WO2019078796A2

WO2019078796A2 - Antibacterial clay

Info

Publication number: WO2019078796A2
Application number: PCT/TR2018/050539
Authority: WO
Inventors: Saadet YAPAR; Seren TURKER
Original assignee: Ege Universitesi
Priority date: 2017-10-07
Filing date: 2018-10-02
Publication date: 2019-04-25
Also published as: WO2019078796A3; TR201715145A2

Abstract

The invention is clay that has been given antibacterial characteristics by modifying it with an antibacterial agent and the production method thereof. The developed clay material can be used in several sectors as a disinfection agent.

Description

ANTI BACTERI AL CLAY

Technical Field of the I nvention

The invention is related to a clay material that has been given antibacterial characteristics by modifying it with a cationic surfactant that is bactericidal and the production method thereof .

Known State of the Art ( Prior Art) Several products such as hygienic, personal hygiene, cosmetics, and dental care products containing antibacterial agents are known to be prevalently used in several sectors in order to eliminate harmful micro organisms from any kind of material, and to remove microbes that may lead to a disease in humans. Nowadays hospital microbes may lead to fatal infections and it is usually a risk against in-patients, patients who have had an operation, are being treated in intensive care units, or who are receiving treatments that weaken the immune system. Bacteria may infect patients not only from unhygienic hospital rooms, but from causes such as violation of hygiene rules by nurses or doctors, that need to be carried out at the hospital during patient check-ups, and food and fruits, and flowers that the visitors or hospital companions bring to the hospital. Many hospitals prohibit food, flowers etc to be brought to the hospital and they publish brochures that show how the bacteria and viruses may infect people and how to take precautions against them. As bacteria and viruses may develop resistance to antibiotics this causes difficulties in solving the problem and sometimes antibiotic usage is meaningless.

As the infections caused by bacteria may be dangerous or even fatal, several agents have been developed or are still being developed including antibiotics which may be effective against such organisms. I n recent years, studies have been carried out to develop materials that may prevent the contact of bacteria with living beings. A definite result has not been obtained from such studies as bacteria develop resistance and as some agents that are produced are not effective against bacteria. Moreover some agents that are produced are used in some formulations (toothpaste, deodorants, disinfections soaps etc.) and compatibility problems that negatively affect the end product quality with other components in the formulations occur. Due to these reasons, studies regarding these issues need sustainability. Clay minerals that have high absorption/adsorption and cation exchange capacities have been used in the production of bricks, ceramic and various household goods since ancient times, and besides these they are also being used in antibacterial agents, and in the health, cosmetics and personal hygiene sectors.

When inventions that are similar to said invention have been searched, the below mentioned documents have been observed:

• US2005271595A1 : I n this American patent application viscous or gel type sterilized compositions suitable to be used for hand cleaning is described. These compositions comprise alcohol, water and thickeners.

• US6140289A: I n this patent document anti-microbial compositions that comprise at least a surfactant that is non-ionic, a cationic surfactant and an amine oxide surfactant and water is described.

• EP2082724B1 : This European patent is related to the usage of cationic surfactants as accelerators of traditional antimicrobial activities in deodorants and dental hygiene.

I n this invention sodium montmorillonite that has been modified with benzethonium chloride which has antibacterial characteristics is produced and an antibacterial clay product is obtained.

Brief Description of the I nvention and its Aims

The antibacterial clay according to the invention comprises the advantages listed below: · It becomes effective in a short period of time and its effects are long lasting.

• The irritation problem that arises during the usage of antibacterial products is significantly eliminated by means of this clay.

• The production time of said clay is short and this enables energy saving.

• It is especially effective in gram positive and gram negative bacteria. • The clay that is used is obtained from the mineral deposits in Turkey and this allows easy access.

Detailed Description of the I nvention The invention is a powder material that formed of sodium montmorillonite that has been given antibacterial characteristics by modifying it with benzethonium chloride which is an antibacterial agent and a cationic surfactant. This agent cannot be dissolved in water. The sodium montmorillonite used is obtained from the Anatolian region.

During the antibacterial clay production, first of all bentonite is purified by means of a sedimentation technique. 6-10% , preferably 10% by weight of montmorillonite-water dispersion is prepared and it is agitated in a water bath in ambient temperature for 20-24 hours, preferably 24 hours. Following agitation, the bentonite-water dispersion that is diluted to 8-10% (v/v) , preferably 10% (v/v) bentonite-water dispersion is centrifuged for 1 -4 minutes, preferably for 1 minute at 2200-2400 rpm, preferably at 2200 rpm and the solid- liquid phases are separated. The supernatant having the clay fraction less than 2 μιτι is collected.

Antibacterial clay subject to the invention is produced by means of two methods. These are the microwave method and the hydrothermal heating method.

Microwave Method

The purified clay is added to water that is being mixed at 700-750 rpm speed in order to obtain a homogenous clay-water dispersion of 9-10wt% , preferably 10 wt% . The 500ml solution containing benzothonium chloride at an amount equal to 100% of the cation exchange capacity of bentonite, is added to the clay-water dispersion prepared. The final dispersion is placed into a microwave bowl and subjected to the microwave irradiation for 5 minutes at 360 Watts. At the end of the process the dispersion is centrifuged for 5-10 minutes, preferably 5 minutes at 3500-4000rpm and the solid-liquid phases are separated. The solid phase is washed twice with 450-500ml_, preferably 500ml_ water each time and then it is dried at 75-80°C, preferably at 80°C.

