Title of Invention

COMPOSITION FOR CONVERSION OF PAINT SLUDGE INTO BITUMEN BLENDABLE MIXTURE, PROCESS FOR PREPARATION THEREOF"

Abstract

The present invention relates to a composition for the conversion of all types of paint sludge into a bitumen blendable mixture useful for road building, to a process for the preparation of said composition and to a process for the conversion of waste paint sludge to bitumen blendable mixture useful for road building. The sludge conversion process of the invention consumes the environmentally hazardous sludge collected from paint application systems by converting this paint sludge into a bitumen blendable mixture useful for road building.

Full Text

COMPOSITION FOR CONVERSION OF PAINT SLUDGE INTO BITUMEN BLENDABLE MIXTURE, PROCESS FOR PREPARATION THEREOF FIELD OF THE INVENTION The present invention relates to a composition for the conversion of all types of paint sludge into a bitumen blendable mixture useful for road building, to a process for the preparation of said composition and to a process for the conversion of waste paint sludge to bitumen blendable mixture useful for road building. The sludge conversion process of the invention consumes the environmentally hazardous sludge collected from paint application systems by converting this paint sludge into a bitumen blendable mixture useful for road building. BACKGROUND OF THE INVENTION Most original equipment manufacturers (OEM's) use spray technique for painting their components. In this process the paint is mixed/thinned with appropriate thinner to get required application viscosity. Then it is applied by spray method on respective components in a paint booth. During spray method some paint adheres on the component being spray painted. Over-sprayed paint goes to water stream as a waste. This over sprayed waste paint gets mixed with water stream and gets coagulated by flocculent booth additives present in water stream. From this water stream the sludge is collected in the form of a lumpy paste. Generally this sludge is either dumped or incinerated by industries, which is environmentally hazardous. Typically, the sludge obtained is either not biodegradable or degrades at a very slow rate. Therefore, dumping or earth filling of such sludge poses an environmental hazard. Burning of this sludge also produces toxic flames causing environment pollution. Therefore dumping, earth filling or burning of paint sludge is not an environmentally safe method for its disposal. It is therefore important to devise a method by which paint sludge can be converted at least in part into reusable product by separating the water component of such sludge. This will assist in reducing the environmental hazards associated with the painting process. To the best of the applicant's knowledge, no processes are known in the art for recycling or recovery of paint from paint sludge such that useful product can be derived out of it, and environmental concerns addressed at the same time. OBJECTS OF THE INVENTION The main object of the invention is to provide a composition useful for the preparation of bitumen blendable mixture useful for road building from paint sludge. It is another object of the invention to provide a process for the preparation of bitumen blendable mixture useful for road building from paint sludge, which is environmentally friendly and inexpensive. The above and other objects of the present invention are attained by the novel composition of this invention which comprises a mixture of solvents in specific amounts with or without resins and a process for the use thereof which enables conversion of paint sludge into bitumen blendable mixture useful for road building. SUMMARY OF THE INVENTION Accordingly, the present invention provides a process for the conversion of paint sludge into bitumen blendable mixture useful for road building, the process comprising drying the paint sludge by any conventional method to obtain a sludge paste free from water, and optionally soaking said dried sludge with a solvent mixture and stirring the resultant product so obtained to obtain a homogenous sludge paste, heating the sludge paste to a temperature in the range of 50 to 100°C and bitumen separately at a temperature in the range of 120 to 130°C, mixing the heated sludge paste and the heated bitumen and adding a solution of resin thereto during continuous stirring while maintaining a temperature in the range of 50 to 100°C, extracting the solvent is used, stirring the mixture formed of sludge paste, bitumen and resin to form a homogeneous mixture to obtain a bitumen blended sludge paste ready to use for road repair or construction. In one embodiment of the invention, the paint sludge is taken from sludge of amino-alkyd based paint sludge, melamine polyester based paint sludge, thermosetting acrylic paint sludge and modified epoxy paint sludge. In another embodiment of the invention, the solvent used to soak the dry paint sludge is dependant on the type of paint sludge used. In one embodiment of the invention, the paint sludge is soaked