Description:FIELD OF INVENTION

The present invention relates to the development of coating composition based on styrene-acrylic emulsion for architectural coating with excellent water resistance, solvent resistance, anti-efflorescent properties. Particularly the present invention relates to coating composition with excellent adhesion on dry, damp and salt deposited substrates like cementitious, masonry, POP (Plaster of Paris), wall putty, etc. More particularly the present invention further relates to preparation of one component, stable emulsion coating composition based on styrene-acrylic and silicate-siliconate chemistry.

BACKGROUND AND PRIOR ART OF THE INVENTION:
In architectural coating, polymeric latex is used in the various form such as paints, transparent coating, waterproofing coating, etc and water resistance of latex is crucial for most of these applications.
The essential raw material for emulsion polymerization contains surfactant, acrylic/vinyl monomers, initiators, buffer, and water. The inevitably used surfactants and hydrophilic monomers reduce the water resistance of polymer. Various ways are already known in the prior art for improvement of water resistance such as incorporation of hydrophobic monomers, crosslinkable monomers, hydrophobic additives, etc. Hydrophobic monomers such as VeoVa-9, VeoVa-10, lauryl methacrylate, Isobornyl methacrylate, etc and hydrophobic additives like CoatOsil DRI, CoatOsil Prim, BUILDO 150NA, ADD SH 150Z, etc are also commercially available. However, most of the hydrophobic moieties are fall in the specialty chemicals category and even incorporation with small quantity, it drastically increases the latex cost. The use of silicate-siliconate component in the emulsion polymer is one of the economical solutions for increasing hydrophobic nature of polymeric coating.

Most of the reported one component silicate emulsion paints are prepared according to DIN 18363, which contains only up to 5% of polymeric emulsion in waterglass. The article titled ‘’The truth about the concreate water proofing’’ published in CONCRETE SEALERS VIEWS On 13th August 2014’’ and the titled ‘’ SILICATES, SILICONATES AND FLUOROSILICATES EXPLAINED’’ published in technical bulletin of The Euclid chemical company explains about working mechanism of silicate, silicate-siliconate mixture and siliconate on concrete waterproofing.
US 20190382612 A1 discloses architectural coating based on sodium/potassium silicate and styrene-acrylic emulsion. This invention provides cost effective usages of silicate binders against organic binder.
WO 200200798 A1 discloses preservative free dispersion paints based which contain 4-15 % polymer dispersion, 10-55 % pigment and/or extender and upto 2% waterglass. Both the above inventions are used only silicate material and does not provide any information about long term stability of silicate-based emulsions.
WO 199824851 discloses hybrid inorganic-organic binder composition for painting and coating applications. The binder composition contains silicates, siliconate, silane and waterborne acrylic resin.
US20210230431A1 discloses silicate-emulsion primer and paints. The coating composition includes an acrylic polymer, a metal silicate, and water which provides improved adhesion of the silicate primer to the concrete, clay, or ceramic substrate and strong cohesion between the primer and topcoat paint allow for a much better overall performance. However, does not provide any information about monomer composition and does not claim on water resistance, solvent resistance, or anti-efflorescent properties of coating composition.
Reference is also drawn to JP2005336357A that has been made in view of improving the physical properties such as stability, odor, and water resistance in an acrylic resin emulsion of (meth)acrylic acid esters and carboxy group-containing monomers that are emulsion-polymerized and mixed with alkali metal siliconates to prepare emulsions having pH 7-10. Thus, a storage-stable almost odorless water-resistant emulsion contained acrylamide-acrylic acid- 2-ethylhexyl acrylate-Methamethacrylate-styrene copolymer and sodium methyl siliconate and had pH 8.5. In this prior art siliconate as an alternative to common bases like ammonia, triethyl amine, NaOH (sodium hydroxide), KOH (potassium hydroxide) has been employed to overcome the inferior water-resistance issue caused by KOH/NaOH, which NaOH/ KOH has not been involved and also does not teach any water proofing effect attained.
WO2019174872A1 relates to a storage-stable composition for forming coatings on built structures and the like comprising at least one organic binder, at least one filler and/or pigment, water for establishing a pasty consistency of the composition, a buffer system comprising at least one basic silicate, at least one substance which retards condensation of the basic silicate and optionally customary additives. The component that retards the condensation of basic silicate is taught to be a water soluble carbohydrate.

