DESC:FIELD OF INVENTION

The present invention relates to water based thermally insulating latex paints/ coating formulations and systems thereof acting as water based thermal insulation and anti-condensation coating suitable for industrial and architectural applications that are not typically acrylic. Preferably, water based polyurethane dispersion including colloidal silica and hollow beads and fibers along with fire retardant, as latex paint and coating system thereof is thus provided that is versatile for variety of different substrates, favouring improved thermal efficiency attained at reduced lower cost with the rheology suitable for building higher dry film thickness per coat without sagging. The formulation/ composition also shows excellent anti-fungal and anti-microbial performance. Moreover, simultaneously it acts as anti-condensation due to presence of colloidal silica nano structure across the thickness of the film.

BACKGROUND ART

Extreme weather conditions necessitate the houses to be air conditioned for well being of the occupants and many industrial processes needing high or low temperatures for carrying some chemical reactions or storage or transfer of the materials as well requires the thermal insulations to ensure that those temperatures does not affect negatively the surroundings environment or people. Many different types of the thermal insulations systems are addressing the above needs prevalent at present time. However, specifically when the air duct carrying the low temperature air if not properly insulated results into condensation of the moisture in the form of the droplets and drips locally causing the relevant hazards to surrounding.
For effective thermal insulation performance need higher thickness of insulation material up to 2-3 cm and still may not be sufficiently efficient or sustainable and require periodic maintenance. Oil and gas industry adopt conventional heat preserving methods such as insulating cotton, foam glass, Rockwool, polyurethane foam for pipelines, cryogenic tank, storage tank which require cladding. Such insulations are fragile, susceptible to vibration which induce damages. The use of conventional insulation in outdoor environment can lead conditions called corrosion under insulation, where trapped moisture penetrates the insulating jacket and get trapped between substrate and insulation where it can both reduce the effectiveness of insulating material and contribute to potential corrosion in metal.
CN113980554A describes anti-condensation heat-insulation coating capable of being used for wet-coating and preparation method of anti-condensation heat-insulation coating. It’s a 2 pack solvent based epoxy polyamide system using the hollow micro beads, aerogel slurry. It is thus not a one pack system.

CN111378347 describes a high-temperature-resistant anti-condensation coating for high-temperature flue gas treatment equipment and preparation method thereof. This prior art is using the composition of 2 pack solvent based epoxy system with expanded perlite powder as key insulating material. This prior art is also not a single pack system to provide for anti-condensation heat-insulation coating anti-condensation heat-insulation.

CN112745729 reveals an anti-condensation thermal insulation latex paint and preparation method thereof. It comprises a mixed emulsion formed by the pure acrylic emulsion and a silicone resin emulsion, and a heat insulation material comprising microbeads, nano silica and aerogel slurry. This prior art is limited to the involvement of acrylic emulsion and a silicone resin emulsion.

CN101293752 presents an acoustic absorption, noise insulation, thermal insulation, condensation resistant building material, preparation method and application thereof. It’s a three component system using plant fibers, styrene, butyl acrylate, silane or methyl methacrylate, fireproofing agent or/and 0.1-1 part by weight of a mildewproofing agent. This prior art is limited to the involvement of the aforesaid latexes. This prior art does not teach about single pack water based polyurethane dispersion.

CN110746798A teaches anti-condensation inorganic silicate inner wall coating and preparation method thereof. It uses inorganic binder potassium silicate, aerogel slurry, vermiculite powdery substance.

WO2021001689A1 is directed to thermally insulating coating composition uses water dispersible polymer (vinyl esters and ethers based polymer and copolymers), hollow glass spheres and inorganic extenders. Does not suggest the involvement of single pack waterborne polyurethane dispersion as a thermal insulator and anti-condensation coating.

CN101381546A teaches microhollow super-fiber heat insulation coatings for building insulation and method of use thereof. It uses aramid fibers, rock wool fibres, pearlescent sand, expanded perlite, floating beads, fibrous vermiculite powder, sepiolite, acrylic resin and fluoro silicone resin and fungicide agent, primarily for wall insulation using white cement as one of the ingredients.

CN112745729 discloses anti-condensation thermal insulation latex paint and preparation thereof. It describes the composition acrylic and silicone resin emulsion, microbeads, nano silica and aerogel slurry.

Reference is also made to Thermal insulation coating based on water-based polymer dispersion Saienko Natalia1, Skripinets Anna2, Gurina Galina2, Saienko Leonid3 and Hryhorenko Oleksandr1Published under licensed by IOP Publishing Ltd. IOP Conference Series: Earth and Environmental Science, Volume 1376, International Conference on Urban Infrastructure Sustainable Development and Renovation 25/01/2024 - 27/01/2024 Kharkiv, Ukraine that presents a study on the development of thin-layer thermal (with a thermal conductivity coefficient ranging from 0.0416 to 0.083 W/(m•K)) insulation coatings based on styrene-acrylic aqueous dispersion with improved adhesion properties and regulated technological characteristics. The simplicity and speed of applying liquid thermal insulation provide significant advantages over standard insulating materials. An advantage is the ability to insulate surfaces of complex configuration.

KR101297222B1 on anti-condensation (condensation preventing) paint composition comprising hollow ceramic beads describes under PURPOSE: A hollow ceramic beads-containing antifreezing paint composition is provided to have excellent heat-shielding performance and durability and to have excellent antifreezing effect by determining the amount of a polymer binder varying with the volume ratio with the hollow ceramic beads. CONSTITUTION: A hollow ceramic beads-containing antifreezing paint composition contains hollow ceramic beads, a polymer binder, additives, and water. The volume ratio of the hollow ceramics beads is 40-70 % based on the total volume of the paint composition, and the polymer binder is 18-30 %. The density of the hollow ceramic beads is 0.125-0.35 g/cc, the fracture strength is 300-500 psi, and the particle size is 50-150 micron. The polymer binder is one or more selected from acryl, an acrylic copolymer, polyurethane, silicon, acrylic silicone hybrid, urethane hybrid, enamel, and latex. The thermal conductivity of the polymer binder is 0.25 w/mk or less. However, there is still a requirement for higher thermal efficiency of thermal insulation at a lower cost.

In spite of the state of the art knowledge on anti-condensation and thermally insulating latex paints there is still a need in the art to develop for said water based anti-condensation coatings that would not only provide for desired thermal insulation but would also enable thermal insulation based anti-condensation effect together with crack-free higher dry film thickness per coat of said paint.

