on standard aluminum ones.

disadvantage Surfaceskins has a limited lifespan - the fabric surface of the Surfaceskins plate must be changed every seven days or after 1000 touches, whichever comes first.

Antibacterial door hardware INOX MicroArmor (works around the clock, disrupting the growth and reproduction of pathogens in four critical ways:

attacks proteins of microbes, causing disruption of basic functions, breaks through the membrane of proteins, causing the loss of essential nutrients, damages the internal systems of the microbe by increasing the level of oxygen in it, affects the DNA and genetics of pathogens, ultimately preventing its growth and reproduction.

But, again, the main weapon in the MicroArmor arsenal is silver ion technology, which is directly embedded in the hardware coating, providing safe, effective and long-term protection against harmful microbes. Silver ions are non-toxic and environmentally friendly. INOX Antimicrobial MicroArmor(Warranty this product for two years for commercial applications and ten years for residential applications.

However, MicroArmor antibacterial door fittings are made to order at a plant in California, and can only be purchased or ordered through INOX distributors in Russia and the CIS.

disadvantages are that this technology uses expensive silver, and MicroArmor antibacterial door hardware is made to order at a California facility, which is practically difficult and expensive to obtain, especially during the period of sanctions.

Antibacterial TESA handles made of copper alloy , capable of destroying bacteria that form on the surface within a few minutes.

According to the authors, the probability of a hospital infection is reduced by 40%. The pens are antimicrobial in nature and contain no chemical additives, non-toxic. Effective even after dry and wet cleaning and polishing. According to the authors, again, the copper alloy resists the following microorganisms: Akinetobacterium baumann, Adenovirus, Aspergillus niger, Candida white, Clostridium difficile, Helicobacter pylori, Influenza A (H1N1) virus, Legionella pneumonia, Listeria monocytogenic, Mycobacterium tuberculosis, Pseudomonas aeruginosa, Salmonella , Tuberculosis bacillus, Polio virus, and that we doubt such a statement, since copper alloys do not have a pronounced antibacterial effect.

Antibacterial TESA handles with silver ions. TESA has also developed antimicrobial stainless steel handles that have a germ-resistant coating. The active component of this coating contains silver ions, which is coated with zeolite, a type of crystal that releases silver ions little by little. Certificates from the University of Pavia confirm the effectiveness of the coating. Such a coating can be found in the TESA Residential and AISI16 series of handles, except for the Solid series. The disadvantage of this proposal is that expensive silver is used as a coating for door handles.

Criticism of analogues. Accordingly, all of the above models of door handles have certain disadvantages, which are given after the description of each of the models of door handles.

Prototype.

As a prototype we have chosen door handles with ABACO antibacterial coating. Scientific tests of the ABACO antibacterial coating, as the authors point out, were carried out by universities in Navarra (Spain) and at the University of Etudes Brescia (Italy). According to the authors, the effectiveness of this coating against a strain of Escherichia coli and Staphylococcus aureus, which belong to the most common bacteria, has been tested on both new and used products. A complex multi-layer coating, as the creators of this coating indicate, destroys the bacterial cell membrane, blocking its reproduction, by interrupting the cycle of cell division. The antibacterial coating is active throughout the entire life cycle of its product.

ABACO is a Vacuum Vapor Deposition (PVD) coating that combines with silver ions to provide excellent antimicrobial and antiviral efficacy. Moreover, the authors guarantee that everyday use not only does not limit, but even enhances the effectiveness of ABACO®, which, in our opinion, is unlikely.

Südmetall guarantees that the coating will retain its antibacterial and antiviral properties for a period of 20 years.

( https://www.suedmetall.com/produkte/beschlaege/antibakterielle-beschlaege/?lang=ru; http://strcon.ru/news/dvernye-ruchki-s-antibakterialnym-pokrytiem-kompanii-sudmetall).

Criticism of the prototype:

1. Antibacterial coating for door handles ABACO(- this is a complex multi-layer coating, and the process itself is multi-stage and laborious.

2. The exact composition of the coating is not published, but it contains expensive silver, which clearly affects the cost of the product.

