WO2023112046A1

WO2023112046A1 - A descaling composition for glass substrates

Info

Publication number: WO2023112046A1
Application number: PCT/IN2022/051011
Authority: WO
Inventors: Indraneel ZOPE; Krishnamoorthy D; Kuppan BALAIAH
Original assignee: Saint-Gobain Glass France
Priority date: 2021-12-17
Filing date: 2022-11-18
Publication date: 2023-06-22

Abstract

The present application provides a descaling composition for glass substrates. Said descaling composition comprises by weight: 40% of at least two recycled abrasive particles; 5 to 10 % of amorphous silica; 30 to 40% of sulphamic acid; 5 to7.5% of sodium lauryl sulphate; and 0 to 2% of cetyl trimethyl ammonium bromide. Said descaling composition utilizing the recycled abrasive particles ensures efficient scale removal and surprisingly exhibiting a haze value of less than 1 for a descaled substrate with heavily built up scales.

Description

A DESCALING COMPOSITION FOR GLASS SUBSTRATES

TECHNICAL FIELD

The present disclosure relates in general to a descaling composition for substrates, and more particularly to a descaling composition for glass substrates, such that the descaling composition ensures excellent removability of scales using recycled abrasive particles, and also the descaled substrate displays a lower haze value thereby ensuring good visual clarity.

BACKGROUND

Generally, formation of crystals which lead to scale-formation is a persistent problem in most of the industries. Specifically, mineral scale or lime-scale formation on substrates such as glass or metals is a specific problem of interest in the present application. The mineral-scale formation on glass surfaces is a persistent issue especially when the glass substrate is used in wet regions like bathroom and kitchen. This could be due to various reasons attributed to, hardness of water, precipitation and further deposition of carbonates or sulfates, high concentration of silica, etc. Specifically, the hard water possibly causes the deposition of hard scale or detergent components on glass substrates in wet environments.

Particularly in glass substrates which are exposed to wet environment, scaling is majorly due to the deposition of inorganic salts or minerals like magnesium and calcium carbonate. These mineral-scales drastically reduce the aesthetic appeal of glass, hence, requiring periodic cleaning with mineral-scale removers.

Age old traditional methods include adding water-softening agent to substitute calcium and the magnesium ion in the hard water as a means to overcome undesirable hard water influence. Numerous cleaning compositions or scale removal formulations have also been disclosed in various prior art. However, a major problem with these scale removal compositions is their inefficiency to remove lime-scale and soap scum from the surface or substrate that is being treated.

Generally, the scale removal compositions known in the art for effectively removing lime-scale deposits are acid-based compositions. Referring to CA2441722 patent application, discloses sulphamic acid based liquid lime-scale remover for hard surfaces. Referring to WO1992019549A1, discloses composition for effectively removing deposits of scale majorly comprising mineral acid such as sulphamic acid, hydrochloric acid or an organic acid such as acetic acid, hydroxy acetic acid and citric acid along with cationic surfactant and desolubiliser.

EP0875555 patent application discloses the use of a polysaccharide polymer or a mixture thereof in a liquid acidic composition for treating a hard-surface, to reduce the formation of lime-scale deposits on the surface when it comes in contact with water. The liquid composition has a pH below 4. Further, EP0875554 patent application teaches the use of an acid-stable polymer selected from the group consisting of a polycarboxylate, a sulphonated polystyrene polymer, a vinylpyrrolidone homo/copolymer, a polyalkoxylene glycol, and mixture thereof, in a liquid acidic composition having a pH below 5. Said acidic compositions are suitable for removing lime-scale-containing stains from a surface of the substrate.

It is also known in the art that the prevention of lime-scale formation or any kind of soap scum buildup on the surfaces can be achieved by using chelating or sequestering agents in alkaline liquid cleaning compositions. JP5694146B2 patent application discloses a scale control component combining a biodegradable chelating agent and a sequestering agent that provides superior control of hard water scale morphology at low use dilution concentrations. Also other existing prior art discloses abrasive hard surface cleaning compositions. US 5,460,742 patent application describes acidic cleaning compositions, which further comprise thixotropic liquids comprising 5-50% abrasive, amphoteric and nonionic surfactant and a hydrated aluminum silicate thickener. US 3,214,380 patent application discloses similar compositions comprising oxalic acid and silex as an abrasive component.

Another common method to counter such build-up of mineral-scales is to treat glass surfaces with hydrophobic coatings. Although, such coating can significantly delay initial scale deposition, these coatings tend to wear-out eventually resulting in mineral scale build-up. To regain hydrophobicity, periodic reapplication of such hydrophobic coatings is required. For such conditions, mineral-scale removers are used to clean the glass surfaces to get rid of any scales and stains before reapplication of hydrophobic coating.