Also thus such coating systems which can simultaneously work as thermal insulation system as well as anti-condensation system to be used for the conventional walls for architectural applications or pipes, ducts, tanks etc. for industrial and transport-automotive uses including in AC ducts needs to be explored.

OBJECTS OF THE INVENTION

It is thus the primary object of the present invention to provide for anti-condensation and thermally insulating latex paint formulation that would be water based and in presence of co-acting rheology modifiers would provide for crack-free high dry film thickness per coat.

It is another object of the present invention to provide for said thermal insulation based anti-condensation latex paint and coating formulations thereof that would even in involving water based polyurethane dispersion and would co-act with synergistic blend of fillers and rheology modifiers to provide for said attributes of thermal insulation based anti-condensation.

It is yet another object of the present invention to provide for said thermal insulation based anti-condensation latex paint and coating formulations thereof that would be applicable on substrates at higher dry film thickness (1 mm to 5 mm per coat) giving excellent thermal insulation and anti-condensation performance free of any crack generation.

It is another object of the present invention to provide for said thermal insulation based anti-condensation latex paint and coating formulations thereof that would provide thermal insulation and anti-condensation performance when applied onto hot/ cold substrates and includes applicability on substrates at temperature range of –40 degree centigrade to +180 degree centigrade enabling said attributes of thermal insulation based anti-condensation.

It is still another object of the present invention to provide for said anti-condensation and thermally insulating latex paint that would be prepared by facile manufacturing process.

SUMMARY OF THE INVENTION
Thus according to the basic aspect of the present invention there is provided water based thermally insulating paint/coating formulations and systems comprising
colloidal silica in rheology modified water dispersion of latex binder and co-acting synergistic blend of hollow beads and hollow microfibers, adapted for simultaneous thermal insulation and anti-condensation attributes of a thick coat free of cracking and sagging.

Preferably said water based thermally insulating paint/coating formulations is provided wherein said rheology modified water dispersion of latex binder includes
5-80 wt.% acrylic, polyurethane, silicone binder or their combinations preferably polyurethane binder with ?35 % polymer solids in water preferably 10-40% polyurethane binder giving improved adhesion over metal surface/ painted old surface with binding efficiency versus acrylics,
5-20 wt. % of colloidal silica;
0.01 to 5 wt. % of said rheology modifier including synthetic phyllosilicate preferably 0.5-2 wt.%;
5-80 wt.% preferably 10-40 wt.% of co-acting synergistic blend of hollow beads and hollow polymer microfibers including polyester, polyamide, acrylic fibers having length of 0.4-0.7 mm and diameter of ? 20 micron;
0.2-2 wt.% epoxy silane coupler.

More preferably said water based thermally insulating paint/coating formulations is provided wherein said water based formulation optionally includes 5-40 wt.% compatible fire retardant slurry having 60% active concentration in water together with optional preferential additives adapted for not only improved thermal resistance based thermal efficiency but also fire protection.

According to another preferred aspect of the present invention there is provided said water based thermally insulating paint/coating formulations that is a versatile single pack water dilute able coating formulation suitable for adhering with varied substrates enabling improved thermal efficiency at lower cost and mechanical attributes together with desired rheology suitable for fabricating dry film of improved thickness of 1-5 mm/ coat free of said cracking and sagging.

Preferably said water based thermally insulating paint/coating formulations is provided that is a seamless monolithic continuous coating adapted for excellent thermal insulation and anti-condensation attributes when applied to hot/ cold substrates and over the substrates carrying low temperature materials/fluids/air in the temperature range of –40 degree centigrade to +180 degree centigrade.

More preferably, said water based thermally insulating paint/coating formulations is provided wherein said water based formulation with optional fire retardant includes 20 wt.% Polyurethane dispersion having 35% solids in water and /or water dispersible silicone binders and 5 wt.% fire retardant slurry having 60% concentration of active Aluminium tri hydroxide in water, together with 1.5 wt. % Laponite RD synthetic phllyosilicate rheology modifier, 7 wt. % Colloidal silica, 11 wt.% hollow beads including of Soda lime borosilicate glass having average particle size ?60 micron, in the range 30-115 micron, 5 wt.% Hollow Polyester microfibre of ?0.7 mm length and 20 micron diameter, favouring thermal insulation coating for high temperature insulations in the range of 200-450 ?C as required in industrial applications.

According to another preferred aspect of the present invention said water based thermally insulating paint/coating formulations is provided wherein said water based formulation includes said preferential additives of 0.01 to 5 wt.% Hydroxy ethyl cellulose (HEC) preferably 0.2 wt. %, 0.01 to 5 wt.% AMP 95 (amino alcohol)/ pH stabilizer preferably 0.1 wt.%, 0.01 to 5 wt.% In can preservative preferably 0.15 wt.%, 0.01 to 5 wt.% Defoamer preferably 0.1 wt.%, 0.01 to 5 wt.% Fluoro surfactant wetting agent preferably 0.2 wt. %, 0.01 to 5 wt.% oligomeric epoxy silane coupling agent of mol. wt. in the range of 200-800 gms preferably 282 gms taken at preferred levels of 0.5 wt.%, 0.01 to 5 wt.% Zinc Omadine dispersion 40% in water preferably 0.5 wt.%.
Preferably said water based thermally insulating paint/coating formulations is provided wherein said thermal efficiency based thermal conductivity values include 0.03968 W/ m.K- 0.04311 W/m.K, mean thermal resistance values include 0.1484 (m²•K)/W-0.1573 (m2.K) / W at formulation rheology modified formulation density of 0.5 to 0.8 g/cm3 with viscous paste like consistency having 56.59% of solids volume.