While several prior arts feature in this domain there is still a need to explore for a suitable styrene-acrylic and silicate-siliconate emulsion based super hydrophobic, solvent resistant, anti-efflorescent architectural coating that would provide for water proofing characteristics with excellent adhesion on dry, damp and salt deposited substrates.

OBJECTIVES OF THE INVENTION
Thus the primary objective of the present invention is to provide for hydroxy functional styrene-acrylic emulsion and coating compositions thereof for architectural coating with excellent water resistance, solvent resistance, anti-efflorescent and water proofing attributes.
Another objective of the present invention is to provide for coating compositions involving hydroxy functional styrene-acrylic emulsion together with silicate-siliconate and stabilized to provide for coating compositions that would have excellent adhesion on dry, damp and salt deposited substrates such as cementitious, masonry, POP, wall putty.
Still another objective of the present invention is to provide process of preparation of emulsion polymer and a process of application on architectural substrates that may be free of any additional stabilizer inspite of involving silicate-siliconates.
SUMMARY OF THE INVENTION

Thus according to the basic aspect of the present invention there is provided a styrene-acrylic emulsion polymer and coating compositions thereof comprising alkali stabilized silicate-siliconate based styrene-acrylic emulsion polymer having high concentration ranges of silicate-siliconate of 8-20 wt.% in the emulsion.
Preferably said styrene-acrylic emulsion and coating compositions thereof is provided as a one component stable emulsion polymer and coating compositions thereof maintaining pH levels of range 11 to 13, Particle size 90 to 180 nm, Viscosity 35 to 200 cP at 30 oC, under accelerated stability tests.
According to a preferred aspect of the present invention there is provided said styrene-acrylic emulsion and coating compositions thereof wherein said styrene acrylic emulsion polymer is a copolymer of monomers including mono functional co-monomers of styrene (5-20 wt. %), methyl methacrylate (0-15 wt. %), butyl acrylate (5-15 wt. %), 2-ethyl hexyl acrylate (5-15 wt. %), VeoVa -9(1-10 wt. %), VeoVa-10 (1-10 wt. %), ethyl acrylate (5-15 wt. %), methacrylic acid (0.1-4 wt. %), silane monomer (0.1-5 wt. %), and, at least 0.5 to 5wt. % hydroxy functional monomer (based on total formulation) including hydroxy ethyl methacrylate, hydroxy ethyl acrylate, hydroxy propyl methacrylate and hydroxy propyl acrylate, leading to a stable emulsion polymer stabilized by (˜14%) 1-1.5 wt.% alkali in the presence of 8-20 wt.% levels of silicate-siliconate in the emulsion.
Preferably said styrene-acrylic emulsion and coating compositions thereof is provided having excellent water resistance, solvent resistance including MTO (mineral turpentine oil) resistance, anti-efflorescent and water proofing attributes due to select styrene acrylic polymer present together with high concentrations of silicate-siliconate and stabilized with alkali yet free of deteriorating water resistance in presence of alkali.
More preferably said styrene-acrylic emulsion and coating compositions thereof is obtained of polymerizing said co-monomers followed by adjusting the pH of the emulsion above pH 11 by alkali preferably by aqueous solution of KOH before adding said high levels of silicate-siliconate additives in the emulsion to enhance the performance and at the same time enabling a stable emulsion free of pH and viscosity change over a long period of time of 180 days.
According to a preferred aspect of the present invention there is provided said styrene-acrylic emulsion and coating compositions thereof wherein said emulsion includes silicate-siliconate as reactive additive is selected from sodium silicate, potassium silicate, lithium silicate, methyl potassium siliconate;
silane functional monomer/crosslinker of alkoxysilanes including vinyl trimethoxy silane, vinyltriethoxysilane, 3-(trimethoxysilyl)propyl methacrylate, methacryloxy propyl triethoxy silane, methacryloxy propyl diethoxy ethylsilane;

