WO2017103801A1

WO2017103801A1 - Environment friendly plaster composition

Info

Publication number: WO2017103801A1
Application number: PCT/IB2016/057599
Authority: WO
Inventors: Binod Kumar BAWRI
Original assignee: Bawri Binod Kumar
Priority date: 2015-12-18
Filing date: 2016-12-14
Publication date: 2017-06-22

Abstract

An environment friendly plaster composition is proposed that provide total replacement of river sand and artificial sand with the industrial waste. The said plaster composition is made up of an industrial waste mixture, Portland cement, plaster of Paris and a plurality of additives. The said industrial waste mixture includes granulated slag and fly ash. The said industrial waste mixture forms a base component of the said plaster composition. The Portland cement is added for imparting hardening and binding property to the said plaster composition. The plaster of Paris is added for imparting initial binding and ceasing a bleeding effect of the said plaster composition. The plurality of additives improves rheological properties of the said plaster composition.

Description

ENVIRONMENT FRIENDLY PLASTER COMPOSITION

FIELD OF THE DISCLOSURE [0001] The invention relates to an environment friendly plaster composition. More specifically, the invention provides a plaster composition which is produced from the industrial waste materials such as slag and fly ash. The said plaster composition provides total replacement of river sand and artificial sand which is currently used as a base material in the plastering industry. Accordingly, the present invention reduces the dependency over the natural sand and also reduces environment burden of industrial waste.

BACKGROUND OF THE DISCLOSURE [0002] Housing, buildings and other infrastructure is considered as the basic pillar of human civilization. Building construction requires lot of materials such as cement, sand, stone and iron. All these materials are derived from natural resources and thus pose a burden over the nature and environment. Continuous mining of these materials creates lot of environment related problems such as flood, soil erosion, and damages to natural flora and fauna.

[0003] Apart from basic construction materials, the modern building construction also requires other ancillary materials such as glass, plaster, plastic and paints. Further, the use of plaster is most common while giving final furnishing to the building. Plaster is commonly known as gypsum plaster or plaster of Paris, lime plaster, or cement plaster.

[0004] Sand is the base component mostly used for manufacturing all types of plasters. The extensive sand use and sand mining creates burden over the ecology and the environment. Moreover, ecology and environmental protection is a global issue and governments around the globe are imposing various restrictions over activities which are harming our environment and ecology. [0005] Environmental protection is also important along with the industrial and social development of the community. Thus, there is a continuous demand for environment friendly products and green technologies. Further, in the construction industry there is a huge demand for green products which have lesser harming effects on the ecology and environment. Similarly, in construction industry, there is a huge demand for plaster products which are environment friendly and completely reduces dependency over sand as a base material.

[0006] There are plaster products claiming lesser use of sand in their overall composition. However, the present available plaster products are not completely replacing sand with any other alternative materials which are environment friendly and help in reducing the environmental degradation. Therefore, it is wise to turn to such sources that are abundant and which do not pose any threat to the environment degradation.

[0007] Further, the current industrialization has increased the mining activities around the world. Moreover, such mining activities also produce a lot of waste materials such as slag, fly ash, dust particles and the like. Such waste materials also pose a threat to our environment and accelerate the environmental degradation and pollution.

[0008] All major iron and steel industries across the world produce slag as a bi-product in terms of millions of tons. One part of this slag is grounded to make GGBS which is an effective cement replacement. However, a major portion of this material is dumped in the form of huge hills and due to dust storming of these glassy based materials there is a major environmental issue to the nearby inhabited areas. This issue can be addressed to a certain extent by utilizing the waste slag material in one of the construction applications such as like plastering. Further, fly ash which is another industrial waste can be effectively used as a replacement for cement to the extent of 40% in one of the construction applications such as like plastering.

[0009] Accordingly, there is a need for using such waste materials for producing useful products. Further, there is a need for using such waste materials for producing various types of construction materials such as plaster and the like. [0010] To achieve a better and stronger plaster product from such industrial wastes there is a need for a composition and a method which modifies the rheological, binding and hardening properties of the final plaster product. Accordingly, there is a need for a composition which provides total replacement of sand for manufacturing the plaster as used in the construction industry. Further, there a need for a method of producing such plaster product.