According to another aspect, a process for the manufacture of water based thermally insulating paint/coating formulations is provided comprising the steps of
preparing water based acrylate/polyurethane dispersion and incorporating colloidal silica, select rheology modifier together with co-acting hollow beads and hollow microfibers and optional compatible fire retardant slurry separately towards obtaining therefrom said water based thermally insulating paint/coating formulations adapted for simultaneous thermal insulation and anti-condensation attributes of fabricated thick coating thereof free of cracking and sagging.
Preferably in said process for the manufacture of water based thermally insulating paint/ coating formulations wherein for preparation of 100 gm of said paint/ coating formulations is based on select sequence of ingredient addition to avoid lump formation includes following sub-steps
[i] Preparation of mill base involving high speed disperser by

a) providing 49.25 gm water and adding synthetic phyllosilicate of laponite RD 1.5 gm under stirring;
b) Gradually increasing RPM to 1000 and mixing till solution becomes clear;
c) Adding 0.2 gm hydroxyethylcellulose (HEC) polymer slowly under stirring;
d) Mixing till solution becomes clear followed by adding 0.1 gm amino alcohol and continuing stirring at same speed for 5 minutes;
e) Adding 0.15 gm chlormethyl/ methylisothiazolone and formaldehyde preservative, 0.2 gm Fluoro surfactant wetting agent, and 0.11 gm polysiloxane and polyglycol blend defoamer, respectively in the above mix of step (d) and continuing stirring at same speed for 10 minutes;
f) adding latex binder dispersion preferably 20gm polyurethane dispersion with select polymer solid levels, 7 gm Collidal silica, and 0.5 gm of Oligomeric Epoxy silane respectively;
g) continuing stirring at 1000 rpm for 10 minutes free of any lump formation in the mill base;
h) adding Zinc Pyrithione as 40% active as fine particle sized dispersion and mixing for 5 min, and optionally, adding fire retardant slurry as compatible slurry and mixing additionally for 5 mins to obtain mill base therefrom.

[ii] Preparation of the thermal insulation, anti-condensation coating formulation by involving Ribbon blender:
a) providing mill base of step (i) to the blender and mixing for 5 min followed by adding 11 gm hollow beads and 5 gm hollow microfibers;
b) Mixing for 15 min to achieve uniform-smooth consistency of the formulation of density in the range of 0.5 to 0.8 g/cm3 with viscous paste like consistency having 50-60% solids volume and pH of 9-9.5.

More preferably a process for the manufacture of water based thermally insulating paint/ coating formulations is provided wherein said optional fire retardant slurry as a compatible slurry is prepared in high speed disperser by including the following steps:
a) Adding in 20 gm water 1.5 gm dispersant sodium salt of carboxylic acid, 0.5 gm non-ionic surfactant of polyoxyethylene alcohol, 0.1 gm defoamer blend of polysiloxane and polyglycol) and 0.15 gm of said preservative of chlormethyl/ methylisothiazolone and formaldehyde;
b) Mixing for 10 min followed by adding 0.15 gm hydroxyethylcellulose (HEC) polymer by gradually increasing RPM to 400 to ensure uniform dissolution in water;
c) Adding 0.15 gm amino alcohol and mixing for 10 min with 1000 RPM;
d) Adding 60 gm of Alumina Trihydrate of ATH 800 grade under slow stirring;
e) Continuing dispersal for 20- 30 minutes till uniform smooth slurry of ATH powder is achieved as confirmed by Hegman Guage finish at 6+ to 7 giving 15 microns or lower particle size.

While conventional water based thermal insulation coatings are typically acrylic latex based with active insulation materials like hollow micro spheres etc., the present invention could surprisingly provide for water based latex/ binder dispersions preferably polyurethane dispersion including colloidal silica and co-acting synergistic blend of hollow beads and hollow microfibers of select diameter together with rheology modifiers preferably Laponite RD that strikes a balance in providing the best synergy which thus not only enables high thickness films free of cracking/ sagging but also achieves thermal insulation and anti-condensation attributes. Optionally, fire retardants as compatible slurry can also be incorporated in the formulation without loss of thermal insulation and anti-condensation attributes thereby resulting in a versatile coating formulation for variety of different substrates favouring improved thermal efficiency at lower cost and also favouring desired rheology suitable for building higher dry film thickness per coat without sagging eventually favouring not only thermal insulation and anti-condensation attributes with said desired rheology but also fire retardency.
Preferably said Polyurethane binder based dispersions have specific advantage of adhesion over metal surface/ painted old surface along with good binding efficiency when having polymer solids in desired levels as is also apparent from Figure 1.

The coating formulation of the present invention also shows excellent anti-fungal and anti-microbial performance allowing incorporation of such additives. Moreover, simultaneously it acts as insulating and anti-condensation coat even in being water based resulting from synergistically co-acting colloidal silica nanostructure present across the thickness of the film.

Thus the special strategic combination of hollow microfibers of select diameter and hollow beads and colloidal silica included preferably in water based polyurethane dispersion along with fire retardants contributes to highly efficient thermal insulation simultaneously with anti-condensation performance at significantly lower cost that too with improved mechanical properties and rheology suitable for one coat application.

The present coating formulation could be thus advantageously provided as water based single pack system dilute able with water and convenient to use. It involves single pack water based polyurethane dispersion, efficient synergistic blend of hollow micro beads and hollow microfibres with or without other additional fibres like mineral fibres, cellulose fibres, fire retardant and hydrophilic agents with special rheology agents enabling crack-free high dry film thickness per coat.
In the present formulation the fire retardant is not essential ingredient to achieve the key performances of thermal insulation leave apart anti-condensation, as it does not have inherent thermal insulation attributes, however, it could be incorporated in the present formulation as a compatible slurry to make the formulation more robust by also including fire retardant attributes without any loss of said key performances, important to have for such product formulations.

Secondly, the combination of hollow micro beads and hollow fibers of select diameter and co-acting colloidal silica nanostructure present across the thickness of the film is essential for the anti-condensation performance due to increased hydrophilicity and microporosity which is validated by water evaporation profile in Figure 2B. Moreover, the combination of hollow micro spheres involved in other prior arts along with solid fibers and not hollow fibers are not as efficient as it is only with hollow fibers of select diameter that was found to strike the desired balance of rheology and thermal insulation performance as is also brought out in Table 4C below.

Added to the above, the select levels of polyurethane binder dispersion and solid polymer content therein also plays an important role in efficiently binding the larger surface area particles which other water based dispersions/emulsions/ latex cannot bind due to their poor binding performance, while the levels of the polyurethane dispersion needs to be also maintained in select levels as otherwise higher level of polymer content was found to reduce thermal insulation performance.

BRIEF DESCRIPTION OF FIGURES

Figure 1: illustrates thermal insulation and anti-condensation performance experimental batch vs. control;
Figure 2: illustrates under Figures 2(A) (a), (b), (c) the thermal insulation performance of the experimental batch at Various DFTs (Dry film thicknesses)while Figure 2B illustrates the anti-condensation and evaporation profile showing water evaporation rate in gram units;
Figure 3: illustrates high temperature insulation performance showing insulated surface temperature being 83 °C when inside thermic fluid temperature is 180 °C;
Figure 4: 4A. illustrates adhesion by pull off ASTM 4541 for experimental composition based on PU Dispersion as binder that gives value of 0.5 MPa and 0.56 MPa. 4B. Adhesion results of the experimental composition based on acrylic dispersion as binder where it is seen that the pull of test values are 0.35 MPa and 0.37 MPa.

