DESC:Field of Invention
The present invention relates to the development of formulation/composition preferably a non-shrinkable cracks/gaps filling paste formulation/composition based on acrylic emulsion for filling cracks in structures e.g. cracks in walls, skirting, ceilings, chajja (balcony), parafit wall, etc. with excellent elongation, water resistance and good adhesion on construction material. More particularly, the present invention relates to said crack filling paste composition for cracks/gaps of 0.5-10 mm in width, and further relates to the preparation of stable one component, ready to use, flexible crack sealer/ crack filling paste composition based on acrylic emulsion, and select amounts of select inorganic fillers including calcium carbonate, dolomite, titanium dioxide, low dense polymeric and/or glass microspheres, glass/polymeric fiber that does not lead to debonding and self- cracking.
Background of the Invention
Cracks on the interior and exterior wall is a major issue in building/houses. The position and nature of the Crack often indicates the seriousness of the crack- which may be structural problem of the house or some small hairline cracks may be purely cosmetic. Whatever may be the origin of the crack- it spoils the beauty of wall and reduce the life span of building due to water and /or air ingress.
The cosmetic cracks occur normally due to thermal contraction and expansion nature of building materials such as cementitious wall, plaster, dry wall, etc. Traditionally, white cement or other cementitious material are used for repairing such cracks. Due to rigid nature of cementitious material, crack reappears/reopens on the same place. Additionally, shrinkage and poor elongation nature of cementitious material leads to debonding and self-cracking. Therefore, flexible crack sealer is urgent need in the market. Reference is invited for related prior arts as follows:
US11198644B2 discloses the “Surface crack filler compound’’. The crack filler compound is based on the black silica, ethylene vinyl acetate, cement, and color cement additives. The filler composition is solidified by water activation mechanism and fill the crack.
D. Ware reports “concrete crack filler composition and method’’ in US7572852 B1. The filler composition is based on multicolored non-homogeneous earth tone sand and liquid bonding agents. Said liquid bonding agent is acrylic polymer bonding agent. With respect to the composition, the sand is present in an amount from about 60% to about 90% (weight/volume), and the liquid acrylic polymer bonding agent is present in the amount ranging from about 15% to about 35% (w/v), of the composition. In addition, the formulation contains a dioctyl phthalate plasticizer and an ester alcohol.
US5063006 discloses the method and composition for repairing cracks in concrete structure such as a tunnel, a basement, a dam, a weir, a swimming pool or an outdoor concrete structure. The main objective of this prior art was to avoid the leakage of water from the cracks and a urethane blowing agent was used for the purpose.
US4745155 discloses an aqueous emulsified cracks or joint filler. The emulsion is synthesized from asphalt, extender oils, mixture of elastomers (includes a mixture of a triblock copolymer of styrene a butadiene and a diblock copolymer of styrene and butadiene), hydroxy-terminated homopolymer of butadiene, acrylamide, and vinyl monomers (styrene). The emulsions of the advancement meet the exacting penetration, flow and cold temperature (0° F) bonding requirements of ASTM Specification D1190. Generally, the emulsions include chemically-modified asphalt compositions emulsified in an aqueous emulsion medium to provide a stable composition which can be poured or pumped without heating directly into a roadway crack or joint.
WO2016050616A1 relates to a method for repairing cracks in a structure, comprising a two-component filler, which comprises A) a solid binding agent component comprising at least one inorganic binding agent and B) an aqueous binding agent component comprising a synthetic resin dispersion, wherein the method comprises the mixing of the solid binding agent component and the aqueous binding agent component in order to obtain a filler, and the filling of one or more cracks in the structure with the filler and/or the levelling out of a surface of the structure comprising the crack or cracks with the filler. The two-component filler is well-suited as a crack filler. The filler enables cracks to be quickly filled and levelled out in a small number of working steps and produces a smooth, viscoelastic and crack-sealing filling layer.
WO2003025075A1 is on material for filling cracks or gaps and methods of applying the same. Flexible filler for filling cracks, gaps or holes in masonry or a rendered finish on masonry, comprising a mixture of an acrylic caulk bulked up with a finely divided particulate material comprising sand preferably soft sand or silver sand of a size to match the roughness of the surface around the crack gap or hole to be filled. The caulk and particulate material are mixed thoroughly to form a homogeneous mixture which is packed into a cylindrical cartridge having a nozzle through which the mixture can be forced when needed. The advancement also discloses a means/ apparatus through which the material for filling cracks or gaps from said cylindrical cartridge can be applied to fill a crack, gap or hole.
