Title of Invention

"AN IMPROVED PROCESS FOR MAKING IMPROVED PACKING COMPOSITION"

Abstract

An improved process for making improved packing composition An improved process for making improved packing composition by mixing lignocellulosic fibre 10 to 60 wt %, thermosetting resin 8 to 60 wt %, fibre reinforced polymer (FRP) waste 5 to 50 wt %, participate filler 0-40 %, additive 0.5 to 3wt% in a mixer having blades rotating at a speed of 8 - 200 rpm, for the time ranging from 15 minutes to 100 minutes to obtain a homogeneous dough, transferring the dough to a preheated metallic moulds maintained at a temperature in the range of 100 to 140°C, subjecting the said mould to a pressure in the range of 10 - 1000 kgf /cm2 for a period in the range of 5 minutes to 50 minutes, post cured the article so obtained in an oven at a temperature in the range of 80 to 120°C for a period in the range of 1 hour to 24 hours, and thereafter allowing the moulded item to cool at room temperature to obtain composition.

Full Text

This invention relates to a process for making improved packing materials. This invention particularly relates to a composition of hybrid composite material for making packing rings for suspension systems. This material will be used in Railway bogies, heavy engineering industries, transport industries and automobiles as load bearing and damping material pads, blocks, and rings. Wood and natural fibre reinforced thermosetting polymer are being used as packing rings in suspension system of locomotives. Due to the poor dimensional stability under variable atmospheric conditions and the shortage of wood, it is being replaced from such applications. Dimension of wood under different climatic conditions change significantly. Wood absorbs moisture in the range of 30 -35% and shrinkage is very high in the dry conditions. It changes upto O|4% in tangential direction and upto 0.2% in the radial direction for each 1% change in moisture. Reference can be made to "Wood and Cellulose Science" by A. J. Stamm, published by Ronald Press Company, New York, 1964, and "Principles of Wood Science and Technology, vol.1, Springer - Verlag, New York Inc. New York 1968 and also in Encyclopedia of Chemical Technology, vol 24, pages 579 - 610, John Willey and Sons, New York, 1984. Natural fibre reinforced composites have a problem of moisture absorption and therefore mechanical properties detonate with time. Natural fibres absorb moisture, change their dimensions, which causes internal stresses, and reduce the mechanical properties of composites. Andrei Hododi has claimed such composite containing 35 - 60% lignocellulosic fibre, 5 -35% lime stone, 5 - 30% resin binder such as Malamine formaldehyde, Polyvinyl alcohol etc. and 5-15% fire proofing material to make composites (US patent 05502088). Till Grether claims a process for wood substitute by using two natural fibres of 2 -150 mm length and binded with polymers and filled with fine powder (US patent 5415736). These along with some other developments in the related field such as US patent 5518802,5656008 etc. are not able to provide a composition with good dimensional stability under different climatic conditions. Another material is ultra high molecular weight polyethylene powder (UHMWPE) which is used for such applications. However, the processing of this thermoplastic is very difficult. This is moulded by using sintering process. Powder of UHMWPE is weighed, pressed and heated at 150°C for 30 minutes. This process consumes a lot of time and high pressure and therefore is very costly. Reference can be made to "Wear" vol. 153, (1992) 331 - 350 wherein T. S. Barrett, G. W. Stachowiak, A. W. Batehelor mentioned the viscosity of molten UHMWPE is so high that it is effectively solid and does not flow. The main objective of the present invention is to provide a process for making improved packing material and packing material made therefrom. The another objective of this invention is to provide a composition of lignocelloulosic fibre, a fraction of fibre reinforced plastic (FRP) waste, a particulate filler and polymer for making hybrid composite which obviate the drawbacks as detailed above. Another objective of present invention is to provide a process for making packing pads and rings by using above composition. Accordingly the present invention provides a process for making improved packing material which comprises mixing lignocellulosic fibre 10 to 60 wt%, thermosetting resin 8 to 60wt%, fibre reinforced polymer (FRP) waste 5 to 50wt%, paniculate filler 0 - 40%, additive 0.5 to 3wt% in a mixer having blades rotating at a speed of 8 - 200 rpm, for the time ranging from 15 minutes to 100 minutes to obtain a homogeneous dough, transferring the dough to a preheated metallic moulds maintained at a temperature in the range of 100 to 140°C, subjecting the said mould to a pressure in the range of 10 - 1000 kgf/cm2 for a period in the range of 5 minutes to 50 minutes, post cured the article so obtained in an oven at a temperature in the range of 80 to 120°C for a period in the range of 1 hour to 24 hours, and thereafter allowing the moulded item to cool at room temperature . In an embodiment of the present invention, the lignocellulosic fibre may be selected from sisal, jute, sun hemp and banana or a mixture of two fibres in the ratio of 