SUMMARY [0011] Aspects of the invention are thus directed to a plaster composition which is environmental friendly as well as provides complete replacement of any conventional fine aggregate presently being used, namely, natural river sand or manufactured sand with the industrial wastes. Initially, the base materials for manufacturing such plaster product are selected from the blast furnace slag and the fly ash. The slag is produced from the metal industry and fly ash is produced from burning of coal in the thermal power plants. Specifically, the slag as used in the present invention is selected from the Iron industry.

[0012] In an aspect, the present invention provides a plaster composition and method for manufacturing a green plaster which reduced the burden of sand mining. The plaster so produced has better and improved physical properties as compared to the conventional plaster products.

[0013] In an aspect, the present invention provides a plaster composition and method for manufacturing a green plaster, wherein, such green plaster includes binding and hardening property enhancers selected from synthetic or natural sources. Accordingly, the plaster as produced by the present invention has better binding and hardening properties than the conventional plaster products. [0014] In an aspect, the present invention provides a plaster composition and method for manufacturing a green plaster, wherein, such green plaster further includes rheology modifiers selected from synthetic or natural sources. Accordingly, the plaster as produced by the present invention has improved surface finish as compared to the conventional plaster products. [0015] In an aspect, the present invention provides a green plaster composition having materials imparting pozzolanic activity to such green plaster composition. Accordingly, the said green plaster has higher durability and strength when compared to the conventional plaster products.

[0016] In another aspect, the present invention provides a green plaster composition having materials imparting plastic property to such green plaster composition. Accordingly, the said green plaster has improved shrinkage reduction, crack resistance and adhesion properties in comparison to the conventional plaster products.

[0017] In yet another aspect, present invention provides a method and composition for manufacturing a green plaster product, wherein, the plaster product completely replaces the use of sand. The green plaster product include:

an industrial waste mixture having slag and fly ash, wherein the industrial waste mixture forms a base component of the said plaster composition;

Portland cement for imparting hardening and binding property to the said plaster composition;

plaster of Paris for imparting initial binding and ceasing a bleeding effect of the said plaster composition; and

a plurality of additives for improving rheological properties of the said plaster composition.

[0018] In another aspect, the present invention provides a green plaster product having improved and modified hardening, binding and rheological properties as compared to the conventional plaster products. The green plaster product includes:

an industrial waste mixture having blast furnace slag in an amount of 1-85 weight percent of the said plaster composition, and fly ash in an amount of 1-5 weight percent of the said plaster composition, wherein the industrial waste mixture forms a base component of the said plaster composition;

a supporting mixture having Portland cement in an amount of 1-15 weight percent of the said plaster composition, and plaster of Paris in an amount of 1-5 weight percent of the said plaster composition, wherein the said supporting mixture impart plastic property to the said plaster composition; and

- A - a plurality of additives for improving rheology of the said plaster composition.

[0019] Thus, the aspects of the present invention are directed to a green plaster composition, method of manufacturing of such green plaster and use of such green plaster in the construction industry.

[0020] Particularly, the ease of manufacture of the green plaster composition, applicability of the green plaster composition to various sites, protection of environment and ecology, recycling of the industrial waste, reduction in sand mining are some examples of the desired benefits achieved by the present invention.

[0021] This together with the other aspects of the present invention along with the various features of novelty that characterized the present disclosure is pointed out with particularity in claims annexed hereto and forms a part of the present invention. For better understanding of the present disclosure, its operating advantages, and the specified objective attained by its uses, reference should be made to the accompanying descriptive matter in which there are illustrated exemplary embodiments of the present invention. DESCRIPTION OF THE INVENTION

[0022] The exemplary embodiments described herein detail for illustrative purposes are subjected to many variations. It should be emphasized, however, that the present invention is not limited to the plaster composition and method of its producing such green plaster composition. It is understood that various omissions and substitutions of equivalents are contemplated as circumstances may suggest or render expedient, but these are intended to cover the application or implementation without departing from the spirit or scope of the present invention. [0023] Unless otherwise specified, the terms, which are used in the specification and claims, have the meanings commonly used in the field of building construction and plastering industry. Specifically, the following terms have the meanings indicated below. [0024] The terms "a" and "an" herein do not denote a limitation of quantity, but rather denote the presence of at least one of the referenced item.

[0025] The terms "having", "comprising", "including", and variations thereof signify the presence of a component.

[0026] The term "GBS" refers here to granulated blast furnace slag as produced from the iron plants. [0027] The term "additives" refers to synthetic or natural occurring materials or compounds or agents which are capable of improving the physical and chemical properties of the plaster composition.

