Title of Invention	A NOVEL COMPOSITION USEFUL FOR MAKING RADIATION SHIELD MATERIAL
Abstract	The present invention provides a novel composition useful as radiation shielding material. The composition comprises of powdered ceramic composition, polymer and additives, wherein the ceramic composition is obtained from industrial wastes such as red mud, fly ash, rice hulls silica etc. The polymers used are thermoplastic or thermoset materials. The present invention also provides the process of production of the novel composition comprising the steps of mixing the ceramics, polymers and additives at a temperature range of 20°C -280°C for a period of 5-180 minutes under shear action and molding to desired shape using conventional molding techniques.

Title of Invention

A NOVEL COMPOSITION USEFUL FOR MAKING RADIATION SHIELD MATERIAL

Abstract

The present invention provides a novel composition useful as radiation shielding material. The composition comprises of powdered ceramic composition, polymer and additives, wherein the ceramic composition is obtained from industrial wastes such as red mud, fly ash, rice hulls silica etc. The polymers used are thermoplastic or thermoset materials. The present invention also provides the process of production of the novel composition comprising the steps of mixing the ceramics, polymers and additives at a temperature range of 20°C -280°C for a period of 5-180 minutes under shear action and molding to desired shape using conventional molding techniques.

Full Text	Field of the invention: This invention relates to a novel composition useful for the preparation of radiation shields. The present invention further relates to a process of production of the said composition. Radiation shield material comprising of dried powdered ceramic composition, polymer and additives. The present invention also relates to a composition useful for radiation shielding application for industrial and medical diagnostic and CT scanner rooms, X-ray facilities. Background and prior art of the invention; Shielding materials are used to provide shielding against radiation to protect sites where radiation is not required. In the field of medicines radiation is used at a required level and at a particular region beyond that it may be harmful. Lead or lead alloys are presently used for protection against radiation. They are melted and shaped to desired dimensions using moulds. Spheres of lead having diameter of a few millimeters are also used to fill the case of desired dimensions. These methods need lots of energy and require fabrication of mould /case and tooling. For minor modifications or adjustments in the shape of shielding component these fabrication methods are not adequate. Production and application of lead based components are facing problems due to their high density that is 11.34 g/cm3 and the toxic nature. The other metals those are capable of attenuation of X-ray include copper, aluminum, titanium, iron/steel, chromium, magnesium and barium etc. as can be referred to scientific paper by Quan Lin et al in journal "Polymer ", volume number 41, year 2000, page 8305 to 8309. P. Soo and L. M. Milian reported in Journal of Material Science Letters, volume number 20, year 2001, page 1345 to 1348 that concrete is also often used as attenuation material. Polymers containing heavy metals in polymeric chains as reported in Japanese patents Kokai Tokkyo Koho, 157092, (1985) and Kokai Tokkyo Koho, 98765, (1986)] or as reported in European Patent application number 19121 wherein the metal oxides dispersed polymer display radio-pack properties. The lead / rare-earths containing glasses made from oxides of silicon/aluminum/zinc etc. also exhibit X-ray attenuation properties as reported by Ching -hwa lee and Chi - Shiung in Environment Science and Technology in the year 2000, volume 36, page 69-75. The processes for making X-ray attenuation materials based on lead metal, lead bearing glasses or lead compound dispersed polymer composites suffer due to toxicity of lead. Further, the lead bearing tiles/sheets/bricks are significantly heavy in weight. The use of concrete for X-ray attenuation suffers on account of a gradual decrease in its mechanical strength with the period of exposure. Lead-free X-ray radiation absorbing composites based on environment friendly powder mixtures of 1) Oxides and fluorides of rare earth metals of a group of cerium and dysprosium family, ii) Chemical compounds of some metals such as Sn, Zn, W, etc.), and iii) the various types of binders (special rubbers, resins, cement composites) have been developed. However, having high advantages in ecological safety, life time, and wider energy range of shielding the new materials apart form being costly, exhibited a high ability to generate secondary fluorescent flov s of radiation. This disadvantage is eliminated by application of lead-free multi-layer shield structure consisting of main X-ray radiation absorbing layer efficiently attenuating the primary radiation flow and auxiliary multi-layer shield efficiently attenuating secondary fluorescent flows in a cascade manner. The positive effect is attained by optimization the composition and uniform distribution of X-ray absorbing components in the main protective layer and proper selection structure and thickness of the auxiliary shield. The technique and principal process for multilayer shields, for instance, to protect doors, window openings, walls, ceilings of X-ray rooms with standard disposition to a radiation source using lead-free rubbers, special paint coatings and non-organic tiles in combination with conventional materials have been developed and tested. Very recently lead containing optical resin has also been reported to exhibit good absorption for X-rays. In the area of shielding materials, on the account of toxic characteristics of lead the alternative materials for shielding are based on Rare Earths. However the cost of rare earths prohibits their wide spread use. Hitoshi Tomita et al claimed in a US patent application number 20040029998 AI a non lead inorganic powders such as Tungsten or Barium sulfate etc of specific gravity above 4 at 70 to 98 % by weight dispersed in a thermoplastic material by melt blending offers radiation shielding properties. This material can be easily cut by a scissor as well. United States Patent 5,550,383 by Haskell claimed a remoldable thermoplastic radiation shield for use during radiation therapy for protecting healthy tissue during radiotherapy of malignant tissue. The shielding device is composed of nontoxic, high atomic weight metal particles that are dispersed in a thermoplastic matrix material that is substantially rigid at temperatures encountered during radiotherapy, yet becomes readily moldable at temperatures that