FIELD OF THE INVENTION

This invention relates to novel silane quaternary ammonium compounds and process for preparing the same. The present invention also relates to a formulation comprising silane quaternary ammonium compound.

BACKGROUND

Antimicrobial agents are used to prevent microbiological contamination and deterioration of products, materials and systems. Of the diverse categories of antimicrobial agents and compositions, quaternary ammonium compounds represent one of the largest of the classes of agents in use. Silicone containing quaternary ammonium compounds are well known and are exemplified in U.S. Patent No. 3560385.

Quaternary ammonium organosilanes are useful as preservative agents for emulsions, dispersions or solutions in a medium where biological growth can be observed, for example in cosmetics, disinfectants, detergent compositions and coatings, in the production of textiles, pulp and paper, food, or oil and gas, and in wood preservation and building material protection.

Quaternary ammonium organosilanes have the advantage compared to most antimicrobial agents of resistance to diffusion or leaching, since the quaternary ammonium group is bound to an organosilane moiety. The quaternary ammonium organosilane remains at the surface to which it has been applied and thus has a longer effective life than other microbial agents such as other quaternary ammonium compounds.

The use of silicone containing quaternary ammonium compounds as antimicrobial agents is taught in a wide variety of patents such as US3730701, US3817739, US3794736 and US3860709.

Further, the use of organosilicon quaternary ammonium compounds for treating the surface of a substrate, such as a cellulose fabric is disclosed in US4282366. The organosilicon quaternary ammonium compounds used are selected from the group consisting of N-(trimethoxy silyl methyl)octadecyldimethylammonium chloride, N-(6-tri methoxy silyl hexyl) tetradecyldimethylammonium chloride, N-(5-tri methoxy silylpentyl) hexa decyl dimethylammonium chloride, N-(5-tri methoxy silylpentyl) tetradecyl dimethylammonium chloride, N-(6-trimetho xysilylhexyl) pentadecyl dimethylammonium chloride, N-(6-trimetho xysilylhexyl)octadecyl di methyl ammonium chloride and N-(5-tri methoxysilylpentyl) octadecyl dimethylammonium chloride.

US4504541 disclose antimicrobial fabrics with improved resistance to discoloration in which the fabric is treated with a quaternary ammonium
base containing an organosilicone. I

US4692374 disclose an antimicrobially active wet wiper comprising an organo-silicon quaternary ammonium salt selected from the group consisting of a 3-(trimethoxysilyl) propyldidecylmethyl ammonium salt and 3-(trimethoxysilyl) propyloctadecyldimethyl ammonium salt.

Quaternary ammonium organosilanes are often applied from solvent solutions such as lower alcohols and the commercial versions of these quaternized organosilanes are commonly provided as methanolic solutions.

The various compositions containing quaternary ammonium organosilanes in the form of emulsion or micro-emulsion are also disclosed in various patent documents.

WO 8700006 discloses a microbiocidal composition for killing microorganisms on plants comprising an aqueous mixture of a surfactant and an effective amount of organo-silicon quaternary amine.

A clear micro-emulsion of a quaternized organosilane using a cosurfactant having an HLB value of at least 1 is taught in U.S. Patent No. 4842766. This patent teaches that the methanol-based solvent in which the organosilane is supplied must be removed before blending the quaternized organosilane with the cosurfactant (e.g., a nonionic surfactant can used). If the methanol is not removed, a creamy white emulsion forms which is unstable and will separate into oil and water phases over time. It also teaches that high shear may have to be applied to the mixtures of organosilane and cosurfactant to ensure codispersion. It has the disadvantage of requiring a homogenization step to prepare such micro-emulsions.

Further, U.S. Patent No. 4631273 disclose oil-in-water emulsions containing 3-(trimethoxysilyl)propyldimethyloctadecyl ammonium chloride as well as, optionally, cosurfactants such as nonionic and cationic surfactants. These emulsions employ a homogenizer using high shear conditions and teach that the quaternized organosilane does not hydrolyze while it is in emulsion form and thus does not polymerize to an insoluble siloxane. The Examples use ARQUAD.RTM. T27W cationic surfactant which is trimethyl tallow ammonium chloride. However, these emulsions also require a water immiscible liquid such as a polydimethylsiloxane or a mineral oil with which the quaternized organosilane associates.