[0028] The term "green plaster" refers to an environmental friendly plaster composition which reduces the burden of sand mining at the same time uses industrial waste as a raw material.

[0029] The term "supporting mixture" refers to synthetic or natural occurring materials or compounds or agents which are imparting hardening and/or binding properties to the plaster composition.

[0030] The term "rheology modifying additive" is understood to mean here a compound or agent capable of modifying the viscosity and/or initial binding property of the plaster composition.

[0031] It should be noted that the term "pozzolanic activity" as referenced hereinbelow means capability of binding calcium hydroxide in the presence of water as understood in the art. [0032] The industrial waste mixture as provided herein is a mixture of blast furnace slag and fly ash, wherein the said slag is selected from the iron and/or steel plants and fly ash is selected from the thermal power plant. The said slag is used in an amount of 1-85 weight percent of the said plaster composition, and the fly ash is used in an amount of 1-5 weight percent of the said plaster composition. The slag as used in the present invention is a granulated slag as produced from the iron plants. Further, such granulated slag from the iron plants is produced either by blast furnace process or by COREX process. [0033] The granulated phase of the slag is termed as GBS, wherein the preferred particle size of such GBS is equal to or less than 2.36 mm. The GBS as produced from iron plants has high amount of CaO and traces of FeO. Accordingly, the GBS having high amount of CaO is considered more desirable for producing the plaster composition having desired hydraulicity. Further, the GBS as provided herein is latent hydraulic in nature i.e. not hydraulic in nature but becomes hydraulic when exposed to calcium-rich solutions. In other words, the GBS as selected herein should have properties between a hydraulic material and non-hydraulic material such as a pozzolanic fly ash.

[0034] Further, the GBS as selected herein should have almost 95% of glass phase in the iron slag and such glass phase of the GBS itself will react with water and thus impart a hydration activity to the overall plaster composition. The glassy phase of the GBS also has small microscopic needle like structures and these structures act as crack arrestors. Thus such latent hydraulic property of the GBS gives a slow and steady increase in the overall sturdiness of the plaster composition, which is opposite when conventional sand is used. The GBS acts both as filler and as a secondary hydration material. Accordingly, the above mentioned GBS ensures the durability of the final plaster composition.

[0035] Due to the immense industrialization around the world, the river mining has reached an alarmingly dangerous stage, which has cropped up many environmental issues like ecological imbalance, changing of river course directions, which has multiple ecosystem impacts. Moreover, plastering is one area where good quality river sand has higher requirement than other construction practices. Hence, the concept of using an alternative like GBS as a complete replacement of natural river sand in plasters has a major positive influence on addressing such environmental issues. Specifically, the present invention provides an environmental friendly plaster composition, where the GBS is used as a total replacement for sand as used in the plastering industry. [0036] The plaster as produced in the present invention is not a gypsum plaster or any kind of specialized product. The basic purpose is the mass production of plaster at low cost and application as a conventional plaster both for internal and external surfaces.

[0037] The fly ash as used in the present invention is pozzolanic in nature and it gives higher later strength and durability to the final plaster composition.

[0038] The supporting mixture as provided herein includes a mixture of Portland cement and plaster of Paris. Such Portland cement is used in an amount of 1-15 weight percent of the said plaster composition, and plaster of Paris is used in an amount of 1-5 weight percent of the said plaster composition.

[0039] The Portland cement is used in a small quantity and imparts hardening and binding property to the said plaster composition. The plaster of Paris is used in a very small quantity and this neutralizes the effect of honeycombed structure in the slag. The honeycombed structure in the slag has a tendency for high initial absorption of water and later on bleeding. The recommended dosage of plaster of Paris will cease this bleeding effect and also impart an initial binding nature to the final plaster composition.

[0040] Thus, the final plaster composition has improved hardening and bleeding effect as compared to the conventional plaster compositions. Moreover, it is not possible by simply mixing the GBS, fly ash, Portland cement, plaster of Paris and water to get a final plaster product having desired hardening and binding properties. The plaster produced by this method never sticks to the wall and has no bonding with the substrate, as slag is totally a non-plastic material. Hence, it is more desirable to identify the environment friendly additives which modify the total rheological properties of the final plaster product.