are within a comfortable range for a patient so as to enable in situ molding of the device. Similarly in US Patent No. 5,190,990 Eichmiller claims nontoxic metal particles dispersed in thermosetting material to give a shielding material. The above-mentioned literature review clearly shows that a non-toxic, lightweight, environment friendly, easily formable economical alternative radiation shield material is not available and hence needed in various applications as indicated earlier. More precisely no reference is available in the literature related to ceramic composition derived from waste material and dispersed in polymer to offer radiation shielding. The present invention provides a novel composition for making radiation-shield material to obviate the drawbacks as detailed above. Objects of the invention: The main object of this invention is to provide a novel composition useful as radiation shield material comprising of dried powdered ceramic composition in the range of 60 to 95°A- by weight, polymer in the range of 5% to 40% by weight and additives in the range of 0 to 20% by weight. Another object of this invention is to provide a process of production of the said composition. Yet another object of this invention is to provide composition useful for radiation shielding application for industrial and medical diagnostic and CT scanner rooms, X-ray facilities Summary of the invention; Accordingly, the present invention provides a novel composition useful for making radiation shield material comprising of dried powdered ceramic composition in the range of 60 to 95% by weight, polymer in the range of 5% to 40% by weight and additives in the range of 0 to 20% by weight. In ah embodiment of the present invention, the ceramic composition is obtained from industrial wastes such as red mud, fly ash and rice hulls silica as claimed in our co-pending application 1888/DEL/2004. In an embodiment of present invention, ceramic composition would be obtained from industrial wastes in the processed forms by mixing industrial waste such as red mud, fly ash and rice hulls silica and barium -containing-compounds such as barium carbonate in the range of 11-88 % and a alkali phosphate binder namely sodium hexa meta phosphate f in the range of 7-15 and compacted in a steel mould at a pressure in the range of 100-300 kg/cm2 to obtain green samples then dried in an air oven at 110°C for a period of 1-3 h. and thermally treated at temperature in the range of 920 to 1300°C for a period of 1-3 h in air environment to form the different silicate phases of oxides of metals such as titanium, barium, iron, aluminum and silicon those already present in red mud, fly ash and rice hulls silica followed by a treatment with ethylene glycol in the range of 0-20 % at temperature in the range of 100 to 130°C as disclosed in prior application number 1888/DEL/2004. In still another embodiment of present invention, the ceramic powder used may be obtained from industrial waste such as red mud, fly ash, rice hulls silica or pure forms of metal silicates selected from barium titanium, iron, alluminium, silicon metals. In yet an another embodiment of present invention, the polymer materials may be selected from thermoplastics: polypropylene, polyethylene, polystyrene, poly vinyl chloride, polyamides, polyacrylates, polycarbonates and thermosets: polyurethane, unsaturated polyester, epoxy resin, modified epoxy resin, phenolic resin, melamine formaldehyde, urea formaldehyde, alkyd resins and cashew nut shell liquid modified resins. In yet another embodiment of the present invention, extruder, kneader, two-roll mill, sigma mixer, and intensive mixer may be utilized for mixing of materials. In yet another embodiment of the present invention, the polymers can be dissolved in suitable solvent such as hydrocarbons, formamides, monomers of polymers mentioned earlier and thereafter mixed with ceramic composition followed by solvent evaporation, grinding and compression molding by conventional methods. In still another embodiment of the present invention, the moulding of tiles can be done by injection moulding technique, compression-moulding technique or through extruder. Further in another embodiment of the present invention, the additives used can be selected from calcium stearate in the range 0 to 2.0 wt%, carbon black 0 to 2 wt%, antioxidant 0 to 1 wt%, titanium dioxide 0 to 20 wt%, zinc oxide 0 to 2 wt%. In another embodiment of the present invention, the antioxidant can be selected from HALS-2 (Hindered Amine Light Stabilizer Tinuvin 622 of Ciba Speciality. Chemicals Limited), Irganox 1010 - Tetra kis [methylene-3(3,5-di-tert-betyl -4 hydroxyphenyl )-Propanoate] methane, Irgafos-168-tris (2,4-di-tert-butylphenyl) phosphit, Sandostab -PEPQ- tetrakis (2,4,di-tert-butyl phenyl) 4, 4 -biphynylen diphosphonite, TNPP - tris(4-nonyl phenyl) phosphite, Ultranox 618-distearyl penta erythrityl diphosphite, BHT - 2,6 di-tert-butyl phenol, Topanol CA (A Trisphenol ), Goodrite 3114 (B. F.Goorich) , Irganox 1330-Ethyl 330. Further in an embodiment of the present invention, the process of production of the said comoosition comprises the steps of mixing the ceramic composition, polymers and additives in a mixer at temperature in the range of 20°C to 280°C under shear action for a period of 5-180 minutes and molded to a desired shape by known molding techniques. In still another embodiment of the present invention, the mixer utilized for mixing the materials is selected from the group of extruder, kneader, two-roll mill, sigma mixer, and intensive mixer. In j'3t another embodiment of the present invention, the polymers are dissolved in suitable solvent selected from the group of hydrocarbons, formamides, monomers of polymers mentioned earlier and thereafter mixed with ceramic composition followed by solvent evaporation, grinding and compression molding by conventional methods. In still another embodiment of the present invention, the hydrocarbon is exemplified as benzene, toluene etc., and formamide exemplified as methyl formamide. In still another embodiment of the present invention, the molding of desired shape is by injection moulding technique, compression-moulding technique or through extruder. In still another embodiment of the present invention, the radiation shielding material of desired shape is used for shielding against radiation such as X ray. In s ill another embodiment of the present invention, the product is capable of shielding photon up to 200kV. The novelty and inventive steps of novel composition useful for making radiation shield material resides in the material selection consisting ceramic powder obtained from industrial wastes, polymer and additives. Detailed description of the invention; The present invention provides a