Preferably said styrene-acrylic emulsion and coating compositions thereof is provided wherein said polymer: said silicate-siliconate reactive additive weight by weight ratio is in the range of 4-11.5.
According to yet another preferred aspect of the present invention there is provided said styrene-acrylic emulsion and coating composition thereof wherein said emulsion contains active content which is total solid content, excluding water in the range of 30-60 weight %.
According to another aspect of the present invention there is provided a process of manufacture of styrene-acrylic emulsion and coating compositions thereof preferably as one pot manufacturing process comprising the steps of
(a) providing said monomers for emulsion polymerization in the presence of surfactants and initiators and obtaining said styrene acrylic emulsion polymer;
(b) adjusting pH levels of said emulsion polymer above pH 11 by alkali prior to adding said high levels of 8-20 wt.% of silicate-siliconate additives in the emulsion to thereby enhance the performance of the emulsion and at the same time enable a stable emulsion free of pH and viscosity change over a long period of time of upto 180 days.
More preferably in said process of manufacture of styrene-acrylic emulsion and coating compositions thereof the same includes the sub-steps of
(i) providing in reactor vessel anionic surfactant and de-mineralized water maintained at temperatures of 80°C.
(ii) providing pre-emulsion as prepared separately filled with anionic surfactant, phosphate-based anionic surfactant, non-ionic surfactant dissolved in de-mineralized water, followed by adding acrylic/vinyl functional monomers in select levels resulting in a milky white pre-emulsion;

(iii) adding methacrylic acid into pre-emulsion just prior to addition of 5% Pre emulsion into the reactor ingredients of step (i);

(iv) adding buffer solution, potassium per sulphate solution into the reactor and observing exotherm as indication of start of reaction followed by addition of said pre-emulsion into reactor for about 240 minutes at uniform rate by maintaining reactor temperature of 80°±2°c;

(v) After 25% completion of pre-emulsion into reactor, silane functional crosslinker was added into the pre-emulsion of step (ii) and addition of said pre-emulsion into said reactor was continued till completion of addition;

(vi) reaction mixture in said reactor was digested for 1 hour with sodium formaldehyde sulphoxylate (SFS) in de-mineralized water followed by the addition of mixture of tert-butyl hydroperoxide and non-ionic surfactant dissolved in de-mineralized water to obtain emulsion polymer;

(vii) bringing down the reactor vessel temperature to below 30°C temperature followed by addition of in-can preservatives, alkali including KOH to reach select pH 11-12 of emulsion polymer alkaline followed by addition of silicate, siliconate, to obtain therefrom said coating composition in one pot.

According to another preferred aspect of the process manufacture of styrene-acrylic emulsion and coating compositions thereof in said step (vii) conventional coating additives employed are added including rheology modifiers, hydrocarbon additives, silane-based additive, acid salts solution and coalescing solvents.
Preferably in said process of manufacture of styrene-acrylic emulsion and coating compositions thereof wherein said
Anionic surfactant includes Disodium ethoxylated alcohol (C10-C12) half ester of sulfosuccinic acid, alkyldiphenyloxide disulfonate sodium salt, fatty alcohol polyglycol ether sulphate sodium salt, sodium lauryl sulphate, sodium dodecyl benzene sulphonate, nonyl phenol sulphonate, octyl phenol sulphonate.
Anionic phosphorous based surfactant includes Monoalkyl phosphate ester, dialkyl phosphate ester, allyl alkyl phosphate ester, etc.
Non-ionic surfactant includes Octyl phenol ethoxylate with 10-40 EO, nonyl phenol ethoxylate with 10-40 EO, alcohol ethoxylate with 10-40 EO.
BRIEF DESCRIPTION OF FIGURES

Figure 1: illustrates negative capillary testing panel: (a) CP-cement putty on normal panel; (b) HP-hand made putty on normal panel; (c) EF- cement putty on salted panel;
Figure 2: illustrates DMA Plots of silicate-siliconate coating compositions: (a) EXP 1, (b) EXP 6.

