Field of the invention
The present invention relates to elastomeric coatings for concrete and cementitious surface and a process thereof. The elastomeric coatings for concrete and cementitious surface comprising monomers, initiators, promoters with variety of cross linkers are flexible breathable flexible breathable with high elongation and weatherability and crack bridging membranes.
Background of the invention:
Elastomers are a class of material which differ quite obviously from all other solid materials in that they can stretched, easily and almost completely reversibly, to high extension and before reaching its ultimate breaking elongation , it can be released and will rapidly recover to almost exactly the original length it had before stretching.
The word membrane generally refers to shingles for sloping roofs and built up roofing (asphalt /bitumen) for flat roofs and in both these system, bitumen or asphalt is used.
Bitumen performs following functions in Built-up Roofing:
■ They act as an adhesive bonding, between the felts or else they are used in the form of a pour coat, the main waterproofing component of the Built-up Roofing.
■ The performance of membrane roofing systems is not dependent solely on climate and weathering it is also influenced by stresses imposed by the building that it is protecting and by the roofing system of which it is a part.
Research over the last 15 years has fully or to a great extent identified the causes for the problems that plagued the flat roof industry.
The use of built-up roof for over a century has made this a class by itself It is still the single biggest type of roofing installed. The new materials introduced as alternatives to

built-up roof are products of different chemical formulations. They do provide a wide range of options that meet required performance characteristics. The first generation of these materials suffered some setbacks due to lack of design and performance criteria and lack of experience. However, improvements in their compositions, reinforcing, and lap joint techniques have resulted in a second generation of products with somewhat better performance.
Besides built-up roof (BUR) there are many different types of new membranes that are mostly prefabricated sheets or liquid applied materials that cure to form waterproof sheets or closed cell foams. They are made from a wide variety of synthetic organic materials (polymers) with various chemical compositions and additives. In some cases natural materials such as bitumen, organic fibers, etc. are compounded with them.
As the environment is becoming a greater concern to people, it is gratifying to see an increased awareness of the environment in the construction and in the rapidly-growing retrofit market, concern for the long-term impact on the environment with products and practices has become evident.
Common membranes are
Conventional roofing : Bituminous built-up roofing (BUR)
Prefabricated sheets : Thermoplastic sheets
PVC and blends EIP (ethylene interpolymer) CPA (copolymer alloys)
: Elastomeric (synthetic rubber) sheets
Vulcanized
EPDM (ethylene-propylene-diene monomer)
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Neoprene (polychloroprene)
Non-vulcanized
CSPE (chlorosulfonated polyethylene) CPE (chlorinated polyethylene) PIB (polyisobutylene) N Modified bituminous sheets SBS (styrene-butadiene-styrene)
Polymer modifiers
APP (atactic polypropylene)
IPP (isotactic polyproylene BP (butadiene-acrylonitrile)
Cast in situ Hot applied rubberized asphalt
Cold applied liquid compounds
• Various polymeric and bituminous materials Polyurethane foam roof with protective coating
Disadvantage of thick toppings are as follows:
1. Blister formation due to out gassing of the slab or the presence of moisture. This is generally found with the single coat liquid applied membrane systems where the membrane thickness is less than 2 mm.
2. Poor resistance to chemical attack.
3. Asphalt shifting occurs under wheel loading. This is generally a function of the asphalt stability and thickness of the membrane.
4. Debonding of membrane where vapour pressures exceed bond strength. This is a particular problem with sheet applied adhesive membranes where vapour gets trapped.
5. Due to the thickness of the system, concrete delaminations on the surface of the slab are not evident at an early date.
6. Mastic type wearing surfaces are not suited to exterior applications.
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7. On exterior applications black surface increases temperature of slab, increasing slab thermal movement and cracking.
8. Additional load to the structure.
9. Need to consider impact on headroom.