novel composition useful for making radiation shield material using ceramic powder obtained from industrial wastes, polymer and additives. Weighed amount of ingredients would be mixed in a suitable mixer. In case of thermoplastic type of polymer, extruder or kneader can be used. Thermoplastics based radiation shield material extruded from extruder would be quenched in cold water and cut to small granules. These granules would be used in injection moulding machine for making tiles. In case of thermosetting type of resin/polymer sigma mixer can be used to mix the desired ingredients. The mixed mass would be transferred to a suitable mould by using a suitable technique. In case of thermoplastic materials injection moulding can be used. Granules would be fed through hopper of injection moulding machine. The temperature of barrel shall have range of 150 to 300°C. The plunger/screw of injection moulding machine shall be operated through electrical motor to inject the molten composite material in the mould of desired shape. For a thermosetting material compression moulding machine can be used. In that case the dough obtained from sigma mixer would be weighed accurately and transferred to the mould of desired shape. The mould shall be transferred to compression moulding machine and pressed between the hot platen of compression molding machine at desired temperature, pressure and time. Thereafter article/ tile would be removed from the mold. The process of making ceramic composition used in this invention as claimed in our co-pending application 1888/DEL/2004, comprising the following constituents: i) Fly ash waste material containing 62 -.64 % silica, 4-6 % iron oxide, 21-27 % alumina, 1.5-2.5 % manganesium oxide, 4- 5 % potassium oxide, 0.5-1.5% calcium oxide, ii) Red mud waste material containing 8.-10 % silica, 28-31. % iron oxide, 20- 24 % alumina, 19-21 % titanium oxide, 6-7 % sodium oxide and 4-5% calcium oxide; iii) Rice husk silica containing 92-93% silica, 0.8-1.0 % iron oxide, magnesium oxide 1.8-2.5% , 1.70-2.50 % sodium oxide and 2-3 % calcium oxide and potassium oxide 0.5-1.5% or; iv) Pyrophyllite containing silica 66 %, alumina 23-25 %, iron oxide 2-3%, titanium oxide 0.98-1.3 %, magnesium oxide 0.5 - 0.82 %, calcium oxide 1-2%, potassium oxide 0.37-0.50 %, sodium oxide 0.13-0.25 %. The, process of production of the ceramic composition useful for radiation shielding, as claimed in another co-pending application 1888/DEL/2004, comprises of the following steps: (a) homogenizing these raw materials along with barium carbonate in the range of 11-88 % and alkali phosphatic binder namely sodium hexa meta phosphate in the range of 7-15%. (b) homogenized raw materials mix as oabtained from step (a) is compacted in a steel mould at a pressure in the range of 100-300 kg/cm to obtain green samples. (c) green samples as obtained from step (b) are dried in an air oven at 110°C for a period of 1 -3 hours. (d) dried samples as obtained from step (c) are then fired in the temperature range of 920 - 1300°C for a soaking time of 1-3 hours in a muffle furnace under air environment. (e) ceramic composition thus produced in step (d) is further treated with ethylene glycol and after oven drying was ready to use with polymer as detailed in earlier paragraphes. The following examples are given by way of illustration and should not be construed to limit the scope of the present invention. Example -1 Following ingredients were taken Ingredients 1. Polypropylene 2. Ceramic powder obtained from red mud 3. Carbon black The Polypropylene and ceramic powder were weighed and dried in an oven at 60°C for 4 hours to remove moisture from the granules in air circulating oven. Thereafter they were dry blended and fed to the hopper of an extruder. The temperature of feed zone, compression zone, melting zone and of the die were kept constant at 180, 200, 220 and 230°C. The speed of extruder was kept at 20 rpm. The extrudate was obtained in the form of strand, which was then cut to 3 mm - 5-mm size. These granules were injection moulded into rectangular piece of 15 mm thickness at 180°C on a conventional injection- molding machine. The industrial waste red mud containing 8.0 % silica, 31.0 % iron oxide, 20.0 %, alumina, 21.0 % titanium oxide, 6.0 % sodium oxide and 4.0 % calcium oxide and the rice husk silica containing 92.2.0 % silica, 0.8 % iron oxide, magnesium oxide 1.8% , 1.70 % sodium oxide and 2.1 % calcium oxide and potassium oxide 0.5%, was used in the present example for making ceramic composition wherein 40 g of red mud, 50 g of barium carbonate, and 10.0 g of sodium hexameta phosphate were mixed thoroughly to obtain a homogeneous powder mix. The mix so obtained was then compacted and samples were then dried in an air-circulating oven for duration of two hours at 110°C. The dried samples were then sintered at 1000 C for one hour in air environment. The shield material prepared by the present invention were evaluated for their X-ray attenuation characteristics using normal beam qualities and characteristics at a distance of 60 cm from the surface of the cone to the center of the chamber (i.e. at a distance of lOOcms from the X-ray focal spot). The testing was carried out using the X-ray normal beam quality of 100 kV with 0.2 mm Cu - Filter and the sample thickness was 15 mm. The sample passed the test; shielding completely the photon at lOOkV. Example -2 Following ingredients were taken Ingredients 1. Polystyrene 2. Ceramic powder from red mud 3. Toluene The polystyrene was dissolved in toluene and mixed with ceramic powder and then solvent was evaporated in the air circulating oven. Polystyrene coated ceramic material was ground to fine size. The powder was pressed at 50 kgf / cm2 on conventional compression molding machine at 140°C for 5 minutes. The mould was cooled by circulating cold water for a uniform cooling of sample before removing from the mould. The industrial waste red mud containing 8.0 % silica, 31.0 % iron oxide, 20.0 %, alumina, 21.0 % titanium oxide, 6.0 % sodium oxide and 4.0 % calcium oxide and the rice husk silica containing 92.2.0 % silica, 0.8 % iron oxide, magnesium oxide 1.8% , 1.70 % sodium oxide and 2.1 % calcium oxide and potassium oxide 0.5%, was used in the present example for making ceramic composition wherein 40 g of red mud, 50 g of barium carbonate, and 10.0 g of sodium hexa-meta phosphate were mixed thoroughly to obtain a homogeneous powder mix. The mix so obtained was then compacted and samples were then dried in an air-circulating oven for duration of two hours at 110°C. The dried samples were then sintered at 1000 °C for one hour in air environment. The shield material prepared by the present invention were evaluated for their X-ray attenuation characteristics using normal