[0041] Accordingly, the additives as used in the present plaster composition are selected from at least a cellulosic material of a natural or a synthetic origin, a rheology modifying additive of a natural or a synthetic origin. [0042] The cellulosic material as used in the present plaster composition is selected from synthetic source such as alkyl cellulose and the said cellulosic material is present in an amount of 0.15-1 weight percent of the said plaster composition. The cellulosic material used in the present plaster composition are selected from cellulose ethers such as Carboxy Methyl Cellulose (CMC), Methyl Cellulose (MC) and derivatives, Hydroxy Ethyl Cellulose (HEC) and derivatives, Hydroxy Propyl Cellulose (HPC), Ethyl Cellulose (EC) and derivatives, and derivatives. The addition of the said cellulose ethers imparts the required plasticity into the plaster mix and improves its cohesion properties.

[0043] Furthermore, the rheology modifying additive as used in the present plaster composition is present in an amount of 0.15-1 weight percent of the said plaster composition. The rheology modifying additive is selected from the stearate salt of alkaline earth metal. Specifically, the said stearate salt of alkaline earth metal is Calcium Stearate.

[0044] The Calcium Stearate improves the water retention property of the said plaster composition and the said plaster composition becomes non-breathable. The Calcium Stearate avoids the requirement for curing and thus provides a self-curing plaster composition. The said Calcium Stearate also drastically reduces the permeability of the plaster in its hardened state. The Calcium Stearate also allows a greater amount of pot life into the said plaster mix thus making it workable for hours after mixing with water.

[0045] Accordingly, each of the said additives has a specific purpose, cellulose ethers when added at recommended dosage provides the cohesion and adhesion properties required for the said plaster.

[0046] In one embodiment, the granulated blast furnace slag (GBS) from the iron plants industry is selected as a base component and mixed with the fly ash as produced from the thermal power industry. The GBS is dried in a sand drier to a moisture level of about 0.5% before such mixing. The mixture of the GBS and the fly ash will be termed as the industrial waste mixture. The said industrial waste mixture has 94:6 weight percentage of the ratio of the GBS and the fly ash. [0047] In another embodiment, the said industrial waste mixture is mixed with the ordinary Portland cement and the plaster of Paris. Further, a plurality of additives is added to the preceding mixture and thus the final composition of the green plaster product is produced. The final green plaster composition has industrial waste mixture, ordinary Portland cement, plaster of Paris and additives in a ratio of 84: 10:5:1 weight percentage of the said green plaster composition. The moisture level of the said green plaster composition is reduced to zero and then such plaster composition is packed in an air and moisture tight bag. [0048] In yet another embodiment, such process provides a dry and ready mix plaster having prolonged self-life and low cost of production. Such dry and ready mix plaster is mixed with water immediate before the application on a desired location.

[0049] The production process pertaining to the claimed green plaster is very much similar to the production of any other conventional ready mix plaster. The production process involves storage of raw materials like GBS, fly ash, Portland cement and plaster of Paris (POP) in their respective storage containers.

[0050] Specifically, the GBS, fly ash, Portland cement and plaster of Paris (POP) are dried to a moisture content of 0.5%. All of the above raw materials are individually batched through pre-designed software and they are dispersed into the central mixer. The central mixer mixes all these ingredients in dry form for about a minute and the mixed material is discharged towards the packing unit, where the final dry ready mix plaster composition is immediately packed in 40/50 kg bags. The shelf life of these water tight bags is about 2.5-3 months.

[0051] Whenever, there is a requirement of a wet plaster to be applied over the wall then water is added to such dry ready mix plaster composition and the wet plaster of desired consistency and parameters is thus prepared. It is recommended to apply a rush coat over the existing wall/site before applying the said wet plaster either onto the wall/site.

[0052] It is to be noted that the production of the present plaster composition does not require any complicated processes like pulverization/calcination etc. as required in a conventional gypsum plaster unit. Further, there is requirement of temperature monitoring except only that the fine aggregate (GBS) is dried. The raw materials are stored respectively in their respective storage containers. [0053] In an embodiment, the present invention provides a green plaster composition providing total replacement of sand with industrial waste. The said green plaster composition includes an industrial waste mixture, Portland cement, plaster of Paris and a plurality of additives. The industrial waste mixture includes GBS in an amount of 1-85 weight percent of the said plaster composition and fly ash in an amount of 1-5 weight percent of the said plaster composition. The said industrial waste mixture forms a base component of the said plaster composition. Specifically, the industrial waste mixture includes GBS and fly ash in a ratio of 94:6 weight percent of the said industrial waste mixture. [0054] The Portland cement is present in an amount of 1-15 weight percent of the said plaster composition. The plaster of Paris is present in an amount of 1-5 weight percent of the said plaster composition. The plurality of additives comprises at least a cellulosic material, and a rheology modifying additive selected from a natural or a synthetic source. The said cellulosic material is present in an amount of 0.15-1 weight percent of the said plaster composition. The rheology modifying additive is present in an amount of 0.15-1 weight percent of the said plaster composition.