US 2005/0193668 A1: K. Hamilton discloses crack filling composition for drywall joint construction. The composition includes, resin, calcium carbonate or gypsum, light weight fillers such as mica, glass bubbles, methyl cellulose. The resulting composition shows flexible, low shrink filling compounds.
SmartCare CrackSeal- Crack Filling Compound - Asian Paints https://www. asianpaints.com › waterproofing-solutions is based on a ready-to-use fiber based compound with crack filling ability for both interior and exterior surfaces ensuring uncomparable crack bridging ability for plaster cracks of up to 3 mm.
CN112322102A covering putty paste for filling splicing seams relates to a putty paste for filling a splicing seam, which comprises the following components in percentage by weight: 10-15% of water, 20-35% of modified acrylic emulsion, 6-11% of fiber medium, 30-45% of talcum powder, 10-25% of calcium carbonate, 5-10% of artificial fine sand, 0.2-1% of dispersing agent, 0.3-1.5% of wetting agent, 0.5-3% of adhesion additive, 0.2-0.5% of bactericide, 0.3-1.5% of pH neutralizing agent, 0.05-0.15% of antifreezing agent and 0.05- 0.5% of antirust agent, wherein the adhesion additive is a mixture consisting of one or more of dodecyl alcohol ester, polyester resin, silane coupling agent, titanate coupling agent and phosphate ester high molecular compound. The disclosed putty paste has enhanced binding force with a smooth surface substrate, the putty paste is not easy to fall off and resistant to pulverization, and the service life is long.
CN106590202A on anti-cracking building exterior wall coating provides acrylic and acrylic derivative based anti-cracking building exterior wall coating involving organic fibre, heavy calcium powder etc. showing good anti-cracking performance; good water resistance and strong adhesion. The prior art formulation contain active epoxy functionality and dichlorosilane, for efficient adhesion of the formulation upon cracked building exterior.
CA2541975A1 includes a cross-linked acrylate compound along with a filler, a rheology modifier, a pigment, an adhesion promoter and a defoamer wherein the filler comprises clay, calcium carbonate or talc, the rheology modifier comprises bentonite clay or fumed silica, the adhesion promoter comprises functional silanes for a composition for sealing cracks in concrete. May further contain epoxy resin comprising liquid epoxy resins, modified epoxy resins and epoxy acrylate resins.
CN106673495A on grouting material for remediating delamination of ancient wall painting based on adobe wall as supporter and preparation method thereof teaches grouting (Grouting is the process of injecting material into cavities or cracks in concrete, masonry structure, soil, rock-mass to increase the structure's material) includes main material and filler, wherein the main material is modified acrylic emulsion, and the filler includes following raw material components: Chengban soil, white carbon black and glass microbead. The developed grouting material is nontoxic, free from environmental pollution, does not injure wall painting historical relic. The glass microbead has the advantages of light weight, low heat conductivity, higher intensity, good chemical stability.
WO2012107254 includes low-shrinkage paste-like knifing filler proposing a composition comprising at least one inorganic filler, at least one film-forming polymer dispersion, at least one plasticizer and water, a process for producing it and the use of this composition as low-shrinkage paste-like knifing filler and/or joint grout. The Composition comprising at least one inorganic filler, at least one film-forming polymer dispersion, at least one plasticizer and water; wherein the inorganic filler is selected from limestone, calcium carbonate, chalk, marble, calcite, aragonite, dolomite, calcium sulphate dihydrate and mixtures thereof, preferably ground limestone and/or ground dolomite; and the film-forming polymer dispersion is an aqueous dispersion selected from among polyacrylates, polyurethanes, polyurethane/polyacrylate hybrids, styrene-acrylate copolymers, styrene-butadiene copolymers, polyvinyl acetates and mixtures thereof; and the plasticizer is polyacrylic acid.
Traversal of the prior art reveals that various non-shrinkable crack/gaps filling paste compositions are reported and available in the market. However, no crack/gaps filling formulation/composition or flexible crack sealer formulation is available that makes it an urgent need to explore showing near zero shrinkage with elongation up to 100 % with a capacity to fill wider range of cracks like 10 mm wide along with excellent adhesion towards cementitious structures that would not debond or self-crack.

