Claims:
WE CLAIM:
1. An aqueous biocidal composition comprising:
a) a biocide;
b) a hydrophilic acrylic polymer component;
c) a hydrophobic acrylic polymer component; and
d) an aqueous fluid medium comprising at least one solvent and water in a solvent to water ratio in the range of 1:1 to 1:19, and optionally at least one additive, wherein the amount of said aqueous fluid medium is in the range of 50 wt.% to 70 wt.% of the total composition,
wherein the combined amount of said biocide, said hydrophilic acrylic polymer component, and said hydrophobic acrylic polymer component is in the range of 30 wt.% to 50 wt.% of the total composition, and
wherein the ratio of said hydrophilic acrylic polymer component to said hydrophobic acrylic polymer component is in the range of 1:1.5 to 1:2.5.
2. The composition as claimed in claim 1, wherein said biocide is at least one selected from the group consisting of algicides, herbicides, fungicides, insectides and pesticides.
3. The composition as claimed in any one of the preceeding claims, wherein said biocide is at least one selected from the group consisting of diuron, terbutryn, isoproturon, metribuzin, linuron, atrazine, metolachlor, diquat, alachlor, terbuthylazine and simazine.
4. The composition as claimed in claim 1, wherein said solvent is at least one selected from the group consisting of alcohols, esters, ethers, ketones, glycol ethers of ethylene glycol, propylene glycol, diethylene glycol, dipropylene glycol, ethylene glycol butyl ether, propylene glycol propyl ether and butyl carbitol.
5. The composition as claimed in claim 1, wherein said additive comprises at least one compound selected from the group consisting of neutralizing agents, defoamers, cross-linking agents and surfactants.
6. The composition as claimed in claim 1, wherein the acid value and the hydroxyl value of the hydrophobic acrylic polymer component is at most 60 mg KOH/g.
7. The composition as claimed in claim 1, wherein the acid value and the hydroxyl value of the hydrophilic acrylic polymer component is in the range of 10 mg KOH/g to 120 mg KOH/g.
8. The composition as claimed in claim 1, wherein said aqueous biocidal composition is a masterbatch composition.
9. The composition as claimed in claim 8, wherein the amount of said biocide in the masterbatch composition is in the range of 5 wt.% to 20 wt.%.
10. The composition as claimed in claim 1, wherein said hydrophobic acrylic polymer component is constituted as a core, surrounded by a shell of said hydrophilic acrylic polymer component, wherein said biocide is incorporated in said core.
11. The composition as claimed in claim 1, wherein the composition comprises:
a) diuron;
b) a hydrophilic acrylic polymer component;
c) a hydrophobic acrylic polymer component; and
d) an aqueous fluid medium comprising at least one solvent and water in a solvent to water ratio in the range of 1:1 to 1:19, and optionally at least one additive, wherein the amount of said aqueous fluid medium is in the range of 50 wt.% to 70 wt.% of the total composition,
wherein the combined amount of the diuron, said hydrophilic acrylic polymer component, and said hydrophobic acrylic polymer component is in the range of 30 wt.% to 50 wt.% of the total composition, and
wherein the ratio of said hydrophilic acrylic polymer component to said hydrophobic acrylic polymer component is in the range of 1:1.5 to 1:2.5.
12. A process for preparing an aqueous biocidal composition, said process comprising adopting a sequence of steps selected from the following sequences consisting of:
Sequence I
(i) polymerizing at least one first monomer in a fluid medium, to obtain a hydrophobic acrylic polymer component;
(ii) separately polymerizing at least one second monomer to obtain a hydrophilic acrylic polymer component;
(iii) mixing said hydrophilic acrylic polymer component with said hydrophobic acrylic polymer component to obtain a first mixture;
(iv) incorporating molecules of at least one biocide into said first mixture to form complexed particles;
(v) entangling said complexed particles to form a second mixture;
(vi) neutralizing said second mixture to obtain a neutralized mixture;
(vii) optionally adding at least one additive to said neutralized mixture; and
(viii) dispersing said neutralized mixture in an aqueous medium to obtain the aqueous biocidal composition.
Sequence II
(i) polymerizing at least one first monomer in a fluid medium, to obtain a hydrophobic acrylic polymer component;
(ii) incorporating molecules of at least one biocide into monomeric units or polymeric chain of said hydrophobic acrylic polymer component to form complexed particles;
(iii) entangling said complexed particles to form a first component comprising said biocide in a core of said hydrophobic acrylic polymer component;
(iv) separately polymerizing at least one second monomer to obtain a second component comprising a hydrophilic acrylic polymer component;
(v) adding said second component to said first component to obtain a mixture;
(vi) agitating said mixture to allow mixing of said hydrophilic acrylic polymer component with the core to form a homogenous mixture;
(vii) neutralizing said homogenous mixture to obtain a neutralized mixture comprising said hydrophobic acrylic polymer component constituted as a core, surrounded by a shell of said hydrophilic acrylic polymer component, wherein said biocide is incorporated in said core;
(viii) optionally adding at least one additive to said neutralized mixture; and
(ix) dispersing said neutralized mixture in an aqueous medium to obtain the aqueous biocidal composition.
13. The process as claimed in claim 12, wherein said first monomer is at least one acrylic monomer selected from the group consisting of methyl methacrylate, butyl acrylate, 2-hydroxyethyl methacrylate, methacrylic acid, diacetone acrylamide, ethylcarbamatoethyl acrylate and butylcarbamatoethyl acrylate.
14. The process as claimed in claim 12, wherein said first monomer comprises a vinylic monomer, wherein said vinylic monomer is styrene.
15. The process as claimed in claim 12, wherein said fluid medium is at least one selected from the group consisting of alcohols, esters, ethers, ketones, glycol ethers of ethylene glycol, propylene glycol, diethylene glycol and dipropylene glycol, ethylene glycol butyl ether, propylene glycol propyl ether and butyl carbitol.
16. The process as claimed in claim 12, wherein the steps (iv), (v) of sequence I or the steps (ii), (iii) of sequence II are independently carried out at a temperature in the range of 60 °C to 140 °C for a time duration in the range of 1 hour to 3 hours.
17. The process as claimed in claim 12, wherein said second monomer is at least one selected from the group consisting of methyl methacrylate, butyl acrylate, tridecafluorooctyl methacrylate, 2-hydroxyethyl methacrylate, methacrylic acid, polyethylene glycol methacrylate, and polypropylene glycol methacrylate.
18. The process as claimed in claim 12, wherein said polymerization is carried out in the presence of at least one initiator, wherein said initiator is selected from azobisisobutyronitrile, tertiary-butyl perbenzoate, dimethyl 2,2'-azobis(2-methylpropionate, ditertiary butyl peroxide, dicumyl peroxide and ditertiary amylperoxide.
19. The process as claimed in claim 12, wherein said first monomer comprises at least 80 wt.% of hydrophobic monomers, wherein said second monomer comprises at least 25 wt.% of hydrophilic monomers.
20. The process as claimed in claim 12, wherein said neutralization is done by using a neutralizing agent, wherein said neutralizing agent is at least one selected from the group consisting of morpholine, primary amines, secondary amines, tertiary amines, aminoalcohols, liquor ammonia, sodium hydroxide and potassium hydroxide.
21. A coating composition comprising:
• an aqueous biocidal composition comprising a biocide, a hydrophilic acrylic polymer component, a hydrophobic acrylic polymer component, in an aqueous fluid medium; and
• a polymeric composition comprising a polymer and a pre-determined additive,
wherein the weight ratio of said aqueous biocidal composition to the polymeric composition is in the range of 1:3 to 1:99.
22. The coating composition as claimed in claim 21, wherein the weight ratio of the aqueous biocidal composition to the polymeric composition is in the range of 1:20 to 1:50.
23. The coating composition as claimed in claim 21, wherein the amount of the biocide in the coating composition is in the range of 0.08 wt.% to 1 wt.%.
24. The coating composition as claimed in claim 21, wherein the ratio of the polymer and pre-determined additive in the polymeric composition is in the range of 5:95 to 95:5.
25. The coating composition as claimed in claim 21, wherein the polymer is at least one selected from the group consisting of acrylic, styrene-acrylics, polyesters, epoxies, polyurethanes, and polysiloxanes.
26. The coating composition as claimed in claim 21, wherein the pre-determined additive is at least one selected from the group consisting of cosolvents, defoamers, thickeners, pH modifier, dispersing agents, wetting agents, coalescents, fluorosurfactants, opacifying polymers, plasticizers, pigments, extenders, colorants, freeze thaw stabilizers, buffers, fire retardants, ultraviolet radiation absorbers, organic fibre material, inorganic fiber materials, flow and levelling agents, adhesion promoters, oil repellants, water repellents and fillers.
27. The coating composition as claimed in claim 21, wherein the aqueous biocidal composition is a masterbatch composition.
28. The coating composition as claimed in claim 21, wherein said hydrophobic acrylic polymer component is constituted as a core, surrounded by a shell of the hydrophilic acrylic polymer component, wherein the biocide is incorporated in said core.
29. A process for preparing a coating composition, said process comprising the following steps:
(i) preparing an aqueous biocidal composition comprising:
a. a biocide;
b. a hydrophilic acrylic polymer component;
c. a hydrophobic acrylic polymer component; and
d. an aqueous fluid medium comprising at least one solvent and water in a solvent to water ratio in the range of 1:1 to 1:19, and optionally at least one additive, wherein the amount of said aqueous fluid medium is in the range of 50 wt.% to 70 wt.% of the total composition,
wherein, the combined amount of said biocide, said hydrophilic polymer component and said hydrophobic acrylic component are in an amount in the range of 30 wt.% to 50 wt.% of the total composition,
wherein the ratio of said hydrophilic polymer component to said hydrophobic acrylic component is in the range of 1:1.5 to 1:2.5; and