The above referenced prior art compositions are either majorly easily dispensable liquids which are expensive than powders and have stipulated shelf life to maintain the solution or suspension integrity is limited due to separation or settlement of abrasive particles from liquid medium. None of the existing prior art disclose the use of recycled abrasive materials being a part of the descaling compositions. It is therefore desirable to develop a low cost or economically significant descaling composition, specifically for substrates, which in fact surprisingly and efficiently removes scales, at the same rate as per the non-recycled scale removal composition or even more in specific instances. With the proposed invention, the customers are not only provided with a sustainable recycled descaling compositions but also benefitted with descaling composition which are available at lower market rates. OBJECT OF INVENTION

The main object of the present invention is to provide a descaling composition for a substrate, said descaling composition ensures efficient removal of heavily built up scale deposits from the surface of a substrate.

Another object of the present invention is to provide a descaling composition for glass substrates, said descaling composition uses recycled abrasive materials, which is recovered from glass polishing waste.

Yet another object of the present invention is to provide a descaling composition for glass substrates, where the recycled abrasive particles act as a functional ingredient by providing an opportunity in upcycling while deriving a value added descaling composition.

Further, yet another object of the present invention is to provide a descaling composition for glass substrates, such that the haze value of the descaled glass substrate is less than 1 , thereby enabling excellent optical visual clarity.

The present disclosure was developed by outlining the above objectives.

SUMMARY OF THE DISCLOSURE

In an aspect of the present disclosure, a descaling composition for glass substrates is disclosed. Said descaling composition comprising, by weight: 40 to 60% of at least two recycled abrasive particles; 5 to 10 % of amorphous silica; 30 to 40% of sulphamic acid; 5 to7.5% of sodium lauryl sulphate; and 0 to 2% of cetyl trimethyl ammonium bromide. The descaled glass substrate after removal of scales exhibits a haze value of less than 1. In another aspect of the present disclosure, a process for descaling deposits on a glass substrate is disclosed. The process comprises the steps of, a) recovering abrasive particles from glass polishing waste; b) manually mixing the descaling composition ingredients with the recycled abrasive particles and water to form a paste; c) transferring the paste onto a cloth; d) spraying water on the surface of a substrate; e) uniformly applying the paste on the surface of the substrate using the cloth; f) scrubbing the surface of the substrate with the cloth for a period of 4 to 5 minutes; and g) rinsing the surface of the substrate with water to obtain a scale free substrate.

Other features and aspects of this disclosure will be apparent from the following description and the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

Embodiments are illustrated by way of example and are not limited in the accompanying figures.

FIG. 1 (a) illustrates images, of a mineral scale deposits on an uncoated glass, in accordance with one embodiment of the present disclosure.

FIG. 1 (b) illustrates images, of a mineral scale deposits on hydrophobic coated glass where the coating is worn out, in accordance with one embodiment of the present disclosure.

FIG. 1 (c) illustrates images, of an uncoated glass, cleaned with the descaling composition in accordance with one embodiment of the present disclosure. FIG. 1 (d) illustrates images, of hydrophobic coated glass where the coating is worn out, cleaned with the descaling composition in accordance with one embodiment of the present disclosure.

FIG. 2 represents the manual cleaning comparison of the inventive example 1 and comparative example 1 on an uncoated glass, using a non-woven scrubber, in accordance with one embodiment of the present disclosure.

FIG. 3 represents the automated cleaning comparison of the inventive example 1 and comparative example 1 on an uncoated glass, using a non-woven scrubber, in accordance with one embodiment of the present disclosure.

FIG. 4 represents the manual cleaning comparison of the inventive example 1 and comparative example 1 on hydrophobic coated glass where the coating is worn out, using a non-woven scrubber, in accordance with one embodiment of the present disclosure.

FIG. 5 represents the automated cleaning comparison of the inventive example 1 and comparative example 1 on hydrophobic coated glass where the coating is worn out, using a non-woven scrubber, in accordance with one embodiment of the present disclosure.

FIG. 6 represents the automated cleaning comparison of the inventive example 1 and comparative example 1 on an uncoated glass, using a micro-fiber cloth, in accordance with one embodiment of the present disclosure. FIG. 7 represents the automated cleaning comparison of the inventive example 1 and comparative example 1 on an uncoated glass, using a felt pad, in accordance with one embodiment of the present disclosure.

FIG. 8 represents the automated cleaning comparison of the inventive example 1 and comparative example 1 on hydrophobic coated glass where the coating is worn out, using a micro-fiber cloth, in accordance with one embodiment of the present disclosure.

FIG. 9 represents the automated cleaning comparison of the inventive example 1 and comparative example 1 on hydrophobic coated glass where the coating is worn out, using a felt pad, in accordance with one embodiment of the present disclosure.