Figure 5: illustrates humidity resistance by IS 101;
Figure 6: illustrates salt spray test as per ASTM B 117
Figure 7: illustrates the preferred fire protection performance as per ASTM D1230 (Flame spread resistance).

DETAILED DESCRIPTION OF THE INVENTION

As described hereinbefore, the present invention provides for water based thermal insulation latex paints/ coating formulations and systems thereof that acts as efficient thermal insulator also enabling anti-condensation performance suitable for industrial and architectural applications, which said formulation is not typically acrylic.

According to an aspect of the present invention there is provided said water based thermal insulation latex paints/ coating formulation as a single pack system dilute able with water and convenient to use that involves rheology modified water based binder preferably polyurethane binder including colloidal silica and co-acting synergistic blend of hollow beads and hollow microfibers along with optionally with fire retardant makes it a versatile coating formulation for variety of different substrates at lower cost, which in being thermally efficient works as thermal insulation system and can also simultaneously act as an anti-condensation coatings that too with desired rheology suitable for building higher dry film thickness per coat without sagging, thereby favouring coating on conventional walls for architectural applications including applications on pipes, ducts, tankages for industrial and transport facilities including automotives.

According to an aspect of the present invention there is provided said latex paints/ coating systems thereof that is water based single pack system dilutable with water and convenient to use, including single pack water based dispersion preferably polyurethane dispersion, together with synergistic blend of select levels of hollow micro beads and hollow fibres with or without additional fibres including mineral fibres, cellulose fibres, fire retardant and hydrophilic agents with special rheology agents enabling crack-free higher dry film thickness per coat of said paint.

According to a preferred aspect of the present invention there is provided said coating system comprising fillers and rheology modifiers including Glass bubble of average particle size 60 micron, range 30-115 micron, Hollow polyster microfibre (of length 0.4-0.7 mm and diameter of 20 microns), Levasil CC-301 colloidal silica, synthetic phyllosilicate of Laponite RD, Polyurethane dispersion Kamthane K 1492, CoatOSil MP 200 oligomeric Epoxy Silane (molecular wt. 200 to 800 gms), Alumina Trihydrate ATH 800 grade, kopthione 40% FPS [Zinc Pyrithione 40% active content as fine particle dispersion (FPS)], along with wetting and dispersing agents, defoamers and biocides, in water based polyurethane dispersion.

According to yet another aspect of the present invention there is provided said coating system as water based coating system which can be applied at higher dry film thickness (1 mm to 5 mm per coat) giving excellent thermal insulation and anti-condensation performance when applied to hot/ cold substrates in the temperature range of –40 degree centigrade to +180 degree centigrade offering the below specific advantages:

Said present coating system is seamless monolithic continuous coating which can be applied over the multiple substrates (including concrete/ masonry/ metals/ wood) with complex geometries (insulation at valve, flanges and joint etc.) hence delivers superior insulation and anti-condensation over the conventional pre-formed insulators.

Said single component water-based coating system is a low VOC (volatile organic compounds) system hence environment friendly over the conventional solvent based systems and easy to apply by conventional application techniques like roller/ brush/ spatula-trowel / spray etc.

Said single component water-based coating system is based on single pack water based dispersion preferably polyurethane dispersion, hollow micro beads, hollow microfibres with or without other fibres like mineral fibres, cellulose fibres, fire retardant and hydrophilic agents with special rheology agents enabling crack-free high dry film thickness per coat.

Said single component water-based coating system imparts excellent thermal insulation performance for both higher temperatures (upto 180 degree centigrade or lower temperature up to -40 degree centigrade) and hence it can be good choice for relevant industrial and architectural application

Said single component water-based coating system having density of 0.5 to 0.8 g/cm3 and mean thermal conductivity of 0.02 to 0.05 W/m.K and Mean Thermal Resistance 0.10 to 0.16 (m²•K)/W.

Said single component water-based coating system provides very good sustained anti-condensation performance when applied over the substrates carrying the low temperature materials/fluids/air.

Said single component water-based coating system has good adhesion on various substrates and imparts good mechanical properties.

Said single component water-based coating system has good compatibility with various paints hence can be top-coated with water based as well as solvent based paints for aesthetic purposes.

Advantages- The present water-based coating system is utilizable as:

1] Thermal insulation and anti-condensation coating for AC duct for varied industrial applications.
2] Thermal insulation system for the interior/ exterior walls for architectural application where it can prevent the heating/cooling loss and thereby help conserving the electrical energy.
3] Industrial pipeline coatings and ducts/ tank coatings needing the thermal insulation and anti-condensation performances for the hot/cold fluids pipeline insulation.
4] The coating system is also resistant to bacterial and fungal growth

The directed objectives that was thus achieved:
The water based coating formulation and systems thereof which can be applied at higher dry film thickness (1 mm to 5 mm per coat) giving excellent thermal insulation and anti-condensation performance when applied to hot/ cold substrates in the temperature range of – 40 degree centigrade to + 180 degree centigrade offering the below specific advantages:
> It is a seamless monolithic continuous coating which can be applied over the multiple substrates (like concrete/ masonry/ metals/ wood etc.) with complex geometries (insulation at valve, flanges and joint etc.) hence delivers superior insulation and anti-condensation over the conventional pre-formed insulators.

>It is a single component water-based system with low VOCs (volatile organic compounds) system hence environment friendly over the conventional solvent based systems and easy to apply by conventional application techniques like roller/ brush/ spatula- trowel / spray etc.

>The composition is based on single pack water based polyurethane dispersion, hollow micro beads, hollow fibres with or without other fibres like mineral fibres, cellulose fibres etc, fire retardant and hydrophilic agents with special rheology agents enabling crack-free high dry film thickness per coat.

>It imparts excellent thermal insulation performance for both higher temperatures (upto 180 degree centigrade) or lower temperature (up to -40 degree centigrade) and hence it can be good choice for relevant industrial and architectural application

>The composition having density of 0.5 to 0.8 g/cm3 and mean thermal conductivity of 0.04311 W/m.K and Mean Thermal Resistance 0.1484 (m²•K)/W.

>It provides very good sustained anti-condensation performance when applied over the substrates carrying the low temperature materials/fluids/air.

> It has good adhesion on various substrates and imparts good mechanical properties.

> It has good compatibility with various paints hence can be top-coated with water based as well as solvent based paints for aesthetic purposes.