Hvdrothermal Heating Method: The clay that has been purified is added to water that is mixed at 700-750 rpm speed in order to obtain 9-10wt% , preferably 10 wt% homogenous clay-water dispersion. 500ml solution containing benzethonium chloride at an equal amount to 100% of the cation exchange capacity of bentonite is added drop-wise to the 9-10wt% , preferably 10 wt% clay-water dispersion at 60-65 °C, preferably at 60°C, stirred at 700-750 rpm speed, preferably at 700 rpm speed. A stirring process for nearly 2.5-3 hours, preferably for 3 hours is applied. At the end of the process the dispersion is centrifuged for 5 minutes at 3500-4000rpm, and the solid and liquid phases are separated. The solid phase is washed twice with 450-500ml_, preferably 500m l_ water each time and following this it is dried at 75-80°C.

The product obtained at the end of both methods is a cream colored, odorless solid that cannot be wetted with water. The antibacterial characteristics of the products have been tested against E Co// and S. Aureus bacteria by applying ASTM 2149 and Agar diffusion methods. The results that have been obtained show that the antibacterial clay that is prepared using the microwave method is more effective against said bacteria.

Claims

CLAI MS

An antibacterial clay production method is characterized by the steps given below; i) Bentonite clay is purified by means of a sedimentation method, ii) The purified clay is added into water that is being mixed at 700-750 rpm speed, in order to obtain 9-10 wt% , preferably 10 wt % homogenous clay-water dispersion, iii) The solution containing benzethonium chloride at an amount equal to 100% of the cation exchange capacity of bentonite, is added to the 9-10 wt% , preferably 10wt % clay-water dispersion prepared and the final dispersion is placed into a microwave bowl and subjected to micro wave irradiation, or the benzotonium chloride solution is added drop-wise to the prepared 9-1 0 wt% , preferably 10wt % of clay-water dispersion at 60-65°C, while it is being stirred at 700-750rpm speed, iv) Following this, the dispersion is centrifuged at 3500-4000 rpm, and the solid- liquid phases are separated, v) The solid phase is washed twice with water,

vi) The washing is followed by drying.

A method according to claim 1 , characterized in that the sedimentation of bentonite clay involves the steps mentioned below;

- Preparation of 6-10% , preferably 10% by weight of montmorillonite-water dispersion,

- Shaking of the dispersion at ambient temperature in a water bath for 20-24 hours, preferably for 24 hours,

- Following agitation, the bentonite-water dispersion that is diluted at 8-10% (v/v) , preferably at 10% (v/v) is centrifuged at 2200-2400 rpm , preferably at 2200 rpm, for 1 -4 minutes, preferably for 1 minute and the solid, liquid phases are separated. A method according to claim 1 , characterized in that the purified clay in process step (ii) is added to water that is being mixed at 700-750 rpm speed in order to obtain a 10% homogenous clay-water dispersion.

A method according to claim 1 , characterized in that, the solution containing benzethonium chloride at an equal amount to 100% of the cation exchange capacity of bentonite is, 500ml_.

A method according to claim 1 , characterized in that, the dispersion that is prepared in the process step (iii) , is taken into a microwave bowl, and subjected to microwave irradiation for 5 minutes at 360 Watts.

Method according to claim 1 , characterized in that the dispersion in the process step numbered (iv) is centrifuged for 5-10 minutes, preferably for 5 minutes.

Method according to claim 1 , characterized in that in process step (v) 450-500m l_, preferably 500ml_ water is added to the solid phase each time and the solid phase is washed.

A method according to claim 1 , characterized in that in process step (iii) the solution containing benzethonium chloride at an equal amount to 100% of the cation exchange capacity of bentonite, is added drop wise to the 10wt % clay-water dispersion that has been prepared previously, while it is being stirred at 60°C, at a speed of 700 rpm , and the mixture is continued to be stirred for 3 more hours.

A method according to claim 1 , characterized in that in the process step (vi) , the solid phase is dried at 75-80°C, preferably at a temperature of 80°C.

0. An antibacterial clay which is produced by adding the solution containing benzethonium chloride in an amount equal to 100% of the cation exchange capacity of bentonite at the process step (iii) by means of the method according to claim 1 , into the 9-10 wt% , preferably 10 wt% of clay-water dispersion and placing the dispersion into a microwave bowl and subjected to microwave irradiation. 1 . An antibacterial clay which is produced by the drop wise addition of the solution containing benzethonium chloride in an amount equal to 100% of the cation exchange capacity of bentonite at the process step (iii) by means of the method according to claim 1 , into the 9-10 wt% , preferably 10 wt% of clay-water dispersion at 60-65°C, preferably at 60°C and a stirring rate of 700-750rpm , preferably at 700rpm , and the stirring is continued further. 2. An antibacterial clay according to 10 or 1 1 , characterized in that it comprises montmorillonite and benzethonium chloride. 3. Usage of the antibacterial clay according to claim 10 or 1 1 in the cosmetic sector. 4. Usage of the antibacterial clay according to claim 10 or 1 1 in the health sector. 5. Usage of the antibacterial clay according to claim 10 or 1 1 in the personal hygiene sector. 6. Usage of the antibacterial clay according to claim 10 or 1 1 in the textile sector in order to produce antibacterial fabrics. 7. Usage of the antibacterial clay according to claim 10 or 1 1 in dental and oral care sector.