(ii) blending said aqueous biocidal composition in a polymeric composition comprising a polymer and a pre-determined additive to obtain a coating composition.
, Description:
FIELD
The present disclosure relates to an aqueous biocidal composition and a process for preparation thereof.
DEFINITIONS
As used in the present disclosure, the following terms are generally intended to have the meaning as set forth below, except to the extent that the context in which they are used indicate otherwise.
Hydrophobic acrylic polymer component refers to an acrylic polymer prepared by using monomer comprising at least 80 wt.% of hydrophobic monomers.
Hydrophilic acrylic polymer component refers to an acrylic polymer prepared by using monomer comprising at least 25 wt.% of hydrophilic monomers.
Acid value refers to the mass of potassium hydroxide (KOH) in milligrams that is required to neutralize one gram of chemical substance.
Hydroxyl value refers to the number of milligrams of potassium hydroxide required to neutralize the acetic acid taken up on acetylation of one gram of a chemical substance that contains free hydroxyl groups.
Biocide refers to a functional active aromatic or aliphatic compound selected from the group consisting of algaecides, herbicides, fungicides, insectides, and pesticides. The biocide comprises at least one functional group selected from the group consisting of carboxylic acid, amine, urea, carbamates, ketone, aldehyde, and the like.
The term “Core” refers to a hydrophobic acrylic polymer component containing biocide.
The term “Shell” refers to hydrophilic acrylic polymer component surrounding the core.
In the present disclosure, Core-shell phenomena refers to a core structure made up of hydrophobic acrylic polymer component surrounded by a shell structure made up of hydrophilic acrylic polymer component, wherein the core contains a biocide.
BACKGROUND
The background information herein below relates to the present disclosure but is not necessarily prior art.
Coatings applied on exterior surfaces are usually exposed to regular changes in environmental conditions and so need protection against growth of algae and fungi. Conventionally, coating compositions are mixed with biocidal compounds such as algaecides/fungicides which have ability to inhibit photosynthesis. It is important to optimize the quantity of the biocidal compound added to the coating compositions since higher quantities of such compounds would be hazardous to the environment.
The conventional processes provide techniques such as melt blending of biocide in resin by extrusion or dispersing biocide in the paint during grinding stage. However, these techniques cause degradation and or inefficient dispersion of the biocide thus lowering the anti-algal performance.
Therefore, there is felt a need for an aqueous biocidal composition that mitigates the drawbacks mentioned hereinabove.
OBJECTS
Some of the objects of the present disclosure, which at least one embodiment herein satisfies, are as follows.
It is an object of the present disclosure to ameliorate one or more problems of the prior art or to at least provide a useful alternative.
Another object of the present disclosure is to provide an aqueous biocidal composition comprising biocide.
Still another object of the present disclosure is to provide an efficient process for preparing an aqueous biocidal composition comprising optimum quantity of biocide without hampering the anti-algal performance.
Still another object of the present disclosure is to provide a coating composition comprising biocide.
Still another object of the present disclosure is to provide a process for preparation of the coating composition comprising biocide.
Yet another object of the present disclosure is to provide a masterbatch composition comprising biocide.
Yet another object of the present disclosure is to provide a process for preparation of the masterbatch composition comprising biocide.
Other objects and advantages of the present disclosure will be more apparent from the following description, which is not intended to limit the scope of the present disclosure.
SUMMARY
In one aspect, the present disclosure provides an aqueous biocidal composition comprising a biocide, a hydrophilic acrylic polymer component, a hydrophobic acrylic polymer component, and an aqueous fluid medium. The aqueous fluid medium comprises at least one solvent and water in a solvent to water ratio in the range of 1:1 to 1:19, and optionally at least one additive. The amount of the aqueous fluid medium is in the range of 50 wt.% to 70 wt.% of the total composition. The combined amount of the biocide, the hydrophilic acrylic polymer component, and the hydrophobic acrylic polymer component is in the range of 30 wt.% to 50 wt.% of the total composition. The ratio of the hydrophilic acrylic polymer component to the hydrophobic acrylic polymer component is in the range of 1:1.5 to 1:2.5.
In another aspect, the present disclosure provides a process for preparing an aqueous biocidal composition.
In accordance with one embodiment of the present disclosure, the process comprises a step of polymerizing at least one first monomer in a fluid medium, to obtain a hydrophobic acrylic polymer component. At least one second monomer is separately polymerized to obtain a hydrophilic acrylic polymer component. The hydrophilic acrylic polymer component is mixed with the hydrophobic acrylic polymer component to obtain a first mixture. The molecules of at least one biocide are incorporated into the first mixture to form complexed particles. The complexed particles are entangled to form a second mixture. The second mixture is neutralized to obtain a neutralized mixture. At least one additive is optionally added to the neutralized mixture. The neutralized mixture is dispersed in an aqueous medium to obtain the aqueous biocidal composition.
In accordance with another embodiment of the present disclosure, the process comprises a step of polymerizing at least one first monomer in a fluid medium, to obtain a hydrophobic acrylic polymer component. Molecules of at least one biocide are incorporated into monomeric units or polymeric chain of the hydrophobic acrylic polymer component to form complexed particles. The complexed particles are entangled to form a first component comprising the biocide in a core of the hydrophobic acrylic polymer component. At least one second monomer is separately polymerized to obtain a second component comprising a hydrophilic acrylic polymer component. The second component is added to the first component to obtain a mixture. The mixture is agitated to allow mixing of the hydrophilic acrylic polymer component with the core to form a homogenous mixture. The homogenous mixture is neutralized to obtain a neutralized mixture comprising the hydrophobic acrylic polymer component constituted as a core surrounded by a shell of hydrophilic acrylic polymer component, wherein the biocide is incorporated in the core. At least one additive is optionally added to the neutralized mixture. The neutralized mixture is dispersed in an aqueous medium to obtain the aqueous biocidal composition.
In still another aspect, the present disclosure provides a coating composition comprising an aqueous biocidal composition and a polymeric composition. The aqueous biocidal composition comprises a biocide, a hydrophilic acrylic polymer component, a hydrophobic acrylic polymer component, in an aqueous fluid medium. The polymeric composition comprises a polymer and a pre-determined additive, wherein the weight ratio of the aqueous biocidal composition to the polymeric composition is in the range of 1:3 to 1:99.
In still another aspect, the present disclosure provides a process for preparing a coating composition. The process comprises preparing an aqueous biocidal composition comprising a biocide, a hydrophilic acrylic polymer component, a hydrophobic acrylic polymer component, and an aqueous fluid medium. The aqueous fluid medium comprises at least one solvent and water, in a solvent to water ratio in the range of 1:1 to 1:19, and optionally at least one additive. The amount of the aqueous fluid medium is in the range of 50 wt.% to 70 wt.% of the total composition. The combined amount of the biocide, the hydrophilic acrylic polymer component, and the hydrophobic acrylic polymer component is in the range of 30 wt.% to 50 wt.% of the total composition. The ratio of the hydrophilic acrylic polymer component to the hydrophobic acrylic polymer component is in the range of 1:1.5 to 1:2.5. The aqueous biocidal composition is blended with a polymeric composition comprising a polymer and a pre-determined additive to obtain a coating composition.
BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWING
The present disclosure will now be described with the help of the accompanying drawing, in which:
Figure 1A illustrates the photographic image displaying no fragmentation of film obtained by the application of aqueous biocidal composition sample 1C;
Figure 1B illustrates the photographic image displaying fragmentation of film obtained by the application of aqueous biocidal composition sample 1D;
Figure 2 illustrates the FTIR spectrum of diuron (biocide) and the aqueous biocidal composition 1A;
Figure 3A illustrates the cylinder testing stability of diluted reference sample (left side) and diluted sample 1C (right side) at 25 °C after 2 hours;
Figure 3B illustrates the cylinder testing stability of diluted reference sample (leftside) and diluted sample 1C (rightside) at 25 °C after 8 hours;
