DESC:FIELD
The present disclosure relates to a primer composition and a process for its preparation. Particularly, the present disclosure relates to the primer composition based on a paint sludge.
DEFINITIONS
As used in the present disclosure, the following terms are generally intended to have the meaning as set forth below, except to the extent that the context in which they are used indicates otherwise.
Washing solvent refers to the solvent mixture used for cleaning and flushing the paint processing equipment.
Paint sludge refers to the low to high viscosity leftover material of the paint composition after distillation of the washing solvents. It is also often referred to as “distillation sludge”.
Non-volatile matter (NVM) refers to the solid or liquid components of a substance that remain after volatile elements have evaporated. The non-volatile matter constitutes the portion of a substance that does not readily evaporate and is vital for a range of applications.
Alkyd resin refers to a polyester modified by the addition of fatty acids and optionally by other components. Alkyd resins combine the properties of both oil-based resins and polyester resins. Alkyd resins are made by reacting polyhydric alcohols (like glycerol or pentaerythritol) with dicarboxylic acids or anhydrides.
Through driers, refer to driers that ensure the drying of a coating at a uniform rate throughout the film thickness.
HG finish refers to the “high gloss” in the context of paint, indicating a shiny and reflective finish.
Stainer refers to the tint or colorant that is added to the paint to match the shade to the standard shade panel, reference paint sample, or master paint sample.
Functional pigment refers to a type of pigment that not only imparts colour to paint but also provides a specific function to paint such as anti-corrosion, flame retardant, glow-in-dark, and the like.
C9 solvent refers to the solvent used in paint to obtain the desired viscosity.
BACKGROUND
The background information hereinbelow relates to the present disclosure but is not necessarily prior art.
During the preparation of paint composition, several equipments’ such as high speed dispenser (HSD), twin shaft disperser (TSD), sand mill, ball mill, trolleys, and the like can be used. These equipments after preparation of the paint compositions are cleaned by using a solvent or solvent mixtures. These solvents for cleaning and flushing purposes include mineral turpentine oil (MTO), Xylene, distilled C9 solvent, and the like. These solvents for cleaning are used for multiple washings; hence, these solvents become dirty and contain a significant amount of paint residue. The solvent mixture with paint residue was distilled to recover the solvent. The left-over solvent mixture contains a high amount of solid content which is known as paint sludge. The viscosity of this paint sludge will vary from low to high viscosity depending upon the extent of distillation.
The paint sludge has significant solid content that cannot be directly disposed of in the environment. The paint sludge is disposed of by subjecting it to incineration. The process of incineration requires the consumption of additional fuel and energy resulting in an increase in the carbon footprint and incurs extra cost.
There is, therefore, felt a need to provide a primer composition that mitigates the aforestated drawbacks or at least provides an alternative solution for putting the paint sludge to a useful purpose.
OBJECTS
Some of the objects of the present disclosure, which at least one embodiment herein satisfies, are as follows.
An object of the present disclosure is to ameliorate one or more problems of the prior art or to at least provide a useful alternative.
Another object of the present disclosure is to provide a primer composition.
Yet another object of the present disclosure is to provide a primer composition comprising a paint sludge.
Yet another object of the present disclosure is to provide a primer composition, which is anti-corrosive and provides adhesion to the paint.
Still another object of the present disclosure is to provide a process for the preparation of a primer composition.
Still another object of the present disclosure is to provide a process for the preparation of a primer composition that is sustainable, economical, and environment friendly.
Other objects and advantages of the present disclosure will be more apparent from the following description, which is not intended to limit the scope of the present disclosure.
SUMMARY
The present disclosure relates to a primer composition and a process for its preparation. In an aspect, the primer composition comprising a) a paint sludge in an amount in the range of 30 mass% to 45 mass% with respect to the total mass of the composition; b) at least one binder in an amount in the range of 12 mass% to 20 mass% with respect to the total mass of the composition; c) at least one fluid medium in an amount in the range of 0 mass% to 6 mass% with respect to the total mass of the composition; d) at least one pigment in an amount in the range of 13 mass% to 25 mass% with respect to the total mass of the composition; e) at least one filler in an amount in the range of 25 mass% to 35 mass% with respect to the total mass of the composition; and f) at least one additive in an amount in the range of 0.5 mass% to 5 mass% with respect to the total mass of the composition.
In an embodiment of the present disclosure, the paint sludge is characterized by having a non-volatile matter (NVM) in the range of 15% to 50%; a viscosity in the range of 10 seconds to 100 seconds as measured by B4 Ford cup viscometer (FCB4) at 30° C; weight per liter is in the range of 0. 85 to 1.1 Kg/Litre; and finish on HG in the range of 0 to 2.
In an embodiment of the present disclosure, the binder is at least one selected from the group consisting of alkyd resin, and PU modified alkyd resin.
In an embodiment of the present disclosure, the alkyd resin is at least one selected from the group consisting of soya alkyd, soya dehydrated castor seed oil (DCO) alkyd resin, and linseed alkyd resin.
In an embodiment of the present disclosure, the fluid medium is at least one selected from the group consisting of mineral turpentine oil (MTO), distilled C9 solvent, and xylene.
In an embodiment of the present disclosure, the pigment is at least one selected from the group consisting of red pigment of ferric oxide, red iron oxide, and synthetic red iron oxide.
In an embodiment of the present disclosure, the filler is at least one selected from the group consisting of dolomite, china clay, calcium carbonate, and talc.
In an embodiment of the present disclosure, the additive is at least one selected from the group consisting of a wetting agent, a thixotropic agent, a functional pigment, a drier, an anti-skinning agent, and a stainer.
In an embodiment of the present disclosure, wherein additive in the composition comprises a) the wetting agent in an amount in the range of 0.1 mass% to 1 mass% with respect to the total mass of the composition; b) the thixotropic agent in an amount in the range of 0.1 mass% to 0.5 mass% with respect to the total mass of the composition; c) the functional pigment in an amount in the range of 0.1 mass% to 0.3 mass% with respect to the total mass of the composition; d) the drier in an amount in the range of 0.3 mass% to 0.5 mass% with respect to the total mass of the composition; e) the anti-skinning agent in the range of 0.1 mass% to 0.3 mass% with respect to the total mass of the composition; and f) the stainer in the range of 0 mass% to 1 mass% with respect to the total mass of the composition.
In an embodiment of the present disclosure, the wetting agent is at least one selected from the group consisting of lecithin, soya lecithin, and sorbitan trioleate (span 85).
In an embodiment of the present disclosure, the thixotropic agent is at least one selected from the group consisting of bentonite clay and hectorite clay.
In an embodiment of the present disclosure, the functional pigment is at least one selected from the group consisting of white seal zinc oxide, zinc phosphate, and aluminium trihydrate.
In an embodiment of the present disclosure, the drier is at least one selected from the group consisting of a surface drier, an auxiliary drier, and a through drier.
In an embodiment of the present disclosure, the surface drier is at least one selected from the group consisting of cobalt octoate and manganese octoate; the through drier is at least one selected from the group consisting of zirconium octoate and strontium octoate; and the auxiliary drier is at least one selected from the group consisting of calcium octoate and zinc octoate.