beam qualities and characteristics at a distance of 60 cm from the surface of the cone to the center of the chamber (i.e. at a distance of lOOcms from the X-ray focal spot). The testing was carried out using the X-ray normal beam quality of 100 kV with 0.2 mm Cu - Filter and the sample thickness was 10.3 mm. The sample passed the test; shielding completely the photon at lOOkV. Example-3 Following ingredients were taken Ingredients 1. Polypropylene 2. Ceramic powder from fly ash 3. Titanium dioxide 4. Zinc oxide 5. Calcium stearate The Polypropylene and ceramic powder were weighed and dried in an oven at 60°C for 4 hours to remove moisture from the granules in air circulating oven. Thereafter they were dry blended with Titanium dioxide, Zinc oxide, Calcium stearate and fed to the two-roll mill. The temperature of rolls was kept constant at 180°C. The mix was obtained in the form of sheets which, was then cut to small size and were injection moulded into rectangular piece of 15 mm thickness at 180°C on a conventional injection-molding machine. The fly ash waste material containing 62 .12% silica, 5.55% iron oxide, 21.30 % alumina, 1.58 % magnesium oxide, 4.24 % potassium oxide, 0.53% calcium oxide and rice husk silica containing 92.2.0 % silica, 0.8 % iron oxide, 1.8% magnesium oxide, 1.70 % sodium oxide, 2.1% calcium oxide and potassium oxide 0.5%, was used in the present example. 40 g of fly ash, 50 g. of barium carbonate, and 10.0 g of sodium hexameta phosphate were mixed thoroughly to obtain a homogeneous powder mix. The mix so obtained was then compacted in a steel mould to obtain green samples. The green samples were then dried in an air oven for a duration of two hours at 110 °C. The dried samples were then sintered at 950 °C, for a period of two hours in air environment. The shield material prepared by the present invention were evaluated for their X-ray attenuation characteristics using normal beam qualities and characteristics at a distance of 60 cm from the surface of the cone to the center of the chamber (i.e. at a distance of lOOcms from the X-ray focal spot). The testing was carried out using the X-ray normal beam quality of 100 kV with 0.2 mm Cu - Filter and the sample thickness was 15 mm. The sample passed the test; shielding completely the photon at lOOkV. Example —4 Ingredients Weight Percent 1. Polysulphide modified epoxy resin system 30% 2. Ceramic powder from fly ash 70 % Both ingredients were mixed in a sigma mixer and dough obtained was transferred to the mold. The dough is pressed with punch in the mould with 15 kg / cm2 pressure at room temperature for 1 h. Sample was post cured at 160°C for 6 hours. The fly ash waste material containing 62.12% silica, 5.55% iron oxide, 21.30 % alumina, 1.58 % magnesium oxide, 4.24 % potassium oxide, 0.53% calcium oxide was used in the present example. 40 g of fly ash, 50 g. of barium carbonate, and 10.0 g of sodium hexameta phosphate were mixed thoroughly to obtain a homogeneous powder mix. The mix so obtained was then compacted in a steel mould to obtain green samples. The green samples were then dried in an air oven for duration of two hours at 110 °C. The dried samples were then sintered at 950 °C, for a period of two hours in air environment. The shield material prepared by the present invention were evaluated for their X-ray attenuation characteristics using normal beam qualities and characteristics at a distance of 60 cm from the surface of the cone to the center of the chamber (i.e. at a distance of lOOcms from the X-ray focal spot). The testing was carried out using the X-ray normal beam quality of 100 kV with 0.2 mm Cu - Filter and the sample thickness was 25 mm. The sample passed the test; shielding completely the photon at 200kV. Advantages: The main advantages of the present invention are i) This composition utilizes the industrial waste. ii) This composition is eco-friendly and helps in utilizing non-degradable industrial waste, iii) This composition can efficiently be used to produce radiation shield material such as tiles, iv) This composition utilizes raw materials such as fly ash and red mud which is available in powder form itself and thus saves grinding energy, which otherwise is necessary for grinding of raw materials in conventional processes to obtain them in powder form. v) The novel composition does not require the use of costly metals and rare earth. We claim: 1. A composition for making radiation shield material comprising of dried ceramic powder in the range of 60 to 95% by weight, polymer material selected from thermoplastic or thermosetting in the range of 5% to 40% by weight and additives in the range of 0 to 20% by weight. 2. The composition as claimed in claim 1, wherein the thermoplastics polymer comprising of polypropylene, polyethylene, polystyrene, polyvinyl chloride, polyamides, polyacrylates, polycarbonates and thermosets polymer comprising of polyurethane, unsaturated polyester, epoxy resin, modified epoxy resin, phenolic resin, melamine formaldehyde, urea formaldehyde, alkyd resins and cashew nut shell liquid modified resins. 3. The composition as claimed in claim 1, wherein the additives are selected from the group comprising of calcium stearate, carbon black, antioxidant, titanium dioxide, zinc oxide. 4. The composition as claimed in claim 3, wherein the additives is selected from the group consisting of calcium stearate in the range 0 to 2.0 wt%, carbon black 0 to 2 wt%, antioxidant 0 to 1 wt%, titanium dioxide 0 to 20 wt%, zinc oxide 0 to 2 wt%. 5. The composition as claimed in claim 3, wherein the antioxidant can be selected from Poly-(N-Beta-hydroxyethyl-2,2,6,6-tetramethyl-4-hydroxy-piperidyl succinate), Pentaerythritol tetrakis(3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate), (2,4-di-tertbutylphenyl) Phosphite, [4-[4-bis(2,4-ditert-butylphenoxy)phosphanylphenyl]phenyl]- bis(2,4-ditert-butylphenoxy)phosphane, tris(4-nonyl phenyl) phosphite, distearyl penta erythrityl diphosphite, 2,6 di-tert-butyl phenol, 4-[I ,3-bis(5-tert-butyl-4- hydroxy-2-methylphenyl)butyl]-2-tert-butyl-5-methylphenol, 1,3,5-Trimethyl-2,4,6- tris(3,5-di-tert-butyl-4-hydroxybenzy1)benzene. 6. A process for production of a composition as claimed in claim 1, comprising; mixing the dried ceramic powder in the range of 60 to 95% by weight, polymer material selected from thermoplastic or thermosetting in the range of 5% to 40% by weight and additives in the range of 0 to 20% by weight in a mixer at temperature in the range of 20°C to 280°C under shear action for a period of 5-180 minutes to obtain said composition. 7. A process as claimed in claim 6, wherein the mixer utilized for mixing the materials is selected from the group of extruder, kneader, two-roll mill, sigma mixer, and intensive mixer.