BEST MODE OF WORKING [0055] In yet another embodiment, the present invention provides a green plaster composition providing 100% replacement of sand with industrial waste in the plastering industry. The said green plaster composition includes an industrial waste mixture, Portland cement, plaster of Paris and a plurality of additives. The industrial waste mixture includes GBS in an amount of 1-90 weight percent of the said plaster composition and fly ash in an amount of 1-4 weight percent of the said plaster composition. The said industrial waste mixture forms a base component of the said plaster composition. [0056] The Portland cement is present in an amount of 1-11 weight percent of the said plaster composition. The plaster of Paris is present in an amount of 1-4 weight percent of the said plaster composition. The plurality of additives comprises at least a cellulosic material selected from a natural or a synthetic source, and a rheology modifying additive selected from a natural or a synthetic source. The cellulosic material is selected from synthetic source such as alkyl cellulose and the said cellulosic material is present in an amount of 0.15-1 weight percent of the said plaster composition. The rheology modifying additive is present in an amount of 0.15-1 weight percent of the said plaster composition.

[0057] All of the above materials are dried and mixed in their respective ratios into the central mixer and then packed in the desired watertight packing bags. Specifically, water is added to the said green plaster composition in an amount of 24-26 % of total weight of said green plaster composition.

[0058] In one exemplary embodiment, the table 1 provides the composition of the green plaster.

Table 1

[0059] In another embodiment, the said green plaster composition is environmental friendly and protects the ecology from degradation as the said green plaster composition is using mostly the waste industrial materials. [0060] In yet another embodiment, the said green plaster composition has improved hardening and binding properties as the said green plaster taps the special latent/hidden properties of the raw materials to an optimum level. [0061] In yet another embodiment, the said green plaster composition has low production cost as the said green plaster composition is using mostly the waste industrial materials and have very simple process of production.

[0062] In yet another embodiment, the said green plaster has lighter density and thus the spread of such green plaster is almost 1.5 times more than any conventional plaster. This is another major property enhancement with respect to the conventional plasters. Moreover, the higher spread value of the plaster is always desirable by structural engineers as it decreases the dead weight of the structure. Further, the higher spread value of the plaster provides cost effectiveness to the end users.

[0063] In yet another embodiment, the said green plaster has improved thermal insulation properties. Hence, the end users have advantages of comfort from the environmental heat/cold when the said green plaster is used both in the internal and external surfaces of the wall. Further, the color of the finished green plaster is lighter (light tan of whitish grey) than that of plaster made with river sand or manufactured sand. The lighter color of the said green plaster gives a broader choice to the end users towards painting the plastered walls with lighter shades of paint.

[0064] In yet another embodiment, the acoustic properties of the green plaster is better than plasters made with river sand or manufactured sand. The said improved acoustic properties of the green plaster are due to the dampening effect created by using slag as sand, which has a semi porous external interface.

[0065] Field studies of using GBS as coarse aggregate in plastering have shown that the calcium oxide in the coarse aggregate react slowly over a longer period of time. Hence, this slow reaction of the calcium oxide gives additional stability to the pavement structures, contributing to its increased service life. Further, the said green plaster has excellent surface finish as compared with the plaster made with river sand. [0066] The present invention provides several other advantages with respect to its use. The manufacturing method is very simple and effective, and the equipment needed is simple and relatively cheap. The green plaster is produced directly from the industrial waste and does not require any complicated processes like pulverization/calcination etc. as required in a conventional gypsum plaster unit.

[0067] While the invention has been described with respect to specific composition which include presently preferred modes of carrying out the invention, those skilled in the art will appreciate that there are numerous variations and permutations of the above described embodiments that fall within the spirit and scope of the invention. It should be understood that the invention is not limited in its application to the details of construction and arrangements of the components set forth herein. Variations and modifications of the foregoing are within the scope of the present invention. [0068] Accordingly, many variations of these embodiments are envisaged within the scope of the present invention.