in the solvent mixture over 1 to 72 hours. In another embodiment of the invention, the solvent is selected from the group consisting of toluene, xylene, benzene, acetone, isobutyl alcohol, n-butyl alcohol, isopropyl alcohol, methyl ethyl ketone and any other conventional solvent or any mixture thereof. In yet another embodiment of the invention, the solvent comprises a mixture of any one of toluene, xylene, benzene, acetone, isobutyl alcohol, n-butyl alcohol, isopropyl alcohol, methyl ethyl ketone and any other conventional solvent with another in an amount of l to 100%. In yet another embodiment of the invention, the amount of solvent added to the dry sludge is in the range of 5 to 50% by weight of the dry sludge. In yet another embodiment of the invention, the bitumen used is selected from bitumen in the range of 80 to 120 grade or any other grade prescribed for road or construction work. In another embodiment of the invention, the resin added is selected from the group consisting of maleic resins, ketonic resins, petroleum resins (cumran indene resins). In yet another embodiment of the invention, the resin is added to the heated sludge and bitumen mixture in the form of a solution in a solvent selected from the group consisting of toluene, toluene with butyl acetate, benzene with butyl acetate and benzene with xylene or any other conventional solvent used for paints. In yet another embodiment of the invention, the resin solution to sludge ratio is in the ratio of 1:0.1 to 1:3 to obtain a resin content of 5 to 30% by weight of the sludge. In yet another embodiment of the invention an octate drying agent selected from the group consisting of cobalt octate, calcium octate, manganese octate, and zirconium octate is added to the mixture comprising the heated sludge, resin and heated bitumen during stirring. In another embodiment of the invention, the paint sludge comprises sludge of amino alkyd based paints. In yet another embodiment of the invention, the solvent mixture comprises toluene in an amount of 20 to 40 %, xylene in an amount of 25 to 35 %, n-butyl alcohol in an amount of 10 to 20 %, butyl cellosolve in an amount of 5 to 20 % and cellosolve acetate in an amount of 1 to 3 %. In a further embodiment of the invention, the paint sludge comprises sludge of polyester melamine based paints. In yet another embodiment of the invention the solvent mixture comprises toluene or benzene in an amount of 28 to 40 %, xylene in an amount of 22 to 38 %, n-butyl alcohol or methyl isobutyl ketone or methyl cellosolve in an amount of 5 to 12 %, diacetone alcohol in an amount of 3 to 10 %, cellusolve acetate or amyl acetate in an amount of 2 to 5 % by weight expressed in terms of the amount of the paint sludge to be treated. The present invention also relates to a novel road repair or construction composition comprising paint sludge, bitumen and resin, the said ingredients being homogeneously mixed together. In one embodiment of the invention, the paint sludge is taken from sludge of amino-alkyd based paint sludge, melamine polyester based paint sludge, thermosetting acrylic paint sludge and modified epoxy paint sludge. In yet another embodiment of the invention, the bitumen used is selected from bitumen in the range of 80 to 120 grade or any other grade specified for road building or construction. In another embodiment of the invention, the resin added is selected from the group consisting of maleic resins, ketonic resins, petroleum resins (cumran indene resins). In yet another embodiment of the invention, the resin is added to the heated sludge and bitumen mixture in the form of a solution in a solvent selected from the group consisting of toluene, toluene with butyl acetate, benzene with butyl acetate and benzene with xylene. In yet another embodiment of the invention, the resin solution to sludge ratio is in the ratio of 1:0.1 to 1:3 to obtain a resin content of 4 to 40% by weight of the sludge. In yet another embodiment of the invention an octate drying agent selected from the group consisting of cobalt octate, calcium octate, manganese octate, and zirconium octate is added to the mixture comprising the heated sludge, resin and heated bitumen during stirring. In another embodiment of the invention, the paint sludge comprises sludge of amino alkyd based paints. In a further embodiment of the invention, the paint sludge comprises sludge of polyester melamine based paints. BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWING The generation and disposal of sludge is explained in Flow Chart-1. DETAILED DESCRIPTION OF THE INVENTION Paint generally comprises of the following materials: 1. Resin 2. Pigment and Extenders 3. Solvents 4. Additives All the ingredients are present in a homogeneous dispersed state. All have their specific roles in paint properties. Over-sprayed paint material consists of all the ingredients but very small percentage of solvents. When it is mixed in water and flocculates, solvent content is reduced further and the paint residuals become small droplets. The coagulation of small