Full Text

Field of the invention:
This invention relates to a novel composition useful for the preparation of radiation shields. The present invention further relates to a process of production of the said composition. Radiation shield material comprising of dried powdered ceramic composition, polymer and additives.
The present invention also relates to a composition useful for radiation shielding application for industrial and medical diagnostic and CT scanner rooms, X-ray facilities.
Background and prior art of the invention;
Shielding materials are used to provide shielding against radiation to protect sites where radiation is not required. In the field of medicines radiation is used at a required level and at a particular region beyond that it may be harmful. Lead or lead alloys are presently used for protection against radiation. They are melted and shaped to desired dimensions using moulds. Spheres of lead having diameter of a few millimeters are also used to fill the case of desired dimensions. These methods need lots of energy and require fabrication of mould /case and tooling. For minor modifications or adjustments in the shape of shielding component these fabrication methods are not adequate. Production and application of lead based components are facing problems due to their high density that is 11.34 g/cm3 and the toxic nature. The other metals those are capable of attenuation of X-ray include copper, aluminum, titanium, iron/steel, chromium, magnesium and barium etc. as can be referred to scientific paper by Quan Lin et al in journal "Polymer ", volume number 41, year 2000, page 8305 to 8309. P. Soo and L. M. Milian reported in Journal of Material Science Letters, volume number 20, year 2001, page 1345 to 1348 that concrete is also often used as attenuation material. Polymers containing heavy metals in polymeric chains as reported in Japanese patents Kokai Tokkyo Koho, 157092, (1985) and Kokai Tokkyo Koho, 98765, (1986)] or as reported in European Patent application number 19121 wherein the metal oxides dispersed polymer display radio-pack properties. The lead / rare-earths containing glasses made from oxides of silicon/aluminum/zinc etc. also exhibit X-ray attenuation properties as reported by Ching -hwa lee and Chi - Shiung in Environment Science and Technology in the year 2000, volume 36, page 69-75.

The processes for making X-ray attenuation materials based on lead metal, lead bearing glasses or lead compound dispersed polymer composites suffer due to toxicity of lead. Further, the lead bearing tiles/sheets/bricks are significantly heavy in weight. The use of concrete for X-ray attenuation suffers on account of a gradual decrease in its mechanical strength with the period of exposure.
Lead-free X-ray radiation absorbing composites based on environment friendly powder mixtures of 1) Oxides and fluorides of rare earth metals of a group of cerium and dysprosium family, ii) Chemical compounds of some metals such as Sn, Zn, W, etc.), and iii) the various types of binders (special rubbers, resins, cement composites) have been developed. However, having high advantages in ecological safety, life time, and wider energy range of shielding the new materials apart form being costly, exhibited a high ability to generate secondary fluorescent flov s of radiation. This disadvantage is eliminated by application of lead-free multi-layer shield structure consisting of main X-ray radiation absorbing layer efficiently attenuating the primary radiation flow and auxiliary multi-layer shield efficiently attenuating secondary fluorescent flows in a cascade manner. The positive effect is attained by optimization the composition and uniform distribution of X-ray absorbing components in the main protective layer and proper selection structure and thickness of the auxiliary shield. The technique and principal process for multilayer shields, for instance, to protect doors, window openings, walls, ceilings of X-ray rooms with standard disposition to a radiation source using lead-free rubbers, special paint coatings and non-organic tiles in combination with conventional materials have been developed and tested. Very recently lead containing optical resin has also been reported to exhibit good absorption for X-rays.
In the area of shielding materials, on the account of toxic characteristics of lead the alternative materials for shielding are based on Rare Earths. However the cost of rare earths prohibits their wide spread use.
Hitoshi Tomita et al claimed in a US patent application number 20040029998 AI a non lead inorganic powders such as Tungsten or Barium sulfate etc of specific gravity above 4 at 70 to 98 % by weight dispersed in a thermoplastic material by melt blending offers radiation shielding properties. This material can be easily cut by a scissor as well. United States Patent 5,550,383 by Haskell claimed a remoldable thermoplastic radiation shield for use during radiation therapy for protecting healthy tissue during radiotherapy of

malignant tissue. The shielding device is composed of nontoxic, high atomic weight metal particles that are dispersed in a thermoplastic matrix material that is substantially rigid at temperatures encountered during radiotherapy, yet becomes readily moldable at temperatures that are within a comfortable range for a patient so as to enable in situ molding of the device. Similarly in US Patent No. 5,190,990 Eichmiller claims nontoxic metal particles dispersed in thermosetting material to give a shielding material. The above-mentioned literature review clearly shows that a non-toxic, lightweight, environment friendly, easily formable economical alternative radiation shield material is not available and hence needed in various applications as indicated earlier. More precisely no reference is available in the literature related to ceramic composition derived from waste material and dispersed in polymer to offer radiation shielding. The present invention provides a novel composition for making radiation-shield material to obviate the drawbacks as detailed above.
Objects of the invention:
The main object of this invention is to provide a novel composition useful as radiation
shield material comprising of dried powdered ceramic composition in the range of 60 to
95°A- by weight, polymer in the range of 5% to 40% by weight and additives in the range
of 0 to 20% by weight.
Another object of this invention is to provide a process of production of the said
composition.
Yet another object of this invention is to provide composition useful for radiation
shielding application for industrial and medical diagnostic and CT scanner rooms, X-ray
facilities
Summary of the invention;
Accordingly, the present invention provides a novel composition useful for making radiation shield material comprising of dried powdered ceramic composition in the range of 60 to 95% by weight, polymer in the range of 5% to 40% by weight and additives in the range of 0 to 20% by weight.