In an embodiment of the present disclosure, the anti-skinning agent is methyl ethyl ketoxime.
In an embodiment of the present disclosure, the stainer is at least one selected from the group consisting of persian gulf red oxide, and red oxide.
In an embodiment of the present disclosure, the mass ratio of the paint sludge to the binder is in the range of 1.5:1 to 4:1.
In an embodiment of the present disclosure, the primer composition is characterized by having a viscosity in the range of 60 to 120 Krebs Unit (KU), weight in the range of 13 kg/10 liter to 14.5 kg/10 liter; and finish on HG is in the range of 0 to 2.
In another aspect, the process for the preparation of the primer composition comprising the steps of blending a first portion of paint sludge, a first portion of at least one binder, and a first portion of at least one additive at a speed in the range of 1500 rpm to 2500 rpm for a first predetermined time period to obtain a first mixture. To the first mixture, a second portion of at least one additive, a predetermined amount of a pigment, and a predetermined amount of filler were added and blended at a speed in the range of 1500 rpm to 2500 rpm for a second predetermined time period to obtain a second mixture. A second portion of the binder and a second portion of the paint sludge are added to the second mixture and blended at a speed in the range of 700 rpm to 800¬¬¬¬ rpm for a third predetermined time period to obtain a third mixture. A third portion of the paint sludge, a predetermined amount of a fluid medium, and a third portion of the additive are added to the third mixture and blended at a speed in the range of 700 rpm to 800 rpm for a fourth predetermined time period to obtain a fourth mixture. A fourth portion of the additive is optionally added to the fourth mixture and blended at a speed in the range of 700 rpm to 800 rpm to obtain a fifth mixture. Further, the fourth portion of the paint sludge and a third portion of the binder are optionally blended with the fifth mixture at a speed in the range of 700 rpm to 800 rpm to obtain the primer composition.
In an embodiment of the present disclosure, the viscosity of the fourth mixture is in the range of 60 to 120 Krebs Unit (KU); and the finish on HG of the second mixture and the third mixture are independently in the range of 0 to 2.
In an embodiment of the present disclosure, the paint sludge is characterized by having a non-volatile matter (NVM) in the range of 15% to 50%; a viscosity in the range of 10 seconds to 100 seconds as measured by B4 Ford cup viscometer (FCB4) at 30° C; weight per liter in the range of 0. 85 to 1.1 Kg/L; and finish on HG in the range of 0 to 2.
In an embodiment of the present disclosure, the binder is at least one selected from the group consisting of an alkyd resin, and PU modified alkyd resin.
In an embodiment of the present disclosure, the alkyd resin is at least one selected from the group consisting of soya alkyd, soya dehydrated castor seed oil (DCO) alkyd resin, and linseed alkyd resin.
In an embodiment of the present disclosure, pigment is at least one selected from the group consisting of red pigment of ferric oxide, red iron oxides, and synthetic red iron oxide.
In an embodiment of the present disclosure, the first portion of the additive comprises a wetting agent, the second portion of the additive comprises a thixotropic agent, and a functional pigment, the third portion of the additive comprises driers and an anti-skinning agent, the fourth portion of additive comprises a stainer.
In an embodiment of the present disclosure, the wetting agent is at least one selected from the group consisting of lecithin, soya lecithin, and sorbitan trioleate.
In an embodiment of the present disclosure, the thixotropic agent is at least one selected from the group consisting of bentonite clay and hectorite clay.
In an embodiment of the present disclosure, the filler is at least one selected from the group consisting of dolomite, china clay, calcium carbonate, and talc.
In an embodiment of the present disclosure, the functional pigment is at least one selected from the group consisting of white seal zinc oxide, zinc phosphate, and aluminium trihydrate.
In an embodiment of the present disclosure, the drier is at least one selected from the group consisting of a surface drier, an auxiliary drier, and a through drier.
In an embodiment of the present disclosure, the surface drier is at least one selected from the group consisting of cobalt octoate, and manganese octoate; the through drier is at least one selected from the group consisting of zirconium octoate and strontium octoate; and the auxiliary drier is at least one selected from the group consisting of calcium octoate and zinc octoate.
In an embodiment of the present disclosure, the anti-skinning agent is methyl ethyl ketoxime.
In an embodiment of the present disclosure, the stainer is at least one selected from the group consisting of persian gulf red oxide, and red oxide.
In an embodiment of the present disclosure, the primer composition is prepared at a temperature in the range of 20°C to 60°C.
In an embodiment of the present disclosure, the first predetermined time period is in the range of 5 minutes to 15 minutes.
In an embodiment of the present disclosure, the second predetermined time period is in the range of 30 minutes to 150 minutes.
In an embodiment of the present disclosure, the third predetermined time period is in the range of 10 minutes to 25 minutes.
In an embodiment of the present disclosure, the fourth predetermined time period is in the range of 10 minutes to 25 minutes.
In an embodiment of the present disclosure, the first portion of the binder is in the range of 70 mass% to 80 mass%; the second portion of the binder is in the range of 5 mass% to 15 mass%; and the third portion of the binder is in the range of 10 mass% to 20 mass% with respect to the total mass of the binder.
In an embodiment of the present disclosure, the first portion of the paint sludge is in the range of 40 mass% to 50 mass%; the second portion of the paint sludge is in the range of 5 mass% to 15 mass%; the third portion of the paint sludge is in the range of 35 mass% to 45 mass%; and the fourth portion of the paint sludge is in the range of 5 mass% to 10 mass% with respect to the total mass of the paint sludge.
In an embodiment of the present disclosure, the fluid medium is at least one selected from the group consisting of mineral turpentine oil (MTO), distilled C9 solvent, and xylene.
BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWING

The present disclosure will now be described with the help of the accompanying drawing, in which:
Figure 1 illustrates a figure depicting the top coat adhesion on the primer composition of the present disclosure.
DETAILED DESCRIPTION
The present disclosure relates to a primer composition and a process for its preparation. Particularly, the present disclosure relates to the primer composition based on paint sludge.
Embodiments, of the present disclosure, will now be described with reference to the accompanying drawing.
Embodiments are provided so as to thoroughly and fully convey the scope of the present disclosure to the person skilled in the art. Numerous details are set forth, relating to specific components, and methods, to provide a complete understanding of embodiments of the present disclosure. It will be apparent to the person skilled in the art that the details provided in the embodiments should not be construed to limit the scope of the present disclosure. In some embodiments, well-known processes, well-known apparatus structures, and well-known techniques are not described in detail.
The terminology used, in the present disclosure, is only for the purpose of explaining a particular embodiment and such terminology shall not be considered to limit the scope of the present disclosure. As used in the present disclosure, the forms "a,” "an," and "the" may be intended to include the plural forms as well, unless the context clearly suggests otherwise. The terms "comprises," "comprising," “including,” and “having,” are open ended transitional phrases and therefore specify the presence of stated features, integers, steps, operations, elements, modules, units and/or components, but do not forbid the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof. The particular order of steps disclosed in the method and process of the present disclosure is not to be construed as necessarily requiring their performance as described or illustrated. It is also to be understood that additional or alternative steps may be employed.
As used herein, the term "and/or" includes any and all combinations of one or more of the associated listed elements.