FIG. 10 represents the automated cleaning comparison of the inventive example 1 and comparative example 2 on an uncoated glass, using a felt pad, in accordance with one embodiment of the present disclosure.

FIG. 11 represents the automated cleaning comparison of the inventive example 1 and comparative example 2 on hydrophobic coated glass where the coating is worn out, using a felt pad, in accordance with one embodiment of the present disclosure.

Skilled artisans appreciate that elements in the figures are illustrated for simplicity and clarity and have not necessarily been drawn to scale.

DETAILED DESCRIPTION

As used herein, in every embodiment, it must be understood that the term ‘scales’ or ‘scale deposits’, refers to deposits which are formed either by precipitation or crystal growth at a surface of the substrate, when in contact with water. Such scale deposits may include lime-scale, white chalk like substance, impurities precipitated out of water, etc.

The term ‘recycled’, as used herein, refers to converting the waste or used abrasive particles from glass polishing, into re-useable abrasive particles. The term ‘upcycling’ refers to re-using the recycled abrasive particles, in another product, i.e., descaling composition to derive value from the recycled abrasive particles.

The term ‘haze’, as used herein is well known to a person skilled in the art, that it refers to indicate the optical effect that is caused by the scattering of some of the light as it travels through a transparent substrate. The lower the haze value, higher is the optical clarity. The term ‘delta haze’, as used herein indicates the difference in the value of haze achieved for a descaled substrate, with respect to a reference glass of same thickness. The reference glass herein refers to an uncoated clear glass and hydrophobic coated glass with haze values of 0.3 and 0.5, respectively. The lower the delta haze value, higher is the optical clarity.

As used herein, and unless defined otherwise, the phrase ‘% by weight’ or ‘wt%’ is meant to denote % by weight of the total descaling composition. The present application provides a descaling composition for a glass substrate. Said descaling composition comprises by weight: 40 to 60% of at least two recycled abrasive particles; 5 to 10 % of amorphous silica; 30 to 40% of sulphamic acid; 5 to7.5% of sodium lauryl sulphate; and 0 to 2% of cetyl trimethyl ammonium bromide. The descaling composition in accordance with the present disclosure comprising the recycled abrasive particles is mixed with water to form a paste and applied onto a glass substrate to remove the scale deposits. Beneficially, the descaling composition in accordance with the present disclosure, enables efficient removal of hard-built up scales. Further, beneficially, and surprisingly the disclosed descaling composition displayed a haze value of less than 1 for a descaled substrate.

The abrasive particles are comprised, at least 40% by weight of the total composition, and range up to 60% by weight of the total composition. The recycled abrasive particles in accordance with the present disclosure comprise cerium oxide and aluminum oxide particles. In an embodiment of the present disclosure, the recycled cerium oxide is present in an amount ranging between 25 to 35 weight percentage of the total composition. In a preferred embodiment, the recycled cerium oxide is present in an amount ranging between 27.5 to 32.5 weight percentage of the total composition. In a further preferred embodiment the recycled cerium oxide is present in an amount of 30.5 weight percentage of the total composition. The cerium oxide particles display chemical-mechanical interaction with the glass substrate wherein a hydrated layer formed on the glass surface chemically interacts with hydroxide sites from cerium oxide. This aids in removal of surface silica carried away by cerium oxide particle, as cerium oxide is known for its stock removal property.

In an embodiment of the present disclosure, the recycled aluminum oxide is present in an amount ranging between 15 to 25 weight percentage of the total composition. In a preferred embodiment, the recycled aluminum oxide is present in an amount ranging between 17.5 to 22.5 weight percentage of the total composition. In a further preferred embodiment the recycled aluminum oxide is present in an amount of 21 weight percentage of the total composition. The aluminum oxide primarily acts as a hard abrasive to mechanically polish the surface of the substrate.

The scales formed due to hard water predominantly consist of carbonates of calcium and magnesium along with silica deposition. In removal of these scales from the surface of a glass substrate, both, cerium oxide and aluminum oxide recovered from the glass polishing waste predominantly act as mechanical abrader. Spent cerium oxide is less likely to continue having a chemical mechanical interaction with the glass surface. However, it can assist in removing organic matter like oil and grease. On the other hand, recycled aluminum oxide cleans the hard silica scales by mechanical abrasion owning to its higher Mohs hardness.