Figure 3C illustrates the cylinder testing stability of diluted reference sample (left side) and diluted sample 1C (right side) at 25 °C after 5 days;
Figure 4 illustrates the Raman microscopic image of the film obtained by application of aqueous biocidal composition (sample 1B);
Figure 5 illustrates QUV data of samples 1B, 1C and a reference standard paint;
Figure 6A illustrates the Scanning Electron Microscope (SEM) data for aqueous biocidal composition sample 1B;
Figure 6B illustrates the chlorine mapping for aqueous biocidal composition sample 1B;
Figures 7A and 7C illustrate the SEM data for coating composition sample 2D;
Figures 7B and 7D illustrate the chlorine mapping for coating composition sample 2D;
Figure 8A illustrates the SEM data for reference standard paint sample;
Figure 8B illustrates the chlorine mapping for reference standard paint;
Figure 9A illustrates cryo-SEM analysis of a reference sample in low magnification (4000x);
Figure 9B illustrates cryo-SEM analysis of the reference sample in high magnification (18000x to 25000x);
Figure 9C illustrates cryo-SEM analysis of the aqueous biocidal composition sample 1C in low magnification (4000x); and
Figure 9D illustrates cryo-SEM analysis of the aqueous biocidal composition sample 1C in high magnification (18000x to 25000x).
DETAILED DESCRIPTION
Embodiments, of the present disclosure, will now be described with reference to the accompanying drawing.
Embodiments are provided so as to thoroughly and fully convey the scope of the present disclosure to the person skilled in the art. Numerous details, are set forth, relating to specific components, and methods, to provide a complete understanding of embodiments of the present disclosure. It will be apparent to the person skilled in the art that the details provided in the embodiments should not be construed to limit the scope of the present disclosure. In some embodiments, well-known processes, well-known apparatus structures, and well-known techniques are not described in detail.
The terminology used, in the present disclosure, is only for the purpose of explaining a particular embodiment and such terminology shall not be considered to limit the scope of the present disclosure. As used in the present disclosure, the forms "a,” "an," and "the" may be intended to include the plural forms as well, unless the context clearly suggests otherwise. The terms "comprises," "comprising," “including,” and “having,” are open ended transitional phrases and therefore specify the presence of stated features, integers, steps, operations, elements, modules, units and/or components, but do not forbid the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof. The particular order of steps disclosed in the method and process of the present disclosure is not to be construed as necessarily requiring their performance as described or illustrated. It is also to be understood that additional or alternative steps may be employed.
The terms first, second, third, etc., should not be construed to limit the scope of the present disclosure as the aforementioned terms may be only used to distinguish one element, component, region, layer or section from another component, region, layer or section. Terms such as first, second, third etc., when used herein do not imply a specific sequence or order unless clearly suggested by the present disclosure.
Outdoor walls are usually exposed to regular changes in environmental conditions and so need protection against growth of algae and fungi. Conventionally, coating compositions are mixed with biocidal compounds such as 3-(3,4-dichlorophenyl)-1,1-dimethyl urea (DCMU) which have ability to inhibit photosynthesis. It is important to optimize the addition of the quantity of the biocidal compound into the coating compositions since higher quantities of such compounds would be hazardous to the environment.
The conventional processes provide techniques such as melt blending of biocide in resin by extrusion or dispersing biocide in the paint during grinding stage. However, these techniques cause degradation or inefficient dispersion of the biocide during grinding thus lowering the anti-algal performance.
The present disclosure provides an aqueous biocidal composition having effective anti-algal performance and a process of preparation thereof. The process yields an aqueous biocidal composition exhibiting reduced leaching of the biocide. The present disclosure also provides a coating composition prepared by using the aqueous biocidal composition.
In one aspect, the present disclosure provides an aqueous biocidal composition comprising a biocide, a hydrophilic acrylic polymer component, a hydrophobic acrylic polymer component and an aqueous fluid medium. The aqueous fluid medium comprises at least one solvent and water in a solvent to water ratio in the range of 1:1 to 1:19, and optionally at least one additive. The amount of the aqueous fluid medium is in the range of 50 wt.% to 70 wt.% of the total composition. The combined amount of the biocide, the hydrophilic acrylic polymer component, and the hydrophobic acrylic polymer component is in the range of 30 wt.% to 50 wt.% of the total composition. The ratio of the hydrophilic acrylic polymer component to the hydrophobic acrylic polymer component is in the range of 1:1.5 to 1:2.5.
The biocide is at least one selected from the group consisting of algicides, fungicides, herbicides, insecticides and pesticides.
The biocide is at least one selected from the group consisting of diuron, terbutryn, isoproturon, metribuzin, linuron, atrazine, metolachlor, diquat, alachlor, terbuthylazine and simazine.
In an exemplary embodiment, the biocide is diuron.
The solvent is at least one selected from the group consisting of alcohols, esters, ethers, ketones, glycol ethers of ethylene glycol, propylene glycol, diethylene glycol, dipropylene glycol, ethylene glycol butyl ether, propylene glycol propyl ether and butyl carbitol.
In an embodiment the solvent is propylene glycol propyl ether.
The additive comprises at least one compound selected from the group consisting of neutralizing agents, defoamers, cross-linking agents and surfactants.
In an embodiment, the cross-linking agent is Adipic Dihydrazide.
The acid value and the hydroxyl value of the hydrophobic acrylic polymer component is at most 60 mg KOH/g. In an embodiment, the acid value of the hydrophobic acrylic polymer component is 28.7 mg KOH/g, and the hydroxyl value of the hydrophobic acrylic polymer component is 58.8 mg KOH/g. In another embodiment, the acid value of the hydrophobic acrylic polymer component is 28.8 mg KOH/g, and the hydroxyl value of the hydrophobic acrylic polymer component is 38.1 mg KOH/g.
The acid value and the hydroxyl value of the hydrophilic acrylic polymer component is in the range of 10 mg KOH/g to 120 mg KOH/g. In an embodiment, the acid value of the hydrophilic acrylic polymer component is 65.1 mg KOH/g, and the hydroxyl value of the hydrophilic acrylic polymer component is 43.0 mg KOH/g.
The acid value and hydroxyl value indicates the extent of the hydrophobicity and hydrophilicity of the polymer, wherein an increase in the acid value or hydroxyl value indicates increase in hydrophilicity of the polymer.
The neutralizing agent is at least one selected from the group consisting of morpholine, primary amines, secondary amines, tertiary amines, aminoalcohols, liquor ammonia, sodium hydroxide and potassium hydroxide. In an exemplary embodiment, the neutralizing agent is morpholine.
In an embodiment, the aqueous biocidal composition is a masterbatch composition.
The amount of the biocide in the masterbatch composition is in the range of 5 wt.% to 20 wt.%. In one embodiment, the amount of biocide is 6 wt.%. In another embodiment, the amount of biocide is 8 wt.%.
The amount of the biocide in the range of 5 wt.% to 20 wt.% is optimum. An amount of the biocide more than 20 wt.% is practically difficult to incorporate into the hydrophobic acrylic polymer, whereas an amount lesser than 5 wt.% would be insufficient to provide effective anti-algal performance of the composition
In an embodiment, the hydrophobic acrylic polymer component is constituted as a core, surrounded by a shell of the hydrophilic acrylic polymer component, wherein the biocide is incorporated in the core. This can be referred as core-shell phenomenon.
In one embodiment, the present disclosure provides an aqueous biocidal composition comprising diuron, a hydrophilic acrylic polymer component, a hydrophobic acrylic polymer component and an aqueous fluid medium. The aqueous fluid medium comprises at least one solvent and water in a solvent to water ratio in the range of 1:1 to 1:19, and optionally at least one additive. The amount of the aqueous fluid medium is in the range of 50 wt.% to 70 wt.% of the total composition. The combined amount of the biocide, the hydrophilic acrylic polymer component, and the hydrophobic acrylic polymer component is in the range of 30 wt.% to 50 wt.% of the total composition. The ratio of the hydrophilic acrylic polymer component to the hydrophobic acrylic polymer component is in the range of 1:1.5 to 1:2.5.
In another aspect, the present disclosure provides a process for preparing an aqueous biocidal composition. In accordance with one embodiment of the present disclosure, the process comprises a step of polymerizing at least one first monomer in a fluid medium, to obtain a hydrophobic acrylic polymer component.