In ah embodiment of the present invention, the ceramic composition is obtained from industrial wastes such as red mud, fly ash and rice hulls silica as claimed in our co-pending application 1888/DEL/2004.
In an embodiment of present invention, ceramic composition would be obtained from industrial wastes in the processed forms by mixing industrial waste such as red mud, fly ash and rice hulls silica and barium -containing-compounds such as barium carbonate in the range of 11-88 % and a alkali phosphate binder namely sodium hexa meta phosphate
f
in the range of 7-15 and compacted in a steel mould at a pressure in the range of 100-300 kg/cm2 to obtain green samples then dried in an air oven at 110°C for a period of 1-3 h. and thermally treated at temperature in the range of 920 to 1300°C for a period of 1-3 h in air environment to form the different silicate phases of oxides of metals such as titanium, barium, iron, aluminum and silicon those already present in red mud, fly ash and rice hulls silica followed by a treatment with ethylene glycol in the range of 0-20 % at temperature in the range of 100 to 130°C as disclosed in prior application number 1888/DEL/2004.
In still another embodiment of present invention, the ceramic powder used may be obtained from industrial waste such as red mud, fly ash, rice hulls silica or pure forms of metal silicates selected from barium titanium, iron, alluminium, silicon metals.
In yet an another embodiment of present invention, the polymer materials may be selected from thermoplastics: polypropylene, polyethylene, polystyrene, poly vinyl chloride, polyamides, polyacrylates, polycarbonates and thermosets: polyurethane, unsaturated polyester, epoxy resin, modified epoxy resin, phenolic resin, melamine formaldehyde, urea formaldehyde, alkyd resins and cashew nut shell liquid modified resins.
In yet another embodiment of the present invention, extruder, kneader, two-roll mill, sigma mixer, and intensive mixer may be utilized for mixing of materials.

In yet another embodiment of the present invention, the polymers can be dissolved in suitable solvent such as hydrocarbons, formamides, monomers of polymers mentioned earlier and thereafter mixed with ceramic composition followed by solvent evaporation, grinding and compression molding by conventional methods.
In still another embodiment of the present invention, the moulding of tiles can be done by injection moulding technique, compression-moulding technique or through extruder.
Further in another embodiment of the present invention, the additives used can be selected from calcium stearate in the range 0 to 2.0 wt%, carbon black 0 to 2 wt%, antioxidant 0 to 1 wt%, titanium dioxide 0 to 20 wt%, zinc oxide 0 to 2 wt%.
In another embodiment of the present invention, the antioxidant can be selected from HALS-2 (Hindered Amine Light Stabilizer Tinuvin 622 of Ciba Speciality. Chemicals Limited), Irganox 1010 - Tetra kis [methylene-3(3,5-di-tert-betyl -4 hydroxyphenyl )-Propanoate] methane, Irgafos-168-tris (2,4-di-tert-butylphenyl) phosphit, Sandostab -PEPQ- tetrakis (2,4,di-tert-butyl phenyl) 4, 4 -biphynylen diphosphonite, TNPP - tris(4-nonyl phenyl) phosphite, Ultranox 618-distearyl penta erythrityl diphosphite, BHT - 2,6 di-tert-butyl phenol, Topanol CA (A Trisphenol ), Goodrite 3114 (B. F.Goorich) , Irganox 1330-Ethyl 330.
Further in an embodiment of the present invention, the process of production of the said comoosition comprises the steps of mixing the ceramic composition, polymers and additives in a mixer at temperature in the range of 20°C to 280°C under shear action for a period of 5-180 minutes and molded to a desired shape by known molding techniques.
In still another embodiment of the present invention, the mixer utilized for mixing the materials is selected from the group of extruder, kneader, two-roll mill, sigma mixer, and intensive mixer.
In j'3t another embodiment of the present invention, the polymers are dissolved in suitable solvent selected from the group of hydrocarbons, formamides, monomers of

polymers mentioned earlier and thereafter mixed with ceramic composition followed by solvent evaporation, grinding and compression molding by conventional methods.
In still another embodiment of the present invention, the hydrocarbon is exemplified as benzene, toluene etc., and formamide exemplified as methyl formamide.
In still another embodiment of the present invention, the molding of desired shape is by injection moulding technique, compression-moulding technique or through extruder.
In still another embodiment of the present invention, the radiation shielding material of desired shape is used for shielding against radiation such as X ray.
In s ill another embodiment of the present invention, the product is capable of shielding photon up to 200kV.
The novelty and inventive steps of novel composition useful for making radiation shield material resides in the material selection consisting ceramic powder obtained from industrial wastes, polymer and additives.
Detailed description of the invention;
The present invention provides a novel composition useful for making radiation shield material using ceramic powder obtained from industrial wastes, polymer and additives. Weighed amount of ingredients would be mixed in a suitable mixer. In case of thermoplastic type of polymer, extruder or kneader can be used. Thermoplastics based radiation shield material extruded from extruder would be quenched in cold water and cut to small granules. These granules would be used in injection moulding machine for making tiles.
In case of thermosetting type of resin/polymer sigma mixer can be used to mix the desired ingredients. The mixed mass would be transferred to a suitable mould by using a suitable technique.
In case of thermoplastic materials injection moulding can be used. Granules would be fed through hopper of injection moulding machine. The temperature of barrel shall have range of 150 to 300°C. The plunger/screw of injection moulding machine shall be operated through electrical motor to inject the molten composite material in the mould of desired shape.
For a thermosetting material compression moulding machine can be used. In that case the dough obtained from sigma mixer would be weighed accurately and transferred to the mould of desired shape. The mould shall be transferred to compression moulding machine and pressed between the hot platen of compression molding machine at desired temperature, pressure and time. Thereafter article/ tile would be removed from the mold.
The process of making ceramic composition used in this invention as claimed in our co-pending application 1888/DEL/2004, comprising the following constituents:
i) Fly ash waste material containing 62 -.64 % silica, 4-6 % iron oxide, 21-27 %
alumina, 1.5-2.5 % manganesium oxide, 4- 5 % potassium oxide, 0.5-1.5%
calcium oxide, ii) Red mud waste material containing 8.-10 % silica, 28-31. % iron oxide, 20- 24
% alumina, 19-21 % titanium oxide, 6-7 % sodium oxide and 4-5% calcium
oxide; iii) Rice husk silica containing 92-93% silica, 0.8-1.0 % iron oxide, magnesium
oxide 1.8-2.5% , 1.70-2.50 % sodium oxide and 2-3 % calcium oxide and
potassium oxide 0.5-1.5% or; iv) Pyrophyllite containing silica 66 %, alumina 23-25 %, iron oxide 2-3%, titanium
oxide 0.98-1.3 %, magnesium oxide 0.5 - 0.82 %, calcium oxide 1-2%,
potassium oxide 0.37-0.50 %, sodium oxide 0.13-0.25 %.
The, process of production of the ceramic composition useful for radiation shielding, as claimed in another co-pending application 1888/DEL/2004, comprises of the following steps:
(a) homogenizing these raw materials along with barium carbonate in the range of
11-88 % and alkali phosphatic binder namely sodium hexa meta phosphate in
the range of 7-15%.
(b) homogenized raw materials mix as oabtained from step (a) is compacted in a
steel mould at a pressure in the range of 100-300 kg/cm to obtain green
samples.
(c) green samples as obtained from step (b) are dried in an air oven at 110°C for a
period of 1 -3 hours.
(d) dried samples as obtained from step (c) are then fired in the temperature range
of 920 - 1300°C for a soaking time of 1-3 hours in a muffle furnace under air
environment.
(e) ceramic composition thus produced in step (d) is further treated with ethylene
glycol and after oven drying was ready to use with polymer as detailed in earlier
paragraphes.
The following examples are given by way of illustration and should not be construed to limit the scope of the present invention.
Example -1