DETAILED DESCRIPTION OF THE INVENTION

As discussed hereinbefore, the present invention provides for emulsion polymers and a process of synthesis thereof synthesized by polymerization of various mono functional monomers such as styrene, methyl methacrylate, butyl acrylate, 2-ethyl hexyl acrylate, VeoVa -9, VeoVa-10, ethyl acrylate, etc and at least one hydroxy functional monomer such as hydroxy ethyl methacrylate, hydroxy ethyl acrylate, hydroxy propyl methacrylate, hydroxy propyl acrylate, etc. Said emulsion was formulated with silicate, silicate-siliconate mixture and siliconate reactive additives. The formulated coating compositions are alkaline in nature and pH and viscosity does not change up to 30 days at accelerated temperature stability testing i.e. 55 oC. The resulting coating composition having excellent water resistance, solvent resistance, and adhesion on dry, damp and salt deposited various substrates such as cementitious, masonry, POP, wall putty, etc.

In the present invention, an emulsion polymer based coating composition could be developed based on styrene-acrylic emulsions which are highly compatible with silicate, silicate-siliconate mixture and siliconate additives. The coating composition shows excellent water resistance, solvent (MTO) resistance, anti-efflorescence, and better adhesion on dry, damp and salt deposited various substrates such as cementitious, masonry, POP, wall putty, etc.
According to an embodiment of the present invention there is provided a composition suitable for coating applications based on hydroxy functional styrene-acrylic emulsion that is highly compatible with silicate-siliconate materials reflecting in its storage stability based on its viscosity that does not change over a long period of time.
Preferably said composition including said hydroxy functional styrene-acrylic emulsion comprises mono functional monomers such as styrene, methyl methacrylate, butyl acrylate, 2-ethyl hexyl acrylate, VeoVa -9, VeoVa-10, ethyl acrylate, etc and at least one hydroxy functional monomer such as hydroxy ethyl methacrylate, hydroxy ethyl acrylate, hydroxy propyl methacrylate and hydroxy propyl acrylate, also includes compatible silicate-siliconate materials selected from silicate, silicate-siliconate mixture, and siliconate reactive additives.
Said coating composition have excellent water resistance, solvent (i.e., Mineral Turpentine Oil (MTO)) resistance anti- efflorescence and shows improvement in adhesion towards dry, damp and salt deposited various substrates such as cementitious, masonry, POP, wall putty, etc.
Preferably said coating composition comprises hydroxy functional styrene-acrylic polymer: reactive additive in weight-by-weight ratio in the range 4-11.5 and wherein said coating composition comprises said emulsion wherein said hydroxyl functional monomer concentration is in the range of 1 to 10 weight % based on total monomer concentration.
In the present invention, extreme water resistance including water proofing, excellent adhesion and anti-efflorescence properties could be accomplished thereby making it suitable for water proofing applications. The desired attributes could be attained only with the involvement of silicate-siliconate at high concentration (8-20% of the emulsion). Additionally, due to having high concentrations of silicate-siliconate for attaining the desired attributes presence of KOH in the present composition gave desired stability of coating compositions that are otherwise highly unstable in absence of KOH unlike prior JP2005336357A not involving any KOH as KOH is normally known to deteriorate water resistance of the products. Whereas in the present invention, in presence of KOH the coating composition withstood 4.5 Bar pressure in ASTM D 7088 test (Resistance to Hydrostatic Pressure for Coatings).

EXAMPLES:
General procedure for Example number 1 to 6.