Objectives of the Invention
Thus, the primary objective of the present invention is to provide for a formulation/composition preferably suitable as a crack filling paste composition based on acrylic emulsion, for filling cracks in structures e.g. cracks in walls, skirting, ceilings, chajja, parafit wall, etc. with excellent elongation, water resistance and good adhesion on construction material.
Yet another objective of the present invention is to provide for said crack filling paste formulation/composition which would be flexible and display near zero shrinkage and elongation up to 100 % to avoid debonding and self-cracking after application.
Another objective of the present invention is to provide for said crack filling paste formulation/composition which would be capable of filling wide range of gaps i.e. 0.5-10 mm wide and would not debond or self-crack to remain flexible and showing excellent adhesion towards cementitious structures.
Still another objective of the present invention is to provide for said crack filling paste formulation/composition which would be stable as a one component, ready to use formulation comprising inorganic fillers such as calcium carbonate, dolomite, titanium dioxide, low dense polymeric and/or glass fillers including glass microspheres, glass/polymeric fiber, etc. along with said acrylic emulsion.
Still another objective of the present invention is to provide a process of manufacturing said crack filling paste formulation/composition which would be cost effective, simple to handle and easy to scale up for industrial manufacturing.

SUMMARY OF THE INVENTION
Primary embodiment of the present invention is directed to provide a flexible ready to use crack filling/ crack sealer paste formulation comprising a synergistic combination of
(a) acrylic based emulsion having active solid content levels of 40-55 wt.% and glass transition temperature range of -10 to + 20 oC;
(b) inorganic fillers including select levels of calcium carbonate 10-50 wt.%;
(c) lightweight glass fillers of 20 to 35 wt%;
(d) plasticizer 1-5 wt.%;
adapted for flexible stable ready to use crack filler/ crack sealer with near zero shrinkage (i.e. < 0.5%) and 100% elongation.
Another embodiment of the present invention is directed to provide said flexible ready to use crack filling/ crack sealer paste formulation wherein said synergistic combination based stable one component formulation having 70-78 % solid level comprises
(a) said acrylic based emulsion having =51 wt.% of active solid content;
(b) said inorganic fillers include said select level of calcium carbonate at = 16 wt.%;

(c) said lightweight glass fillers including glass microspheres or glass bubbles are = 20 % wt.% ; and
(d) said plasticizer at = 3wt.% wherein said plasticizer is a non-pthalate based plasticizer molecule preferably dialkylene glycol dibenzoate synergizing to improve freeze thaw stability in addition to near zero shrinkage and 100% elongation;
(e) silicone emulsion in the levels of 0-5 wt.% to improve water resistant property.

Yet another embodiment of the present invention is directed to provide said flexible ready to use crack filling/crack sealer paste formulation wherein said acrylic based emulsion is a copolymer of acrylic monomers or is a styrene-acrylic copolymer emulsion of styrene and acrylic monomers having particle size in the range of 80- 250 nm, minimum film forming temperature in the range of 0 to +10oC, pH in the range of 5 to 8, viscosity in the range of 50-350 poise suitable as a flexible stable ready to use single component paste formulation.

Further embodiment of the present invention is directed to provide said flexible ready to use crack filling/crack sealer paste formulation wherein
said acrylic based emulsion is selected from pure acrylic emulsion, VAM-acrylic emulsion, styrene-acrylic-butadiene emulsion, styrene-acrylic emulsion preferably styrene acrylic emulsion;
said inorganic fillers include calcium carbonate, dolomite, titanium dioxide, low dense polymeric fillers;
said glass fillers include glass microspheres or glass bubbles having particle size of 2-200 micron; and glass fibers having fiber length of 1 to 3 mm.