Following ingredients were taken Ingredients
1. Polypropylene
2. Ceramic powder obtained from red mud
3. Carbon black
The Polypropylene and ceramic powder were weighed and dried in an oven at 60°C for 4 hours to remove moisture from the granules in air circulating oven. Thereafter they were dry blended and fed to the hopper of an extruder. The temperature of feed zone, compression zone, melting zone and of the die were kept constant at 180, 200, 220 and 230°C. The speed of extruder was kept at 20 rpm. The extrudate was obtained in the form of strand, which was then cut to 3 mm - 5-mm size. These granules were injection moulded into rectangular piece of 15 mm thickness at 180°C on a conventional injection-
molding machine. The industrial waste red mud containing 8.0 % silica, 31.0 % iron oxide, 20.0 %, alumina, 21.0 % titanium oxide, 6.0 % sodium oxide and 4.0 % calcium oxide and the rice husk silica containing 92.2.0 % silica, 0.8 % iron oxide, magnesium oxide 1.8% , 1.70 % sodium oxide and 2.1 % calcium oxide and potassium oxide 0.5%, was used in the present example for making ceramic composition wherein 40 g of red mud, 50 g of barium carbonate, and 10.0 g of sodium hexameta phosphate were mixed thoroughly to obtain a homogeneous powder mix. The mix so obtained was then compacted and samples were then dried in an air-circulating oven for duration of two hours at 110°C. The dried samples were then sintered at 1000 C for one hour in air environment.
The shield material prepared by the present invention were evaluated for their X-ray attenuation characteristics using normal beam qualities and characteristics at a distance of 60 cm from the surface of the cone to the center of the chamber (i.e. at a distance of lOOcms from the X-ray focal spot). The testing was carried out using the X-ray normal beam quality of 100 kV with 0.2 mm Cu - Filter and the sample thickness was 15 mm. The sample passed the test; shielding completely the photon at lOOkV.
Example -2

Following ingredients were taken Ingredients
1. Polystyrene
2. Ceramic powder from red mud
3. Toluene
The polystyrene was dissolved in toluene and mixed with ceramic powder and then solvent was evaporated in the air circulating oven. Polystyrene coated ceramic material was ground to fine size. The powder was pressed at 50 kgf / cm2 on conventional compression molding machine at 140°C for 5 minutes. The mould was cooled by circulating cold water for a uniform cooling of sample before removing from the mould. The industrial waste red mud containing 8.0 % silica, 31.0 % iron oxide, 20.0 %, alumina, 21.0 % titanium oxide, 6.0 % sodium oxide and 4.0 % calcium oxide and the rice husk silica containing 92.2.0 % silica, 0.8 % iron oxide, magnesium oxide 1.8% ,
1.70 % sodium oxide and 2.1 % calcium oxide and potassium oxide 0.5%, was used in the present example for making ceramic composition wherein 40 g of red mud, 50 g of barium carbonate, and 10.0 g of sodium hexa-meta phosphate were mixed thoroughly to obtain a homogeneous powder mix. The mix so obtained was then compacted and samples were then dried in an air-circulating oven for duration of two hours at 110°C. The dried samples were then sintered at 1000 °C for one hour in air environment. The shield material prepared by the present invention were evaluated for their X-ray attenuation characteristics using normal beam qualities and characteristics at a distance of 60 cm from the surface of the cone to the center of the chamber (i.e. at a distance of lOOcms from the X-ray focal spot). The testing was carried out using the X-ray normal beam quality of 100 kV with 0.2 mm Cu - Filter and the sample thickness was 10.3 mm. The sample passed the test; shielding completely the photon at lOOkV.
Example-3