The terms first, second, third, etc., should not be construed to limit the scope of the present disclosure as the terms may be only used to distinguish one element, component, region, layer or section from another component, region, layer or section. Terms such as first, second, third etc., when used herein do not imply a specific sequence or order unless clearly suggested by the present disclosure.
During the preparation of paint composition, several equipments such as high speed dispenser (HSD), twin shaft disperser (TSD), sand mill, ball mill, trolleys, and the like can be used. These equipments after preparation of the paint compositions are cleaned by using a solvent or solvent mixtures. These solvents for cleaning and flushing purposes include mineral turpentine oil (MTO), xylene, distilled C9 solvent, and the like. These solvents for cleaning are used for multiple washings; hence, these solvents become dirty and contain a significant amount of paint residue. The solvent mixture with paint residue was distilled to recover the solvent. The left-over solvent mixture contains a high amount of solid content that is known as paint sludge. The viscosity of this paint sludge will vary from low to high viscosity depending upon the extent of distillation.
The paint sludge has significant solid content that cannot be directly disposed of in the environment. The paint sludge is disposed of by subjecting it to incineration. The process of incineration requires the consumption of additional fuel and energy resulting in an increase in the carbon footprint and incurs extra cost.
The present disclosure provides a primer composition and a process for the preparation of a primer composition.
In an aspect of the present disclosure, there is provided a primer composition.
The primer composition comprises a) a paint sludge in an amount in the range of 30 mass% to 45 mass% with respect to the total mass of the composition; b) at least one binder in an amount in the range of 12 mass% to 20 mass% with respect to the total mass of the composition; c) at least one fluid medium in an amount in the range of 0 mass% to 6 mass% with respect to the total mass of the composition; d) at least one pigment in an amount in the range of 13 mass% to 25 mass% with respect to the total mass of the composition; e) at least one filler in an amount in the range of 25 mass% to 35 mass% with respect to the total mass of the composition; and f) at least one additive in an amount in the range of 0.5 mass% to 5 mass% with respect to the total mass of the composition.
In an embodiment of the present disclosure, the paint sludge is characterized by having a non-volatile matter (NVM) in the range of 15% to 50%; a viscosity in the range of 10 seconds to 100 seconds as measured by B4 Ford cup viscometer (FCB4) at 30° C; weight per liter is in the range of 0. 85 to 1.1 Kg/Litre; and finish on HG is in the range of 0 to 2.
In an exemplary embodiment, the paint sludge is present in an amount of 40.50 mass% with respect to the total mass of the composition. In another exemplary embodiment, the paint sludge is present in an amount of 35.50 mass% with respect to the total mass of the composition. In yet another exemplary embodiment, the paint sludge is present in an amount of 30.5 mass% with respect to the total mass of the composition.
In an embodiment of the present disclosure, the binder is at least one selected from the group consisting of alkyd resin, and PU modified alkyd resin.
In an embodiment of the present disclosure, the alkyd resin is at least one selected from the group consisting of soya alkyd, soya dehydrated castor seed oil (DCO) alkyd, and linseed alkyd. In an exemplary embodiment, the alkyd resin is 60% soya dehydrated castor seed oil (DCO) alkyd.
In an embodiment of the present disclosure, the binder acts as a film-forming agent.
In an exemplary embodiment, the binder is present in an amount of 13.70 mass% with respect to the total mass of the composition. In another exemplary embodiment, the binder is present in an amount of 16.2 mass% with respect to the total mass of the composition. In yet another exemplary embodiment, the binder is present in an amount of 18.7 mass% with respect to the total mass of the composition.
In an embodiment of the present disclosure, the fluid medium is at least one selected from the group consisting of mineral turpentine oil (MTO), distilled C9 solvent, and xylene. In an exemplary embodiment, the fluid medium is mineral turpentine oil (MTO).
In an exemplary embodiment, the fluid medium is present in an amount of 2.5 mass% with respect to the total mass of the composition. In another exemplary embodiment, the fluid medium is present in an amount of 5 mass% with respect to the total mass of the composition.
In an embodiment of the present disclosure, the pigment is at least one selected from the group consisting of red pigment of ferric oxide, red iron oxide, and synthetic red iron oxide. In an exemplary embodiment, the pigment is the synthetic red iron oxide.
In an embodiment of the present disclosure, the pigment imparts colour to the composition.
In an exemplary embodiment, the pigment is present in an amount of 15.75 mass% with respect to the total mass of the composition.
In an embodiment of the present disclosure, the filler is at least one selected from the group consisting of dolomite, china clay, calcium carbonate, and talc. In an exemplary embodiment of the present disclosure, the filler is a combination of dolomite and china clay.
In an exemplary embodiment of the present disclosure, the filler is present in an amount of 27.75 mass% with respect to the total mass of the composition.
In an embodiment of the present disclosure, the additive is at least one selected from the group consisting of a wetting agent, a thixotropic agent, a functional pigment, a drier, an anti-skinning agent, and a stainer.
In an exemplary embodiment of the present disclosure, the additive is present in an amount of 2.3 mass% with respect to the total mass of the composition.
In an embodiment of the present disclosure, the wetting agent is at least one selected from the group consisting of lecithin, soyalecithin, and sorbitan trioleate (span 85). In an exemplary embodiment of the present disclosure, the wetting agent is soyalecithin and sorbitan trioleate (Span 85).
In an embodiment of the present disclosure, the wetting agent also acts as an emulsifier.
In an embodiment of the present disclosure, the wetting agent is in an amount in the range of 0.1 mass% to 1 mass% with respect to the total mass of the composition. In an exemplary embodiment of the present disclosure, the wetting agent is present in an amount of 0.75 mass% with respect to the total mass of the composition.
In an embodiment of the present disclosure, the thixotropic agent is at least one selected from the group consisting of bentonite clay, and hectorite clay. In an exemplary embodiment of the present disclosure, the thixotropic agent is bentonite clay.
In an embodiment of the present disclosure, the thixotropic agent is in an amount in the range of 0.1 mass% to 0.5 mass% with respect to the total mass of the composition. In an exemplary embodiment of the present disclosure, the thixotropic agent is present in an amount of 0.3 mass% with respect to the total mass of the composition.
In an embodiment of the present disclosure, the thixotropic agent also acts as an anti-settling agent.
In an embodiment of the present disclosure, the thixotropic agent imparts rheological properties to the composition, thereby, increasing the viscosity of the composition. They also reduce the sagging of the coatings on the substrate.
In an embodiment of the present disclosure, the functional pigment is at least one selected from the group consisting of white seal zinc oxide, zinc phosphate, and aluminium trihydrate. In an exemplary embodiment, the functional pigment is white seal zinc oxide.
The functional pigment is in an amount in the range of 0.1 mass% to 0.3 mass% with respect to the total mass of the composition. In an exemplary embodiment of the present disclosure, the functional pigment is present in an amount of 0.2 mass% with respect to the total mass of the composition.
In an exemplary embodiment of the present disclosure, the drier is at least one selected from the group consisting of a surface drier, an auxiliary drier, and a through drier.