10. Generally unstable on steep sloped applications.
11. In the temperate climate of India some of the roofs are exposed to sun's rays faro sunrise to sunset and much of the sunlight strikes the roof surfaces at the steep angle. A dark roof coated by bitumen can attain a very high surface temperature and in addition the reflected radiation from adjacent surface can raise the surface temperature much above than attained by direct radiation. We all know that colour has a great role to play on the Absorption of solar irradiation by surface for example: - If white surface absorbs 40%, Black surface would absorb 90%. This results in photo oxidation and disintegration cause by ultra violet rays in the presence of oxygen and the bitumen material produces water soluble and volatile products.
12. Indian climate which has Summer, Winter and Monsoon seasons and each season having different range of temperatures and this fluctuation can contribute to the breakdowTi of bitumen and in addition it can also lead to the large thermal movements of the total membranes. The seasonal variation is not the only cause but in towns like Bangalore short time variation in temperature also effects the durability of bitumen.
13. If there is a fire in a structure, roof structures and materials reduces the risk of spreading of fire fi-om neighbour buildings. However the resistance of bitumen materials is generally poor and that is an additional problem with bitumen surfaces.
14. Roof Membrane can be damaged by pollutants from the environment and local pollution, which is quite high in Bangalore. These pollutants deposited on the roof surface may form acids and this can damage the exposed Bitumen membrane. This process of damage continues until rain-washes the waste into the drain.
15. While laying bitumen/tarfelt membrane basic flaws and defects in structural membrane are not taken into consideration, since it is just covering the surface.
16. Tarfelt or any bituminous products is prone to oxidation there by it slowly becomes brittle and develop cracks. Since these type of treatments are physical barrier, the

trapped moisture tends to come out in hot weather cycle and form blister which subsequently break and creates opening for water entry cracks which happen due to aging also contributes to water entry and once water enters below the tarfelt layer water tends to come out through slab or any weak points in structure thus damaging reinforcement.
Prior Art:
US Patent 7,070,844 teaches highly reflective asphalt-based roofing membrane prefabricated asphalt-based waterproof roofing membrane for use in a multi-ply asphalt-based commercial roofing system, e.g. a cap sheet that forms the exposed layer of a multi-ply built-up roofing system, is manufactured at a factory to have a highly reflective thermoplastic elastomeric sheet layer with a top surface that has a reflectance that meets current EPA Energy Star requirements.
US Patent No. 7,395,999 teaches reinforced polymer panel and method for building construction, a method and apparatus for manufacturing reinforced wall panels and reinforced roof panels and using the pre-manufactured reinforced wall and roof panels in the construction of a building structure at a building site. The reinforced wall and roof panels are molded using a molding medium consisting of two part polyurethane which is mixed with Portland cement.
US Patent No. 5,587,234 teaches an elastomeric polysulfide composite in which rubber particles, particularly crumb rubber, are distributed substantially uniformly through an elastomeric polysulfide layer, roofing made from such composites, and the method of forming roofing in which the composite is associated with a rubber particle mat.
Object of the invention:
The main object of the present invention is to overcome all the above mentioned
problems and to develop a surface membrane or coating having following characteristics:
• Tensile strength
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Elongation
Crack bridging
Fatigue resistance
Thermal shock
Tear resistance
Abrasion resistance
Lap joint integrity
Static puncture
Impact resistance
Temperature flexibility
Weatherability
Temperature and pollutant aging
Dimensional stability
Granule embedment
Interply adhesion (bonding)
Membrane attachment
Flashing attachment
Materials compatibility
Wind uplift resistance
Summary of the invention:
The present invention relates to a elastomeric coating composition for concrete and cementitious surface and a process thereof, hereinafter called Protekta flexjoint / Protekta flexphalt / Protekta Unicoat, wherein a process for preparing an elastomeric coating for concrete and cementitious surface comprising the following steps:
a) Taking distilled water 5 to 30% by w./v. in a reactor vessel fitted with a homogenizer,
b) Adding monomers 30 to 90% by w/v. with stirring the solution
c) Adding cross linking agent 0.1 to 5 % by w/v.
d) Stirring for 5 to 10 minutes,
e) Adding cellulose fibers 0.1 to 4% by w/v.