Anionic surfactant and de-mineralized water were charged into a kettle fitted with a three necked lid and the assembly was heated to 80°C.
In a separate pre-emulsion flask filled with anionic surfactant, phosphate-based anionic surfactant, non-ionic surfactant dissolved in de-mineralized water, acrylic/vinyl functional monomers were weighed and stirred to form a milky white pre-emulsion (as per table 1). Methacrylic acid was added into pre-emulsion, just prior to addition of 5% Pre emulsion into the reactor kettle. 5% of pre-emulsion was added into reactor followed by addition of buffer solution and potassium per sulphate solution into the reactor. Once, the exotherm is observed indicating the start of reaction, to this reaction mixture, the pre-emulsion was added for a period of 240 minutes, by maintaining the temperature at 80°±2°c. After 25% completion of pre-emulsion, silane functional crosslinker monomer was added into the pre-emulsion and addition was continued. After the completion of pre-emulsion addition, de-mineralised water was used to flush the peristaltic pump used to pump the pre-emulsion mixture into the reactor. Upon completion of addition, sodium formaldehyde sulphoxylate (SFS) in de-mineralized water was added to the reaction mixture followed by the addition of mixture of tert-butyl hydroperoxide and non-anionic surfactant dissolved in de-mineralized water. The digestion process was completed in one hour. Below 30°C temperature, in reactor vessel, in-can preservative was added followed by the pH made alkaline by the addition of KOH solution. In reactor vessel, rheology modifier, silicate, siliconate, hydrocarbon additives solution, silane-based additives solution, acid salts solution and coalescing solvents were added.

Table No 1: Experiment Nos. 1 to 6
Sr. No. Chemical formulation/composition Exp. 1 Exp. 2 Exp. 3 Exp. 4 Exp. 5 Exp. 6
1 Reactor charge-I (80 deg C)
De-mineralised water 13.3 13.3 13.3 13.3 13.3 13.3
Anionic surfactant 0.18 0.18 0.18 0.18 0.18 0.18
2 5% pre-emulsion seed


Buffer 0.11 0.11 0.11 0.11 0.11 0.11
De-mineralised water 1.61 1.61 1.61 1.61 1.61 1.61
Initiator 0.14 0.14 0.14 0.14 0.14 0.14
De-mineralised water 1.75 1.75 1.75 1.75 1.75 1.75
3 Pre-emulsion
De-mineralised water 14.99 14.99 14.99 14.99 14.99 14.99
Anionic surfactant 0.14 0.14 0.14 0.14 0.14 0.14
Phosphorus based Surfactant 0.35 0.35 0.35 0.35 0.35 0.35
Non- ionic surfactant 0.35 0.35 0.35 0.35 0.35 0.35
Methyl Methacrylate 11.9 11.9 11.9 11.9 11.9 12.95
2-Ethyl hexyl acrylate 11.2 11.2 11.2 11.2 11.2 11.2
Styrene 7 7 7 7 7 7
Methacrylic Acid 0.7 0.7 0.7 0.7 0.7 0.7
Hydroxy Ethyl Methacrylate 1.05 1.05 1.05 1.05 1.05 00
Coalescing solvent 0.7 0.7 0.7 0.7 0.7 0.7
4 Pre-emulsion Addition stage (feed over 240 minutes at uniform rate)
5 After 25% pre-emulsion addition
Silane Monomer 0.7 0.7 0.7 0.7 0.7 0.7
De-mineralised water 0.14 0.14 0.14 0.14 0.14 0.14
6 De-mineralised water
For flushing 0.7 0.7 0.7 0.7 0.7 0.7
7 Digestion catalysts
TBHP 0.04 0.04 0.04 0.04 0.04 0.04
Non- ionic surfactant 0.07 0.07 0.07 0.07 0.07 0.07
De-mineralised water 0.35 0.35 0.35 0.35 0.35 0.35
SFS 0.04 0.04 0.04 0.04 0.04 0.04
De-mineralised water 0.35 0.35 0.35 0.35 0.35 0.35
8 Additives
Biocide 0.14 0.14 0.14 0.14 0.14 0.14
Defoamer 0.01 0.01 0.01 0.01 0.01 0.01
KOH Solution (14%) 1.00 1.00 1.00 1.00 1.00 1.00
De-mineralised water 0.92 0.92 0.92 0.92 0.92 0.92
Rheology modifier 0.368 0.368 0.368 0.368 0.368 0.368
Sodium Silicate 8.2 16.4 8.2
Potassium silicate 16.4
Lithium Silicate 16.4
Methyl potassium Siliconate 8.2 8.2 8.2
Coalescing solvent 1.4 1.4 1.4 1.4 1.4 1.4
Silane additives 0.2 0.2 0.2 0.2 0.2 0.2
Hydrocarbon additive 0.2 0.2 0.2 0.2 0.2 0.2
Acid salts 0.2 0.2 0.2 0.2 0.2 0.2
Water 11.302 11.302 11.302 11.302 19.502 11.302
Total 100 100 100 100 100 100