Technology Approach:
The anti-condensation and thermal insulation coating formulation and systems thereof is provided that utilizes two important synergists namely hollow micro glass bubbles and hollow microfibers of select length and diameter along with polymer dispersion as binder (preferably polyurethane dispersion as binder having improved and sustainable adhesion on metals as compared to Acrylic dispersion as per Figures 4A that sustains pull off value of 0.5 MPa, 0.56 MPa and 4B revealing pull off values of 0.35 MPa and 0.37 MPa, showing the high adhesion performance of PU Dispersion based system. colloidal silica and synthetic (modified) phyllosilicate rheology control agent which synergistic combination gives excellent thermal insulation, non crack, non sagging high DFT (upto 5 mm/ single coat application) coating. The hydrophilicity imparting agent like the colloidal silica in select environment enables the non-sweating/ non-dripping coating specially suited for such architectural and industrial applications.

Water based acrylic dispersions can also be involved in the formulation, however, polyurethane dispersions have specific advantage of adhesion over metal surface/ painted old surface giving good binding efficiency at the desired polymer solid levels as is apparent from said described Figures 4A and 4B.

The other additives like anti-fungal agents and in can preservations ensure the microbial stability.

The composition is such that it can be applied over various substrates for architectural and industrial applications wherever the thermal insulation along with the non-sweating/ anti-condensation performance is desired.

The use of optional fire retardants most importantly as a compatible slurry makes the formulation of the present invention suitable for the sensitive applications where human safety from fire is also an important aspect to meet.

EXAMPLES:-
Materials used and their properties: The Table 1 below shows the key ingredients used and their role in the end performances of the thermal insulation/ anti-condensation coating
Table 1: Key ingredients used in the study and their role in the formulation
Sr.No. Ingredient description Chemical composition Function of the ingredient in coating formulation
1 Kamthane K 1492* Waterborne Polyurethane dispersion Polymer binder, Air dry, waterborne urethane gives multi substrate adhesion and film integrity
2 Laponite RD* LAPONITE RD is a Synthetic (modified) phyllosilicate Rheology along with the synergy of film cracking resistance and non sagging rheology
3 Rocima 623 Preparation of chlormethyl/ methylisothiazolone and formaldehyde In can preservative
4 Levasil CC-301* Colloidal silica Hydrophilicity agent
5 3M Glass bubble k 15*, average particle size 60 micron, range 30-115 micron. Soda lime borosilicate glass Stable void for lower thermal conductivity, low density, chemically stable bubble
6 Hollow polymer fibers including Recron 3S polyster fibre (0.4-0.7 mm length, and 20 micron diameter)* Polyester fibre, polyamide fiber, acrylic fibers can be employed to achieve similar effect. Crack reduction, sagging, reinforcement
7 CoatOSil MP 200 Epoxy Silane Oligomeric Epoxy silane with mol. wt. 200 to 800 gms Coupling agent, reacting with silica surface and substrate, crack prevention, crosslinking with PUD. The specific grade of epoxy silane Y 19534 is easy to incorporate in water based system when required addition in high amount about > 0.5 %
8 Capstone FS-93/ Capstone FS 30 Fluoro surfactant wetting agent For substrate wetting
9 BYK 022 Blend polysiloxane and polyglycol Defoamer
10 ATH 800 Aluminium tri hydroxide active slurry For fire retardancy
11 INDOFIL 850 Sodium salt of carboxylic acid Dispersing agent
12 SYPRONIC A9 Polyoxyethylene alcohol Non-ionic surfactant for substrate wetting
13 kopthione 40% FPS, having said active content as fine particle suspension Zinc Pyrithione Anti-fungal agent for dried coating film

[Note: The starred RMs-raw materials are critical for the present formulation and the rest are additional optional additives can be included in the formulation without hampering the improved thermal efficiency and simultaneous insulating and anti-condensation attributes of the formulation. Also, water dispersible silicone binder is employed either replacing the PU dispersion or in combination to give similar attributes enabling high temperature thermal insulations at the levels of 200 to 450 ?C suiting industrial applications].

In the above table Sodium salt of carboxylic acid and polyoxyethylene alcohol are the dispersant and wetting agent for the pigments and are optional ingredients, hence they are used in the formulation of the ATH-Fire retardant slurry Table 3 below, which slurry is used as an intermediate to add into Final formulation of anti-condensation and thermal insulation coating as given in Table 4 below.
Preparation of Thermal insulation, Anti-condensation coating: (Stepwise process for preparing 100 gm paint)
A) Preparation of ATH 800 (fire retardant active) slurry (HSD disperser) as per Table 3 below.
1) In 20 gm water and is added Indofil 850 (Sodium salt of carboxylic acid), synperonic A9 (Polyoxyethylene alcohol), BYK 022 (Blend polysiloxane and polyglycol) and Rocima 623 (chlormethyl/ methylisothiazolone and formaldehyde)– 1.5 gm, 0.5 gm, 0.1 gm and 0.15 gm respectively;
2) Mixing for 10 min then added natrosol 250 MHR (hydroxyethylcellulose (HEC) is a nonionic, water-soluble polymer) of 0.15 gm by gradually increasing RPM to 400;
3) Ensuring that natrosol 250 MHR is uniformly dissolved in water;
4) Adding AMP 95 (amino alcohol)-0.15 gm mix for 10 min with 1000 RPM;
5) Adding ATH 800 (Alumina Trihydrate ATH 800 grade)-60 gm under slow stirring;
6) Continuing the dispersion for 20 to 30 minutes till the smooth slurry of ATH powder is achieved, confirmed by the finish on Hegman Guage at 6+ to 7 (about 15 microns or lower).

B) Preparation of the thermal insulation, anti-condensation coating in two parts is given as per Table 4 below
[i] Part 1: Preparation of the mill base using High speed disperser:

1) Taking 49.25 gm water in container and adding laponite RD 1.5 gm under stirrer;
2) Gradually increasing RPM to 1000 and mixing till solution becomes clear;
3) Adding 0.2 gm Natrosol 250 MHR (hydroxyethylcellulose (HEC) that is a nonionic, water-soluble polymer) slowly under stirring;
4) Mixing till clear solution becomes clear followed by adding 0.1 gm AMP 95 (amino alcohol) and continuing stirring at same speed for 5 minutes;
5) Adding [Rocima 623 (chlormethyl/ methylisothiazolone and formaldehyde), Capstone FS-93 (Fluoro surfactant wetting agent), BYK 022 (Blend polysiloxane and polyglycol) 0.15 gm, 0.2 gm and 0.11 gm respectively in the above mixture and continue stirring at same speed for 10 minutes;
6) Then added [kamthane K 1492 (Polyurethane dispersion), Levasil CC-301 (Collidal silica), COATOSIL MP 200 (Oligomeric Epoxy silane) 20gm, 7 gm and 0.5 gm respectively;
7) Continuing stirring at 1000 rpm for 10 minutes and ensuring that there is no lump formation in the mill base;
8) Then adding kopthione 40% FPS (Zinc Pyrithione) mix it for 5 min;
9) Thereafter, optionally, adding ATH slurry and mix for 5 minutes.