3. This antibacterial coating is made using PVD (or CVD) technology, which is as follows: all precursors are fed into the reactor at the same time, and the reaction proceeds over the substrate, and the resulting film is then deposited on the substrate. Therefore, it is practically impossible to control the thickness of the target film in the case of PVD or CVD.

4. Antibacterial nanofilms obtained on the basis of PVD or CVD in ABACO® technology are uneven and inhomogeneous, i.e. no conformity. In addition, in PVD or CVD processes, precursor depletion limits uniform coverage over large areas of the substrate surface. The coating is not conformal (conformity is less than 70%, i.e. a stepped coating with uncoated areas; aerosol particles appear on the film surface - the composition of the film is inhomogeneous).

5. In the plasma PVD process used in the ABACO technology ((process activated by plasma, usually microwave plasma), an electric discharge in a gas, at pressures <100 Pa, is used to accelerate the kinetics of the CVD reaction due to the additional activation energy of precursor molecules This can lower the reaction temperature by several hundred degrees (conventional CVD is carried out at temperatures in excess of 600°C) and at the same time the coating rate is drastically reduced.

6. The process based on PVD or CVD is done only by creating a high vacuum, in contrast to the ALD method, which we used to obtain antibacterial nanofilms on door handles.

The purpose of the proposed method

The purpose of the proposed method is to provide door handles of any design and shape: a strong, wear-resistant, uniform and non-toxic nanofilm of adjustable thickness with antibacterial properties, to reduce the cost of coating using inexpensive, non-toxic, sufficiently strong and affordable materials (vanadium and titanium oxides).

The goal is realized as follows: aluminum oxide substrates 10 nm thick are preliminarily applied to any door handles, and then a nanofilm of titanium and vanadium oxides (at least 25 nm from titanium and vanadium oxides) is created on the surface of the substrate cycle by cycle using the technology ALD (atomic layer deposition).

The technology of ALD (atomic layer deposition) consists in the fact that one of the precursors is exposed to the vapors of the previous precursor, which forms a monolayer on the surface of the substrate. After removing the excess precursor from the vapor phase with a purge gas (e.g., argon, Ar), the reagent gas reacts with the adsorbed layer of the precursor, forming a layer of the target film-forming material, i.e., the precursors are fed sequentially and in turn, and the reaction flows directly on the surface of the substrate.

The essence of the proposed method

According to the proposed method, the target film is built up layer by layer on the substrate, which makes it possible to control the thickness of the resulting nanofilm of titanium and vanadium oxides on any door handles: the film thickness is 25 nm or more, applied layer by layer: one layer of titanium oxide, a layer of vanadium oxide is applied to it, and so, repeating layer after layer, 224 cycles or more: titanium oxide (112 cycles or more) and vanadium oxide (112 cycles or more). To create the desired film thickness, only the number of repetitions of the cycles used in the process is traced.

Comparative analysis of the characteristics of the prototype and the method proposed as an invention

- According to the proposed method, ASO technology is used to apply a nanofilm of controlled thickness (accurate to 1 angstrom), to achieve uniformity and purity of the coating. ACO technology used according to the proposed method allows the use of low temperatures for applying a nanofilm to products made of refractory materials.

- According to the prototype, PVD (or CVD) technology is used, which is as follows: all precursors are fed into the reactor at the same time, and the reaction proceeds over the substrate, and the resulting film is then deposited on the substrate. Therefore, it is practically impossible to control the thickness of the target film in the case of PVD or CVD.

- According to the proposed method, the conformity of the coating is 100% and the composition of the coating is precisely controlled, and according to the prototype, the conformity of the film is low.

- According to the prototype, the coating is applied using PVD or CVD, where the depletion of precursors occurs, which limits uniform coating over large areas of the substrate surface. The coating is not conformal (conformity is less than 70%, i.e. a stepped coating with uncoated areas; aerosol particles appear on the film surface - the composition of the film is inhomogeneous).

- According to the proposed method, nano-coating is applied to door handles at a temperature of 150 degrees Celsius, without creating a vacuum.

- According to the prototype, the coating is applied at temperatures above 600 degrees Celsius under vacuum.