In an embodiment of the present disclosure, the surface drier is at least one selected from the group consisting of cobalt octoate, and manganese octoate; the through drier is at least one selected from the group consisting of zirconium octoate and strontium octoate; and the auxiliary drier is at least one selected from the group consisting of calcium octoate and zinc octoate. In an exemplary embodiment, the surface drier is cobalt octate, the through drier is zirconium octate, and auxiliary drier is calcium octate.
In an embodiment of the present disclosure, the through drier ensures drying of the underneath coated surface. Further, the through driers ensure that a coating dries at a uniform rate throughout the film thickness.
In an embodiment of the present disclosure, the drier is in an amount in the range of 0.3 mass% to 0.5 mass% with respect to the total mass of the composition. In an exemplary embodiment of the present disclosure, the amount of driers is present in an amount of 0.35 mass% with respect to the total mass of the composition. In an exemplary embodiment of the present disclosure, the amount of the surface drier is present in an amount of 0.04 mass% with respect to the total mass of the composition. In an exemplary embodiment of the present disclosure, the amount of the auxiliary drier is present in an amount of 0.17 mass% with respect to the total mass of the composition. In an exemplary embodiment of the present disclosure, the amount of the through drier is present in an amount of 0.14 mass% with respect to the total mass of the composition.
In an embodiment of the present disclosure, the anti-skinning agent is methyl ethyl ketoxime (MEK Oxime).
In an embodiment of the present disclosure, the anti-skinning agent is in an amount in the range of 0.1 mass% to 0.3 mass% with respect to the total mass of the composition. In an exemplary embodiment of the present disclosure, the amount of anti-skinning agent is present in an amount of 0.2 mass% with respect to the total mass of the composition.
In an embodiment of the present disclosure, the stainer is at least one selected from the group consisting of persian gulf red oxide, and red oxide. In an exemplary embodiment of the present disclosure, the stainer is persian gulf red oxide.
In an embodiment of the present disclosure, the stainer is in an amount in the range of 0 mass% to 1 mass% with respect to the total mass of the composition. In an exemplary embodiment of the present disclosure, the amount of stainer is present in an amount of 0.5 mass% with respect to the total mass of the composition.
In an embodiment of the present disclosure, the mass ratio of the paint sludge to the binder is in the range of 1.5:1 to 4:1. In an exemplary embodiment of the present disclosure, the mass ratio of the paint sludge to the binder is 2.96:1. In another exemplary embodiment, the mass ratio of the paint sludge to the binder is 2.2:1. In yet another exemplary embodiment, the mass ratio of the paint sludge to the binder is 1.6:1.
In an embodiment of the present disclosure, the primer composition imparts anti-corrosive properties when applied on substrates.
In an embodiment of the present disclosure, the primer composition is characterized by having a viscosity in the range of 60 to 120 KU, weight in the range of 13 Kg/10 Litre to 14.5 Kg/10 Litre; and finish on HG is in the range of 0 to 2.
In an exemplary embodiment of the present disclosure, the viscosity of the primer composition is 68 KU. In another exemplary embodiment of the present disclosure, the viscosity of the primer composition is 66 KU. In still another exemplary embodiment of the present disclosure, the viscosity of the primer composition is 65 KU.
In another aspect of the present disclosure, there is provided a process for the preparation of the primer composition.
The process for preparation of primer composition is described in detail.
In a first step, a first portion of a paint sludge is blended with a first portion of at least one binder, and a first portion of at least one additive at a speed in the range of 1500 rpm to 2500 rpm for a first predetermined time period to obtain a first mixture.
In an embodiment of the present disclosure, the paint sludge is characterized by having a non-volatile matter in the range of 15% to 50%; a viscosity in the range of 10 seconds to 100 seconds as measured by B4 Ford cup viscometer (FCB4) at 30°C; weight per liter in the range of 0.85 to 1.1 Kg; and finish on HG in the range of 0 to 2.
In an embodiment of the present disclosure, the binder is at least one selected from the group consisting of an alkyd resin, and PU modified alkyd resin; wherein the alkyd resin is at least one selected from the group consisting of soya alkyd, soya dehydrated castor seed oil (DCO) alkyd, and linseed alkyd. In an exemplary embodiment of the present disclosure, the alkyd resin is 60% Soya dehydrated castor seed oil (DCO) alkyd.
In an embodiment of the present disclosure, the first predetermined time period is in the range of 5 minutes to 15 minutes. In an exemplary embodiment of the present disclosure, the first predetermined time period is 10 minutes.
In an embodiment of the present disclosure, the first portion of the additive comprises a wetting agent.
In a second step, a second portion of the additive, a predetermined amount of a pigment, and a predetermined amount of a filler were added to the first mixture and blended at a speed in the range of 1500 rpm to 2500 rpm for a second predetermined time period to obtain a second mixture.
In an embodiment of the present disclosure, the pigment is at least one selected from the group consisting of red pigment of ferric oxide, red iron oxide, and synthetic red iron oxide.
In an embodiment of the present disclosure, the filler is at least one selected from the group consisting of dolomite, china clay, calcium carbonate, and talc. In an exemplary embodiment of the present disclosure, the filler is a combination of dolomite and china clay.
In an embodiment of the present disclosure, the second portion of the additive comprises a thixotropic agent and a functional pigment.
In an embodiment of the present disclosure, the second predetermined time period is in the range of 30 minutes to 150 minutes. In an exemplary embodiment, the second predetermined time period is 90 minutes.
In a third step, a second portion of the binder and a second portion of the paint sludge are added to the second mixture and blended at a speed in the range of 700 rpm to 800 rpm for a third predetermined time period to obtain a third mixture.
In an embodiment of the present disclosure, the third predetermined time period is in the range of 10 minutes to 25 minutes. In an exemplary embodiment of the present disclosure, the third predetermined time period is 15 minutes.
In a fourth step, a third portion of the paint sludge, a predetermined amount of a fluid medium, and a third portion of the additive is added to the third mixture and blended at a speed in the range of 700 rpm to 800 rpm for a fourth predetermined time period to obtain a fourth mixture.
In an embodiment of the present disclosure, the fourth predetermined time period is in the range of 10 minutes to 25 minutes. In an exemplary embodiment, the fourth predetermined time period is 20 minutes.
In an embodiment of the present disclosure, the third portion of the additive comprises driers and an anti-skinning agent.
In a fifth step, optionally a fourth portion of additive is added to the fourth mixture and blended at a speed in the range of 700 rpm to 800 rpm to obtain a fifth mixture to obtain a fifth mixture.
In an embodiment of the present disclosure, the fourth portion of the additive comprises a stainer.
In the final step, optionally a fourth portion of the paint sludge and a third portion of the binder are added to the fifth mixture and blended at a speed in the range of 700 rpm to 800 rpm to obtain the primer composition.
In an embodiment of the present disclosure, the primer composition is prepared at a temperature in the range of 20°C to 60°C. In an exemplary embodiment of the present disclosure, the temperature is 45°C.
In an embodiment of the present disclosure, the primer composition obtained from the process of the present disclosure is characterized by having a viscosity in the range of 60 KU to 120 KU, weight in the range of 13.0 Kg/10 Litre to 14.5 Kg/10 Litre; and finish on HG is in the range of 0 to 2.