f) Continuously stirring the solution for 5 minutes,
g) Adding amines 0.2 to 8% by w/v to the solution and stirring the solution,
h) Adding organic additives and oxidizing agent dissolved in water to obtain a thick pasty
material and stirring this paste for 8 to 10 minutes.
Thus obtaining an elastomeric coating composition for concrete and cementitious surface.
According to the another embodiment of the invention, a process for preparing an elastomeric coating for concrete and cementitious surface hereinafter called "Protekta flexphalt" comprising the following steps:
a) Taking distilled water 10 to 30% by w/v. in a reactor vessel fitted with homogenizer,
b) Adding hard acrylic polymer 15 to 30% by w/v. to the solution,
c) Adding soft acrylic polymer 15 to 30% by w/v. to the solution,
d) Stirring the solution for 10 minutes.
e) Making a mixture in powder form of inorganic fillers 15 to 30%, metal silicates Ito 18% and titanium dioxide 4 to 6%,
f) Adding half of this mixture in to the solution of the reaction vessel,
g) Adding cellulose fiber 2 to 4% by w/v and dispersing agent 0.4 to 1.5% by w/v to the solution
h) Stirring the solution for 5 to 10 minutes,
i) Adding remaining mixture and continue stirring,
j) Adding distilled water 5 to 10% by w/v. and Stirling the solution for 5 to 10 minutes
k) Adding biocides 0.20 to 0.25% by wt./vol. and stirring for 5 to 10 minutes,
1) Adding cellulose fiber 0.2 to 0.4% with slowing stirring to obtain an elastomeric
coating composition for concrete and cementitious surface..
According to another embodiment of the invention a process for preparing an elastomeric coating for concrete and cementitious surface hereinafter called "Protekta Unicoat" comprising the following steps: a) Taking monomer 15 to 35% in a reactor vessel fitted with homogenizer.

b) Making a mixture in powder form of Lime 0.75 to 1.85%, titanium dioxide 2 to 6%, natural clay 2 to 6%, tartaric acid 0.5 to 0.7% or any other fatty acid, metal silicates 0.5 to 0.9%, surfactant 0.5 to 0.7%, cellulose or starch ether 0.10 to 0.20 in separate container
c) Adding slowly this powder in to the reactor vessel while stirring
d) Stirring for 30 minutes, thus obtaining an elastomeric coating composition for concrete and cementitious surface.
According to another embodiment of the invention the monomers are acrylic or styrene or acrylic polypropylene, or acrylic ester.
According to another embodiment amines are either aliphatic or aromatic amines.
According to another embodiment of the invention the cellulose fibers are hydro cellulose fibers or natural cellulose fibers.
According to another embodiment of the invention the oxidizing agent is persulphate or peroxide.
According to another embodiment of the invention the inorganic fillers are metal carbonate and metal oxides.
According to another embodiment of the invention the elastomeric coating composition for concrete and cementitious surface comprises distilled water 5 to 30% by wt./vol , monomers 30 to 90% by w/v, cross linking agent 0.1 to 5 % by w/v., cellulose fibers 0.1 to 4% by w/v, organic additives and oxidizing agent dissolved in water.
According to another embodiment of the invention the elastomeric coating composition for concrete and cementitious surface comprises distilled water 10 to 30% by w/v, hard

acrylic polymerlS to 30% by w/v , soft acrylic polymer 15 to 30% by w/v , inorganic fillers 15 to 30%), metal silicates 1 to 18% and titanium dioxide 4 to 6%, cellulose fiber 2 to 4% by w/v , dispersing agent 0.4 to 1.5%) by w/v and biocides 0.20 to 0.25% by wt./vol..
According to another embodiment of the invention an elastomeric coating composition for concrete and cementitious surface comprises monomer 15 to 35%), a mixture of Lime 0.75 to 1.85%), titanium dioxide 2 to 6%, natural clay 2 to 6%, tartaric acid 0.5 to 0.7% or any other fatty acid, metal silicates 0.5 to 0.9%, surfactant 0.5 to 0.7%, cellulose or starch ether 0.10 to 0.20%
Description of the invention
The minimum requirement or the performance consideration of the roofing membranes can be summarized as follows:
1. Remain waterproof
2. Withstand all weather factors (such as wind, rain, snow, hail, solar radiation, temperature extremes, and thermal shocks) during its intended service life.
3. Resist various stresses fi-om internal or external causes during manufacture, application and service.
4. The performance of roofs, as mentioned above, is related to numerous variables concerning weather factors and stresses.
5. Other variables are the chemical composition of materials, the quality control of the constituent materials and products during manufacture, storage, transportation, installation and maintenance.
Most of these conditions vary from one situation to another, so that a large number of performance requirements and criteria are identifiable.