In accordance with the present disclosure, the hydrophobic acrylic polymer component refers to an acrylic polymer prepared by using monomer comprising at least 80 wt.% of hydrophobic monomers.
The first monomer is at least one acrylic monomer selected from the group consisting of methyl methacrylate, butyl acrylate, 2-hydroxyethyl methacrylate, methacrylic acid, diacetone acrylamide, butylcarbamatoethyl acrylate, and ethylcarbamatoethyl acrylate.
In an embodiment, the first monomer comprises at least one vinylic monomer. In an embodiment, the vinylic monomer is styrene.
In accordance with an embodiment, the first monomer comprises a mixture of methyl methacrylate, butyl acrylate, 2-hydroxyethyl methacrylate, methacrylic acid and styrene.
In accordance with another embodiment, the first monomer comprises a mixture of methyl methacrylate, butyl acrylate, 2-hydroxyethyl methacrylate, methacrylic acid, ethylcarbamatoethyl acrylate and styrene.
In accordance with still another embodiment, the first monomer comprises a mixture of methyl methacrylate, butyl acrylate, 2-hydroxyethyl methacrylate, methacrylic acid, diacetone acrylamide and styrene.
The fluid medium is at least one water miscible solvent selected from the group consisting of alcohols, esters, ethers, ketones, glycol ethers of ethylene glycol, propylene glycol, diethylene glycol, dipropylene glycol, ethylene glycol butyl ether, propylene glycol propyl ether and butyl carbitol. In an exemplary embodiment, the fluid medium is propylene glycol propyl ether.
In an embodiment, the step of polymerizing the first monomer is carried out in the presence of at least one initiator selected from the group consisting of azobisisobutyronitrile, tertiary-butyl perbenzoate, dimethyl 2,2'-azobis(2-methylpropionate), ditertiary butyl peroxide, dicumyl peroxide and ditertiary amylperoxide. In an exemplary embodiment, the initiator is tertiary-butyl perbenzoate.
In the next step of the process, molecules of at least one biocide are incorporated into monomeric units or polymeric chain of the hydrophobic acrylic polymer component to form complexed particles. The complexed particles are entangled to form a first component comprising the biocide in a core of the hydrophobic acrylic polymer component.
The hydrophobic acrylic polymer component has better adherence of the biocide molecules to the monomeric units or the polymeric chain of the hydrophobic acrylic polymer component, thus reducing the leaching of the biocide molecules.
The molecules of the biocide are incorporated into the monomeric units or the polymeric chain of the hydrophobic acrylic polymer component by agitating at a speed in the range of 100 rpm to 200 rpm. The molecules of the biocide come in proximity to the monomeric units or the polymeric chain of thehydrophobic acrylic polymer component, upon agitation. The monomeric units or the polymeric chain of the hydrophobic acrylic polymer component are capable of forming hydrogen bonds with the molecules of the biocide, thus forming the complexed particles.
In an embodiment, the complexed particles are entangled by agitating the complexed particles at a speed in the range of 100 rpm to 200 rpm.
The step of incorporation of biocide and the step of entangling of complexed particles are independently carried out at a temperature in the range of 60 °C to 140 °C for a time duration in the range of 1 hour to 3 hours.
In an embodiment, the complexed particles are entangled by agitiating at 150 rpm for 120 minutes at 120?C.
The biocide is selected from the group consisting of algicides, herbicides, fungicides, insectides and pesticides. In accordance with the present disclosure, the biocide is selected from the group consisting of diuron, terbutryn, isoproturon, metribuzin, linuron, atrazine, metolachlor, diquat, alachlor, terbuthylazine and simazine. In an exemplary embodiment, the biocide is diuron.
In one embodiment, prior to the step of incorporating molecules of the biocide, the hydrophobic acrylic polymer component is digested at a temperature in the range of 60 °C to 140 °C for a time duration in the range of 1 hour to 3 hours. In another embodiment, the digestion is done after the step of incorporating molecules of the biocide. In an exemplary embodiment, the hydrophobic acrylic polymer component is digested at 135 °C for 1.5 hours.
Typically, the step of digestion is done in presence of an initiator and a co-solvent. The co-solvent is added during digestion to aid in viscosity control and dissolve the initiator.
The initiator is selected from the group consisting of azobisisobutyronitrile, tertiary-butyl perbenzoate, dimethyl 2,2'-azobis(2-methylpropionate), ditertiary butyl peroxide, dicumyl peroxide and ditertiary amylperoxide. In an embodiment, the initiator is tertiary-butyl perbenzoate.
The co-solvent is at least one selected from the group consisting of alcohols, esters, ethers, ketones, glycol ethers of ethylene glycol, propylene glycol, diethylene glycol, dipropylene glycol, ethylene glycol butyl ether, propylene glycol propyl ether and butyl carbitol. In an exemplary embodiment, the co-solvent is propylene glycol propyl ether.
The step of digestion ensures that all free monomers are consumed and the polymerization of the first monomer is complete.
At least one second monomer is separately polymerized to obtain a second component comprising a hydrophilic acrylic polymer component.
In accordance with the present disclosure, a hydrophilic acrylic polymer component refers to an acrylic polymer prepared by using monomer comprising at least 25 wt.% of hydrophilic monomers.
The second monomer is at least one selected from the group consisting of methyl methacrylate, butyl acrylate, tridecafluorooctyl methacrylate, 2-hydroxyethyl methacrylate, methacrylic acid, polyethylene glycol methacrylate, and polypropylene glycol methacrylate. In an exemplary embodiment, the second monomer is a mixture of methyl methacrylate, butyl acrylate, 2-hydroxyethyl methacrylate, methacrylic acid, tridecafluorooctyl methacrylate and polyethylene glycol methacrylate.
In an embodiment, the first monomer and the second monomer independently comprises at least one monomer selected from the group consisting of esters of acrylic acid, esters of methacrylic acid, hydroxyl functional monomers, alkoxy functional derivatives of polyalkyleneglycol methacrylate, hydroxy functional derivatives of polyalkyleneglycol methacrylate, vinyl monomers, carboxyl functional monomers and fluorinated monomers.
The ester of acrylic acid or methacrylic acid is at least one derivative selected from the group consisting of methyl ester, ethyl ester, n-propyl ester, isopropyl ester, n-butyl ester, isobutyl ester, sec-butyl ester, tert-butyl ester, n-pentyl ester, neopentyl ester, n-hexyl ester, cyclohexyl ester, n-octyl ester, 2-ethylhexyl ester, lauryl ester and isobornyl ester.
The hydroxyl functional monomer is at least one selected from the group consisting of hydroxyethyl acrylate, hydroxypropyl acrylate, hydroxybutyl acrylate, hydroxyethyl methacrylate, hydroxypropyl methacrylate and hydroxybutyl methacrylate.
The hydroxy or alkoxy derivative of polyalkyleneglycol methacrylate is at least one selected from polyethyleneglycol methacrylate and polypropyleneglycol methacrylate.
The vinyl monomer is at least one selected from the group consisting of styrene, alpha-methyl styrene and para-methyl styrene.
The carboxyl functional monomer is at least one selected from the group consisting of acrylic acid, methacrylic acid, fumaric acid, crotonic acid, itaconic acid, maleic acid, cinnamic acid and 2-acrylamide-2-methylpropanesulfonic acid.
The fluorinated monomer is at least one selected from trifluoroethyl methacrylate and tridecafluorooctyl methacrylate.
In an embodiment, the step of polymerizing the second monomer is carried out in the presence of at least one initiator.
The initiator is selected from the group consisting of azobisisobutyronitrile and tertiary-butyl perbenzoate, dimethyl 2,2'-azobis(2-methylpropionate), ditertiary butyl peroxide, dicumyl peroxide and ditertiary amylperoxide. In an exemplary embodiment, the initiator is tertiary-butyl perbenzoate.
The step of polymerizing the second monomer is done in the presence of a water miscible solvent selected from the group consisting of alcohols, esters, ethers, ketones, glycol ethers of ethylene glycol, propylene glycol, diethylene glycol and dipropylene glycol, ethylene glycol butyl ether, propylene glycol propyl ether and butyl carbitol.
In an embodiment, the process of polymerization of the at least one second monomer involves a step of digesting the hydrophilic acrylic polymer component at a temperature in the range of 60 °C to 140 °C for a time duration in the range of 1 hour to 3 hours. In an embodiment, the hydrophilic acrylic polymer component digested at 135 °C for 1.5 hours.
The step of digestion is done in the presence of an initiator and a co-solvent.
The initiator is selected from the group consisting of azobisisobutyronitrile and tertiary-butyl perbenzoate, dimethyl 2,2'-azobis(2-methylpropionate), ditertiary butyl peroxide, dicumyl peroxide and ditertiary amylperoxide. In an exemplary embodiment, the initiator is tertiary-butyl perbenzoate.
The co-solvent is at least one selected from the group consisting of alcohols, esters, ethers, ketones, glycol ethers of ethylene glycol, propylene glycol, diethylene glycol, dipropylene glycol, ethylene glycol butyl ether, propylene glycol propyl ether and butyl carbitol. In an exemplary embodiment, the co-solvent is propylene glycol propyl ether.