In an embodiment of the present disclosure, the first portion of the binder is in the range of 70 mass% to 80 mass%; the second portion of the binder is in the range of 5 mass% to 15 mass%; and the third portion of the binder is in the range of 10 mass% to 20 mass% with respect to the total mass of the binder.
In an embodiment of the present disclosure, the first portion of the paint sludge is in the range of 40 mass% to 50 mass%; the second portion of the paint sludge is in the range of 5 mass% to 15 mass%; the third portion of the paint sludge is in the range of 35 mass% to 45 mass%; and the fourth portion of the paint sludge is in the range of 5 mass% to 10 mass% with respect to the total mass of the paint sludge.
In an embodiment of the present disclosure, the fluid medium is at least one selected from the group consisting of mineral turpentine oil (MTO), distilled C9 solvent, and xylene.
The primer composition of the present disclosure on application provides adhesion to the top coat and better anti-corrosion performance. The primer composition also helps in reducing the energy requirements. The primer composition of the present disclosure effectively uses the paint sludge in the paint composition, thus avoiding disposal of chemicals, hence the process is environment friendly.
The foregoing description of the embodiments has been provided for purposes of illustration and not intended to limit the scope of the present disclosure. Individual components of a particular embodiment are generally not limited to that particular embodiment, but, are interchangeable. Such variations are not to be regarded as a departure from the present disclosure, and all such modifications are considered to be within the scope of the present disclosure.
The present disclosure is further described in light of the following experiments which are set forth for illustration purposes only and not to be construed for limiting the scope of the disclosure. The following experiments can be scaled up to industrial/commercial scale and the results obtained can be extrapolated to industrial scale.
EXPERIMENTAL DETAILS
EXAMPLE 1: Evaluation and testing of the paint sludge from different plants
The contents of the paint sludge will vary based on the paints manufactured at the respective plant. The characteristics of the paint sludge obtained from various manufacturing plants (A, B, C, D, and E) are provided below in Table 1.
Table 1: Characteristics of the distillation sludge (paint sludge)
Sr. No.
Properties
Paint manufacturing plants
A
B
C
D
(67+33 wt%)
(Sludge C + Xylene) E
Composite mixture (25+25+50 wt%)
(A + B + C)
1 % NVM
(120 °C for 1.5 Hrs) 32.88 18.5 71.81 48 48.75
2 Viscosity on FCB4 @ 30°C (Sec) 54 15 Thick
(Not measurable) 80 78
3 Weight per Litre (KG) 0.95 0.9 1.02 0.96 0.96
4 Finish HG 2+ 2+ Zero Zero Zero

The characteristics of the paint sludge suitable for the preparation of the primer composition are provided in Table 2.
Table 2: Specification for the paint sludge
Sr. No. Properties Range
1 % NVM (120 °C for 1.5 Hours) 15% to 50%
2 Viscosity on FCB4 at 30°C 10 sec -100 sec
3 Weight (kg) per liter 0.85-1.1
4 Finish HG 0 to 2

The paint sludge was filtered through a 100-mesh sieve to remove any foreign particles.
The primer composition was prepared by using the paint sludge obtained from various plants; the characteristics of the primer composition by using the paint sludge were compared with the primer composition prepared without using the paint sludge. A detailed comparison of the characteristics is provided below in Table 3.
Table 3: Test results of the finished product Red Oxide Zinc Chromate (ROZC) primer based on paint sludge from different plants.
ROZC Primer (IS 2074 (P) standard) Primer composition using paint sludge
Sr. No. Properties Standard Test Method Standard
A
B
C
Properties of Paint sludge
1 % NVM of sludge
(120°C for 1.5 Hrs) ASTM E1235 NA 32.88 18.5 71.81
2
Viscosity of sludge on FCB4 @ 30°C (Sec) IS 101
Part1/Sec 5 NA
54
15
Thick
(Not measurable)
Paint properties
3 Processing On HSD HSD HSD HSD
4 Viscosity @ 30°C (KU) ASTM:
D 562 – 01 111.6 91.8 66.7 147
5 Wt / 10 Litre (Kg) IS 101
(Part 1/Sec 7) 13.3 13.5 13.5 13.8
6 GRINDING H.G. Smooth on Panel Comp. to Std Comp. to Std Comp. to Std
7 Drying IS 101
(Part 3/Sec 1)
Surface dry (Mins) 10 15 15 15
Hard dry (Hrs) 24 24 24 24
8 Nail hardness Satisfactory Comp. to Std Comp. to Std Comp. to Std
9 Stability (incubator/oven at 60°C for 10 days)
a. Medium separation Nil Nil Nil Nil
b. Settling Nil Nil Nil Nil
c. Skinning Nil Nil Nil Nil
d. Viscosity @ 30°C (KU) 129.2 101.3 87.3 147.4
Viscosity Pickup in KU 17.6 9.5 20.6 0.4
5. Drying IS 101
(Part 3/Sec 1)
a) Surface dry (Mins) 10 15 15 15
b) Hard dry (Hrs) 24 24 24 24
Performance testing
10 Corrosion Resistance (SST)
(R=0 Poor & R=10 Best) ASTM B117
A) Primer
(After 120 Hrs SST) R=5 R=7.5 R=8 R=8.5
B) Primer Followed by two coat topcoat (After 200 Hrs SST) R=8 R=9 R=9 R=9
C) Adhesion (R=0 Poor & R=10 Best) R=9 R=9 R=9 R=9
D) Cross-cut adhesion R=9 R=9 R=9 R=9

It is evident from the above table that the primer composition prepared by using the paint sludge obtained from different plants exhibited better anti-corrosion performance as compared to the primer composition without paint sludge. However, some variation w.r.t. anti-corrosion performance was observed due to various paint sludge from different plants.
EXAMPLE 2: Process for the preparation of the primer composition in accordance with the present disclosure
10.2 g of 60% soya dehydrated castor seed oil (DCO) alkyd resin, 18.5 g of paint sludge A, 0.5 g of Soyalecithin, and 0.25g of Sorbitan trioleate (span 85) were added into a blender and blended at a speed of 2000 rpm for 10 minutes to obtain a first mixture. 0.3 g of Bentonite clay, 15.75g of Synthetic red iron oxide (400 mesh), 8.75 g of Dolomite (500 mesh), 19 g of China clay (10 microns), and 0.2 g of White seal Zinc oxide were slowly added to the first mixture while blending at a speed of 2000 rpm for 90 minutes to obtain a second mixture. The slow addition of ingredients was required to avoid lump formation. The finish of the second mixture on Hegman Gauge was 2+. To the second mixture, 4 g of the paint sludge and 1.5 g of 60% Soya DCO alkyd resin were added while blending at a speed of 800 rpm for 15 minutes to obtain a third mixture. 0.04 g of Cobalt octoate (12%), 0.14g of Zirconium octoate (18%), 0.17g of Calcium octoate (10%), 0.2g of Methyl Ethyl Ketone, and 15g of the paint sludge were added sequentially to the third mixture while blending at a speed of 800 rpm for 15 minutes to obtain a fourth mixture.