It was found necessary to have elastomeric coatings which should have the following properties and differentiate between elastomeric coatings and membranes

Tensile strength Elongation Crack bridging Fatigue resistance Thermal shock Tear resistance Abrasion resistance Lap joint integrity Static puncture Impact resistance

Temperature flexibility Weatherability
Temperature and pollutant aging Dimensional stability Granule embedment Interply adhesion (bonding) Membrane attachment Flashing attachment Materials compatibility Wind uplift resistance

Let us understand elastomeric coatings. Elastomeric coatings are flexible breathable flexible, breathable with high elongation and weatherability and crack bridging membranes rather than coating which have several problems.
To understand this concept we must address ourselves to basic questions to why latest membranes in this field are different than the conventional coating membranes.
Let us understand the term elastomers. Elastomers are a class of materials which differ quite obviously from all other solid materials in that they can be stretched, easily and almost completely reversibly, to high extensions and before reaching its ultimate breaking elongation - it can be released and will rapidly recover to almost exactly the original length it had before stretching. The material is said to be elastic.
Most synthetic elastomers are not as elastic as natural rubber, but all can be stretched (or otherwise deformed) in a reversible maimer to an extent, which easily distinguishes them from all other solid materials.
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Elastomers are a special case of the wider group of materials known as polymers. Polymers are not made up of discrete compact molecules like most materials, but are made of long, flexible, chain-like or string-like, molecules. At this scale the inside of a piece of rubber can be thought of as resembling a pile of cooked spaghetti. In spaghetti, however, the chains, though intertwined, are all separate. But in most practical elastomers each chain will be joined together occasionally along its length to one or more nearby chains with just a very few chemical bridges, known as cross¬links. So the whole structure forms a coherent network which stops the chains from sliding past
one another indefinitely - although leaving the long sections of chain between cross links free to move. The process by which cross-links are added is known as vulcanization.
Different types of elastomeric coating for concrete and cementitious surface are made by working on monomers which can be modified into cross linked elastomers by taking different monomers, initiators, promoters with variety of cross linkers .
Example 1
Take a clean and dry 200 Itr stainless steel reactor fitted with homogeniser. Take 5 to 25% of distilled water in the reactor, by stirring add 40 to 90% of acrylic or styrene or acrylic polypropylene, add 0.1 to 2 .5 % of cross linking agent stir for 5 min, add 0.1 to 2.5 % kg of hydro cellulose stir for 5 min, add 0.2 to 2.6 % any aliphatic or aromatic amine stir for 5min, add minor amount of organic additive and oxidizing agent like persulphate or peroxide. After 30 minutes you will get a thick pasty material Protekta Flexjoint and stir this paste for 10 min.
Example 2
Take a clean and dry 200 Itr stainless steel reactor fitted with homogeniser. Take 10 to 30 % of distilled water in the reactor, by stirring add 30 to 80% of acrylic esters of different polymer chain
like acrylic, acrylritat , add 1 to 5 % of cross linking agent stir for 5 min, add 1 to 4 % of natural
cellulose fibers stir for 5 min, add 4 to 8 % of any aliphatic or aromatic amine stir for 5min, add minor amount of organic additive and oxidizing agent like persulphate or peroxide dissolved in
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water was added drop wise. The polymerization takes play with exothermically and the product Protekta Flexjoint was obtained.
Example 3
Take a clean and dry 200 Itr stainless steel reactor fitted with homogeniser. Take 20 to 40% of distilled water in the reactor, add 20 to 40 kg of acrylic or styrene, add 15-25 % of acrylic emulsion and stir for 10 minutes. In a powder mixer make the mixture of 15 -30% of inorganic fillers like metal carbonate and metal oxides, 1 to 8 % of metal silicates and 4 to 6 % of titanium dioxide, add this powder into the reaction vessel slowly, after adding half of the powder slowly add 2 to 4% fiber and 0.4 to 1.1% dispersing agent and stir for 15 minutes. Add remaining powder and continue stirring. Add 5 to 20% of distilled water and stir for 5 minutes. Add 0.20 to 0.25% of biocides and stir for 5 minutes. By stirring slowly add 0.2 to 0.4 % of fiber and stir for 15 minutes. Store the final product Protekta Flexphalt in a closed can.