- According to the proposed method, a non-toxic, low-cost nanofilm of titanium and vanadium oxides is applied to door handles, which exhibits bactericidal properties, sufficient strength and wear resistance.

- According to the prototype, a multi-layer coating containing silver is applied, which increases the cost of door handles.

Examples of specific implementation of the method

Extract from the laboratory journal of the FGUZ "Dagestan anti-plague station" of Rospotrebnadzor.

An experiment was set up to establish the bactericidal properties of a titanium / vanadium oxide nanofilm deposited on metal plates (in the form of a circle - from steel (Fig. 1a), in the form of a square - from brass (Fig. 1b), i.e. materials from which most often simple door handles are made). To do this, swabs were taken from samples coated and uncoated with a nanofilm and sown in a nutrient broth (Fig. 2) for cultivating microorganisms (GRM-broth, manufacturer: FBUN SRC PMB Obolensk) and on dense nutrient media (Fig. 3 a, 6, c, d): nutrient agar for cultivating microorganisms (GRM-agar, manufacturer: FBUN SRC PMB Obolensk), blood agar (GRM agar with the addition of 10% blood), Endo-GRM agar (manufacturer: FBUN SRC PMB Obolensk) and salt agar-M (manufacturer: JSC NPO Microgen).

The experiments were carried out in three stages:

Stage I. Sowing swabs from samples on dense nutrient media and nutrient broth.

Stage II. After 24 hours, view the crops. Sowing from nutrient broth on dense nutrient media.

Stage III. After 48 hours from the start of the study. Re-view of crops.

Comparative analysis of the experimental results showed:

1. Inoculation of swabs from samples coated with our proposed nanofilm of titanium/vanadium oxides deposited using the ASO technology, the growth of cultures on nutrient media (sample) after 24 and 48 hours was practically not given on any of the dense nutrient media used, while crops swabs from samples not covered with nanofilm (control) gave a clear, even continuous culture growth 24 and 48 hours after inoculation on dense nutrient media: nutrient agar for cultivating microorganisms (GRM agar, Fig. 3a) and blood agar (GRM agar with the addition of 10% blood, Fig. 3b). Slight growth was observed on yolk-salt agar (saline agar-M, Fig. 3c) and growth was observed on Endo medium (Endo-GRM agar, Fig. 3 d). Gram-stained smears prepared from the grown culture and examined under a microscope showed the presence of gram-positive cocci in the smears, as well as gram-negative and gram-positive rods.

2. The experiment shows that the titanium/vanadium oxide nanofilm exhibits good bactericidal (bacteriostatic) properties.

The positive effect of the proposed method

The usefulness of the developed method proposed as an invention is based on the following properties of a nanofilm of titanium and vanadium oxides with an aluminum oxide substrate deposited on samples of steel and brass (on door handles) using ACO technology: a nanofilm of titanium and vanadium oxides exhibits pronounced bactericidal (bacteriostatic) properties, in addition, the ASO technology used creates 100% coating conformity and film uniformity (up to 1 angstrom), which forms an ideally smooth, wear-resistant and durable surface of the product (door handle).

The creation of a preliminary substrate of aluminum oxide promotes better adhesion of the nanofilm of titanium and vanadium oxides, and contributes to the strength of the film.

The developed method for imparting antibacterial properties to door handles and common items using antibacterial nanocoatings obtained by atomic layer deposition by applying a nanocoating of titanium and vanadium oxides with an aluminum oxide substrate is technically simple to perform and allows coating several samples at the same time, which, in turn, turn, reduce material costs and improve economic efficiency.

Information taken into account:

1. https://inoxproducts.ru/antimicrobial-coating/

2. http://strcon.ru/sudmetall-germaniya-dvernye-ruchki-s-antibakterialnym/ - prototype

Claims (1)

A method for imparting antibacterial properties to door handles, which consists in using a surface coating, characterized in that a 10 nm thick aluminum oxide substrate is applied to the door handles, and then a nanofilm of titanium and vanadium oxides with a thickness of 25 nm or more using atomic layer deposition technology, The coating is applied at a temperature of 150 degrees Celsius.

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