The above emulsion/ formulation and coating compositions thereof are as apparent from section 8 reactive additives apart from conventional coating additives including anyone or more rheology modifiers, hydrocarbon additives, silane-based additive, acid salts solution, coalescing solvents of the above Table no 1 thus favours a one pot system leading to the final coating composition due to the stability attained by the emulsion and the resulting properties attained thereof.
TABLE 2-Characterization and Performance Properties:
Sr. No. Test Test Method Description Exp-1 Exp-2 Exp-3 Exp-4 Exp-
5
1 Hydrostatic Pressure (Bar) ASTM D 7088
on dry substrate 4.5 4.5 4.5 3.5 4.5
2 Negative capillary On wet substrate (70% moisture content), No efflorescence up to 60 Days Pass Failed
4 Negative capillary On wet effloresce substrate (70% moisture content) Pass Failed
5 Negative capillary On wet substrate (70% moisture content) followed by MTO containing putty Pass Failed
6 MTO tolerance ISO 2812 4.5/5 4.5/5 4.5/5 4.5/5 3.5/5
7 Initial viscosity 130 cP 150 cP 158 cp 172 cp 140 cP
8 Natural Stability Viscosity after 30 Days at 30 oC 140 cP 155 cP 160 cp 170 cp 143cP
9 Accelerated Stability Viscosity after 30 Days at 55 oC 160 cP 150 cP 158 cp 173 cp 140 cP
10 Initial pH 12.00 11.80 11.70 11.40 11.7
11 Natural Stability pH after 30 Days at 30 oC 11.98 11.56 11.50 11.20 11.5
12 Accelerated Stability pH after 30 Days at 55 oC 11.91 11.50 11.54 11.20 11.6
13 Particle size (nm) Measured in Malvern Zetasizer nano at 0.1% concentration. 118 nm 118 nm 118 nm 118 nm 125 nm

Ex 2-5 are comparatives in not involving silicate-siliconate additive showing failure of water resistance properties even when select levels of styrene-acrylic emulsion monomers are involved, and even when the process is conducted as per the necessary sequence as elaborated above.
Effect of hydroxy functionality on crosslinking density
The effect of hydroxyl functionality on crosslinking density of coating compositions were tested by Dynamic Mechanical Analysis (DMA). Results are summarized in Table No. 3.
Coating composition containing hydroxy functional polymer (Exp.1) backbone showed approximate 60% higher crosslinking density than without hydroxy functional polymer (EXP-06) backbone. Therefore, hydroxy functionality is playing crucial role for improvement of water and MTO/solvent resistant properties.
Table No. 3: DMA analysis of silicate-siliconate coating compositions.
Exp No. Description E’25 (MPa) at 30?C E”25 (MPa) at 30?C Tg (°C) Tan d Crosslink Density (mol cm-3)
EXP. 1 With hydroxy functional polymer 295.7 146.8 39.2 0.8 7.9 × 10-4
EXP. 6 Without hydroxy functional polymer 397.0 179.4 40.4 0.9 4.9 × 10-4