Example 4
A mixture of hard acrylic polymer and soft acrylic polymer was taken. The hard was 15 to 25%, soft was also of the same quantity. These two polymers were mixed in a separate vessel and in another container 2-6% of water was taken and 1 to 3 % of titanium dioxide was added, along with it filler like calcium carbonate 20 to 50 % was added. The mixture was stirred and antifoaming products like Nuketone from BASF or SAPCO was added. Different dispersing agents like sodium polyacrylate and other fillers like oxide, zinc, magnesium, silicates like calcium silicate or
aluminum silicate cellulose fiber and hydroxy propyl cellulose was added and the whole mixture was stirred and got a final product Protekta Flexphalt.
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Example 5
Take a clean and dry 200 Itr stainless steel reactor fitted with homogeniser. In a separate container prepare a powder a mixture of 0.75 to 1.85%) of lime, 2 to 6 % of titanium dioxide, 2 to 6%o of natural clays like dolomite, 0.5 to 0.7 % of tartaric acid or any fatty acid, 0.5 to 0.7 % kg of any surfactant, 0.10 to 0.20 % of starch ether or cellulose, 0.5 to 0.9 % of metal silicates and mix thoroughly. Add 15 to 35 % of acrylate like butyl, methyl, HEMA, MMA or any other acrylic polymer. By stirring add slowly the above powder into the reactor vessel, stir for 30 minutes. Store the final product Protekta Unicoat in a closed can.
Example 6
Take a clean and dry 200 Itr stainless steel reactor fitted with homogeniser. In a separate container prepare a powder a mixture of 0.5 to 2 % of lime, 4 to 9 %> of titanium dioxide, 0.5 to 3 % of natural clays like dolomite, 0.50 to 0.70 % of tartaric acid or any fatty acid, 0.50 to 0.70 % of any surfactant, 0.10 to 0.20 % of starch ether or cellulose, 0.5 to 0.9%) of metal silicates and mix thoroughly. Add 15 to 35%o of acrylate like thermoplastic acrylic resins. By stirring add slowly the above powder into the reactor vessel, stir for 30 minutes. Store the final product Protekta Unicoat in a closed can.
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We claim:
1. A process for preparing an elastomeric coating for concrete and cementations surface
hereinafter called Protekta flexjoint Protector flexphalt / Protekta Unicoat comprising the
following steps:
a) Taking distilled water 5 to 30% by wt./vol. in a reactor vessel fitted with a homogenizer,
b) Adding monomers 30 to 90% by w/v. with stirring the solution
c) Adding cross linking agent 0.1 to 5 % by w/v.
d) Stirring for 5 to 10 minutes,
e) Adding cellulose fibers 0.1 to 4% by w/v.
f) Continuously stirring the solution for 5 minutes,
g) Adding amines 0.2 to 8% by w/v to the solution and stirring the solution,
h) Adding organic additives and oxidizing agent dissolved in water to obtain a thick pasty material and stirring this paste for 8 to 10 minutes to obtain an elastomeric coating composition for concrete and cementitious surface.
2. A process for preparing an elastomeric coating for concrete and cementitious surface
hereinafter called "" comprising the following steps:
a) Taking distilled water 10 to 30% by w/v. in a reactor vessel fitted with homogenizer,
b) Adding hard acrylic polymerlS to 30% by w/v. to the solution,
c) Adding soft acrylic polymer 15 to 30% by w/v. to the solution,
d) Stirring the solution for 10 minutes.
e) Making a mixture in powder form of inorganic fillers 15 to 30%, metal silicates Ito 18%> and titan vim dioxide 4 to 6%,
f) Adding half of this mixture in to the solution of the reaction vessel,
g) Adding cellulose fiber 2 to 4%) by w/v and dispersing agent 0.4 to 1.5% by w/v to the
solution
h) Stirring the solution for 5 to 10 minutes,
i) Adding remaining mixture and continue stirring,
j) Adding distilled water 5 to 10% by w/v. and stirring the solution for 5 to 10 minutes
k) Adding biocides 0.20 to 0.25%) by wt./vol. and stirring for 5 to 10 minutes,
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1) Adding cellulose fiber 0.2 to 0.4% with slowing stirring to obtain an elastomeric coating composition for concrete and cementitious surface.
3. A process for preparing an elastomeric coating for concrete and cementitious surface
comprising the following steps:
a) Taking monomer 15 to 35% in a reactor vessel fitted with homogenizer,
b) Making a mixture in powder form of Lime 0.75 to 1.85%, titanium dioxide 2 to 6%, natural clay 2 to 6%, tartaric acid 0.5 to 0.7% or any other fatty acid, metal silicates 0.5 to 0.9%, surfactant 0.5 to 0.7%, cellulose or starch ether 0.10 to 0.20 in separate container
c) Adding slowly this powder in to the reactor vessel while stirring
d) Stirring for 30 minutes, thus obtaining an elastomeric coating composition for concrete and cementitious surface.