[ii] Part 2: Preparation of the thermal insulation, anti-condensation coating using Ribbon blender:
1) Adding mill base as prepared in Part 1 to the blender mix for 5 min, then adding 3M glass bubble K 15 and recron 3 s polymer microfiber including polyester microfibre 11 gm and 5 gm respectively.
2) Mixing this material for 15 min to achieve uniform-smooth consistency.
The experimental composition prepared above was characterized for the basic physical properties; the results are listed in Table 2 below.
Table 2: Physical properties of the prepared formulation
Sr. No Properties Results (Experimental formulation)
1 Density Kg/ lit or g/cm3 0.5 to 0.8 preferably 0.62
2 NVM % 31.15%
3 Volume solid % 56.59%
4 Consistency Viscous paste consistency
5 pH 9.2

Table 3: Formulation of Fire retardant ATH 800 active slurry
Sr. no. Ingredient Wt. % Preferred Range Wt. %
1 Water 20.0 5 to 60
2 Sodium polyacrylates/ Indofil 850, 1.50 0.01 to 5%
3 Non-ionic surfactant synperonic A9, 0.50 0.01 to 5%
4 Defoamer BYK 022 0.10 0.01 to 5%
5 In can preservative Rocima 623 0.15 0.01 to 5%
6 HEC thickeners/ Natrosol 250 MHR 0.15 0.01 to 5%
7 pH Stabilizer MP 95 0.15 0.01 to 5%
8 Aluminum Trihydrate ATH 800 60.0 5 to 80%
9 PUD/ Kamthene 1492 10.0 5 to 80%
10 Water 7.45 2 to 20%

Table 4. Formulation of Thermal insulation and anti-condensation Coating as preferred formulation with flame retardant activity including optional ingredients
Sr. no. Ingredient Wt. % Preferred Range wt. %
1 Water 48.75 5 to 60
2 Synthetic (modified) phyllosilicate 1.5 0.01 to 5%
3 Hydroxy ethyl cellulose 0.2 0.01 to 5%
4 AMP 95/ pH stabilizer 0.1 0.01 to 5%
5 In can preservative 0.15 0.01 to 5%
6 Defoamer 0.1 0.01 to 5%
7 Fluoro surfactant 0.2 0.01 to 5%
8 Polyurethane dispersion (35% solids) 20 5 to 80%
9 Colloidal silica 7 5 to 80%
10 Oligomeric Epoxy Silane coupling agent (Mol wt. 282 gms) 0.5 0.01 to 5%
11 Zinc Omadine dispersion 40% in water 0.5 0.01 to 5%
12 ATH 800 (60% in water) 5 5 to 40 %
13 3M Glass bubble k 15, 60 micron, range 30-115 micron 11 5 to 80 %
14 Hollow polymer fibers (length of 0.4 to 0.7 mm and diameter of 20 microns) 5 5 to 80 %

Table 4A. Formulation of Thermal insulation and anti-condensation Coating based on the synergy attributing ingredients
Sr. no. Ingredient Wt. % Preferred Range wt. %
1 Synthetic (modified) phyllosilicate 1.5 0.5 to 2%
2 Polyurethane dispersion in water (35% solids) 20 10 to 40%
3 Colloidal silica 7 5 to 20%
4 Epoxy Silane coupling agent 0.5 0.2 to 2%
5 3M Glass bubble k 15 11 5 to 20 %
6 Hollow polymer fibers 5 5 to 20 %

Water based thermally insulating paint/coating formulations revealing synergistic co-action with hollow fibers:
Two compositions were prepared with the only difference of the type of the fibers used, one having hollow fiber and the other with solid fibers of same dimensions and chemistry. The compositions were applied on test panel and fixed amount of water was spread across the coating and the evaporation of the water was measured by weight difference on weighing balance. The results are depicted in below Table 4C.

Table 4C: Effect of hollow fibers
Sr.no Time in min Rate of evaporation
of coating with hollow fibre in gram Rate of evaporation
of coating with solid fibre in gram
1 5 0.0876 0.0361
2 10 0.1129 0.0783
3 15 0.1672 0.1273
4 20 0.2031 0.1633
5 25 0.2424 0.2095
6 30 0.2778 0.2456

From the results, the same evidences that the formulation with hollow polymer fiber is showing high rate of water evaporation under identical conditions, thereby proving its worthiness of anti-condensation.
Evaluation at low temperature 0-5°C – Shortlisted design was assessed by applying 1 liter aluminium bottle at 2mm, 3mm, 4mm thicknesses and chilled water of 0°C poured into aluminium bottle assessed for 6 hr for anti-condensation in comparison with the blank bottle as control. Fig. 1 shows that the present coating could give insulation at low temperature and no condensation could be seen for 6 hrs while the control showed the condensation of water just within 10 min.
Fig. 2A (a), (b), (c) illustrates the thermal insulation performance of the experimental batch at Various DFTs (Dry film thicknesses) revealing that with the increase in thickness increases the thermal insulation and anti-condensation performance.

Table 5: Thermal insulation performances of the experimental batch at Various DFTs
Insulation thickness on Aluminium bottle Chilled water temperature inside the bottle Outside temperature (Temperature difference is seen to increase with thickness and the coating does not advantageously sag or crack at such thickness)
Uncoated bottle (Control) 0 °C 7.7 °C
3 mm insulation coating 0 °C 14.3 °C
4 mm insulation coating 0 °C 16.9 °C