droplets results in mass formation i.e. sludge. The sludge available comprise either amino-alkyd based paint sludge, modified single pack epoxy base paint sludge, thermosetting acrylic (TSA) base sludge, polyester base sludge, 2K epoxy base sludge or 2K polyurethane based sludge. The last two are however difficult to recycle since after addition of catalyst hardener, curing takes place in a definite time frame. When used in the formulations of the invention, the2K epoxy base sludge or 2K polyurethane based sludge are used in an amount of 55-65%. A mixture of these with other paint sludges may also be used in the invention The process for conversion of the sludge into a bitumen based paint sludge bland Mixture, useful for road repair or construction according to the present invention comprises separation of contaminants and addition of solvents and resins in specific proportions. The collected sludge is a semisolid mass containing paint residuals, water, (optional) oil/greases along with flocculent Booth Additive. Water, Oil/grease and Flocculent Booth Additive has detrimental effect on paint properties and its reusability. These contaminants are either have to be eliminated or prevented from coming into the process. Flocculent having acidic/alkaline properties will deteriorate the paint and will be creating problems. To avoid this problem, the additive to be used should have alkaline nature instead of acidic. Oil/Grease contamination into the sludge should be avoided during the sludge formation and collection process. Water also to be removed from the sludge, which will be discussed in the process itself. The composition of the invention is a synergistic admixture with unknown and unexpected properties and not mere aggregation of properties of the individual ingredients. CONVERSION PROCESS: The sludge to be converted contains residual paints, acidic flocculent additive and water. The process of conversion to a bitumen blendable mixture comprises 1. De-watering and Solvent Removal. a) Pressing: Sludge is pressed to remove water and solvent from the mass. b) Heating: The Sludge mass is heated naturally or mechanically for maximum removal of water and solvents contents. 2. Soaking of dried sludge either in a mixture of resin and solvents or only solvents for few hours depending on the final properties of the required product and the duration of soaking depends on the condition or aging of the sludge. 3. Dispersion: The dispersion of the soaked sludge (viscous mass) can be achieved using high speed or low speed dispersers or stirrers etc. 4. Filtration, testing of final bitumen blended mix properties and packing for usage or dispatch. Example 1: Sludge from amino alkyd type paint mixed with epoxy based paint was first dried and homogenized as described in Flow Sheet n. Different samples were made with different amounts of sludge in the range of 1% to 85% by weight. To this sludge bitumen in an amount of 1 to 80% by weight was added in a melted form. The bitumen comprised of Grade 60 to Grade 100. The resin mixture employed comprised of petroleum resin in an amount of 1 to 30% by weight mixed optionally with maleic resin in an amount of up to 25% by weight, ketonic resin in an amount of 20% by weight, all dissolved in appropriate solvents. The final composition comprised of sludge in an amount of 1 to 80% by weight, bitumen in an amount of 1 to 80% by weight, and 10 to 60% by weight of a resin mixture comprising petroleum resin an amount of 1 to 30% by weight, maleic resin in an amount of up to 25% by weight of the resin mixture, ketonic resin in an amount of up to 20% by weight of the resin mixture. If desired any other suitable resin can also be used depending on the properties of the resin mixture. Example 2: Sludge from a thermosetting acrylic based paint mixed with polyester based paint was taken and the same procedure as discussed above was followed. The final bitumen blended mixture comprised of 5 to 80% by weight of sludge, 2 to 95% by weight of bitumen, and 10 to 70% by weight of a resin mixture comprising maleic resin, ketonic resin, petroleum resin and any other suitable resin. Example 3 Different mixtures were formed of paint sludge and bitumen and a resin where the sludge was present in an amount of 10-85% of the formulation. The resins when used were selected from petrase resin (0-20%), maleic resin (0-15%), ketonic resin (0-10%), cashew nut shell resin (0-10%), BNSL resin (0-10%) or short or medium alkyd resin (0-10%). In some samples, 0-3% of stand oil or CNS oil was also mixed depending on the strength/flexibility required for the bitumen in final application. The formulations used had the following composition: 1. TSA sludge and amino alkyd - 55-65% Bitumen - 25-35% Petrase resin - 2.0-3.5% Dispersion agent 0-0.2% Homogenising solvent - balance All proportions being by weight. 2. TSA sludge and amino alkyd - 55-65% Bitumen -25-35% Maleic resin - 2-5% Petrase resin - 2.0-3.0% Dispersion agent 0-0.2% Homogenising solvent - balance All proportions being by weight. 