0.50g of persian gulf red oxide stainer was slowly added to the fourth mixture under stirring at a speed of 800 rpm to obtain a fifth mixture. To the fifth mixture, 2 g of 60% soya DCO alkyd and 3 g of the paint sludge were added to obtain the primer composition. The viscosity of the primer composition was 68 KU and weight per 10 litre was 13.5 Kg.
The temperature during the preparation of the primer composition was maintained at 45 °C by using water cooling.
EXAMPLES 3 to 7: Primer compositions
The primer compositions of examples 3 to 7 were prepared similarly to the process as disclosed in Example 2 by varying the components or amount of components present in the primer composition. In the process of the preparation of the primer composition, the fluid medium was added to the third mixture along with the third portion of the paint sludge and the third portion of the additive. The composition details are provided below in Table 4.
Table 4: Primer composition details
Ingredients Example 2 Example 3 Example 4 Example 5 Example 6 Example 7
(gm) (gm) (gm) (gm) (gm) (gm)
60% Soya DCO ALKYD 10.20 10.20 10.20 10.20 10.20 10.20
Paint Sludge A 18.50 18.50 18.50 18.50 16.50 11.50
Fluid medium 0.00 0.00 0.00 0.00 2.00 7.00
Soyalecithin 0.50 0.50 0.50 0.50 0.50 0.50
Span 85 0.25 0.25 0.25 0.25 0.25 0.25
Bentonite clay 0.30 0.30 0.30 0.30 0.30 0.30
Synthetic Red Iron Oxide 15.75 15.75 15.75 15.75 15.75 15.75
Dolomite 8.75 8.75 8.75 8.75 8.75 8.75
China Clay 19.00 19.00 19.00 19.00 19.00 19.00
White Seal Zinc Oxide 0.20 0.20 0.20 0.20 0.20 0.20
60% Soya DCO ALKYD 1.50 1.50 1.50 1.50 1.50 1.50
Paint Sludge A 4.00 4.00 4.00 4.00 4.00 4.00
Cobalt Octoate (12%) 0.04 0.04 0.04 0.04 0.04 0.04
Zirconium Octoate (18%) 0.14 0.14 0.14 0.14 0.14 0.15
Calcium Octoate (10%) 0.17 0.17 0.17 0.17 0.17 0.17
Methyl Ethyl Ketoxime 0.20 0.20 0.20 0.20 0.20 0.20
Paint Sludge A 15.00 10.00 8.00 3.00 0.00 0.00
Fluid Material 0 2.50 5.00 7.50 8.00 5.50
Persian gulf red oxide for tinting 0.50 0.50 0.50 0.50 0.50 0.50
60% Soya DCO ALKYD 2.00 4.50 7.00 9.50 12.00 14.50
Paint Sludge A 3.00 3.00 0 0 0 0
Total 100 100 100 100 100 100

Characteristic features of the primer composition in accordance with the present disclosure
The primer compositions obtained from examples 2 to 7 were evaluated on various parameters such as surface drying, hard drying, corrosion, and the like. The details of the various tests, test methods, and results are provided below in Table 5.
Table 5: Properties of the primer compositions
Properties Std Test Method Example 2 Example 3 Example 4 Example 5 Example 6 Example 7 Specification
Processing On high speed disperser (HSD) HSD HSD HSD HSD HSD HSD
Viscosity @ 30°C (KU) ASTM:
D 562 – 01 68 66 65 64 63 61 60 - 120
Wt / 10 Litre (Kg) IS 101
(Part 1/Sec 7) 13.5 13.45 13.45 13.46 13.42 13.42 13 to 14.5
Smoothness on panel *Comp. to Std *Comp. to Std *Comp. to Std *Comp. to Std *Comp. to Std *Comp. to Std *Comp. to Std
Drying
Surface dry (mins) IS 101
(Part 3/Sec 1) 15 15 15 15 15 15 30
Hard dry (Hrs.) IS 101
(Part 3/Sec 1) 24 24 24 24 24 24 24
Nail hardness *Comp. to Std *Comp. to Std *Comp. to Std *Comp. to Std *Comp. to Std *Comp. to Std *Comp. to Std
Oven Stability (After 10 days)
1. Medium separation Nil Nil Nil Nil Nil Nil
2. Settling Nil Nil Nil Nil Nil Nil
3. Skinning Nil Nil Nil Nil Nil Nil
4. Viscosity @ 30°C (KU) ASTM:
D 562 – 01 87.3 86 84 84 84 83
Viscosity Pickup in KU 19.3 20 19 20 21 22
Performance testing (Corrosion Resistance (SST))
(R=0 Poor & R=10 Best)

A) Primer (120 Hrs SST) ASTM B117 R=8.5 R=8.5 R=8.5 R=8.75 R=8.75 R=9 R=5
B) Primer Followed by two coat topcoat (200 Hrs SST) ASTM B117 R=9 R=9 R=9 R=9.25 R=9.25 R=9.5 R=8
Adhesion (R=0 Poor & R=10 Best) ASTM B117 R=9 R=9 R=9 R=9 R=9 R=9 R=9
Cross cut adhesion ASTM B117 R=9 R=9 R=9 R=9 R=9 R=9 R=9
*Comp. to Std refers to comparable to standard
It is evident from the above results that the viscosity of the primer composition of example 2, example 3, and example 4 contains a high amount of the paint sludge and has a viscosity in the range of 65 KU to 68 KU at 30 °C which is similar to the primer composition prepared without using paint sludge. Further, it was observed that the primer composition of example 2, example 3, and example 4 has similar anti-corrosion properties when compared with examples 5, 6, and 7.
The primer composition of the present disclosure exhibits consistent characteristics, even when a substantial high quantity of the paint sludge is employed, in contrast to the primer compositions with a minimal paint sludge content.
Example 8: Comparative study
The properties of the primer composition containing a high amount of paint sludge (Example 2) of the present disclosure were compared with the primer composition without paint sludge. The results are provided in Table 6 below
Table 6: Properties of the primer compositions
Sr. No. Properties Standard Test Method Standard
(Existing design without sludge) Primer Composition Example (2)
Specification
1 Processing On HSD HSD
2 Viscosity @ 30°C (KU) ASTM:
D 562 – 01 111.6 68 60 – 120
3 Wt / 10 Litre (Kg) IS 101
(Part 1/Sec 7) 13.3 13.5 13 – 14.5
4 Smoothness on panel Std Comp. to Std Comp to std
5 Drying IS 101
(Part 3/Sec 1)
Surface dry (Mins) 10 15 30
Hard dry (Hrs) 24 24 24
6 Nail hardness Satisfactory Comp. to Std Comp to std
7 Inq. Stability (After 10 days)
a. Medium separation Nil Nil
b. Settling Nil Nil
c. Skinning Nil Nil
d. Viscosity @ 30°C (KU) 129.2 87.3
Viscosity Pickup in KU 17.6 19.3
e. Drying IS 101
(Part 3/Sec 1)
i) Surface dry (Mins) 10 15
ii) Hard dry (Hrs) 24 24
Performance testing
8 Corrosion Resistance (SST)
(R=0 Poor & R=10 Best) ASTM B117
A) Primer
(After 120 Hrs SST) R=5 R=8.5
B) Primer Followed by two coat topcoat (After 200 Hrs SST) R=8 R=9
C) Adhesion (R=0 Poor & R=10 Best) R=9 R=9
D) Cross cut adhesion R=9 R=9

Based on the data presented above, it is clear that the experimental results of the primer composition of example 2 demonstrated superior anti-corrosion performance when compared to the standard primer composition, which does not include the paint sludge.