The disclosed abrasive particles in the present invention are primarily obtained from the industrial waste such as glass polishing slurries. Generally, for glass polishing, cerium oxide and aluminum oxide based slurries are used and are considered as a potential source of particulate abrasives. Because of the superior glass-polishing ability, cerium oxide and aluminum oxide are consumed in great quantities in manufacturing precise optics and other branches of the glass industry. These abrasive particles act as polishing agents and are used in the form of an aqueous suspension or slurry. As a result of mechanical crushing and chemical reactions, during glasspolishing process, the polishing agents or the abrasive particles referred in the present disclosure, gradually lose their efficiency and must therefore be replaced, or discarded without further exploitation for the same use.

The recovery of these abrasive particles comprising cerium oxide and aluminum oxide is performed using the known technology in the state of art, as described in US9309447B2 and various other articles. The abrasive waste discarded after glass polishing, is collected and organic matter which is used to maintain colloidal stability and preliminary screening of particles greater than 50 pm, is removed by filtration method. Further the recovered material is suspended and flocculated. The organic matter is further removed by filtration, post which the recovered solids are dried under room conditions or under forced drying conditions. As a final step the recovered abrasive particles are milled to attain desired particle size of 1 to 50 pm for D50 and less than or equal to 50 pm for D90. The recycled abrasive particles in accordance with the present disclosure essentially comprise a mixture of cerium oxide, aluminum oxide and calcium carbonate. Specifically, in an embodiment, the cerium oxide abrasive particles consist of cerium oxide and calcium carbonate. And in another embodiment, the aluminum oxide abrasive particles consist of aluminum oxide and calcium carbonate. The weight percentage of calcium carbonate present in these abrasive particles is up to 37% of the total composition. The particle size of the calcium carbonate present in the abrasive particles is in the range of 1 to 10 pm. In a preferred embodiment the average particle size of the calcium carbonate is 4 pm.

The recycled cerium oxide and aluminum oxide thus recovered from the glass polishing slurry, are mixed in a weight ratio ranging from 1.5: 1 to 2: 1. In a specific embodiment, the cerium oxide and aluminum oxide are mixed in a weight ratio ranging from 1.5: 1 to 1.75: 1. In a preferred embodiment the cerium oxide and aluminum oxide are mixed in a weight ratio of 1.5 : 1. The recycled abrasive particles in accordance with the present disclosure have an average particle size in the range of 1 to 50 pm. In a preferred embodiment the average particle size of the abrasive particle is 10 pm. The abrasive particles with a larger size of 30 to 50 pm act as scrubber while smaller sized abrasive particles of 2 to 10 pm, act as polisher to remove any residual scale or superficial scratches.

The descaling composition in accordance with the present disclosure comprises amorphous silica as an additional abrasive particulate in the descaling composition. The amorphous silica in an embodiment is present in the range of 5 to 10% by weight of the total composition. In a preferred embodiment, the amorphous silica is present in the range of 7 to 9% by weight of the total composition. In a most preferred embodiment the amorphous silica is present in an amount of 8% by weight of the total composition. The amorphous silica in accordance with the present disclosure has an average particle size in the range of 2 to 50 pm. In a preferred embodiment the average particle size of the abrasive particle is 27pm. In accordance with an embodiment of the present disclosure, the descaling composition comprises acids selected from the group consisting sulphamic acid, citric acid, oxalic acid, disodium phosphate, lactic acid. In a preferred embodiment the acid is sulphamic acid, which is present in the range of 30 to 40% by weight of the total composition. In a most preferred embodiment the sulphamic acid is present in an amount of 30% by weight of the total composition. In an alternate embodiment, in accordance with the present disclosure, instead of or in addition to sulphamic acid; di- or polycarboxylic acid for example, oxalic acid and citric acid or their combinations thereof can be used. The acids disclosed in accordance with the present disclosure have a pH between 0 and 3, preferably 2.5 or below, more, preferably at or below 2. Acids are essential to remove mineral scales developed on substrates. Acids chemically attack the mineral salts and convert them into water soluble compounds. For example, hydrochloric acid converts insoluble mineral carbonate into water soluble mineral chloride which can be easily removed. The preferred sulphamic acid in accordance with the present disclosure has two major advantages over citric acid which is most widely reported for lime-scale cleaning or removal. Firstly, sulphamic acid is not hygroscopic in nature, thereby limiting moisture absorption of powder formulation during storage. And secondly, it has higher capacity to dissolve calcium based lime-scales.