3. Amino alkyd and modified single pack epoxy and TSA - 50-60% Stand oil- 1-2% Bitumen - 30-40% CNS resin - 1-2% BNSL resin- 1% Dispersion agent 0-0.2% Homogenising solvent - balance All proportions being by weight 4. Amino alkyd and modified single pack epoxy and TSA - 65-85% Bitumen- 10-15% Petrase resin - 0-2% Ketonic resin - 0-5% Homogenising solvent - balance All proportions being by weight The bitumen used was 60/70 grade bitumen. The sludge was blended with the bitumen following the methods described above. It was observed that a blend comprising 2-8% sludge provided excellent strength and penetration resistance to the bitumen. (Table Removed) The above illustrative and non-limiting examples relate to various paint sludge from different sources which have been converted to bitumen blendable mixtures for use in road repair or construction. The procedure followed in each of the above examples are discussed above under the heading 'Conversion Process'. It must be understood that work is still underway in completing and further validating the results obtained herein in this invention. Modifications and variations of the process are possible without departing from the spirit and scope of the invention. Some of the paint systems where the process of the invention can be used are Epoxy-amino/phenolic system (Single Pack - Stoving System), Alkyd-amino system, Thermosetting acrylic systems, Thermoplastic-acrylic system. The present invention provides a process for the conversion of paint sludge into bitumen blendable mixture useful for road building, the process comprising drying the paint sludge by any conventional method to obtain a sludge paste, and optionally soaking said dried sludge with a solvent mixture and stirring the resultant product so obtained to obtain a homogenous sludge paste, heating the sludge paste to a temperature in the range of 60 to 100°C and bitumen separately at a temperature in the range of 120 to 130°C, mixing the heated sludge paste and the heated bitumen and adding a solution of resin thereto during continuous stirring while maintaining a temperature in the range of 60 to 100°C, extracting the solvent is used, stirring the mixture formed of sludge paste, bitumen and resin to form a homogeneous mixture to obtain a bitumen blended sludge paste ready to use for road repair. The paint sludge is taken from sludge of amino-alkyd based paint sludge, melamine polyester based paint sludge, thermosetting acrylic paint sludge and modified epoxy paint sludge. The solvent used to soak the dry paint sludge is dependant on the type of paint sludge used. The paint sludge is soaked in the solvent mixture over 1 to 48 hours. The solvent is selected from the group consisting of toluene, xylene, benzene, acetone, isobutyl alcohol, n-butyl alcohol, isopropyl alcohol, methyl ethyl ketone and any other conventional solvent or any mixture thereof. The solvent can also comprises a mixture of any one of toluene, xylene, benzene, acetone, isobutyl alcohol, n-butyl alcohol, isopropyl alcohol, methyl ethyl ketone and any other conventional solvent with another in an amount of 1 to 50%. The amount of solvent added to the dry sludge is in the range of 10 to 50% by weight of the dry sludge. The bitumen used is selected from bitumen in the range of 60 to 100 grade or any other grade prescribed for road repair or construction work. The resin added is selected from the group consisting of maleic resins, ketonic resins, petroleum resins (cumran indene resins). The resin is added to the heated sludge and bitumen mixture in the form of a solution in a solvent selected from the group consisting of toluene, toluene with butyl acetate, benzene with butyl acetate and benzene with xylene. The resin solution to sludge ratio is in the ratio of 1:0.1 to 1:3 to obtain a resin content of 5 to 40% by weight of the sludge. An octate drying agent selected from the group consisting of cobalt octate, calcium octate, manganese octate, and zirconium octate is added to the mixture comprising the heated sludge, resin and heated bitumen during stirring. It must be understood that the foregoing disclosure is illustrative and various modifications are possible without departing from the spirit and scope of the invention. We claim: 1. A process for the conversion of paint sludge into bitumen blendable mixture useful for road building, the process comprising drying the paint sludge by any conventional method to obtain a sludge paste free from water, and optionally soaking said dried sludge with a solvent mixture and stirring the resultant product so obtained to obtain a homogenous sludge paste, heating the sludge paste to a temperature in the range of 60 to 100°C and bitumen separately at a temperature in the range of 120 to 130°C, mixing the heated sludge paste and the heated bitumen and adding a solution of resin thereto during continuous stirring while maintaining a temperature in the range of 60 to 100°C, extracting the solvent is used, stirring the mixture formed of sludge paste, bitumen and resin to form a homogeneous mixture to obtain a bitumen blended sludge paste ready to use for road repair or construction. 