WO2011032188A1

WO2011032188A1 - Process for producing antibacterial granites coated and the granites by the process

Info

Publication number: WO2011032188A1
Application number: PCT/VN2010/000005
Authority: WO
Inventors: Duc Ceramics Limited Company My; Albert Low Seng Chua
Original assignee: Duc Ceramics Limited Company My; Albert Low Seng Chua
Priority date: 2009-09-09
Filing date: 2010-09-08
Publication date: 2011-03-17

Abstract

Process for producing antibacterial granites is disclosed. The process comprises the steps of: (a) creating the coating mixture containing nano silver particles, in which the coating mixture comprising nitrate silver salt ( AgNO3), distilled water, PVA glue, Hydrazin hydrate reducing agent, oil VIO 102, fine organic powder, these components have a certain percentage by mass, (b) applying, by screen printing method, the coating mixture onto the clean surface of the granites prepared (c) calcinating the granites prepared in the above step in the furnace at a temperature and in the period of time sufficient for the fine organic powder to be burned off completely to obtain granites having antibacterial surface.

Description

PROCESS FOR PRODUCING ANTIBACTERIAL GRANITES COATED AND THE GRANITES BY THE PROCESS

Field of the invention

The invention relates to processes used in manufacturing granites, and more particularly to the production of antibacterial granites by coating antibacterial glaze.

Background of the invention

It is known that, during the manufacture of granites or other similar products, titanium oxide (Ti02) is used to prepare the solution (with titanium particles of size nanometer), then this solution is coated on the surface of the products, then the the products are dried at low temperatures or are set to dry naturally. This method enables the products to be able to self-clean their surface better than other products of the type that are not applied this technique.

However, the method of application of titanium nano materials mentioned above bears the following disadvantages:

- requiring environments with optical catalysts, that is it is necessary to have strong impact by light (from the sun or lights) in order to promote better self-cleaning properties on the surface of the product.

- cementation strength (decisive factor in life of raw materials) is not high due to only one sprayed coat on the surface as the normal glue, which is easily scratched or worn through use

- In nature, material titanium does not characterize in property of killing bacteria as well as silver .

Thus, there exists the need for other methods of producing granites which are highly resistant to bacteria and suitable for use in polluted environmental conditions of today, especially in areas with high risk of pollution, like hospitals, schools, etc.

Summary of the invention

Methods of producing granites coated with antibacterial layers on the surface are provided in the invention. With the layers of antibacterial material on the surface, it is achieved highly environmental sanitation. Hence the granites are produced by the method of the invention can overcome the disadvantages of granites in prior art.

To implement this purpose, it is, according to the invention, proposed the creation of a membrane of nano silver (Ag) coated granites surface. The membrane is created by nano silver colloidal solution with antimicrobial Ag, colloidal solution is to be coated onto granites 's surfaces. Next, the granites coated with layers of colloidal silver is calcinated in the furnace at high temperature (960°C), at this temperature the silver nanoparticles will be fused and firmly mounted to the enamel on the surface of the granites to ensure the property of anti bacterium for a long time for the products.

Principle of operation making antibacterial properties of silver is that nano silver particles can powerfully and fastly destroy the DNA structure of bacteria, particularly strains of the bacteria E -coli (which is the bacteria that causes diarrhea and other bacteria weakening the immune system of humans).

Products applied technique of nano silver if used in hospitals, laboratories or in other public areas such as offices, buildings, schools, or even in the kitchen and family toilet, etc, will ensure environment to be clean, sanitary. In addtion, these products will reduce the chemical cleaning which has been often used so far and is the main cause to environmental pollution and the damage to human health.

Brief description of the drawings Figure 1 is a diagram showing the manufacturing process of antibacterial granites, according to the invention.

Detailed description

As shown in Figure 1, the production process of antibacterial granites coated according to the invention includes three main steps: step of creating nano silver membrane which is to be sprayed onto the surface of the granites; step of coating priting mixture onto the surface of the granites, this step coating mixture (menbrance) prepared in the first step to create prepared products for the final step; the final step of the process is to put prepared granites in kilns for a certain period of time at a certain temperature to obtain granites products. The following section will describe in detail the steps of a process through a non-limiting example of the invention.

The example for carrying the invention

Invention will be now described in detail through examples detailing the steps in the production process of antibacterial tiles. Three steps are carried as follows:

- Stepl : creating nano silver membrance:

To create a nano-silver membrane to be coated, antimicrobial solution is prepared first. The materials needed include:

• Salt nitrate silver (AgN03) in

• Distilled water.

• PVA (polyvinyl acetate) glue.

• Reducing agent Hydrazine hydrate.

• Stirring machine with glass shaft, adjustable speed.

• Heat-resistant glass tank.