Furthermore, the descaling composition according to the present disclosure comprises a surfactant which is suitable to form a structured liquid with the acids. In an embodiment the surfactant is selected from the group consisting of anionic surfactants like sodium lauryl sulphate, sodium lauryl ether sulphate, sodium palmityl sulphate, sodium octyl sulphate, sodium n-dodecyl benzene sulphonate, 2-acrylamido-2- methylpropane sulfonic acid, phosphoric acid esters and carboxylic acid salts. In a preferred embodiment the surfactant is sodium lauryl sulphate which is present in the range of 5 to7.5% by weight of the total composition. In a most preferred embodiment the surfactant sodium lauryl sulphate is present in an amount of 6% by weight of the total composition. The anionic surfactants in the presence of water ionize and have a negative charged terminal groups. These negative terminal groups bind with positively charged particles. They are well suited to remove particulate soils, dirt and clay. They generally have higher frothing capacity which facilitates in flocculation and removal of particulates. In a further embodiment of the present disclosure, in addition to sodium lauryl sulphate, cationic surfactants like cetyl trimethyl ammonium bromide surfactant may or may not be present. In cases where the additional surfactant ammonium bromide surfactant is present, the weight percentage is in the range of 0.05 to 2 by weight of the total composition. The cationic surfactants have a positively charged group and are known for their antimicrobial activities.

The disclosed descaling composition comprises a viscosity modifier which functions as a thickening agent and is present in an amount ranging from 0 to 2 by weight of the total composition. The viscosity modifier is incorporated in the disclosed composition to adjust the viscosity of the paste to act as a gelling agent in the descaling composition. The viscosity modifier in an embodiment is selected from the group consisting of bentonite clay, attapulgite clay, precipitated calcium carbonate, fumed silica, methyl cellulose, hydroxypropyl methyl cellulose, and poly (ethylene oxide). In a preferred embodiment the viscosity modifier is bentonite clay. In a preferred embodiment the viscosity modifier is present in an amount of 1% by weight of the total composition. The bentonite clay is aluminium silicate from smectite family. It has a layered platelet structure with high surface area and high water absorption capacity and readily swell in presence of water giving a thickening effect. The viscosity modifier montmorillonite clay also functions as a thickener to achieve thick and consistent paste after addition of water to the descaling composition.

In accordance with the present disclosure, the descaling composition also comprises a wetting agent which functions to reduce the surface tension and ensure that the paste wets the surface of the glass substrate completely. The wetting agent is present in an amount ranging from 0 to 2 by weight of the total composition. The wetting agent also aids in dispersing the particulate powder in water to form paste with good consistency. The wetting agent in an embodiment, is selected from the group consisting of poly(vinylpyrrolidone), lauryl dimethyl amine oxide, ethoxylated lauryl alcohol, and ethoxylated steryl alcohol. In a preferred embodiment the wetting agent is poly (vinylpyrrolidone). The wetting agent poly(vinylpyrrolidone) facilitates complete wetting of the surface of the scaled substrate.

The descaling composition in accordance with the present disclosure is in the form a powder, is further mixed with water to form a consistent thick paste which can be easily applied over the scales surface of any substrate. In an embodiment the descaling composition is in the form of powder, can be mixed with water either in 1 : 1 parts or 3: 1 parts, depending on the severity of scale build-up. The disclosed descaling composition consists of powdered ingredients only. Unlike liquid lime-scale removers, where liquid (suspension) stability is critical during shelf-life, the disclosed descaling composition in the form of a powder is stable. As the liquid lime-scale removers in the form of liquid, tend to lose suspension integrity over a period of time due to liquid separation or settlement of abrasive particles from liquid medium. The powder-based descaling composition in accordance with the present disclosure do not display such behavior provided they have anti-caking property. Logistics and transportation is also easier for powders as they can be contained better than liquid. Transportation of powder is also cost effective as almost 50-70 % of weight in liquid based descaler is water while for powder based descaler, water is added on site. Additional advantage of powder based descaling composition is the flexibility to adjust the abrasive content based on severity of scale build-up by modifying the powder to water ratio. In present disclosure, presence of amorphous silica imparts anti-caking property to the powdered composition over extended time as well. It was surprisingly found by the inventors of the present application, that while using recycled abrasive particles as part of the scale removal composition, the heavily built up scales have been efficiently and effortlessly removed. This has been clearly achieved when the glass substrates post removal of scales have been measured for the haze values, which was found to be less than 1. It was surprisingly found that delta haze value, which is the difference in the haze of substrate after descaling and the original haze value of the substrate, which was found to be less than 0.5. The values obtained are way less than industrially acceptable criteria for haze value for reflective coated glass which is 1.5.

Further, using recycled abrasive particles comprising cerium oxide and aluminum oxide, has clearly gained an excellent economic significance, by providing descaling composition powder which is at least 41% cheaper than commercially available lime scale removal formulations in the market.

Further not only is the waste slurry (generated by glass manufacturing industry) being recovered and upcycled to get a cheaper and efficient product, additionally the disclosed descaling composition allows to recycle and use the abrasive particles. In one way, the cost involved in processing of waste coming from glass industry before disposal is also reduced. The waste disposal from glass polishing not only incurs cost but also a loss of valuable material which can otherwise be reused especially in such scale removal applications, ensuring surprising results by achieving efficient scale removal equivalent or even much higher than commercially available products, at a beneficially low price.