4. A process for preparing an elastomeric coating for concrete and cementitious surface as claimed in any of the preceding claims, wherein monomers are selected from the group consisting of acrylic or styrene or acrylic polypropylene, or acrylic ester.
5. A process for preparing an elastomeric coating for concrete and cementitious surface as claimed in any of the preceding claims, wherein the amines are either aliphatic or aromatic amines.
6. A process for preparing an elastomeric coating for concrete and cementitious surface as claimed in any of the preceding claims, wherein the cellulose fibers are hydro cellulose fibers or natural cellulose fibers.
7. A process for preparing an elastomeric coating for concrete and cementitious surface as claimed in any of the preceding claims, wherein the oxidizing agent is selected food the group consisting of persulphate or peroxide.
8. A process for preparing an elastomeric coating for concrete and cementitious surface as
claimed in any of the preceding claims, wherein inorganic fillers are metal carbonate and
metal oxides.
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9. An elastomeric coating composition for concrete and cementitious surface as claimed in claim 1 comprising distilled water 5 to 30% by wt./vol, monomers 30 to 90% by w/v, cross linking agent 0.1 to 5 % by w/v., cellulose fibers 0.1 to 4% by w/v, organic additives and oxidizing agent dissolved in water.
10. An elastomeric coating composition for concrete and cementitious surface claimed in claim 9, wherein monomers are selected from the group consisting of acrylic or styrene or acrylic polypropylene, or acrylic ester.
11. An elastomeric coating composition for concrete and cementitious surface as claimed in claim 2 comprising distilled water 10 to 30% by w/v, hard acrylic polymerlS to 30% by w/v , soft acrylic polymer 15 to 30% by w/v , inorganic fillers 15 to 30% , metal silicates 1 to 18% and titanium dioxide 4 to 6%, cellulose fiber 2 to 4% by w/v , dispersing agent 0.4 to 1.5% by w/v and biocides 0.20 to 0.25% by wt./vol..
12. An elastomeric coating composition for concrete and cementitious surface as claimed in claim 10, wherein inorganic fillers are metal carbonate and metal oxides.
13. An elastomeric coating composition for concrete and cementitious surface as claimed in claim 10, wherein the soft acrylic polymer is acrylic polymer emulsion.
14. An elastomeric coating composition for concrete and cementitious surface as claimed in claim 10, wherein the cellulose fibers are hydro cellulose fibers or natural cellulose fibers.
15. An elastomeric coating composition for concrete and cementitious surface as claimed in claim 3 comprising monomer 15 to 35%, a mixture of Lime 0.75 to 1.85%), titanium dioxide 2 to 6%, natural clay 2 to 6%, tartaric acid 0.5 to 0.7% or any other fatty acid, metal silicates 0.5 to 0.9%), surfactant 0.5 to 0.7%, cellulose or starch ether 0.10 to 0.20.
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16. An elastomeric coating composition for concrete and cementitious surface as claimed in
claim 14, wherein the monomers are selected from the group consisting of acrylic or
styrene or acrylic polypropylene, or acrylic ester.
17. A process for preparing an elastomeric coating composition for concrete and cementitious
surface substantially as hereinafter described with reference to the accompanying
examples.
18. An elastomeric coating composition for concrete and cementitious surface substantially as
hereinafter described with reference to the accompanying examples.