Table 3 above shows significant improved cross link density of coating compositions involving hydroxy functional polymer, at select levels only, to show improvement of water and MTO/solvent resistant attributes, whereby such select levels of said hydroxyl functional monomer are also important for stability of the emulsion and paint coating compositions with no loss of attributes of MTO and water resistance properties as hydroxy functional monomers are hydrophilic in nature, and therefore needs to be maintained at select levels of hydroxy functionality.
It is thus the surprising finding of the present invention in attaining styrene-acrylic emulsion polymer and coating compositions thereof comprising alkali stabilized silicate-siliconate based styrene-acrylic emulsion polymer having silicate-siliconate at high concentration ranges of 8-20 wt.% in the emulsion.
Said emulsion polymer being a copolymer of monomers including mono functional co-monomers of styrene, methyl methacrylate, butyl acrylate, 2-ethyl hexyl acrylate, VeoVa -9, VeoVa-10, ethyl acrylate, and, at least one 1 to 10 wt. % hydroxy functional monomer (based on total monomer concentration) including hydroxy ethyl methacrylate, hydroxy ethyl acrylate, hydroxy propyl methacrylate and hydroxy propyl acrylate, is stabilized by (˜14%) 1-1.5 wt.% alkali in the presence of said high levels of 8-20 wt.% of silicate-siliconate in the emulsion enabling performance properties free of any quaternary ammonium based stabilizer.
Such said performance properties include excellent water resistance, solvent resistance including MTO resistance, anti-efflorescent and water proofing attributes due to select styrene acrylic polymer present together with high concentrations of silicate-siliconate that could be stabilized with select levels of alkali, and is yet free of deteriorating water resistance due to the presence of alkali. It was found that even in presence of KOH the emulsion polymer and coating compositions thereof could withstand 4.5 Bar pressure in ASTM D 7088 test (Resistance to Hydrostatic Pressure for Coatings).
Also the present alkali stabilized silicate-siliconate based styrene-acrylic emulsion polymer could be advantageously obtained of polymerizing said co-monomers based on select levels of co-monomers and by following a select process followed by adjusting the pH of the emulsion above pH 11 by alkali preferably by aqueous solution of KOH before adding high levels of silicate-siliconate additives in the emulsion to enhance the performances of the emulsion and at the same time enabling a stable emulsion free of pH and viscosity change over a long period of time of upto 180 days.
, Claims:We Claim:
1. Styrene-acrylic emulsion polymer and coating compositions thereof comprising alkali stabilized silicate-siliconate based styrene-acrylic emulsion polymer having high concentration ranges of silicate-siliconate of 8-20 wt.% in the emulsion.

2. The styrene-acrylic emulsion and coating compositions thereof as claimed in claim 1 as a one component stable emulsion polymer and coating compositions thereof maintaining pH levels of range 11 to 13, Particle size 90 to 180 nm, Viscosity 35 to 200 cP at 30 oC, under accelerated stability tests.

3. The styrene-acrylic emulsion and coating compositions thereof as claimed in claims 1 or 2 wherein said styrene acrylic emulsion polymer is a copolymer of monomers including mono functional co-monomers of styrene (5-20 wt. %), methyl methacrylate (0-15 wt. %), butyl acrylate (5-15 wt. %), 2-ethyl hexyl acrylate (5-15 wt. %), VeoVa -9(1-10 wt. %), VeoVa-10 (1-10 wt. %), ethyl acrylate (5-15 wt. %), methacrylic acid (0.1-4 wt. %), silane monomer (0.1-5 wt. %), and, at least 0.5 to 5wt. % hydroxy functional monomer (based on total formulation) including hydroxy ethyl methacrylate, hydroxy ethyl acrylate, hydroxy propyl methacrylate and hydroxy propyl acrylate, leading to a stable emulsion polymer stabilized by (˜14%) 1-1.5 wt.% alkali in the presence of 8-20 wt.% levels of silicate-siliconate in the emulsion.

4. The styrene-acrylic emulsion and coating compositions thereof as claimed in claims 1-3 having excellent water resistance, solvent resistance including MTO (mineral turpentine oil) resistance, anti-efflorescent and water proofing attributes due to select styrene acrylic polymer present together with high concentrations of silicate-siliconate and stabilized with alkali yet free of deteriorating water resistance in presence of alkali.

5. The styrene-acrylic emulsion and coating compositions thereof as claimed in claims 1-4 obtained of polymerizing said co-monomers followed by adjusting the pH of the emulsion above pH 11 by alkali preferably by aqueous solution of KOH before adding said high levels of silicate-siliconate additives in the emulsion to enhance the performance and at the same time enabling a stable emulsion free of pH and viscosity change over a long period of time of 180 days.