Evaluation of rate of water condensation and water evaporation, creating the profile of experimental vs. control system (Uncoated bottle)
The experimental composition was applied over the aluminum bottle vs. control to study the rate of water condensation as well as the evaporation of the condensed water if any. Both the type of bottles were filled with the chilled water (zero degree centigrade temperature) and kept at room temperature (28 degree centigrade) on the weighing balance. The weight gain due to water condensation and weight loss as water evaporation was monitored for both the bottles. The results are expressed in Table 6 and the profile is plotted in Fig. 3.
The experimental formulation/composition being a hydrophilic-porous formulation generates very high surface area for uniform and improved water evaporation and anti-condensation. The results hence confirms that the condensation of the water is low due to thermal insulation and whatever is condensed gets uniformly evaporated as seen in the evaporation profile below. This confirms the performance of the anti-condensation and thermal insulation under Table 6 below.
Also 1 gm of water evaporation tested on 10*10 cm panel leads to approximately 27.78 g of water evaporation for 1 m2 area by hollow fibre based formulation of the present invention after 30 min, whereas keeping all the other essential components constant 24.56 g of water gets evaporated when solid fiber is employed in the formulation after 30 min.
Table 6: Evaluation of experimental vs. control systems for rate of water condensation and rate of water evaporation
Time Blank bottle
(Control), Gms of water condensed and dripped from the surface of the bottle Coated bottle with insulation formulation, Experimental
Gms of water evaporated from the surface in a more controlled manner
20 min 2.43 0.72
40 min 4.08 1.49
1 hr 5.39 1.94
1 hr 20 min 5.54 2.62
1 hr 50 min 5.45 2.84
2 hr 10 min 5.08 2.99
3 hr 3.44 2.91
4 hr 2.57 2.52
5 hr 2.06 1.59
7 hr 30 min 0.63 0.2

Thermal insulation performance at high temperature 180 to 200 °C for the Experimental vs. Control systems
To establish the high temperature insulation performance and hence the utility of the experimental system, the same was tested against the control system at high temperature 180 to 200 degree centigrade. The experimental design was externally applied at 2 mm, 3 mm, 4 mm thickness on mild steel pipe which was filled inside with the thermic fluid and kept constant at 180 to 200?C as shown in Fig. 3. The difference in the temperature of external surface which is coated with the experimental coating vs. the temperature of the uncoated pipe (kept at 180 to 200 degree centigrade) was monitored for 6 to 8 hrs. It was confirmed that the experimental coating coated system showed continuous temperature difference of about 60 to 80 degree centigrade compared to the thermic fluid temperature. Also as the thickness of the coating increased the difference in the temperature also increased. At 5 mm coating thickness the outside temperature of the coated pipe was less than 80 degree centigrade which can be touched by the human hand without any burn injury. This confirms the thermal insulation performance of the experimental coating system.
The above results could be attained with or without the optional fire retardant ingredient. Any wt. % or change in characteristics of fiber and beads or any variants thereto of ingredients concerned specifically synthetic phyllosilicate of laponite RD affects the synergistic attributes attained.
Evaluation of mechanical and other coating performances for thermal insulation and anti-condensation coating Vs Control
Adhesion: Tested pull off adhesion (DFT 3 mm) according to ASTM 4541 after 7 days curing of the experimental system. The results are shown in Fig. 4A, 4B. Shows better adhesion of PU based system compared to acrylic based system.
Humidity: Tested humidity according IS 101 on epoxy primed (50–60-micron DFT) aluminium panel at 2 mm DFT of the experimental thermal insulation coating system. The coating passes 1000 hr humidity exposure test without rust spot and blister formation as seen in Fig. 5.
Salt spray: Tested corrosion performance according to ASTM B 117 on epoxy primed (50–60-micron DFT) aluminium panel at 2 mm thermal insulation coating system. Coating passes 1000 hr of salt spray test without any rust spot and blister as seen in Fig. 6.
Fire protection performance as per ASTM D 1230 as said standard of flame spread test is typically used to test the flammability of the materials. The experimental composition showed very good flame spread resistance. The experimental coating showed very good result complying with ASTM D 1230 due to 5% ATH 800 for the flame spread resistance as shown in Fig 7.
Anti-microbial and Anti-fungal performance of the Anti-condensation and thermal insulation coating:
In-can preservation of the experimental composition: The experimental composition was evaluated for the in-can preservation performance by ASTM D 2574. This test characterizes the performance of the wet coating in the can w r to its resistance against the growth of the bacteria during the storage. The liquid sample was exposed to Pseudomonas aeruginosa for 7 days and observed for the growth. The results are expressed as pass or fail basis the growth of these bacteria when introduced into the experimental sample.
The experimental sample passed the above test when performed in the laboratory.
Moreover, Anti-fungal performance was assessed of the dried films of the experimental composition of anti-condensation and thermal insulation coating using the standard test method ASTM 3274. The coated test panels were exposed to closed chamber having known amount of fungal spores and observed for the specified time period for any growth of fungus and resulting disfigurement. The performance is expressed on the scale of 0 (poor performance) and 10 (best performance)

The results are expressed below:
S. No. Sample Description Antifungal performance rating
1 Anti-fungal test of insulation control
(Commercial interior Luxury Emulsion Paint) 10
2 Anti-fungal test of insulation coating Prototype 2 10

The thermal conductivity value: 0.03968 W/ (m.K), Mean Thermal resistance value: 0.1573 (m2.K) / W were obtained when tested according to ASTM C 518.

In can be concluded from the above results that the water based thermally insulating paint/coating formulations and systems with the thermal insulation and anti-condensation performance could be successfully developed and the performances are as demonstrated for its thermal insulation and anti-condensation aspects along with very good mechanical and resistance properties including the microbial performances in context to their potential use in architectural and industrial applications.

,CLAIMS:We Claim:

1. Water based thermally insulating paint/coating formulations and systems comprising
colloidal silica in rheology modified water dispersion of latex binder and co-acting synergistic blend of hollow beads and hollow microfibers, adapted for simultaneous thermal insulation and anti-condensation attributes of a thick coat free of cracking and sagging.

2. The water based thermally insulating paint/coating formulations as claimed in claim 1 wherein said rheology modified water dispersion of latex binder includes
5-80 wt.% acrylic, polyurethane, silicone binder or their combinations preferably polyurethane binder with ?35 % polymer solids in water preferably 10-40% polyurethane binder giving improved adhesion over metal surface/ painted old surface with binding efficiency versus acrylics,
5-20 wt. % of colloidal silica;
0.01 to 5 wt. % of said rheology modifier including synthetic phyllosilicate preferably 0.5-2 wt.%;
5-80 wt.% preferably 10-40 wt.% of co-acting synergistic blend of hollow beads and hollow polymer microfibers including polyester, polyamide, acrylic fibers having length of 0.4-0.7 mm and diameter of ? 20 micron;
0.2-2 wt.% epoxy silane coupler.

3. The water based thermally insulating paint/coating formulations as claimed in claims 1 or 2 wherein said water based formulation optionally includes 5-40 wt.% compatible fire retardant slurry having 60% active concentration in water together with optional preferential additives adapted for not only improved thermal resistance based thermal efficiency but also fire protection.