Still further embodiment of the present invention is directed to provide said flexible ready to use crack filling paste formulation that displays a 24 hr Drying Time for 3 mm Bed, 70-78% solid (Non-volatile matter, NVM), 118 % and 107 % for Elongation @ break, @ 7 Days and 14 days respectively and Volume Shrinkage, % of 0.11.
Another preferred embodiment of the present invention is directed to provide a process for preparation of flexible ready to use crack filling paste formulation comprising the steps of
(a) providing acrylic based emulsion having active solid content levels of 40- 55 % with glass transition temperature in the range of -10 to + 20 oC;
(b) providing inorganic fillers including select levels of calcium carbonate 10-50 wt.%;
(c) providing lightweight glass fillers in the range of 20 to 35 wt%; and
(d) providing plasticizer 1-5 wt.%; and
sequentially adding and blending to obtain therefrom flexible stable ready to use one component uniform crack filler/ crack sealer paste formulation showing near zero shrinkage (i.e. < 0.5%) and ~100% elongation.

Another embodiment of the present invention is directed to provide said process for preparation including the sub-steps of
i) adding anionic surfactant, defoamer, biocide, dispersant, non-ionic surfactant, preservative, adhesion promoter, plasticizer, diethylene glycol in the cleaned planetary mixer keeping mixer RPM 200-300, Planetary RPM 12-15, Jacket temp <45 deg and mixing time 5-10min;
ii) providing styrene/acrylic emulsion slowly portionwise under stirring, keeping identical condition as of step 1 to the mixer and mixed for 10 -15 min to ensure the homogeneity;
iii) adding glass filler portionwise and slowly under stirring, keeping MIXER RPM 500-600, Planetary RPM 20-23, Jacket temp <45 deg and continue Mixing for 10 -15min until smooth paste is formed;
iv) pouring neutralizer/pH stabilizer, coalescing agent slowly and successively under stirring, without altering the mixer conditions of step iii and mixing for 10 -15 min, to ensure homogeneity;
v) adding thickener slowly in step by step under stirring keeping MIXER RPM 700-900, Planetary RPM 20-23, Jacket temp <45 deg and Mixed for 20- 25min until smooth paste formation;
vi) providing glass fibres slowly in the mixture under stirring, keeping MIXER RPM 500-600, Planetary RPM 20-23, Jacket temp <45 deg and continued Mixing for 10 -15 min ensuring the homogeneity;
vii) adding optionally silicon emulsion slowly in step by step under stirring, keeping MIXER RPM 400-500, Planetary RPM 20-23, Jacket temp <45 deg and continuing Mixing 10 -15min; and
viii) removing the air bubble from the mixture by vacuum (0 to 80 mmHg @ 25 deg C) for 30 min to provide the final product.

DETAILED DESCRIPTION OF THE INVENTION
As stated hereinbefore, the present invention provides for a formulation/ composition of a crack filling paste composition suitable for filling cracks/gaps of 0.5-10 mm in width and a process for the preparation of said crack filling paste composition which is based on providing select level of acrylic emulsion, together with select levels of select inorganic fillers including calcium carbonate, dolomite, titanium dioxide, low dense polymeric and/or glass microspheres, glass/polymeric fiber, preferably suiting a stable one component, ready to use flexible formulation/composition.

In the primary embodiment, the present invention provides ready to use, non-shrinkable crack/gaps filling paste formulation/composition based on acrylic / styrene-acrylic emulsion and with select levels of select inorganic fillers including calcium carbonate, dolomite, titanium dioxide, low dense polymeric and/or glass microspheres, glass/polymeric fiber. Said acrylic emulsion is a copolymer of acrylic monomers and Styrene-acrylic emulsion is copolymer of styrene and acrylic monomers having particle size in the range of 80-250 nm, glass transition temperature in the range of -10 to + 20 oC, minimum film forming temperature in the range of 0 to +10 oC, active solid content levels in the range of 40 to 55 %, pH in the range of 5 to 8, viscosity in the range of 50-350 poise. Said acrylic based emulsion is selected from pure acrylic emulsion, VAM-acrylic emulsion, styrene-acrylic-butadiene emulsion, styrene-acrylic emulsion preferably styrene acrylic emulsion; with select active content of acrylic emulsion from 40-55% preferably 50%.
Glass microspheres are low dense hollow material made from water-resistant and chemically stable soda-lime-borosilicate glass, appear as a white free-flowing powder. Glass microspheres have an exceptional ability to reduce the weight of composite parts. The select microspheres used for the present invention is a low dense hollow material having particle size in the range of 2-200 micron and true density in the range of 0.15-0.3 g/cm3. In an embodiment of the present invention minimum 20% lightweight glass filler is required to achieve near zero shrinkage. However, other ingredients are also required in select concentrations to get water resistance, elongation, tensile strength and drying time. For the present invention glass filler, glass bubble and glass microspheres have been used interchangeably.