In another aspect of the present disclosure, a process for descaling deposits on a substrate is disclosed. The process in accordance with the present disclosure comprises the steps of a) recovering abrasive particles from glass polishing waste; b) manually mixing the powder ingredients of the disclosure, with the recycled abrasive particles and water in a ratio 1 : 1 to 3: 1, to form a paste; c) transferring the paste onto a cloth; d) spraying water on the surface of a substrate; e) uniformly applying the paste on the surface of the substrate using the cloth; f) scrubbing the surface of the substrate with the cloth for a period of 4 to 5 minutes; and g) rinsing the surface of the substrate with water to obtain a scale free substrate.

The disclosed abrasive particles which are recovered from the glass polishing waste, are manually mixed with the remaining ingredients of the descaling composition in accordance with the present disclosure. The mixing of all the powdered ingredients is done manually, using tumble blender or high speed powder mixer, known to an ordinary person in the art.

The descaling composition, for example, in the form of paste is formed by adding water either in 1 :1 equivalent parts or 3:1 parts, depending on the severity of scale build-up on the surface of the glass substrate that is to be cleaned. The formed paste is applied on to the substrate manually, using an applicator made up of either felt pad, micro-fiber cloth or non-woven scrubber. Before the application of the formed thick consistent paste onto the glass substrate, the substrate is pre-washed and thoroughly pre-wetted by spraying water on the surface of the substrate. The paste is uniformly applied on the surface of the substrate using either a felt pad or micro-fiber cloth or a non-woven scrubber in accordance with multiple embodiments of the present disclosure and scrubbed for a period of 4 to 5 minutes. Alternatively, in another embodiment, automated buffing machine with appropriate buffing pads can also be used for cleaning.

The process disclosed in accordance with the present invention, further comprises rinsing the surface of the substrate with water to obtain a scale free substrate. This process can be repeated by reapplying the paste and rinsing the surface of the substrate with water, to obtain scale free surface.

Post the application of the descaling composition in the form of a paste on the substrate and rinsing thoroughly, it has been surprisingly observed by the inventors of the present disclosure, that the scale deposit removal is higher than what is achieved by using a commercially available product. The inventive aspect of the present disclosure is attributed to the presence of the recycled abrasive particles comprising cerium oxide and aluminum oxide which are recovered from glass polishing waste. Although the scope of the substrate in accordance with the present disclosure is a glass, in alternate embodiments the substrate is not limited to, a wood, metal, ceramic, plywood, laminates, mirror, lacquered glass, colored glass, tinted glass, patterned glass or a tempered glass.

In accordance with the present disclosure, the descaled substrate has been subjected to detect the haze value and it has been surprising found by the inventors, the haze value as less as 1 which is considered to be industrially acceptable. Also the delta haze of the glass substrate has been measured, and is found to be consistently less than or equal to 0.5.

Thus, the descaling composition formed as per the present invention, is beneficial in ways, that it helps the consumer to achieve equivalent or at par or in some instance even higher removal of scale deposits from the surface of a substrate at a cheaper value, thereby gaining economic significance.

EXAMPLES

Inventive Example 1 Table 1 discloses a descaling composition according to an inventive Example 1 :

Table 1

The above disclosed, descaling composition was used to remove the scale deposits from a surface, by following the below steps:

1. manually mixing the powder ingredients of the disclosure, with the recycled abrasive particles and water in a ratio 1.25: 1.

2. transferring the paste onto a cloth, or non-woven scrubber or felt pad.

3. spraying water on the surface of a substrate.

4. uniformly applying the paste on the surface of the substrate using the cloth.

5. scrubbing the surface of the substrate with the non-woven scrubber for a period of 5 minutes; and

6. rinsing the surface of the substrate with water to obtain a scale free substrate.

Comparative Example 1 Table 2 discloses a descaling composition according to comparative Example 1 (commercially available):

Table 2

The above disclosed, descaling composition in table 1, after application on the glass substrate and descaling, was then tested for the following to evaluate the efficient removal of scale deposits:

Cleaning Performance Evaluation against Comparative example 1 :

With increase in mineral scale deposition, the optical clarity of clear glass reduces. In other words, the haze increases. To evaluate the effect of cleanability, haze value measurement was carried out before cleaning and after cleaning using mineral scale remover as per the Inventive Example 1 and Comparative example 1.

To evaluate the cleaning efficiency, two methods have been used viz. manual cleaning method and automated cleaning using Taber abrasion instrument. The inventive and comparative samples were used against uncoated glass and a glass which has been coated with hydrophobic coating (worn out over a period of time).