2. A process as claimed in claim 1 wherein the paint sludge is taken from sludge of amino-alkyd based paint sludge, melamine polyester based paint sludge, thermosetting acrylic paint sludge and modified epoxy paint sludge. 3. A process as claimed in claim 1 wherein the solvent used to soak the dry paint sludge is dependant on the type of paint sludge used. 4. A process as claimed in claim 1 wherein the paint sludge is soaked in the solvent mixture over 1 to 72 hours. 5. A process as claimed in claim 1 wherein the solvent is selected from the group consisting of toluene, xylene, benzene, acetone, isobutyl alcohol, n-butyl alcohol, isopropyl alcohol, methyl ethyl ketone and any other conventional solvent or any mixture thereof. 6. A process as claimed in claim 1 wherein the solvent comprises a mixture of any one of toluene, xylene, benzene, acetone, isobutyl alcohol, n-butyl alcohol, isopropyl alcohol, methyl ethyl ketone and any other conventional solvent with another in an amount of 1 to 100%. 7. A process as claimed in claim 1 wherein the amount of solvent added to the dry sludge is in the range of 5 to 50% by weight of the dry sludge. 8. A process as claimed in claim 1 wherein the bitumen used is selected from bitumen in the range of 60 to 120 grade or any other grade prescribed for road or construction work. 9. A process as claimed in claim 1 wherein the resin added is selected from the group consisting of maleic resins, ketonic resins, petroleum resins (cumran indene resins), CNS resin and BNSL resin. 10. A process as claimed in claim 1 wherein the resin is added to the heated sludge and bitumen mixture in the form of a solution in a solvent selected from the group consisting of toluene, toluene with butyl acetate, benzene with butyl acetate and benzene with xylene. 11. A process as claimed in claim 1 wherein the resin solution to sludge ratio is in the ratio of 1:0.1 to 1:3 to obtain a resin content of 5 to 30% by weight of the sludge. 12. A process as claimed in claim 1 wherein an octate drying agent selected from the group consisting of cobalt octate, calcium octate, manganese octate, and zirconium octate is added to the mixture comprising the heated sludge, resin and heated bitumen during stirring. 13. A process as claimed in claim 1 wherein the paint sludge comprises sludge of amino alkyd based paints. 14. A process as claimed in claim 13 wherein the solvent mixture comprises toluene in an amount of 20 to 40 %, xylene in an amount of 25 to 35 %, n-butyl alcohol in an amount of 10 to 20 %, butyl cellulose in an amount of 5 to 20 % and cellosol acetate in an amount of 1 to 3 %. 15. A process as claimed in claim 1 wherein the paint sludge comprises sludge of polyester melamine based paints. 16. A process as claimed in claim 15 wherein the solvent mixture comprises toluene or benzene in an amount of 28 to 40 %, xylene in an amount of 22 to 38 %, n-butyl alcohol or methyl isobutyl ketone or methyl cellosol in an amount of 5 to 12 %, diacetone alcohol in an amount of 3 to 10 %, cellusol acetate or amyl acetate in an amount of 2 to 5 % by weight expressed in terms of the amount of the paint sludge to be treated. 17. A novel road repair or construction composition comprising paint sludge, bitumen and resin, the said ingredients being homogeneously mixed together. 18. A composition as claimed in claim 17 wherein paint sludge is taken from sludge of amino-alkyd based paint sludge, melamine polyester based paint sludge, thermosetting acrylic paint sludge and modified epoxy paint sludge. 19. A composition as claimed in claim 17 wherein bitumen used is selected from bitumen in the range of 50 to 120 grade or any other grade specified for road building or construction and the resin added is selected from the group consisting of maleic resins, ketonic resins, petroleum resins (cumran indene resins). 20. A composition as claimed in claim 17 wherein the resin is in the form of a solution in a solvent selected from the group consisting of toluene, toluene with butyl acetate, benzene with butyl acetate and benzene with xylene. 21. A composition as claimed in claim 17 wherein the resin solution to sludge ratio is in the ratio of 1:0.1 to 1:3 to obtain a resin content of 4 to 40% by weight of the sludge. 22. A composition as claimed in claim 17 wherein an octate drying agent selected from the group consisting of cobalt octate, calcium octate, manganese octate, and zirconium octate is added to the mixture comprising the heated sludge, resin and heated bitumen during stirring. 23. A composition as claimed in claim 17 wherein the paint sludge comprises sludge of amino alkyd based paints, or paint sludge comprises sludge of polyester melamine based paints. 24. A process for the preparation of a bitumenous composition substantially as described hereinbefore and with reference to the foregoing examples. 25. A novel road repair or construction composition substantially as described hereinbefore and with reference to the foregoing examples.