Example 9: Comparative study
The properties of the primer composition containing a high amount of paint sludge A (Example 2) of the present disclosure were compared with the similar primer composition by replacing the paint sludge A with B and C of Example 1.
The primer compositions were evaluated for top coat adhesion and anti-corrosive properties.
Top-coat adhesion:
The adhesion test was performed to evaluate the adhesion strength of oil-based enamel applied to mild steel (MS) panels.
The MS panels were cleaned followed by applying a primer composition and allowed it to cure for 24 hours. Subsequently, two coats of oil-based enamel was applied with 8-hour recoating interval, followed by 7-day curing period. On the cured surface, carefully scribed 100 squares of 1 mm x 1 mm and a transparent cellophane tape was applied by firmly pressing onto the scribed area before slowly pulling it off at 90-degree angle. Finally, the scribed squares for any paint detachment were examined under magnification to assess adhesion strength.
The test is considered successful if no flaking or peeling of the paint film is observed beyond the scribed lines or at the corners of the squares after the tape removal. The results are illustrated in Figure 1.
It is evident from the results that the primer composition of the present disclosure provides better adhesion compared to primer composition having other sludges (B, C and A+B+C).
Anti-Corrosion Performance:
The anti-corrosive test was performed to evaluate the resistance of oil-based enamel applied to primer coated MS panels against corrosion in a salt spray environment.
The MS panels were cleaned followed by applying a primer composition and allowed to cure for 24 hours. Subsequently, two coats oil-based enamel was applied with 8-hour recoating interval, followed by 7-day curing period. An "X" shaped cut was scribed through the coating to expose the metal, and the panel sides were sealed. The primer coated panels were exposed in a salt spray chamber for 100 hours, while primer and enamel coated panels were exposed for 200 hours. After exposure, the panels were examined for visual signs of corrosion to assess the salt spray resistance of the oil-based enamel coating system. The test was performed as per the ASTM B117. The panels were visually examined for extent of corrosion on the exposed metal and the surrounding coated areas and signs of blistering, delamination, rust formation, discoloration, or other deterioration of the coating. The results are illustrated in Figure 1.
It is evident from the results that the primer composition of the present disclosure provides corrosion resistance compared to the primer composition having other sludges (B, C and A+B+C).
TECHNICAL ADVANCEMENT
The present disclosure described hereinabove has several technical advantages including, but not limited to, the realization of a primer composition that:
• uses a high amount of paint sludge;
• has increased volume of solids to provide an improved covering capacity and dry film thickness to the substrate;
• has better anti-corrosive properties;
• utilizes waste paint sludge;
• avoids the use of water and solvents;
• is sustainable;
• reduces carbon footprint, thus environment friendly;
• avoids incineration for the disposal of the paint sludge; and
• saves fuel, energy, and cost for incineration of the paint sludge, thus economical.
and
a process for the preparation of the primer composition is simple, economical, and environment friendly.
Throughout this specification the word “comprise”, or variations such as “comprises” or “comprising”, will be understood to imply the inclusion of a stated element, integer or step, or group of elements, integers or steps, but not the exclusion of any other element, integer or step, or group of elements, integers or steps.
The use of the expression “at least” or “at least one” suggests the use of one or more elements or ingredients or quantities, as the use may be in the embodiment of the disclosure to achieve one or more of the desired objects or results.
Any discussion of documents, acts, materials, devices, articles or the like that has been included in this specification is solely for the purpose of providing a context for the disclosure. It is not to be taken as an admission that any or all of these matters form a part of the prior art base or were common general knowledge in the field relevant to the disclosure as it existed anywhere before the priority date of this application.
The numerical values mentioned for the various physical parameters, dimensions or quantities are only approximations and it is envisaged that the values higher/lower than the numerical values assigned to the parameters, dimensions or quantities fall within the scope of the disclosure, unless there is a statement in the specification specific to the contrary.
While considerable emphasis has been placed herein on the components and component parts of the preferred embodiments, it will be appreciated that many embodiments can be made and that many changes can be made in the preferred embodiments without departing from the principles of the disclosure. These and other changes in the preferred embodiment as well as other embodiments of the disclosure will be apparent to those skilled in the art from the disclosure herein, whereby it is to be distinctly understood that the foregoing descriptive matter is to be interpreted merely as illustrative of the disclosure and not as a limitation. ,CLAIMS:WE CLAIM:
1. A primer composition comprising:
a. a paint sludge in an amount in the range of 30 mass% to 45 mass% with respect to the total mass of the composition;
b. at least one binder in an amount in the range of 12 mass% to 20 mass% with respect to the total mass of the composition;
c. at least one fluid medium in an amount in the range of 0 mass% to 6 mass% with respect to the total mass of the composition;
d. at least one pigment in an amount in the range of 13 mass% to 25 mass% with respect to the total mass of the composition;
e. at least one filler in an amount in the range of 25 mass% to 35 mass% with respect to the total mass of the composition; and
f. at least one additive in an amount in the range of 0.5 mass% to 5 mass% with respect to the total mass of the composition.
2. The composition as claimed in claim 1, wherein said paint sludge is characterized by having
• a non-volatile matter (NVM) in the range of 15 wt% to 50 wt%;
• viscosity in the range of 10 seconds to 100 seconds as measured by a B4 Ford cup viscometer at 30°C;
• weight per litre in the range of 0.85 to 1.1 kg/litre; and
• finish on HG in the range of 0 to 2.
3. The composition as claimed in claim 1, wherein said binder is at least one selected from the group consisting of an alkyd resin, and PU modified alkyd resin; wherein said alkyd resin is at least one selected from the group consisting of soya alkyd resin, soya dehydrated castor seed oil (DCO) alkyd resin, and linseed alkyd resin.
4. The composition as claimed in claim 1, wherein said fluid medium is at least one selected from the group consisting of mineral turpentine oil (MTO), distilled C9 Solvent, and xylene.
5. The composition as claimed in claim 1, wherein said pigment is at least one selected from the group consisting of red pigment of ferric oxide, red iron oxide, and synthetic red iron oxide.
6. The composition as claimed in claim 1, wherein said filler is at least one selected from the group consisting of dolomite, china clay, calcium carbonate, and talc.
7. The composition as claimed in claim 1, wherein said additive is at least one selected from the group consisting of a wetting agent, a thixotropic agent, a functional pigment, a drier, an anti-skinning agent, and a stainer.
8. The composition as claimed in claim 7, wherein
a. said wetting agent in an amount in the range of 0.1 mass% to 1 mass% with respect to the total mass of the composition;
b. said thixotropic agent in an amount in the range of 0.1 mass% to 0.5 mass% with respect to the total mass of the composition;
c. said functional pigment in an amount in the range of 0.1 mass% to 0.3 mass% with respect to the total mass of the composition;
d. said drier in an amount in the range of 0.3 mass% to 0.5 mass% with respect to the total mass of the composition;
e. said anti-skinning agent in an amount in the range of 0.1 mass% to 0.3 mass% with respect to the total mass of the composition; and
f. said stainer in an amount in the range of 0 mass% to 1 mass% with respect to the total mass of the composition.