Manual Cleaning: 5 Manual scrubbing was carried out using non-woven scrubber pad. Pressure applied during cleaning may not be uniform across the surface due to manual variability. To minimize this variation, scrubbing was carried out for 5 min by having rotational hand motion on glass surface.

10 Automated Cleaning:

Automated taber abrasion tester was used to evaluate the cleaning efficiency of mineral scale remover using 425g load and with three different tools, i.e. non-abrasive nonwoven pad, micro-fiber cloth and Hl felt pad. It was observed that all three tools were efficient in cleaning the mineral deposits and are at par with commercially available

15 product or comparative example 1. This confirms that mineral scale remover is an efficient cleaner irrespective of the cleaning method.

Table 3 as produced below discloses the delta haze values after cleaning the scaled glasses.

20 Table 3

It was clearly observed from various graphical representations from FIG. 2 to 9, that the descaling composition in accordance with the present disclosure has shown significantly at par or even higher removal of scale deposits from glass substrates, which is in turn shown by the less haze value which is industrially acceptable. Lesser the haze and delta haze value of the descaled substrate, it indicates the acceptable optical clarity of glass. This in turn indicates the improved aesthetics and also gaining end user satisfaction. The results indicate that the delta haze value is at par over the commercially available products, when recovered abrasive particles were used in the inventive example. And also the descaling composition comprising such recycled abrasive particles is as cheap as 1.7 times over the commercially available products. The delta haze values achieved were consistently less than or equal to 0.5 for the descaled substrate, thereby making the glass optically clear.

Comparative Example 2:

Table 4 discloses a descaling composition according to comparative Example 2 which uses non-recycled abrasive particles:

Table 4

The sample prepared in accordance with the comparative example 2 was also applied in the form of a paste to descale the uncoated glass and hydrophobic coating worn out glass and was tested for both manual cleaning and automated cleaning, as shown in FIG. 10.

It was clearly observed from various graphical representations from FIG. 10 to 11, that the descaling composition in accordance with the present disclosure, that the effect on cleaning efficiency based on use of recycled material has achieved a haze value of less than 1 (which is industrially acceptable) for non-woven scrubber used for manual and automated cleaning, while felt pad has been used in automated cleaning. Lesser the haze and delta haze value of the descaled substrate, it indicates the acceptable optical clarity of glass. This in turn indicates the improved aesthetics and also gaining end user satisfaction. The results indicate that the delta haze value is at par over the commercially available products, when recovered abrasive particles were used in the inventive example. And also the descaling composition comprising such recycled abrasive particles is as cheap as 1.4 times over the commercially available products.

Following table summarizes the delta haze value achieved for the manual and automated cleaning performed using nonwoven scrubber, and felt pad, post removal of scale deposits on uncoated glass and hydrophobic coated glass worn out.

Table 5 as produced below discloses the delta haze values after cleaning the scaled glasses. Table 5

It is evident that the delta haze values were consistently less than or equal to 0.5 post cleaning. This makes the glass optically clear, thereby improving aesthetics and end 10 user satisfaction.

INDUSTRIAL APPLICABILITY

Thus from the above inventive and comparative examples, the descaling composition of the present disclosure is very unique with significantly improved optical clarity, by 15 ensuring the scale deposits are efficiently removed. The descaling composition achieved same or higher scale removals, at a cheaper price, thereby making it economically viable for end users and suitable for various cleaning applications. Specifically, the disclosed sealant is preferred for cleaning glass substrates in wet environment, mineral scale removal from metallic surfaces, cleaning outdoor glass 20 balustrades, cleaning glass top of dining tables and the like.

Note that not all of the activities described above in the general description or the examples are required, that a portion of a specific activity may not be required, and that one or more further activities may be performed in addition to those described. Still further, the order in which activities are listed is not necessarily the order in which they are performed.

Benefits, other advantages, and solutions to problems have been described above with regard to specific embodiments. However, the benefits, advantages, solutions to problems, and any feature(s) that may cause any benefit, advantage, or solution to occur or become more pronounced are not to be construed as a critical, required, or essential feature of any or all the claims.

The specification and illustrations of the embodiments described herein are intended to provide a general understanding of the structure of the various embodiments. The specification and illustrations are not intended to serve as an exhaustive and comprehensive description of all of the elements and features of apparatus and systems that use the structures or methods described herein. Certain features, that are for clarity, described herein in the context of separate embodiments, may also be provided in combination in a single embodiment. Conversely, various features that are, for brevity, described in the context of a single embodiment, may also be provided separately or in a sub combination. Further, reference to values stated in ranges includes each and every value within that range. Many other embodiments may be apparent to skilled artisans only after reading this specification. Other embodiments may be used and derived from the disclosure, such that a structural substitution, logical substitution, or another change may be made without departing from the scope of the disclosure. Accordingly, the disclosure is to be regarded as illustrative rather than restrictive.