WO2008076839 discloses aqueous compositions of silane quaternary ammonium compounds prepared by diluting an alkanol solution of the silane quaternary ammonium compound in water with at least one nonionic surfactant. The weight ratio of the silane quaternary ammonium compound and nonionic surfactant is provided to yield a composition which can remain stable in dilute aqueous compositions, can be applied to any surface and dry quickly to provide an anti-microbial film. The alkali metal bicarbonate salts are added to the composition to improve the anti-microbial properties as well as the drying time of the composition.

These available formulations of quaternary ammonium silanes suffer from several shortcomings. Firstly and fore mostly, the active content of the presently available formulations is on a lower side, (less than 5%). Furthermore, the presence of additives such as surfactants reduces the antimicrobial activity of the active present in the formulation. Therefore, there exists a need for a simple and stable formulation that contains a higher proportion of the active, and is devoid of any formulation additives.

Definitions

As used in the present specification, the following words and phrases are generally intended to have the meanings as set forth below, except to the extent that the context in which they are used indicates otherwise.

Quaternary ammonium silane means compound wherein silicon is attached to a quaternary ammonium group and hydrolysable groups.

Quaternary ammonium group means a functional group wherein the nitrogen atom is attached to different groups on all its four valences.
Active site means that portion of the molecule which acts on the bacterial wall to destroy it.

Reactive site means that site in the molecule which gets attached to any substrate and binds the molecule to the substrate.

Substrate Finishing Agent means a finishing composition meant for deposition onto a textile substrate to give a specific property to the substrate like smooth feel, antistatic property, antimicrobial property etc.

Antimicrobial agent means a compound which inhibits the growth of microbes by virtue of its properties.

Antistatic agent means a compound used for treatment of materials or their surfaces in order to reduce or eliminate the buildup of static electricity Durability means the extent to which a molecule withstands different types of stress.

OBJECTS OF THE INVENTION

It is an object of the present invention to provide novel silane quaternary ammonium compounds which are highly water soluble.

It is another object of the present invention to provide a simple and economic process for the preparation of silane quaternary ammonium compounds which are highly water soluble.

It is still another object of the present invention to provide a composition that comprises a water soluble silane quaternary ammonium compound.

It is yet another object of the present invention to provide a stable composition that contains a higher proportion of the active.

It is a further object of the present invention to provide a stable composition which is devoid of any formulation additives such as surfactant.

It is still further object of the present invention to provide a composition having enhanced anti-microbial activity.

SUMMARY OF THE INVENTION

In accordance with the present invention there is provided a silane quaternary ammonium compound of formula I:

Typically, the R1 is selected from the group consisting of mono-alkylene glycol, di-alkylene glycol, poly-alkylene glycol and hydroxyethyl ethoxy ether.
In accordance with one preferred embodiment of the present invention the Ri is diethylene glycol.

In accordance with another preferred embodiment of the present invention the Ri is polyethylene glycol.

In accordance with still another preferred embodiment of the present invention the R1 is hydroxyethyl ethoxy ether.

Typically, the silane quaternary ammonium compound of formula I is selected from the group consisting of 3 - ( diethylene glycoxy , dimethoxy silyl)- propyl - dimethyl octadecyl ammonium chloride, 3 - ( polyethylene glycoxy , dimethoxy silyl)- propyl - dimethyl octadecyl ammonium chloride and 3 - ((hydroxyethyl ethoxyether) dimethoxy silyl)- propyl - dimethyl octadecyl ammonium chloride.

In accordance with another aspect of the present invention there is provided a process for the preparation of silane quaternary ammonium compound of formula I, said process comprises reacting a compound of formula II:

with alkylene glycol at a temperature of about 120°C to obtain a silane quaternary ammonium compound of formula I.

(formula I)

Typically, the compound of formula II is dimethyloctadecyl[3-(trimethoxysilyl) propyl] ammonium chloride.