The step of digestion ensures that all free monomers are consumed and the polymerization of the second monomer is complete.
In the next step of the process, the second component is added to the first component to obtain a mixture.
The mixture is agitated to allow mixing of the hydrophilic acrylic polymer component with the core to form a homogenous mixture.
The agitation is done at a speed in the range of 200 rpm to 400 rpm. In an exemplary embodiment, the agitation is done at 300 rpm.
Further, the homogenous mixture is neutralized to obtain a neutralized mixture comprising the hydrophobic acrylic polymer component constituted as a core, surrounded by a shell of the hydrophilic acrylic polymer, wherein the biocide incorporated in the core. This can be referred as core-shell phenomenon.
The neutralization of the homogenous mixture is done by using a neutralizing agent in an amount in the range of 1 wt.% to 5 wt.%. The neutralizing agent is added in the range of 50% to 100% of the acid content to form a salt.
The neutralizing agent is at least one selected from the group consisting of morpholine, primary amines, secondary amines, tertiary amines, aminoalcohols, liquor ammonia, sodium hydroxide and potassium hydroxide. In an exemplary embodiment, the neutralizing agent is morpholine.
The neutralizing agent is used to neutralize the acidic groups in the homogenous mixture, which affects the stability, colour, water resistance, viscosity and other significant properties of the composition.
In the next step, at least one additive is optionally added to the neutralized mixture. The neutralized mixture is dispersed in an aqueous medium to obtain the aqueous biocidal composition.
In accordance with another embodiment of the present disclosure, the process comprises a step of polymerizing at least one first monomer in a fluid medium, to obtain a hydrophobic acrylic polymer component. At least one second monomer is separately polymerized to obtain a hydrophilic acrylic polymer component. The hydrophilic acrylic polymer component is mixed with the hydrophobic acrylic polymer component to obtain a first mixture. The molecules of at least one biocide is incorporated into the first mixture to form complexed particles. The complexed particles are entangling to form a second mixture. The second mixture is neutralized to obtain a neutralized mixture. At least one additive is optionally added to the neutralized mixture. The neutralized mixture is dispersed in an aqueous medium to obtain the aqueous biocidal composition.
In yet another aspect, the present disclosure provides a coating composition comprising an aqueous biocidal composition and a polymeric composition. The aqueous biocidal composition comprises a biocide, a hydrophilic acrylic polymer component, a hydrophobic acrylic polymer component, in an aqueous fluid medium. The polymeric composition comprises a polymer and a pre-determined additive, wherein the weight ratio of the aqueous biocidal composition to the polymeric composition is in the range of 1:3 to 1:99.
In an embodiment, the weight ratio of the aqueous biocidal composition to the polymeric composition is in the range of 1:20 to 1:50.
The amount of biocide in the coating composition is in the range of 0.08 wt.% to 1 wt.%. In an embodiment, the amount of biocide is 0.5 wt.%.
The ratio of the polymer and pre-determined additive in the polymeric composition is in the range of 5:95 to 95:5.
The polymer is at least one selected from the group consisting of acrylic, styrene-acrylics, polyesters, epoxies, polyurethanes, and polysiloxanes. In an exemplary embodiment, the polymer is acrylic.
The pre-determined additive comprises at least one compound selected from the group consisting of cosolvents, defoamers, thickeners, pH modifier, dispersing agents, wetting agents, coalescents, opacifying polymers, plasticizers, pigments, extenders, colorants, freeze thaw stabilizers, buffers, fire retardants, ultraviolet radiation absorbers, organic fibre material, inorganic fiber materials, flow and levelling agents, adhesion promoters, oil repellants, water repellents and fillers. In an exemplary embodiment, the pre-determined additive comprises thickeners, dispersing agents, wetting agents and pigments.
In yet another aspect, the present disclosure provides a process for preparing a coating composition. The process comprises a step of preparing an aqueous biocidal composition comprising a biocide, a hydrophilic acrylic polymer component, a hydrophobic acrylic polymer component and an aqueous fluid medium. The aqueous fluid medium comprises at least one solvent and water in a solvent to water ratio in the range of 1:1 to 1:19, and optionally at least one additive. The amount of the aqueous fluid medium is in the range of 50 wt.% to 70 wt.% of the total composition. The combined amount of the biocide, the hydrophilic acrylic polymer component, and the hydrophobic acrylic polymer component is in the range of 30 wt.% to 50 wt.% of the total composition. In the next step, the aqueous biocidal composition is blended with a polymeric composition comprising a polymer and a pre-determined additive to obtain a coating composition.
The present disclosure provides a simple and effective process for the preparation of the aqueous biocidal composition and the coating composition showing reduced leaching and improved anti-algal performance.
The foregoing description of the embodiments has been provided for purposes of illustration and not intended to limit the scope of the present disclosure. Individual components of a particular embodiment are generally not limited to that particular embodiment, but, are interchangeable. Such variations are not to be regarded as a departure from the present disclosure, and all such modifications are considered to be within the scope of the present disclosure.
The present disclosure is further described in light of the following laboratory scale experiments which are set forth for illustration purpose only and not to be construed for limiting the scope of the disclosure. These laboratory scale experiments can be scaled up to industrial/commercial scale and the results obtained can be extrapolated to industrial/commercial scale.
Experimental Details
Experiment 1: Preparation of an aqueous biocidal composition (sample 1A)
Experiment 1a: Preparation of first component comprising core of hydrophobic biocidal acrylic component (Polymer A) and diuron
In a reaction vessel, fitted with an agitator and water condenser, 5 g of propylene glycol n-propyl ether (Dowanol PnP) was added and heated to 135°C. To this reaction vessel, a mixture of a first monomer (monomer mix A as given in Table 1) and an initiator (tertiary butyl perbenzoate) were added over a period of 150 minutes, and the resulting mixture was stirred at 150 rpm to obtain a hydrophobic acrylic polymer component. The hydrophobic acrylic polymer component was digested at 135 °C for 90 minutes in the presence of tertiary-butyl perbenzoate and propylene glycol n-propyl ether to ensure completion of the polymerization reaction which was confirmed by gravimetry and gas chromatography. To the hydrophobic acrylic polymer component (Polymer A), diuron (15 wt.% on solids) was incorporated and the resulting mixture was stirred at 150 rpm for 60 minutes at 100 ?C to form a first component comprising the biocide in a core of the hydrophobic biocidal acrylic component.
Experiment 1b: Preparation of second component comprising hydrophilic biocidal acrylic component (Polymer B)
In a reaction vessel, fitted with an agitator and water condenser, 15 g of propylene glycol n-propyl ether (Dowanol PnP) was added and heated to 135 °C. To this reaction vessel, a mixture of monomers (monomer mix B as given in Table 2) and an initiator (tertiary butyl perbenzoate) were added over a period of 150 minutes, and the resulting mixture was stirred at 150 rpm to obtain a hydrophilic acrylic polymer component. The hydrophilic acrylic polymer component was digested at 135 °C for 90 minutes in the presence of tertiary-butyl perbenzoate and propylene glycol n-propyl ether to ensure completion of the polymerization reaction which was confirmed by gravimetry and gas chromatography.
Experiment 1c: Preparation of aqueous biocidal composition (sample 1A)
The second component (Polymer B), as obtained in Experiment 1b was added to the first component (comprising the biocide in the core of hydrophobic acrylic polymer component as obtained in the experiment 1a) and the resulting mixture was agitated at 300 rpm for 60 mins to form a homogenous mixture. The homogenous mixture was neutralized with morpholine (as given in Table 1) to obtain a neutralized mixture comprising the hydrophobic acrylic polymer component constituted as a core, surrounded by a shell of the hydrophilic acrylic polymer component, wherein the biocide incorporated in the core. The additives were added to the neutralized mixture as mentioned in Table 1 (Post neutralization additive addition) to obtain a mixture which was further dispersed into water, to obtain an aqueous biocidal composition (Sample 1A).
Experiment 2: Preparation of aqueous biocidal compositions (samples 1B-1F)
The aqueous biocidal compositions 1B-1F were prepared using the procedure as described in Experiment 1, except that the first monomer (monomer mix A) and the second monomer (monomer mix B) varied, as illustrated in Table 1 and Table 2.