• Heating equipment. • Printing oil VIO 102

• Fine organic powder

Then, preparing a suspension containing nanosilver particles by dissolving a volume of nitrate silver salt (AgN03) with distilled water to create a AgN03 solution. AgN03 solution is contained in the reaction tank (of heat-resistant glass). Next, slowly poring fouring PVA glue by a certain proportion of volume into the tank containing the above AgN03 solution, stirring for a period of time, to dissolve PVA glue at a certain temperature, the temperature is chosen to ensure PVA glue to be dissolved in solution of nitrate silver. After this step, nitrate silver solution is formed.

Quick addition a volume of solution Hydrazine Hydrate in a predetermined concentration into the above solution. Then in the reaction tank, the reduction reaction of silver ions Ag⁺ to Ag silver particles will happens under the effect of reducing agent Hydrazin hydrate. It takes a while for this reduction reaction is carried completely at room temperature, and the resulting suspension containing nano silver particles will be achieved, which is in a state ready to be coated onto ceramic surfaces.

Next is the process of creating a coating mixture onto the surface of the granites.

To facilitate the process of printing the mixed suspension of silver particles onto the ceramic surface, this mixed suspension must be in the viscosity and density suitable for the coating by flat screen printing method. The fillers must be organic, non-reactive with Ag suspension. The presence of these fillers will help the coating process easier and ensure the content of silver clinging to the surface of the ceramic tioes to be stabilized. The organic fillers are selected so as they will be burned off during the calcinating of the granites.

Organic fillers used are oil VIO 102 and fine organic powder. Oil VIO 102 is added to Ag suspension prepared above, then the system is stirred in a certain period of time until it becomes a homogeneous system; stirring time is usually 60 minutes at temperature of 60°C. Add organic powder with a certain proportion of volume in the system and well stir to obtain a mixture containing silver particles in the nanometer size known as suspension systems.

Step 2: Coating the suspension systems onto the surface of the granites.

After ceating the suspension systems (the mixture), the next step of the process is to coat the mixture onto the surface of the granites. To fufil this, the the following operations are done:

- Preparatory steps:

Preparing calcined granites with clean surface, no defects and no chemical marks on the surface.

Preparation of printing screen with a certain aperture depending on the requirements of the products and having the frame level to suit the size of the granites.

At most flat printers are used and the volume of pringting material on each granites must be sufficient.

Preparation of Dryer, offset printing machines and production line. Coating methods:

The mixture containing silver particles in the nanometer size (suspension system) above - obtained is coated onto the surface of the granites by flat screen printing method, printer calibration satisfies the following requirements:

- Tongue brushing has enough compression force onto the surface mesh.

- Distance from the granites to the mesh face is reasonable so that the surface of the granites not sticking to the mesh again when the knives are out.

- A table in a uniform flatness.

- The granites after the printer have homogenous coverage layer in thickness on the surface.

- The print in the edges of the granites has little excess ink and little chance to peel. the granites are printed on line with speed suitable, the dryer and parameters need to be adjusted suitablly to make sure the surface is dry before the next printer.

- Step 3 : calcinating granites

Granites coated with the suspension containing nanometer sized silver particles will be heated in the furnace, the temperature in the furnace and the period of time to calcinate are chosen so that the organic filler on the surface of the granites will be burned completely after calcination. Usually

calcinating temperature is chosen 960°C and calcinating time is 72 minutes.

The silver nanoparticles are firmly attached to the surface of the products and make silver lining of nanometer size desired.

Applicability of the invention

The ancients knew the silver used as raw materials for manufacturing supplies (cups, bowls, glass cups, knives, spoons, chopsticks ...) to check and remove the toxins (or rather the harmful bacteria) in food products. Science has also discovered the ability of bactericidal of silver material in nanoscale.

- Products applied silver nano technology if used in hospitals, laboratories or in other public areas such as offices, buildings, schools, even in family kitchens, toilets, etc., will ensure the environment clean and hygiene. - Saving up costs for common chemicals used for cleaning granites (often causing environmental pollution and harm to human health).

While the present invention has been shown and described in connection with the preferred embodiments, it will be apparent to those skilled in the art that modifications and variations can be made without departing from the spirit and scope of the invention as defined by the appended claims.

Claims

What is claimed is

1. Process for producing antibacterial granites, the process comprises the steps of: (a) creating the coating mixture containing nano silver particles, in which the coating mixture comprising nitrate silver salt ( AgN03), distilled water, PVA glue, Hydrazin hydrate reducing agent, oil VIO 102, fine organic powder, these components have a certain percentage by mass, (b) applying, by screen printing method, the coating mixture onto the clean surface of the granites prepared (c) calcinating the granites prepared in the above step in the furnace at a temperature and in the period of time sufficient for the fine organic powder to be burned off completely to obtain granites having antibacterial surface.

2. Granites are produced by the process according to claim 1.