[0069] The foregoing descriptions of specific embodiments of the present invention have been presented for purposes of description. They are not intended to be exhaustive or to limit the present invention to the precise forms disclosed, and obviously many modifications and variations are possible in light of the above teaching. The embodiments were chosen and described in order to best explain the principles of the present invention and its practical application, and to thereby enable others skilled in the art to best utilize the present invention and various embodiments with various modifications as are suited to the particular use contemplated. It is understood that various omissions and substitutions of equivalents are contemplated as circumstances may suggest or render expedient, but such omissions and substitutions are intended to cover the application or implementation without departing from the spirit or scope of the present invention.

Claims

CLAIMS What is claimed is:

1. An environment friendly plaster composition providing replacement of sand with industrial waste, the said plaster composition comprising:

2. The plaster composition as claimed in claim 1, the industrial slag waste is a granulated blast furnace slag obtained from metallurgy industry, wherein the slag acts as a filler and as a secondary hydration material.

3. The plaster composition as claimed in claim 2, wherein the granulated blast furnace slag is selected from iron industry, and wherein the said granulated blast furnace slag is present in an amount of 1-85 weight percent of the said plaster composition.

4. The plaster composition as claimed in claim 1 , wherein the said fly ash is present in an amount of 1-5 weight percent of the said plaster composition, and wherein the industrial fly ash waste imparts pozzolanic activity to the said plaster composition..

5. The plaster composition as claimed in claim 1, wherein the said granulated blast furnace slag and the said fly ash are present in a ratio of 94:6 weight percent of the said industrial waste mixture.

6. The plaster composition as claimed in claim 1, wherein the Portland cement is present in an amount of 1-15 weight percent of the said plaster composition.

7. The plaster composition as claimed in claim 1, wherein the plaster of Paris is present in an amount of 1-5 weight percent of the said plaster composition.

8. The plaster composition as claimed in claim 1, wherein the plurality of additives comprises at least a cellulosic material selected from a natural or a synthetic source, and a rheology modifying additive selected from a natural or a synthetic source.

9. The plaster composition as claimed in claim 8, wherein the cellulosic material is a cellulose ether selected from the group of Methyl Cellulose (MC), Carboxy Methyl Cellulose (CMC), Ethyl Cellulose (EC), Hydroxy Ethyl Cellulose (HEC), Hydroxy Propyl Cellulose (HPC), and derivatives thereof.

10. The plaster composition as claimed in claim 9, wherein the said cellulose ether is present in an amount of 0.15-1 weight percent of the said plaster composition.

11. The plaster composition as claimed in claim 8, wherein the said rheology modifying additive is present in an amount of 0.15-1 weight percent of the said plaster composition, wherein the rheology modifying additive is selected from the stearate salt of alkaline earth metal.

12. The plaster composition as claimed in claim 10, wherein the said stearate salt of alkaline earth metal is Calcium Stearate. .

13. An environment friendly plaster composition providing replacement of sand with industrial waste in the said plaster, the plaster composition comprising:

a supporting mixture having Portland cement in an amount of 1-15 weight percent of the said plaster composition, and plaster of Paris in an amount of 1-5 weight percent of the said plaster composition, wherein the said supporting mixture imparts plastic property to the said plaster composition; and a plurality of additives for improving rheology of the said plaster composition.

14. The plaster composition as claimed in claim 12, wherein the Portland cement is present in an amount of 1-10 weight percent of the said plaster composition.

15. The plaster composition as claimed in claim 12, wherein the plurality of additives comprises at least a cellulosic material selected from a natural or a synthetic source, and a rheology modifying additive selected from a natural or a synthetic source.

16. The plaster composition as claimed in claim 15, wherein the cellulosic material is a cellulose ether selected from the group of Methyl Cellulose (MC), Carboxy Methyl Cellulose (CMC), Ethyl Cellulose (EC), Hydroxy Ethyl Cellulose (HEC), Hydroxy Propyl Cellulose (HPC), and derivatives thereof.

17. The plaster composition as claimed in claim 16, wherein the said cellulose ether is present in an amount of 0.15-1 weight percent of the said plaster composition.

18. The plaster composition as claimed in claim 15, wherein the said rheology modifying additive is present in an amount of 0.15-1 weight percent of the said plaster composition, wherein the rheology modifying additive is selected from the stearate salt of alkaline earth metal.

19. The plaster composition as claimed in claim 18, wherein the said stearate salt of alkaline earth metal is Calcium Stearate.