Table 1: Formulation of aqueous biocidal composition

Aqueous biocidal composition 1A 1B 1C 1D 1E 1F
Polymer

Monomer mix (A) A-01 A-02 A-03 A-01 A-05 A-06
Methyl methacrylate (MMA) 7.8 5.6 5 7.8 5.6 5.6
Butyl acrylate (BA) 8.9 7.1 7.7 8.9 7.1 7.1
Hydroxyethylmethacrylate (HEMA) 3.1 2 2 3.1 2 2
Styrene 1.9 1.9 1.9 1.9 1.9 1.9
Methacrylic acid (MAA) 1 1 1 1 1 1
Diacetone acrylamide (DAAM) 0 0 5 0 5 0
Butylcarbamatoethyl acrylate 0 0 0 0 0 5
Ethylcarbamatoethyl acrylate 0 5 0 0 0 0
Acid Value (mg KOH/g) 28.72 28.85 28.85 28.72 28.85 28.85
Hydroxyl value (mg KOH/g) 58.86 38.14 38.14 58.86 38.14 38.14
tertiary-butyl perbenzoate (TBPB) 0.5 0.5 0.5 0.5 0.5 0.5
Reactor charge
Propylene glycol n-propyl ether 5 5 5 5 5 5
Methoxy Propyl acetate 0 0 0 0 0 0
Digestion stage
Tertiary-butyl perbenzoate (TBPB) 0.05 0.05 0.05 0.05 0.05 0.05
Diuron (Diuron on solids) [in g and (wt.%)] 6 (15%) 8 (20%) 8 (20%) 8 (20%) 8(20%) 8(20%)
Polymer B B-01 B-01 B-02 B-01 B-01 B-01
12.3 11.5 11.5 11.5 11.5 11.5
Neutralization stage
Morpholine 1 1 1 1 0.7 1
DM Water 52.4 51.3 47.1 51.2 48.6 51.3
Post neutralization additive addition
Adipic Dihydrazide 0 0 0.7 0 1 0
Non-ionic surfactant (Alcohol ethoxylate) 0 0 0.5 0 0 0
Water 0 0 3 0 3 0
Defoamer (Mineral oil) 0.05 0.05 0.05 0.05 0.05 0.05
TOTAL 100 100 100 100 100 100

Table 2: Formulation of hydrophilic acrylic polymer component (Polymer B)
Polymer
Monomer mix B B-01 B-02
Methyl methacrylate (MMA) 25.90 24.25
Butyl acrylate (BA) 37.30 33.45
Hydroxyethylmethacrylate (HEMA) 8.30 8.3
Methacrylic acid (MAA) 8.30 8.3
Polyethylene glycol methacrylate 3.30 3.3
Tridecafluorooctyl methacrylate (Perfluorinated monomer) 0.00 4
Acid Value (mg KOH/g) 65.12 66.32
Hydroxyl value (mg KOH/g) 43.05 43.84
TBPB 1.80 1.7
Reactor charge
Propylene glycol n-propyl ether 15.00 16.6
DIGESTION
Tertiary-butyl perbenzoate (TBPB) 0.10 0.1
TOTAL 100 100