Documents:

13-10-2014_377-del-2004-abstract.pdf

13-10-2014_377-del-2004-claims.pdf

13-10-2014_Complete Specification.pdf

13-10-2014_Letter.pdf

13-10-2014_Reply to FER.pdf

377-del-2004-Abstract-(20-10-14}-1.pdf

377-DEL-2004-Abstract-(23-12-2014).pdf

377-del-2004-abstract.pdf

377-del-2004-Claims-(20-10-14}-1.pdf

377-DEL-2004-Claims-(23-12-2014).pdf

377-del-2004-claims.pdf

377-del-2004-Correspondance-(20-10-14}-1.pdf

377-del-2004-Correspondance-(20-10-14}.pdf

377-del-2004-Correspondence Others-(15-10-2014).pdf

377-DEL-2004-Correspondence Others-(23-12-2014).pdf

377-del-2004-Correspondence Others-(27-12-2012).pdf

377-del-2004-Correspondence Others-(29-05-2014).pdf

377-del-2004-correspondence-others.pdf

377-del-2004-correspondence-po.pdf

377-DEL-2004-Description (Complete)-(23-12-2014).pdf

377-DEL-2004-Description (Complete).pdf

377-del-2004-drawings.pdf

377-DEL-2004-Form-1-(23-12-2014).pdf

377-del-2004-form-1.pdf

377-del-2004-form-18.pdf

377-DEL-2004-Form-2-(23-12-2014).pdf

377-del-2004-Form-2-(29-05-2014).pdf

377-del-2004-form-2.pdf

377-del-2004-form-3.pdf

377-del-2004-form-5.pdf

377-del-2004-GPA-(20-10-14}.pdf

377-del-2004-gpa.pdf

377-del-2004-Others (Claims copy)-(20-10-14}-1.pdf

Complete Specification.pdf

Letter.pdf

Reply to FER.pdf