6. The styrene-acrylic emulsion and coating compositions thereof as claimed in claims 1-5 wherein said emulsion includes silicate-siliconate as reactive additive is selected from sodium silicate, potassium silicate, lithium silicate, methyl potassium siliconate;
silane functional monomer/crosslinker of alkoxysilanes including vinyl trimethoxy silane, vinyltriethoxysilane, 3-(trimethoxysilyl)propyl methacrylate, methacryloxy propyl triethoxy silane, methacryloxy propyl diethoxy ethylsilane;

7. The styrene-acrylic emulsion and coating compositions thereof as claimed in claims 1-6 wherein said polymer: said silicate-siliconate reactive additive weight by weight ratio is in the range of 4-11.5.

8. The styrene-acrylic emulsion and coating composition thereof as claimed in Claims 1-7 wherein said emulsion contains active content which is total solid content, excluding water in the range of 30-60 weight %.

9. A process of manufacture of styrene-acrylic emulsion and coating compositions thereof as claimed in claim 1-8 preferably as one pot manufacturing process comprising the steps of
(a) providing said monomers for emulsion polymerization in the presence of surfactants and initiators and obtaining said styrene acrylic emulsion polymer;
(b) adjusting pH levels of said emulsion polymer above pH 11 by alkali prior to adding said high levels of 8-20 wt.% of silicate-siliconate additives in the emulsion to thereby enhance the performance of the emulsion and at the same time enable a stable emulsion free of pH and viscosity change over a long period of time of upto 180 days.

10. The process of manufacture of styrene-acrylic emulsion and coating compositions thereof as claimed in claim 9 including the sub-steps of
(i) providing in reactor vessel anionic surfactant and de-mineralized water maintained at temperatures of 80°C.
(ii) providing pre-emulsion as prepared separately filled with anionic surfactant, phosphate-based anionic surfactant, non-ionic surfactant dissolved in de-mineralized water, followed by adding acrylic/vinyl functional monomers in select levels resulting in a milky white pre-emulsion;

(iii) adding methacrylic acid into pre-emulsion just prior to addition of 5% Pre emulsion into the reactor ingredients of step (i);

(iv) adding buffer solution, potassium per sulphate solution into the reactor and observing exotherm as indication of start of reaction followed by addition of said pre-emulsion into reactor for about 240 minutes at uniform rate by maintaining reactor temperature of 80°±2°c;

(v) After 25% completion of pre-emulsion into reactor, silane functional crosslinker was added into the pre-emulsion of step (ii) and addition of said pre-emulsion into said reactor was continued till completion of addition;

(vi) reaction mixture in said reactor was digested for 1 hour with sodium formaldehyde sulphoxylate (SFS) in de-mineralized water followed by the addition of mixture of tert-butyl hydroperoxide and non-ionic surfactant dissolved in de-mineralized water to obtain emulsion polymer;

(vii) bringing down the reactor vessel temperature to below 30°C temperature followed by addition of in-can preservatives, alkali including KOH to reach select pH 11-12 of emulsion polymer alkaline followed by addition of silicate, siliconate, to obtain therefrom said coating composition in one pot.

11. The process of manufacture of styrene-acrylic emulsion and coating compositions thereof as claimed in claims 9 or 10 wherein in said step (vii) conventional coating additives employed are added including rheology modifiers, hydrocarbon additives, silane-based additive, acid salts solution and coalescing solvents.
12. The process of manufacture of styrene-acrylic emulsion and coating compositions thereof as claimed in claims 9 - 11 wherein said
Anionic surfactant includes Disodium ethoxylated alcohol (C10-C12) half ester of sulfosuccinic acid, alkyldiphenyloxide disulfonate sodium salt, fatty alcohol polyglycol ether sulphate sodium salt, sodium lauryl sulphate, sodium dodecyl benzene sulphonate, nonyl phenol sulphonate, octyl phenol sulphonate.
Anionic phosphorous based surfactant includes Monoalkyl phosphate ester, dialkyl phosphate ester, allyl alkyl phosphate ester, etc.
Non-ionic surfactant includes Octyl phenol ethoxylate with 10-40 EO, nonyl phenol ethoxylate with 10-40 EO, alcohol ethoxylate with 10-40 EO.

Dated this the 28th day of March, 2023 Anjan Sen
Of Anjan Sen and Associates
(Applicants Agent)
IN/PA-199