The acid value of the hydrophobic acrylic polymer component (Table 1) and the hydrophilic acrylic polymer component (Table 2) were determined by known method of titration of respective resin samples with 0.1 M Potassium hydroxide solution, using phenolphthalein as an indicator. The hydroxyl value of the hydrophobic acrylic polymer component (Table 1) and the hydrophilic acrylic polymer component (Table 2) were determined by known method of titration of acetyl derivatives of the respective resin samples with 0.5 N sodium hydroxide solution, using phenolphthalein as an indicator. The acetyl derivatives of the resin samples were obtained by using acetylating reagent (mixture of acetic anhydride and pyridine).
The aqueous biocidal compositions (samples 1A-1F) were characterized to evaluate their properties and the stability. The results are summarized in Table 3.
Table 3: Property measurements for aqueous biocidal compositions (1A-1F)

Property Sample 1A Sample 1B Sample 1C Sample 1D Sample 1E Sample 1F
Flow White flow able Paste Yellow flow able Paste Yellow flow able Yellow paste Yellow stiff paste Yellow flow able
% Non-volatile matter 40.18 40.2 41.05 40.5 41.5 40.1
PSD (nm) NA 308.5(83.5%) 97.18(27.6%) 150.5(98.8%) 5526(1.2%) NA 922.9(38.3%) 4640(61.7%) 148.8(98.5%) 5560(1.5%)
pH 8.7 8.7 8.9 8.8 8.6 8.8
Film drawdown on glass plate Smooth Smooth Smooth Bitty film Smooth Smooth

As observed in Table 3, the aqueous biocidal composition samples are in the form of a flowable paste at 40 + 1.5% solids. They are all anionic dispersions with a pH of 8 to 9. Sample 1A which had 15% Diuron loading on solids resulted into a smooth film whereas sample 1D (20% Diuron on solids) which does not have monomers capable of Hydrogen bonding with the Diuron resulted into a bitty and discontinuous film. The other samples such as 1B and 1C (20% Diuron on solids) which have Ethylcarbamatoethyl acrylate and diacetoneacrylamide respectively gave a smooth continuous film.
Further, with reference to Figures 1A and 1B, it was observed that the aqueous biocidal compositions 1C and 1D, upon application on glass surface, lead to films with different nature. It was observed that a film obtained by the application of the aqueous biocidal composition 1D leads to a fragmented film whereas a film obtained by applying aqueous biocidal composition 1C leads to a film having no fragmentation. This is because the presence of hydrogen-bonding monomer (diacetone acrylamide) in the aqueous biocidal composition 1C which leads to better dissolution of higher concentration of diuron, thus causing no fragmentation.
Experiment 3: FTIR analysis of aqueous biocidal composition
The FTIR spectra of the aqueous biocidal composition 1A (spectrum B in Figure 2) was compared with the FTIR spectrum of diuron (spectrum A in Figure 2).
It is observed that the peaks around 3200 cm-1 to 3300 cm-1 and 1648 cm-1 to 1654 cm-1 represent the amide functional group of the diuron which indicates the presence of diuron in the aqueous biocidal composition. Further, the peaks around 2900 cm-1 represent the alkyl groups of diuron and the acrylic resin. The peak around 1700 cm-1 represents the carbonyl group of the acrylic polymer.
Experiment 4: Cylinder stability testing
The aqueous biocidal composition (sample 1C) was diluted with distilled water in a ratio of 1:10 and kept in a cylinder to check dispersion stability. The result was compared with a commercial reference Paxguard DU50 which is aqueous diuron dispersion having an assay of 46 to 48%. The resulting stability (at 25 °C) of the aqueous biocidal sample 1C as shown on the right side and that of Paxguard DU50 on the left side in Figures 3A to 3C corresponding to standing time of 2 hours, 8 hours and 5 days respectively. It is observed in Figures 3A-3C that the reference sample Paxguard DU50 showed significant settling of diuron whereas the aqueous biocidal composition sample 1C comprising diuron in the core of the hydrophobic acrylic polymer component surrounded by a shell of the hydrophilic acrylic polymer component, showed relatively lesser settling and better uniformity of the dispersion.
The difference in properties between aqueous biocidal composition (sample 1C) of the present disclosure and the commercial reference Paxguard DU50 is provided in Table 4.
Table 4: Properties of the sample 1C and the commercial sample Paxguard DU50

Parameter Paxgard DU50 Sample 1C
Solids Non-volatile matter (Nvm) 50-55, Assay 46-48 Non-volatile matter (Nvm) 40, Assay 8
Viscosity 20 – 25 poise 20-25 poise
pH 6.5 8+
Film clarity Opaque film (picture not given here) Translucent film (picture given in Figure 5A)
Film water resistance Fails in 1 rub Can withstand over 50 rubs
As observed in Table 4, the film obtained by using Paxgard DU50 is opaque whereas that obtained by using sample 1C is translucent. Further, the Paxgard DU50 film has less water resistance than film of sample 1C.
Experiment 5: Raman spectroscopic analysis of aqueous biocidal composition
The film obtained by the application of the aqueous biocidal sample 1B was subjected to Raman microscopy to obtain a spectrum as shown in Figure 4. The spectrum indicated the presence of Diuron (rod shaped structures).
Experiment 6: Durability studies of aqueous biocidal composition
The aqueous biocidal composition samples 1B and 1C were tested in comparison with a reference standard paint comprising diuron powder for QUV accelerated weathering test. The resulting QUV data is provided in Figure 5. The results showed comparable performance of the aqueous biocidal compositions of the present disclosure in comparison to the standard paint. The paint formulas are given in Table 6.
As observed in Figure 5, the aqueous biocidal composition samples 1B and 1C showed lower color change (lower Delta E values) after 1500 hours of QUV A exposure as compared to the standard paint. This is because lower amount of Diuron was added in the aqueous biocidal composition samples 1B and 1C, as it was more effective at a lower dose. Further, the uniform distribution in the coating film and low leaching (as indicated by Table 7) also led to greater durability of the aqueous biocidal composition samples 1B and 1C.
Experiment 7: Preparation of clear coating composition (sample 2A)
2.5 grams of the aqueous biocidal composition (sample 1A), as obtained in Experiment 1, was mixed with 100 grams of an acrylic Emulsion (commercially obtained as R56) having a pH of 8, average particle size of 200 nm and containing 50% solids, to give a clear coating composition (sample 2A).
Experiment 8: Preparation of clear coating compositions (samples 2B-2E)
The coating compositions 2B-2E were prepared using the procedure as described in Experiment 7, except that the type and amount of the aqueous biocidal composition as well as the amount of the acrylic Emulsion (R56) were varied, as given in Table 5.
Table 5: Formulation of clear coating compositions (samples 2A-2E)

Sample 2A 2B 2C 2D 2E
R 56 (in g) Acrylic emulsion 100 100 100 100 100
Effective Diuron Content (in g) 0.3 0.3 0.3 0.3 0.3
Aqueous biocidal composition 1A 1E 1F 1B 1C
Aqueous biocidal composition added (in g) 2.5 1.9 1.9 1.9 1.9
Uniform clear coatings were obtained using compositions 2A-2E. The SEM analysis showing uniform distribution of Diuron in clear coating 2D is shown in Figure 7.
Experiment 9: Preparation of white paint composition
Two batches of white paints (6A and 6B) were prepared. A white formulation was mixed with powdered diuron, in accordance with the prior art, to obtain a reference composition 6A. Another sample 6B was prepared by mixing a white formulation with a aqueous biocidal composition, in accordance with the present disclosure. The composition of the samples 6A and 6B are tabulated in Table 6.