Typically, the R1 is selected from the group consisting of mono-alkylene glycol, di-alkylene glycol, poly-alkylene glycol and hydroxyethyl ethoxyether.

In accordance with one preferred embodiment of the present invention the R1 is diethylene glycol.

In accordance with another preferred embodiment of the present invention the R1 is polyethylene glycol.

In accordance with still another preferred embodiment of the present invention the R1 is hydroxyethyl ethoxy ether.

Typically, the silane quaternary ammonium compound of formula I is selected from the group consisting of 3 - ( diethylene glycoxy , dimethoxy silyl)- propyl - dimethyl octadecyl ammonium chloride, 3 - ( polyethylene glycoxy , dimethoxy silyl)- propyl - dimethyl octadecyl ammonium chloride and 3 - ((hydroxyethyl ethoxyether) dimethoxy silyl)- propyl - dimethyl octadecyl ammonium chloride.

In accordance still another aspect of the present invention there is provided a surfactant-free aqueous anti-microbial composition comprising: a) a silane quaternary ammonium compound of formula I:

(formula I) in an amount of about 5 to 10 % of the mass of the composition; and
b) at least one aqueous vehicle in an amount of about 90 to 95 % of the mass of the composition. Typically, the R1 is selected from the group consisting of mono-alkylene glycol, di-alkylene glycol, poly-alkylene glycol and hydroxyethyl ethoxyether.
In accordance with one preferred embodiment of the present invention the R1 is diethylene glycol.

In accordance with another preferred embodiment of the present invention the R1 is polyethylene glycol.

In accordance with still another preferred embodiment of the present invention the R1 is hydroxyethyl ethoxy ether.

Typically, the silane quaternary ammonium compound of formula I is selected from the group consisting of 3 - ( diethylene glycoxy , dimethoxy silyl)- propyl - dimethyl octadecyl ammonium chloride, 3 - ( polyethylene glycoxy , dimethoxy silyl)- propyl - dimethyl octadecyl ammonium chloride and 3 - ((hydroxyethyl ethoxyether) dimethoxy silyl)- propyl - dimethyl octadecyl ammonium chloride.
Typically, the vehicle is water.

DETAILED DESCRIPTION OF THE INVENTION

Considering the drawbacks such as solubility problem, stability problem and reduced activity, associated with the available quaternary ammonium silane compounds and their formulation, the inventors of the present invention developed novel quaternary ammonium silanes which are highly water soluble. The developed silane compounds of the present invention contain sufficient number of active and reactive sites to balance solubility and antimicrobial performance. This number improves its binding to the surface of a substrate by inter - condensation reaction. As a result, the stability of the product on the substrate increases with excellent property antimicrobial efficiency, antistatic efficiency and durability.

In accordance with the present invention there is provided a silane quaternary ammonium compound of formula I:

(formula I)

In accordance with the present invention the R1 is selected from the group consisting of mono-alkylene glycol, di-alkylene glycol, poly-alkylene glycol and hydroxyethyl ethoxy ether.

In accordance with one preferred embodiment of the present invention the R1 is diethylene glycol and the silane quaternary ammonium compound of formula I is 3 - ( diethylene glycoxy , dimethoxy silyl)- propyl - dimethyl octadecyl ammonium chloR1de.
In accordance with another preferred embodiment of the present invention the R1 is polyethylene glycol and the silane quaternary ammonium compound of formula I is 3 - ( polyethylene glycoxy , dimethoxy silyl)-propyl - dimethyl octadecyl ammonium chloR1de.
In accordance with another preferred embodiment of the present invention the R1 is hydroxyethyl ethoxyether and the silane quaternary ammonium compound of formula I is 3 - ((hydroxyethyl ethoxyether) dimethoxy silyl)-propyl - dimethyl octadecyl ammonium chloR1de.

In accordance with another aspect of the present invention there is provided
a process for the preparation of silane quaternary ammonium compound of
formula I.