In another embodiment the present invention advantageously provides said crack/gaps filling paste composition which is suitable for stable one component, paste composition and demonstrates near zero shrinkage with elongation up to 100 %. As stated hereinbefore, shrinkage and poor elongation of cementitious material for crack filing lead to debonding and self-cracking. Thus, the crack/gaps filling paste composition in accordance to the present invention having near zero shrinkage and elongation upto 100 % is a flexible crack sealer, therefore does not crack & accommodates minor movements in the crack providing long service life.

In another embodiment, the present invention provides said non-shrinkable and flexible cracks/gaps filling paste formulation/ composition based on select acrylic emulsion for application on cracks in structures e.g. cracks in walls, skirting, ceilings, chajja, parafit wall, etc. with excellent elongation, water resistance and good adhesion on construction material.

Another embodiment of the present invention provides said crack/gaps filler formulation/composition having an excellent adhesion towards cementitious structures and able to fill wide range gaps i.e. 0.5-10 mm.

To the best of Inventor’s knowledge, one component, stable, ready to use crack filling formulation/composition having a near zero shrinkage, that is flexible with 100% elongation that does not de-bond from substrates or self-crack, has not yet been reported.

It is to be understood that both the foregoing general description and the following detailed description are exemplary, and are intended to provide further explanation of the invention as claimed. The advancement according to the present invention is discussed in further detail in relation to the following non-limiting exemplary illustrations wherein
Figure- 1: Impression of filled and non-filled cracks