Table 6: Formulation of white paint composition

Components/additives of the composition Quantity
(in wt.%) Quantity (in wt%)
6A 6B
Water 14.8 14.95
Mineral oil (Defoamer) 0.1 0.1
Cellulosic thickener (Rheological agent) 0.4 0.4
Liquor Ammonia (pH adjustment) 0.2 0.2
Ammonium salt of copolymer with acidic groups (Pigment Dispersing and wetting agent) 1 1
Titanium Dioxide (White pigment) 20 20
Silicate filler 10 10
Diethylene glycol monobutyl ether (Coalescing agent) 2 2
R56 Acrylic Emulsion (50% Solids) 50 47.6
Diuron (Biocide) 1.5 0
Aqueous biocidal composition of present disclosure 0 3.75
100.0 100

Experiment 10: Scanning Electron Microscopy (SEM) and chlorine mapping
Scanning electron microscopy and chlorine mapping were done for sample 1B and the results were compared with the coating composition 2D and also with a reference standard paint comprising diuron powder (Paint formula 6A, Table 6). The SEM of the sample 1B is depicted in Figure 6A and the chlorine mapping data is depicted in Figure 6B. The SEM of the coating composition 2D is depicted in Figure 7A (also Figure 7C) and the chlorine mapping data for the coating composition 2D is depicted in Figure 7B ((also Figure 7D). For comparison purpose, a commercial paint made with powdered Diuron (formula given in Table 6, sample 6A) was also tested, wherein the SEM of the commercial paint is as shown in Figure 8A and the chlorine mapping is shown in Figure 8B.
It is observed that, in case of aqueous biocidal composition sample 1B, diuron appears to be present across the sample, however, at few places diuron crystallizes in the form of needles. It is noted that the amount of chlorine, which comes from diuron, is higher on needles compared to the background matrix. This is due to the higher concentration of diuron in the aqueous biocidal composition. In case of the coating composition 2D, the film does not show the presence of any needles, and the distribution of diuron was uniform.
However, the film obtained by applying standard paint having diuron powder instead of the aqueous biocidal composition of the present disclosure, indicates presence of agglomerates of diuron powder in the paint film.
Therefore, the presence of diuron in the core of the hydrophobic acrylic polymer component surrounded by the shell of hydrophilic acrylic polymer component, leads to uniform distribution of diuron, thus avoiding formation of agglomerates which otherwise reduce the effectiveness of diuron and also the anti-algal performance of the composition.

Experiment 11: Cryo-SEM analysis of aqueous biocidal composition
The aqueous biocidal composition 1C was subjected to cryo-SEM analysis (Figures 9C and 9D showing low magnification and high magnification respectively) and the results were compared with the cryo-SEM data of a reference sample comprising blend of commercial diuron dispersion Paxguard DU50 with the acrylic emulsion (R56), as shown in Figures 9A and 9B. Both low magnification i.e. 4000x (Figures 9A, 9C) and high magnification 18000x to 25000x (Figures 9B, 9D) cryo SEM were performed. It was observed that while particles ranging in size from 1.7 µm to 5.8 µm (which could be possibly diuron) were detected in the reference sample, however, no large sized particles were detected in the aqueous biocidal composition.
Experiment 12: Leaching test of coating composition
The coating composition (paint composition 6B, Table 6) of the present disclosure was subjected to leaching test. Eight cement fiber panels having dimensions of 6 inches x 3 inches were coated with the diluted forms of the samples mentioned in Table 7 (40% dilution). The coated films were cured for 7 days followed by subjecting to a leaching chamber containing a measured quantity of water. The water was leached out of the chamber with the help of a peristaltic pump for a period of 400-500 minutes. After completion, the panels were dried in an environmental chamber overnight. The complete process was repeated for 10 times. Each time, an aliquot of the leached water was collected and subjected to HPLC studies to test diuron concentration in the water.
The percentage diuron leached after 10 cycles were calculated based on the initial weight and the HPLC results.

Table 7: Leaching studies

Diuron Additive Diuron Content % Leaching
Reference coating composition comprising diuron powder Powder Diuron 0.3 48
Coating composition sample Table 6B (with aqueous biocidal composition sample 1B) 1B 0.3 25
Coating composition sample Table 6B (with aqueous biocidal composition sample 1A) 1A 0.3 32
Commercial paint comprising Paxguard DU50 Diuron powder 0.3 44

As seen from Table 7, the initial concentration of Diuron is confirmed by HPLC to be 0.3%. This indicates that there is no degradation of Diuron taking place during the preparation of the aqueous biocidal composition. Further, it can be seen from Table 7 that the coating compositions of Table 6 (containing aqueous biocidal composition 1B and 1A) exhibit higher durability i.e. lower leaching of 25% and 32% respectively, even after 10 cycles of showering, in comparison to the reference coating composition samples exhibiting 44% and 48% leaching.
Experiment 13: Anti-algal performance of the coating composition
The anti-algal performance was tested by coating three concrete panels with dimensions 6” x 3” with diluted paint followed by curing for 7 days. Further, the dried films of the coating compositions were exposed to algae species in a chamber having a moist environment suitable to algae growth. The algal growth, as observed, after 30 days were rated according to the algae coverage on the surface. The rating given was on a scale of 1 to 10 wherein 10 relates to no growth on the surface.
The results are summarized in Table 8. The paint compositions are given in Table 6 (6A and 6B).
Table 8: Antialgal studies

Sr.
No. Paint Composition Anti-algal performance rating
1 White reference paint (1.5% Diuron) 7
2 White reference paint (0.3% Diuron) 6
3 White paint with aqueous biocidal composition 1A having 0.3 % effective diuron 7
4 White paint with aqueous biocidal composition 1E having 0.3 % effective diuron 7
5 White paint with aqueous biocidal composition 1F having 0.3 % effective diuron 6
6 White paint with aqueous biocidal composition 1B having 0.3 % effective diuron 7
7 White paint with aqueous biocidal composition 1C having 0.3 % effective diuron 7
8 White reference paint (without diuron) 5

As shown in Table 8, although the paint compositions formed by incorporation of aqueous biocidal compositions of the present disclosure have lower diuron content than the standard paints, their anti-algal performance is comparable with that of the standard compositions containing higher amounts of Diuron powder.
From all the experimentation and testing carried out, it is evident that biocide can be effectively incorporated into the polymer matrix by using the process of the present disclosure, such that the diuron is entangled in the core of the hydrophobic acrylic polymer component surrounded by the shell of hydrophilic acrylic polymer component, thereby enhancing the anti-algal performance.

TECHNICAL ADVANCEMENTS
The present disclosure described herein above has several technical advantages including but not limited to the realization of a process for preparing an aqueous biocidal composition that:
? is simple and economical;
? gives a aqueous biocidal composition that comprises biocide entangled in a core of the hydrophobic acrylic polymer component surrounded by a shell of the hydrophilic acrylic polymer component; and
? gives a coating composition that shows improved anti-algal performance with moderate amount of biocide.
Throughout this specification the word “comprise”, or variations such as “comprises” or “comprising”, will be understood to imply the inclusion of a stated element, integer or step, or group of elements, integers or steps, but not the exclusion of any other element, integer or step, or group of elements, integers or steps.
The use of the expression “at least” or “at least one” suggests the use of one or more elements or ingredients or quantities, as the use may be in the embodiment of the disclosure to achieve one or more of the desired objects or results.
Any discussion of documents, acts, materials, devices, articles or the like that has been included in this specification is solely for the purpose of providing a context for the disclosure. It is not to be taken as an admission that any or all of these matters form a part of the prior art base or were common general knowledge in the field relevant to the disclosure as it existed anywhere before the priority date of this application.
The numerical values mentioned for the various physical parameters, dimensions or quantities are only approximations and it is envisaged that the values higher/lower than the numerical values assigned to the parameters, dimensions or quantities fall within the scope of the disclosure, unless there is a statement in the specification specific to the contrary.
While considerable emphasis has been placed herein on the components and component parts of the preferred embodiments, it will be appreciated that many embodiments can be made and that many changes can be made in the preferred embodiments without departing from the principles of the disclosure. These and other changes in the preferred embodiment as well as other embodiments of the disclosure will be apparent to those skilled in the art from the disclosure herein, whereby it is to be distinctly understood that the foregoing descriptive matter is to be interpreted merely as illustrative of the disclosure and not as a limitation.