The process of the present invention involves reaction of a compound of
formula II (dimethyloctadecyl[3-(trimethoxysilyl) propyl] ammonium
chloR1de):

(formula II)

and alkylene glycol at a temperature of about 120°C obtain a silane quaternary ammonium compound of formula I.

(formula I)

Typically, alkylene glycol is selected from the group consisting of mono-alkylene glycol, di-alkylene glycol and poly-alkylene glycol. In accordance with the present invention the reaction involves substitution of one of the methoxy group of the compound of formula II with the alkylene glycoxy group /hydroxyethyl ethoxy ether with release of methanol.

In accordance with the present invention the R1 is selected from the group consisting of mono-alkylene glycol, di-alkylene glycol, poly-alkylene glycol and hydroxyethyl ethoxy ether.

In accordance with one preferred embodiment of the present invention the R1 is diethylene glycol and the silane quaternary ammonium compound of formula I is 3 - ( diethylene glycoxy , dimethoxy silyl)- propyl - dimethyl octadecyl ammonium chloR1de.
Reaction scheme:

In accordance with another preferred embodiment of the present invention the R1 is polyethylene glycol and the silane quaternary ammonium compound of formula I is 3 - ( polyethylene glycoxy, dimethoxy silyl)-propyl - dimethyl octadecyl ammonium chloR1de.

In accordance with another preferred embodiment of the present invention the R] is hydroxyethyl ethoxyether and the silane quaternary ammonium compound of formula I is 3 - ((hydroxyethyl ethoxyether) dimethoxy silyl)-propyl - dimethyl octadecyl ammonium chloR1de.

The inventors of the present invention found that the silane quaternary ammonium compound of formula I of the present invention is highly water soluble due to the presence of water soluble alkyleneglycoxy group / hydroxyethyl ethoxyether group.
Because of the enhanced solubility of the molecule of the present invention it can be used directly in the form of anti-microbial aqueous composition without the use of any emulsifying agent or surfactant.

In accordance still another aspect of the present invention there is provided a surfactant-free aqueous anti-microbial composition compR1sing: a) a silane quaternary ammonium compound of formula I:

(formula I) in an amount of about 5 to 10 % of the mass of the composition; and
b) at least one aqueous vehicle in an amount of about 90 to 95 % of the mass of the composition.

In accordance with the present invention the R1 is selected from the group consisting of mono-alkylene glycol, di-alkylene glycol, poly-alkylene glycol and hydroxyethyl ethoxy ether.

In accordance with one preferred embodiment of the present invention the R1 is diethylene glycol and the silane quaternary ammonium compound of formula I is 3 - ( diethylene glycoxy , dimethoxy silyl)- propyl - dimethyl octadecyl ammonium chloR1de.
In accordance with another preferred embodiment of the present invention the R1 is polyethylene glycol and the silane quaternary ammonium compound of formula I is 3 - ( polyethylene glycoxy , dimethoxy silyl)-propyl - dimethyl octadecyl ammonium chloR1de.
In accordance with another preferred embodiment of the present invention the R1 is hydroxyethyl ethoxyether and the silane quaternary ammonium compound of formula I is 3 - ((hydroxyethyl ethoxyether) dimethoxy silyl)-propyl - dimethyl octadecyl ammonium chloR1de.

Typically, the vehicle is water.

Comparative Antimicrobial Activity:

The anti-microbial study was carR1ed out using ASTM E2149 standard test. The results are shown in the following tables (Table 1 & 2)

The composition of the present invention can be used for applying on the surfaces or it can also be used as an additive in other products as an antimicrobial agent.

Technical Advance and economic significance:

- The present invention provides novel quaternary ammonium silane compounds with water soluble active sites for improved solubility and stability in water and reactive sites for anchoR1ng on the substrate surface.

- The compounds of the present invention are water soluble and form a stable clear solution.
- The compounds of the present invention are prepared by a simple and economic process.
- Further, the composition of the present invention compR1sing quaternary ammonium silane compound is highly stable without the use of surfactant.

- Still further the composition of the present invention has improved antimicrobial activity, antistatic efficiency and durability on fabR1cs and garments.

- The composition of the present invention is highly active at low concentration.