Following ingredients were taken Ingredients
1. Polypropylene
2. Ceramic powder from fly ash
3. Titanium dioxide
4. Zinc oxide
5. Calcium stearate
The Polypropylene and ceramic powder were weighed and dried in an oven at 60°C for 4 hours to remove moisture from the granules in air circulating oven. Thereafter they were dry blended with Titanium dioxide, Zinc oxide, Calcium stearate and fed to the two-roll mill. The temperature of rolls was kept constant at 180°C. The mix was obtained in the form of sheets which, was then cut to small size and were injection moulded into rectangular piece of 15 mm thickness at 180°C on a conventional injection-molding machine.
The fly ash waste material containing 62 .12% silica, 5.55% iron oxide, 21.30 % alumina, 1.58 % magnesium oxide, 4.24 % potassium oxide, 0.53% calcium oxide and rice husk silica containing 92.2.0 % silica, 0.8 % iron oxide, 1.8% magnesium oxide,
1.70 % sodium oxide, 2.1% calcium oxide and potassium oxide 0.5%, was used in the present example. 40 g of fly ash, 50 g. of barium carbonate, and 10.0 g of sodium hexameta phosphate were mixed thoroughly to obtain a homogeneous powder mix. The mix so obtained was then compacted in a steel mould to obtain green samples. The green samples were then dried in an air oven for a duration of two hours at 110 °C. The dried samples were then sintered at 950 °C, for a period of two hours in air environment. The shield material prepared by the present invention were evaluated for their X-ray attenuation characteristics using normal beam qualities and characteristics at a distance of 60 cm from the surface of the cone to the center of the chamber (i.e. at a distance of lOOcms from the X-ray focal spot). The testing was carried out using the X-ray normal beam quality of 100 kV with 0.2 mm Cu - Filter and the sample thickness was 15 mm. The sample passed the test; shielding completely the photon at lOOkV.
Example —4
Ingredients Weight Percent
1. Polysulphide modified epoxy resin system 30%
2. Ceramic powder from fly ash 70 %
Both ingredients were mixed in a sigma mixer and dough obtained was transferred to the mold. The dough is pressed with punch in the mould with 15 kg / cm2 pressure at room temperature for 1 h. Sample was post cured at 160°C for 6 hours.
The fly ash waste material containing 62.12% silica, 5.55% iron oxide, 21.30 % alumina, 1.58 % magnesium oxide, 4.24 % potassium oxide, 0.53% calcium oxide was used in the present example. 40 g of fly ash, 50 g. of barium carbonate, and 10.0 g of sodium hexameta phosphate were mixed thoroughly to obtain a homogeneous powder mix. The mix so obtained was then compacted in a steel mould to obtain green samples. The green samples were then dried in an air oven for duration of two hours at 110 °C. The dried samples were then sintered at 950 °C, for a period of two hours in air environment. The shield material prepared by the present invention were evaluated for their X-ray attenuation characteristics using normal beam qualities and characteristics at a distance of 60 cm from the surface of the cone to the center of the chamber (i.e. at a distance of
lOOcms from the X-ray focal spot). The testing was carried out using the X-ray normal beam quality of 100 kV with 0.2 mm Cu - Filter and the sample thickness was 25 mm. The sample passed the test; shielding completely the photon at 200kV.
Advantages:
The main advantages of the present invention are
i) This composition utilizes the industrial waste.
ii) This composition is eco-friendly and helps in utilizing non-degradable industrial
waste, iii) This composition can efficiently be used to produce radiation shield material such
as tiles, iv) This composition utilizes raw materials such as fly ash and red mud which is
available in powder form itself and thus saves grinding energy, which otherwise is
necessary for grinding of raw materials in conventional processes to obtain them
in powder form. v) The novel composition does not require the use of costly metals and rare earth.

We claim:
1. A composition for making radiation shield material comprising of dried ceramic
powder in the range of 60 to 95% by weight, polymer material selected from
thermoplastic or thermosetting in the range of 5% to 40% by weight and additives in
the range of 0 to 20% by weight.
2. The composition as claimed in claim 1, wherein the thermoplastics polymer
comprising of polypropylene, polyethylene, polystyrene, polyvinyl chloride,
polyamides, polyacrylates, polycarbonates and thermosets polymer comprising
of polyurethane, unsaturated polyester, epoxy resin, modified epoxy resin,
phenolic resin, melamine formaldehyde, urea formaldehyde, alkyd resins and
cashew nut shell liquid modified resins.
3. The composition as claimed in claim 1, wherein the additives are selected from
the group comprising of calcium stearate, carbon black, antioxidant, titanium
dioxide, zinc oxide.
4. The composition as claimed in claim 3, wherein the additives is selected from the
group consisting of calcium stearate in the range 0 to 2.0 wt%, carbon black 0 to 2
wt%, antioxidant 0 to 1 wt%, titanium dioxide 0 to 20 wt%, zinc oxide 0 to 2 wt%.
5. The composition as claimed in claim 3, wherein the antioxidant can be selected from
Poly-(N-Beta-hydroxyethyl-2,2,6,6-tetramethyl-4-hydroxy-piperidyl succinate),
Pentaerythritol tetrakis(3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate), (2,4-di-tertbutylphenyl)
Phosphite, [4-[4-bis(2,4-ditert-butylphenoxy)phosphanylphenyl]phenyl]-
bis(2,4-ditert-butylphenoxy)phosphane, tris(4-nonyl phenyl) phosphite, distearyl
penta erythrityl diphosphite, 2,6 di-tert-butyl phenol, 4-[I ,3-bis(5-tert-butyl-4-
hydroxy-2-methylphenyl)butyl]-2-tert-butyl-5-methylphenol, 1,3,5-Trimethyl-2,4,6-
tris(3,5-di-tert-butyl-4-hydroxybenzy1)benzene.
6. A process for production of a composition as claimed in claim 1, comprising; mixing
the dried ceramic powder in the range of 60 to 95% by weight, polymer material selected
from thermoplastic or thermosetting in the range of 5% to 40% by weight and additives in the
range of 0 to 20% by weight in a mixer at temperature in the range of 20°C to 280°C under
shear action for a period of 5-180 minutes to obtain said composition.
7. A process as claimed in claim 6, wherein the mixer utilized for mixing the materials
is selected from the group of extruder, kneader, two-roll mill, sigma mixer,
and intensive mixer.

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Patent Number

259564

Indian Patent Application Number

777/DEL/2006

PG Journal Number

12/2014

Publication Date

21-Mar-2014

Grant Date

18-Mar-2014

Date of Filing

22-Mar-2006

Name of Patentee

COUNCIL OF SCIENTIFIC & INDUSTRIAL RESEARCH

Applicant Address

ANUSANDHAN BHAWAN, RAFI MARG, NEW DELHI-110001, INDIA.

Inventors:

#	Inventor's Name	Inventor's Address
1	NARAYAN RAO RAMAKRISHNAN	REGIONAL RESEARCH LABORATORY, HABIB GANJ NAKA, HOSHANGABAD ROAD, BHOPAL-462026 (M.P.) INDIA
2	SYED AZHAR RASHEED HASHMI	REGIONAL RESEARCH LABORATORY, HABIB GANJ NAKA, HOSHANGABAD ROAD, BHOPAL-462026 (M.P.) INDIA
3	SUDHIR SITARAM AMRITPHALE	REGIONAL RESEARCH LABORATORY, HABIB GANJ NAKA, HOSHANGABAD ROAD, BHOPAL-462026 (M.P.) INDIA

PCT International Classification Number

B22D 27/00

PCT International Application Number

N/A

PCT International Filing date

PCT Conventions:

#	PCT Application Number	Date of Convention	Priority Country
1			NA