The description in combination with the figures is provided to assist in understanding the teachings disclosed herein, is provided to assist in describing the teachings, and should not be interpreted as a limitation on the scope or applicability of the teachings. However, other teachings can certainly be used in this application.

As used herein, the terms "comprises," "comprising," "includes," "including," "has," "having" or any other variation thereof, are intended to cover a non-exclusive inclusion.

Also, the use of "a" or "an" is employed to describe elements and components described herein. This is done merely for convenience and to give a general sense of the scope of the invention. This description should be read to include one or at least one and the singular also includes the plural, or vice versa, unless it is clear that it is meant otherwise. For example, when a single item is described herein, more than one item may be used in place of a single item. Similarly, where more than one item is described herein, a single item may be substituted for that more than one item.

Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. The materials, methods, and examples are illustrative only and not intended to be limiting. To the extent that certain details regarding specific materials and processing acts are not described, such details may include conventional approaches, which may be found in reference books and other sources within the manufacturing arts.

While aspects of the present disclosure have been particularly shown and described with reference to the embodiments above, it will be understood by those skilled in the art that various additional embodiments may be contemplated by the modification of the disclosed machines, systems and methods without departing from the spirit and scope of what is disclosed. Such embodiments should be understood to fall within the 5 scope of the present disclosure as determined based upon the claims and any equivalents thereof.

Reference Numerals:

1. Manually cleaned zone

2. Cleaned using non-woven pad

3. Cleaned using micro-fiber cloth

4. Cleaned using felt pad 5. Uncleaned zone

Claims

We Claim:

1) A descaling composition for a glass substrate, the composition comprising, by weight:

40 to 60% of at least two recycled abrasive particles;

5 to 10 % of amorphous silica;

30 to 40% of sulphamic acid;

5 to7.5% of sodium lauryl sulphate; and

0 to 2% of cetyl trimethyl ammonium bromide, characterized in that the descaled glass substrate exhibits a haze value of less than 1.

2) The descaling composition as claimed in claim 1 , wherein the recycled abrasive particles comprise cerium oxide and aluminum oxide.

3) The descaling composition as claimed in any of the preceding claims, wherein the recycled abrasive particles is obtained from glass polishing slurries.

4) The descaling composition as claimed in any of the preceding claims, wherein the recycled cerium oxide is present in an amount ranging between 25 to 35 weight percentage of the total composition.

5) The descaling composition as claimed in in any of the preceding claims, wherein the recycled aluminum oxide is present in an amount ranging between 15 to 25 weight percentage of the total composition.

6) The descaling composition as claimed in in any of the preceding claims, wherein the cerium oxide and aluminum oxide are mixed in a weight ratio of 1.5: 1 to 2:1.

28 ) The descaling composition as claimed in in any of the preceding claims, wherein the average particle size of the recycled abrasive particles is in the range of 1 to 50 pm. ) The descaling composition as claimed in claim 1 further comprises a viscosity modifier selected from the group consisting of montmorillonite methyl cellulose, hydroxypropyl methyl cellulose and poly (ethylene oxide). ) The descaling composition as claimed in claim 1 further comprises a wetting agent selected from the group consisting of poly(vinylpyrrolidone), lauryl dimethyl amine oxide, ethoxylated lauryl alcohol and ethoxylated steryl alcohol. 0) The descaling composition as claimed in in any of the preceding claims, wherein the recycled cerium oxide essentially consists of a mixture of cerium oxide and calcium carbonate. 1) The descaling composition as claimed in in any of the preceding claims, wherein the recycled aluminum oxide essentially consists of a mixture of aluminum oxide and calcium carbonate. 2) The descaling composition as claimed in claim 1 is in the form of a powder. 3) The descaling composition as claimed in in any of the preceding claims wherein delta haze of the descaled substrate is less than or equal to 0.5. 4) A process for descaling deposits on a substrate, the process comprising the steps of: i. recovering abrasive particles from glass polishing waste; ii. manually mixing the ingredients as claimed in claim 1, with the recycled abrasive particles and water in a ratio 1 : 1 to 3: 1 to form a paste; iii. transferring the paste onto a cloth; iv. spraying water on the surface of a substrate; v. uniformly applying the paste on the surface of the substrate using the cloth; vi. scrubbing the surface of the substrate with the cloth for a period of 4 to 5 minutes; and vii. rinsing the surface of the substrate with water to obtain a scale free substrate. ) The process as claimed in claim 14 further comprises reapplying the paste and rinsing with water to remove heavily built up scales.