4. The water based thermally insulating paint/coating formulations as claimed in claims 1-3 that is a versatile single pack water dilute able coating formulation suitable for adhering with varied substrates enabling improved thermal efficiency at lower cost and mechanical attributes together with desired rheology suitable for fabricating dry film of improved thickness of 1-5 mm/ coat free of said cracking and sagging.

5. The water based thermally insulating paint/coating formulations as claimed in claims 1-4 as a seamless monolithic continuous coating adapted for excellent thermal insulation and anti-condensation attributes when applied to hot/ cold substrates and over the substrates carrying low temperature materials/fluids/air in the temperature range of –40 degree centigrade to +180 degree centigrade.

6. The water based thermally insulating paint/coating formulations as claimed in claims 1-5 wherein said water based formulation with optional fire retardant includes 20 wt.% Polyurethane dispersion having 35% solids in water and /or water dispersible silicone binders and 5 wt.% fire retardant slurry having 60% concentration of active Aluminium tri hydroxide in water, together with 1.5 wt. % Laponite RD synthetic phllyosilicate rheology modifier, 7 wt. % Colloidal silica, 11 wt.% hollow beads including of Soda lime borosilicate glass having average particle size ?60 micron, in the range 30-115 micron, 5 wt.% Hollow Polyester microfibre of ?0.7 mm length and 20 micron diameter, favouring thermal insulation coating for high temperature insulations in the range of 200-450 ?C as required in industrial applications.

7. The water based thermally insulating paint/coating formulations as claimed in claims 1-6 wherein said water based formulation includes said preferential additives of 0.01 to 5 wt.% Hydroxy ethyl cellulose (HEC) preferably 0.2 wt. %, 0.01 to 5 wt.% AMP 95 (amino alcohol)/ pH stabilizer preferably 0.1 wt.%, 0.01 to 5 wt.% In can preservative preferably 0.15 wt.%, 0.01 to 5 wt.% Defoamer preferably 0.1 wt.%, 0.01 to 5 wt.% Fluoro surfactant wetting agent preferably 0.2 wt. %, 0.01 to 5 wt.% oligomeric epoxy silane coupling agent of mol. wt. in the range of 200-800 gms preferably 282 gms taken at preferred levels of 0.5 wt.%, 0.01 to 5 wt.% Zinc Omadine dispersion 40% in water preferably 0.5 wt.%.

8. The water based thermally insulating paint/coating formulations as claimed in claims 1-7 wherein said thermal efficiency based thermal conductivity values include 0.03968 W/ m.K- 0.04311 W/m.K, mean thermal resistance values include 0.1484 (m²•K)/W-0.1573 (m2.K) / W at formulation rheology modified formulation density of 0.5 to 0.8 g/cm3 with viscous paste like consistency having 56.59% of solids volume.

9. A process for the manufacture of water based thermally insulating paint/coating formulations as claimed in claims 1-8 comprising the steps of
preparing water based acrylate/polyurethane dispersion and incorporating colloidal silica, select rheology modifier together with co-acting hollow beads and hollow microfibers and optional compatible fire retardant slurry separately towards obtaining therefrom said water based thermally insulating paint/coating formulations adapted for simultaneous thermal insulation and anti-condensation attributes of fabricated thick coating thereof free of cracking and sagging.

10. The process for the manufacture of water based thermally insulating paint/ coating formulations as claimed in claim 9 wherein for preparation of 100 gm of said paint/ coating formulations is based on select sequence of ingredient addition to avoid lump formation includes following sub-steps
[i] Preparation of mill base involving high speed disperser by

a) providing 49.25 gm water and adding synthetic phyllosilicate of laponite RD 1.5 gm under stirring;
b) Gradually increasing RPM to 1000 and mixing till solution becomes clear;
c) Adding 0.2 gm hydroxyethylcellulose (HEC) polymer slowly under stirring;
d) Mixing till solution becomes clear followed by adding 0.1 gm amino alcohol and continuing stirring at same speed for 5 minutes;
e) Adding 0.15 gm chlormethyl/ methylisothiazolone and formaldehyde preservative, 0.2 gm Fluoro surfactant wetting agent, and 0.11 gm polysiloxane and polyglycol blend defoamer, respectively in the above mix of step (d) and continuing stirring at same speed for 10 minutes;
f) adding latex binder dispersion preferably 20gm polyurethane dispersion with select polymer solid levels, 7 gm Collidal silica, and 0.5 gm of Oligomeric Epoxy silane respectively;
g) continuing stirring at 1000 rpm for 10 minutes free of any lump formation in the mill base;
h) adding Zinc Pyrithione as 40% active as fine particle sized dispersion and mixing for 5 min, and optionally, adding fire retardant slurry as compatible slurry and mixing additionally for 5 mins to obtain mill base therefrom.

[ii] Preparation of the thermal insulation, anti-condensation coating formulation by involving Ribbon blender:
a) providing mill base of step (i) to the blender and mixing for 5 min followed by adding 11 gm hollow beads and 5 gm hollow microfibers;
b) Mixing for 15 min to achieve uniform-smooth consistency of the formulation of density in the range of 0.5 to 0.8 g/cm3 with viscous paste like consistency having 50-60% solids volume and pH of 9-9.5.

11. The process for the manufacture of water based thermally insulating paint/ coating formulations as claimed in claims 9 or 10 wherein said optional fire retardant slurry as a compatible slurry is prepared in high speed disperser by including the following steps:
a) Adding in 20 gm water 1.5 gm dispersant sodium salt of carboxylic acid, 0.5 gm non-ionic surfactant of polyoxyethylene alcohol, 0.1 gm defoamer blend of polysiloxane and polyglycol) and 0.15 gm of said preservative of chlormethyl/ methylisothiazolone and formaldehyde;
b) Mixing for 10 min followed by adding 0.15 gm hydroxyethylcellulose (HEC) polymer by gradually increasing RPM to 400 to ensure uniform dissolution in water;
c) Adding 0.15 gm amino alcohol and mixing for 10 min with 1000 RPM;
d) Adding 60 gm of Alumina Trihydrate of ATH 800 grade under slow stirring;
e) Continuing dispersal for 20- 30 minutes till uniform smooth slurry of ATH powder is achieved as confirmed by Hegman Guage finish at 6+ to 7 giving 15 microns or lower particle size.

Dated this the by 19th day of March, 2025 Anjan Sen
(Applicants Agent & Advocate)
IN/PA-199