EXAMPLES
The present invention is now demonstrated to provide stable ready to use and flexible crack filling paste formulation/composition suitable for filling cracks/gaps of 0.5-10 mm in width which neither de-bonds from substrates nor develops any cracks. All the reagents and chemicals are industrial grade and used without any purification for the formulation and were purchased from local vendors. It is to be noted that no biologically sourced material was used for the present invention.
Method for Crack seal Preparation:
Before the formulation the planetary mixer is cleaned with water and /or acetone to make sure mixing pot is free from any contaminations.
The method for manufacturing said crack sealer/ crack-filling formulation in accordance with the present invention comprises the following steps:
1) Add anionic surfactant, defoamer, biocide, dispersant, non-ionic surfactant, preservative, adhesion promoter, plasticizer, diethylene glycol in the planetary mixer keeping mixer RPM 200-300, Planetary RPM 12-15, Jacket temp <45 deg, mix 5-10 min.
2) Add styrene-acrylic/acrylic emulsion slowly in step by step under stirring, keeping identical condition as of step 1 to the mixer and mixed for 10 -15 min to ensure the homogeneity.
3) Add glass filler slowly in step by step under stirring, keep MIXER RPM 500-600, Planetary RPM 20-23, Jacket temp <45 deg, Mix 10 -15 min until smooth paste is formed.
4) Add neutralizer/pH stabilizer, coalescing agent slowly in step by step under stirring, keep MIXER RPM 500-600, Planetary RPM 20-23, Jacket temp <45 deg, Mix 10 - 15min, to ensure homogeneity.
5) Add thickener slowly in step by step under stirring keep MIXER RPM 700-900, Planetary RPM 20-23, Jacket temp <45 deg, Mix 20-25 min until smooth paste is formed.
6) Add glass fibers slowly in step by step under stirring, keep MIXER RPM 500-600, Planetary RPM 20-23, Jacket temp <45 deg, Mix 10 -15 min ensuring the homogeneity.
7) Add silicon emulsion slowly in step by step under stirring, keep MIXER RPM 400-500, Planetary RPM 20-23, Jacket temp <45 deg, Mix 10 -15min.
To remove the air bubble vacuum is applied (0 to 80 mmHg @ 25 deg C) for 30 min in the final product. The material is checked for physical parameters and is transferred to drum with the help of drum press.
Based on the above procedure different formulations with varying quantities of Styrene acrylic/acrylic emulsion, Calcium carbonate, diethylene glycol, glass filler plasticizer and glass fiber keeping all other ingredients constant as provided under Table-1 are prepared. Evaluation of different properties of the as prepared formulations are presented in Table-2.
TABLE 1 – Examples of different formulations
Raw Materials EX-1 EX - 2 EX - 3 EX - 4 EX - 5 EX – 6 EX - 7 EX - 8 EX - 9
Anionic surfactant 0.40 0.40 0.40 0.40 0.40 0.40 0.40 0.40 0.4
Defoamer 0.50 0.50 0.50 0.50 0.50 0.50 0.50 0.50 0.5
Biocide 0.35 0.35 0.35 0.35 0.35 0.35 0.35 0.35 0.35
Dispersing agent 0.60 0.60 0.60 0.60 0.60 0.60 0.60 0.60 0.6
Non-anionic surfactant 0.20 0.20 0.20 0.20 0.20 0.20 0.20 0.20 0.2
Adhesion promoter 0.10 0.10 0.10 0.10 0.10 0.10 0.10 0.10 0.1
Thickener 0.30 0.30 0.30 0.40 0.40 0.40 0.40 0.40 0.4
AMP-95 0.10 0.10 0.10 0.10 0.10 0.10 0.10 0.10 0.1
Silicon emulsion 3.00 3.00 3.00 3.00 3.00 3.00 3.00 3.00 3.00
Styrene acrylic emulsion 41.00 44.50 44.50 44.50 44.50 44.50 44.50
51 51
Calcium carbonate 43.80 38.30 35.30 31.20 29.20 27.20 25.70 16.2 16.5
Titanium dioxide 0.25 0.25 0.25 0.25 0.25 0.25 0.25 0.25 0.25
Diethylene glycol 2.50 1.00 1.00 2.00 2.00 2.00 2.00 2.00 5
Coalescing agent 0.40 0.40 0.40 0.40 0.40 0.40 0.40 0.40 0.4
Glass bubbles 3.50 7.00 10.00 13.00 15.00 17.00 20.00 20 20
Plasticizer, non-pthalate based 0 0 0 0 0 0 0 3 0
Glass fibers 2.00 2.00 2.00 2.00 2.00 2.00 0.50 0.50 0.5
Dipentene 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.0
Total 100.00 100.00 100.00 100.00 100.00 100.00 100.00 100 100

TABLE 2 – END CHARACTERISTICS/ PROPERTIES
EX-1 EX - 2 EX - 3 EX - 4 EX - 5 EX - 6 EX - 7 EX - 8 Ex-9
WPL (Weight per liter) 1.16 1.02 0.98 0.85 0.8 0.78 0.68 0.55 0.54
NVM, % 78.05 76.15 76.21 76.15 76.5 76.21 76.22 71.51 71.93
Surface Drying Time, Min @ 28 Degree C 50 Min 45 Min 45 Min 45 Min 45 Min 45 Min 45 min 45 min 45 min
Drying Time 3 mm Bed, Hr. 48 Hr 55 Hr 55 Hr 65 Hr 65 Hr 65 Hr 60 hr 24 Hr 24 Hr
Tensile strength, N/sq mm @ 7 days 0.26 0.16 0.13 0.11 0.11 0.09 0.14 0.044 0.2
Elongation @ break, % @ 7 Days 101 36 30 22 18 12 16 118 18.3
Tensile strength, N/sq mm @ 14 days 0.39 0.2 0.18 0.15 0.14 0.12 0.16 0.05 0.29
Elongation @ break, % @ 14 Days 71 22 17 18 12 11 12 107 17
Volume Shrinkage, % 8.13 7.1 5.89 4.5 3.51 2.1 0.11 0.11 0.1