9. The composition as claimed in claim 7, wherein said wetting agent is at least one selected from the group consisting of lecithin, soyalecithin, sorbitan trioleate.
10. The composition as claimed in claim 7, wherein said thixotropic agent is at least one selected from the group consisting of bentonite clay and hectorite clay.
11. The composition as claimed in claim 7, wherein said functional pigment is at least one selected from the group consisting of white seal zinc oxide, zinc phosphate, and aluminium trihydrate.
12. The composition as claimed in claim 7, wherein said drier is at least one selected from the group consisting of a surface drier, an auxiliary drier, and a through drier.
13. The composition as claimed in claim 12, wherein said surface drier is at least one selected from the group consisting of cobalt octoate and manganese octoate; said through drier is at least one selected from the group consisting of zirconium octoate and strontium octoate and said auxiliary drier is at least one selected from the group consisting of calcium octoate and zinc octoate.
14. The composition as claimed in claim 7, wherein said anti-skinning agent is methyl ethyl ketoxime.
15. The composition as claimed in claim 7, wherein said stainer is at least one selected from the group consisting of persian gulf red oxide, and red oxide.
16. The composition as claimed in claim 1, wherein a mass ratio of said paint sludge to said binder is in the range of 1.5:1 to 4:1.
17. The composition as claimed in claim 1, wherein said primer composition is characterized by having a viscosity in the range of 60 to 120 Krebs Unit (KU), weight in the range of 13 kg/10 liter to 14.5 kg/10 liter; and finish on HG in the range of 0 to 2.
18. A process for the preparation of the primer composition, said process comprising the following steps:
a. blending a first portion of paint sludge, a first portion of at least one binder, and a first portion of at least one additive at a speed in the range of 1500 rpm to 2500 rpm for a first predetermined time period to obtain a first mixture;
b. adding a second portion of said at least one additive, a predetermined amount of a pigment, and a predetermined amount of a filler to said first mixture and blending at a speed in the range of 1500 rpm to 2500 rpm for a second predetermined time period to obtain a second mixture;
c. adding a second portion of said binder and a second portion of said paint sludge to said second mixture and blending at a speed in the range of 700 rpm to 800 rpm for a third predetermined time period to obtain a third mixture;
d. adding a third portion of said paint sludge, a predetermined amount of a fluid medium, and a third portion of said additive to said third mixture and blending at a speed in the range of 700 rpm to 800 rpm for a fourth predetermined time period to obtain a fourth mixture;
e. optionally adding a fourth portion of said additive to said fourth mixture and blending at a speed in the range of 700 rpm to 800 rpm to obtain a fifth mixture; and
f. optionally mixing a fourth portion of said paint sludge and a third portion of said binder to said fifth mixture and blending at a speed in the range of 700 rpm to 800 rpm to obtain said primer composition.
19. The process as claimed in claim 18, wherein the viscosity of said fourth mixture is in the range of 60 to 120 Krebs Unit (KU); and finish on HG of said second mixture and said third mixture are independently in the range of 0 to 2.
20. The process as claimed in claim 18, wherein said paint sludge is characterized by having
• a non-volatile matter (NVM) in the range of 15% to 50%;
• viscosity in the range of 10 seconds to 100 seconds as measured by B4 Ford cup viscometer at 30°C;
• weight per litre in the range of 0. 85 to 1.1 kg; and
• finish on HG in the range of 0 to 2.
21. The process as claimed in claim 18, wherein said binder is at least one selected from the group consisting of an alkyd resin, and PU modified alkyd resin; wherein said alkyd resin is at least one selected from the group consisting of soya alkyd resin, soya dehydrated castor seed oil (DCO) alkyd resin, and linseed alkyd resin.
22. The process as claimed in claim 18, wherein said pigment is at least one selected from the group consisting of red pigment of ferric oxide, red iron oxides, and synthetic red iron oxide.
23. The process as claimed in claim 18, wherein said first portion of said additive comprises a wetting agent, said second portion of said additive comprises a thixotropic agent, and a functional pigment, said third portion of said additive comprises driers and an anti-skinning agent, and said fourth portion of said additive comprises a stainer.
24. The process as claimed in claim 23, wherein said wetting agent is at least one selected from the group consisting of lecithin, soya lecithin, sorbitan trioleate.
25. The process as claimed in claim 23, wherein said thixotropic agent is at least one selected from the group consisting of bentonite clay, and hectorite clay.
26. The process as claimed in claim 23, wherein said filler is at least one selected from the group consisting of dolomite, china clay, calcium carbonate, and talc.
27. The process as claimed in claim 23, wherein said functional pigment is at least one selected from the group consisting of white seal zinc oxide, zinc phosphate, and aluminium trihydrate.
28. The process as claimed in claim 23, wherein said drier is at least one selected from the group consisting of a surface drier, an auxiliary drier, and a through drier.
29. The process as claimed in claim 28, wherein said surface drier is at least one selected from the group consisting of cobalt octoate, and manganese octoate; said through drier is at least one selected from the group consisting of zirconium octoate and strontium octoate; and said auxiliary drier is at least one selected from the group consisting of calcium octoate and zinc octoate.
30. The process as claimed in claim 23, wherein said anti-skinning agent is methyl ethyl ketoxime.
31. The process as claimed in claim 23, wherein said stainer is at least one selected from the group consisting of persian gulf red oxide, and red oxide.
32. The process as claimed in claim 18, wherein said first predetermined time period is in the range of 5 minutes to 15 minutes.
33. The process as claimed in claim 18, wherein said second predetermined time period is in the range of 30 minutes to 150 minutes.
34. The process as claimed in claim 18, wherein said third predetermined time period and said fourth predetermined time period are independently in the range of 10 minutes to 25 minutes.
35. The process as claimed in claim 18, wherein said first portion of said binder is in the range of 70 mass% to 80 mass%; said second portion of said binder is in the range of 5 mass% to 15 mass%; and said third portion of said binder is in the range of 10 mass% to 20 mass% with respect to the total mass of the binder.
36. The process as claimed in claim 18, wherein said first portion of said paint sludge is in the range of 40 mass% to 50 mass%; said second portion of said paint sludge is in the range of 5 mass% to 15 mass%; said third portion of said paint sludge is in the range of 35 mass% to 45 mass%; and said fourth portion of said paint sludge is in the range of 5 mass% to 10 mass% with respect to the total mass of the paint sludge.
37. The process as claimed in claim 18, wherein said primer composition is prepared at a temperature in the range of 20°C to 60°C.
38. The process as claimed in claim 18, wherein said fluid medium is at least one selected from the group consisting of mineral turpentine oil (MTO), distilled C9 solvent, and xylene.

Dated this 27th day of March, 2024

_______________________________
MOHAN RAJKUMAR DEWAN, IN/PA – 25
OF R. K. DEWAN & CO.
AUTHORIZED AGENT OF APPLICANT

TO,
THE CONTROLLER OF PATENTS
THE PATENT OFFICE, AT MUMBAI