While considerable emphasis has been placed herein on the specific ingredients of the preferred embodiment, it will be appreciated that many further elements can be added and that many changes can be made in the preferred embodiment without departing from the pR1nciples of the invention. These and other changes in the preferred embodiment of the invention will be apparent to those skilled in the art from the disclosure herein, whereby it is to be distinctly understood that the foregoing descR1ptive matter is to be interpreted merely as illustrative of the invention and not as a limitation.

We claim:

1. A silane quaternary ammonium compound of formula I:
(formula I)

2. The silane quaternary ammonium compound of formula I as claimed in claim 1, wherein the Rj is selected from the group consisting of mono-alkylene glycol, di-alkylene glycol, poly-alkylene glycol and hydroxyethyl ethoxy ether.

3. The silane quaternary ammonium compound of formula I as claimed in claim 1, wherein the R1 is diethylene glycol.

4. The silane quaternary ammonium compound of formula I as claimed in claim 1, wherein the Rj is polyethylene glycol.

5. The silane quaternary ammonium compound of formula I as claimed in claim 1, wherein the R1 is hydroxyethyl ethoxy ether.

6. The silane quaternary ammonium compound of formula I as claimed in claim 1, selected from the group consisting of 3 - ( diethylene glycoxy , dimethoxy silyl)- propyl - dimethyl octadecyl ammonium chloride, 3 - ( polyethylene glycoxy , dimethoxy silyl)- propyl - dimethyl octadecyl ammonium chloride and 3 - ((hydroxyethyl ethoxyether) dimethoxy silyl)- propyl - dimethyl octadecyl ammonium chloride.

7. A process for the preparation of silane quaternary ammonium compound of formula I comprises reacting a compound of formula II: (formula II) with alkylene glycol at a temperature of about 120°C to obtain a silane quaternary ammonium compound of formula I.
(formula I)

8. The process as claimed in claim 7, wherein the R1 is selected from the group consisting of mono-alkylene glycol, di-alkylene glycol, poly- alkylene glycol and hydroxyethyl ethoxy ether.

9. The process as claimed in claim 7, wherein the R1 is selected from the group consisting of diethylene glycol, polyethylene glycol and hydroxyethyl ethoxy ether.

10. The process as claimed in claim 7, wherein the alkylene glycol is selected from the group consisting of mono-alkylene glycol, di-alkylene glycol and poly-alkylene glycol.

11. The process as claimed in claim 7, wherein the silane quaternary ammonium compound of formula I is selected from the group consisting of 3 - ( diethylene glycoxy , dimethoxy silyl)- propyl - dimethyl octadecyl ammonium chloride, 3 - ( polyethylene glycoxy , dimethoxy silyl)- propyl - dimethyl octadecyl ammonium chloride and 3 -((hydroxyethyl ethoxyether) dimethoxy silyl)- propyl - dimethyl octadecyl ammonium chloride.

12. A surfactant-free aqueous anti-microbial composition comprising: a) a silane quaternary ammonium compound of formula I:
(formula I) in an amount of about 5 to 10 % of the mass of the composition; and
b) at least one aqueous vehicle in an amount of about 90 to 95% of the mass of the composition.

13. The composition as claimed in claim 12, wherein the R1 is selected from the group consisting of mono-alkylene glycol, di-alkylene glycol, poly-alkylene glycol and hydroxyethyl ethoxy ether.

14. The composition as claimed in claim 12, wherein the R1 is selected from the group consisting of diethylene glycol, polyethylene glycol and hydroxyethyl ethoxy ether.

15. The composition as claimed in claim 12, wherein the silane quaternary ammonium compound of formula I is selected from the group consisting of 3 - ( diethylene glycoxy , dimethoxy silyl)- propyl - dimethyl octadecyl ammonium chloride, 3 - ( polyethylene glycoxy , dimethoxy silyl)- propyl - dimethyl octadecyl ammonium chloride and 3 -((hydroxyethyl ethoxyether) dimethoxy silyl)- propyl - dimethyl octadecyl ammonium chloride.

16. The composition as claimed in claim 12, wherein the vehicle is water.