From the above tables it is evident that
a) Near zero shrinkage (i.e. <0.5%) is achieved with 100% elongation in formulation containing 70-78 % solids (Example no. 8). It is very interesting to note the role of the plasticizer here in the formulation. In Example-9 all the ingredients are kept identical including the quantities with respect to example- 8, only plasticizer is not used, instead diethylene glycol is increased from 2% to 5%, still then the formulation showed very poor elongation property.
b) Minimum 20% lightweight glass filler including glass bubbles is required to achieve near zero shrinkage (i.e. < 0.5%). However, interplay of other ingredients are required in the select concentration levels and the concentrations effectively scoped to get desired water resistance, elongation, tensile strength and drying time. Silicone emulsion Polydimethoxysilane (PDMS) remains a clearly optional ingredient allowing additional enhancement of water resistant properties. Spherical shape and surface areas of glass filler is critical to essential properties. From experimental results, it is also observed that as the glass filler dosage increases, the reduction in volume shrinkage % is observed from Example No. 1 through Example No. 8. Quantity of glass filler (wt%) and corresponding-volume shrinkage % are as follows: (3.50-8.13, 7.00-7.1, 10.00-5.89, 13.00-4.5, 15.00-3.51, 17.00-2.1 and 20.00-0.11) indicates that at 20% filler concentration in the composition leads to near zero shrinkage.
c) Interestingly, both tensile strength and elongation decrease with increasing glass filler concentration, however except in Example No. 8 based on select remaining ingredients of the composition and even if considering the involvement of plasticizer which when taken together with very selective levels of calcium carbonate are found to show surprising and special co-action with increased glass filler concentration to provide desired higher elongation and much reduced volume shrinkage, not shown by rest of the comparative examples 1-7, 9.
d) The plasticizer involved in the present invention is phthalate based or non-pthalate based and in presence of non-pthalate molecule the same synergizes to provide for the desired attributes of the composition. For similar kind of formulation use of phthalate base plasticizers are reported in the literature. For the present invention dialkylene glycol benzoate as non-pthalate based plasticizer is found to be compatible with other formulation ingredients taken at select levels and additionally it helps to improve freeze thaw stability and elongation of the formulation. As stated hereinbefore, 100 % elongation is achieved only in the presence of said plasticizer when selectively combined with rest of the select levels of formulation ingredients.
Thus it is possible for the present invention to provide for non-shrinkable cracks/gaps filling ready-to-use, stable paste formulation/composition with enabled successful method of preparation of the same having near zero shrinkage (i.e. < 0.5%) and 100% elongation and suitable for filling cracks/gaps of 0.5-10 mm in width. For the present invention involvement of light weight filler such as spherical glass filler (glass bubbles or glass microspheres), fibers preferably of glass along with silicon, styrene acrylic/ acrylic emulsion and plasticizers contributes to better non-shrink, waterproof and elongation properties. Interestingly, said formulation with a concentration of more than or equal to 20% of glass fillers and in a formulation having 70-78 % solid level with select levels of acrylics when combined with select plasticizer in select levels together with select levels of inorganic fillers including calcium carbonate provides for the synergistic, ready to use, stable crack filling/flexible crack sealer paste formulation/ composition.
,CLAIMS:We Claim:

1. A flexible ready to use crack filling/ crack sealer paste formulation comprising a synergistic combination of
(a) acrylic based emulsion having active solid content levels of 40-55 wt.% and glass transition temperature range of -10 to + 20 oC;
(b) inorganic fillers including select levels of calcium carbonate 10-50 wt.%;
(c) lightweight glass fillers of 20 to 35 wt%;
(d) plasticizer 1-5 wt.%;
adapted for flexible stable ready to use crack filler/ crack sealer with near zero shrinkage (i.e. < 0.5%) and 100% elongation.

2. The flexible ready to use crack filling/ crack sealer paste formulation as claimed in claim 1 wherein said synergistic combination based stable one component formulation having 70-78 % solid level comprises
(a) said acrylic based emulsion having =51 wt.% of active solid content;
(b) said inorganic fillers include said select level of calcium carbonate at = 16 wt.%;
(c) said lightweight glass fillers including glass microspheres or glass bubbles are = 20 % wt.% ; and
(d) said plasticizer at = 3wt.% wherein said plasticizer is a non-pthalate based plasticizer molecule preferably dialkylene glycol dibenzoate synergizing to improve freeze thaw stability in addition to near zero shrinkage and 100% elongation;
(e) silicone emulsion in the levels of 0-5 wt.% to improve water resistant property

3. The flexible ready to use crack filling/crack sealer paste formulation as claimed in claims 1-2 wherein said acrylic based emulsion is a copolymer of acrylic monomers or is a styrene-acrylic copolymer emulsion of styrene and acrylic monomers having particle size in the range of 80- 250 nm, minimum film forming temperature in the range of 0 to +10oC, pH in the range of 5 to 8, viscosity in the range of 50-350 poise suitable as a flexible stable ready to use single component paste formulation.

4. The flexible ready to use crack filling/crack sealer paste formulation as claimed in claims 1-3 wherein
said acrylic based emulsion is selected from pure acrylic emulsion, VAM-acrylic emulsion, styrene-acrylic-butadiene emulsion, styrene-acrylic emulsion preferably styrene acrylic emulsion;
said inorganic fillers include calcium carbonate, dolomite, titanium dioxide, low dense polymeric fillers;
said glass fillers include glass microspheres or glass bubbles having particle size of 2-200 micron; and
glass fibers having fiber length of 1 to 3 mm.

5. The flexible ready to use crack filling paste formulation as claimed in claims 1-4 that displays a 24 hr Drying Time for 3 mm Bed, 70-78% solid (Non-volatile matter, NVM), 118 % and 107 % for Elongation @ break, @ 7 Days and 14 days respectively and Volume Shrinkage, % of 0.11.

6. A process for preparation of flexible ready to use crack filling paste formulation as claimed in claims 1-5 comprising the steps of
(a) providing acrylic based emulsion having active solid content levels of 40- 55 % with glass transition temperature in the range of -10 to + 20 oC;
(b) providing inorganic fillers including select levels of calcium carbonate 10-50 wt.%;
(c) providing lightweight glass fillers in the range of 20 to 35 wt%; and
(d) providing plasticizer 1-5 wt.%; and
sequentially adding and blending to obtain therefrom flexible stable ready to use one component uniform crack filler/ crack sealer paste formulation showing near zero shrinkage (i.e. < 0.5%) and ~100% elongation.

7. The process for preparation as claimed in claim 6 including the sub-steps of
i) adding anionic surfactant, defoamer, biocide, dispersant, non-ionic surfactant, preservative, adhesion promoter, plasticizer, diethylene glycol in the cleaned planetary mixer keeping mixer RPM 200-300, planetary RPM 12-15, Jacket temp <45 deg and mixing time 5-10min;
ii) providing styrene/acrylic emulsion slowly portionwise under stirring, keeping identical condition as of step 1 to the mixer and mixed for 10 -15 min to ensure the homogeneity;
iii) adding glass filler portionwise and slowly under stirring, keeping MIXER RPM 500-600, planetary RPM 20-23, Jacket temp <45 deg and continuing mixing for 10 -15 min until smooth paste is formed;
iv) pouring neutralizer/pH stabilizer, coalescing agent slowly and successively under stirring, without altering the mixer conditions of step iii and mixing for 10 -15 min, to ensure homogeneity;
v) adding thickener slowly in step by step under stirring keeping MIXER RPM 700-900, planetary RPM 20-23, Jacket temp <45 deg and mixed for 20 -25 min until smooth paste formation;

vi) providing glass fibres slowly in the mixture under stirring, keeping MIXER RPM 500-600, planetary RPM 20-23, Jacket temp <45 deg and continued mixing for 10 -15 min ensuring the homogeneity;
vii) adding optionally silicon emulsion slowly in step by step under stirring, keeping MIXER RPM 400-500, planetary RPM 20-23, Jacket temp <45 deg and continued mixing 10 -15min; and
viii) removing the air bubble from the mixture by vacuum (0 to 80 mmHg @ 25 deg C) for 30 min to provide the final product.

Dated this the 23th day of November, 2023 Anjan Sen
Of Anjan Sen and Associates
(Applicants Agent)
IN/PA-199