0.1-10. In another embodiment of the present invention, the thermosetting polymer used may be selected from phenol formaldehyde, unsaturated polyester, epoxy resin, poly amides, melamine formaldehyde and polyurethane resin systems. In still another embodiment of the invention, the fraction of FRP waste useful in this composition may be obtained from the waste generated during machining, polishing, cutting, and fabrication of FRP items such as insulation boxes, printed circuit board, sheets, blocks, insulators, covers, frames etc. and may be preferably used in the size ranging from powder to fibres up to 25 mm length and/or the pieces of FRP upto 1 cm3 volume which can be separated from the bulk waste by screening, hand sorting, gravity separation method. In another embodiment the particulate filler may be selected from red mud, fly ash, saw dust, silica, Calcium carbonate and talc or a mixture of two fillers in a ratio of 0.1 to 10. In yet another embodiment of the invention the additive used may be selected from benzoyl peroxide, methyl ethyl ketone (MEK) peroxide, and preferably used in the range of 0.5 to 3% of resin with or without accelerator selected from cobalt naphthanate or alkyl mercaptans in the range 0 to 1.5% of resin. The detailed process steps of present invention are: a) The ingredients lignocellulosic fibres, FRP waste, particulate filler are dried at a temperature in the range of 50 - 80°C for a period of 45 to 120 minutes. b) The dried ingredients obtained in step a) are mixed in a mixer with thennosetting resin and additive in the composition range to obtain dough like consistency. c) This dough like material obtain in step b) is transferred to the mould preheated to a temperature in the range of 100 to 140°C, maintaining the said mould temperature and subjecting the pressure in the range of 10 to 1000 kg f/cm2 for 5 to 50 minutes. d) Post curing of the article obtains in step c) at a temperature in the range of 80 to 120°C for a period in the range of 1 hour to 24 hours. e) Allowing the article cool at room temperature. The novelty and inventive steps of composition useful for making packing material resides in the material selection consisting lignocellulsic fibre, a component from FRP waste, filler and polymer. The following examples are given by the way of illustration and therefore should not construed to limit the scope of present invention. Example 1 Following ingredients were taken Ingredients Weight percentage 1. Jute Fibre (fibre length less than 5 mm) 20% 2. FRP Machining Waste (Cantaing fines as well as 40% glass fibre of less than 15 mm length) 3. Commercial Unsaturated Polyester resin 40% (Fire retardant grade) containing 2% MEK peroxide (Additive / Hardener) Lignocellulosic jute fibre was cut to the size (approximately 5mm long) in a fibre cutting machine. The jute fibre obtained after cutting is then mixed with the FRP machining waste in the above proportion. Then approximately half of this mixture is taken in a mechanical mixer and unsaturated polyester resin containing 2% hardener (MEK peroxide) is added to the above mixture and mixed thoroughly in a sigma mixer. The remaining mix of jute fibre and FRP waste is then added in a small quantity in many steps until it is totally consumed in the above resin mixture. The mixture finally prepared is called "Dough". The dough prepared by above process is then weighed and spread uniformly in a mould. The dough is then pressed with punch in the mould with 15 kg/sq. cm pressure. The temperature of mould is kept 120°C. The heating is carried out for 12 minutes at the same temperature and pressure mentioned above. After 12 minutes, the sample is taken out of the mould. Post curing of rings are carried out at 120°C for 2 hours. Machining and grinding of sample is done to get the desired size. This is a known compression moulding process. Packing rings for suspension system were made by using the same dough. The die/mould for the packing ring was made by using stainless steel with a mirror finish surface. 13-mm thick packing rings having 254-mm outer diameter and 120 mm inner diameter were fabricated as mentioned above. The packing ring developed by using above composition and process yields following results SN. Properties i Density(gm/cc) ii Compressive Strength (proof load), tonnes iii Water absorption (%), Max. iv Resistant to Boiling water a) Water Absorped(%), Max b) Increase in thickness, (%), Max Example 2 Following ingredients were taken Ingredients L Jute Fibre (fibre length less than 5mm) 2. FRP Machining Waste(containing fines as well as glass fibre of length 15mm) 3. Commercial grade Unsaturated Polyester resin 'Zj/MEK. peroxide (Additive /hardener) Values 1.46 6 0.36 0.63 1.0 Weight percentage 25% 35 % 40% Lignocellulosic jute fibre cut to the size ( approximately 5mm long) in a fibre cutting machine. The jute fibre obtained after cutting is then mixed with the FRF machining waste in the above proportion. Then approximately half of this mixture is taken in a mechanical mixer and unsaturated polyester resin containing 2% hardener is added to the above mixture and mixed thoroughly in a mechanical/sigma mixer. The remaining mix of jute fibre and FRP waste is then added in a small quantity in many steps until it is totally consumed in the above resin mixture. The mixture finally prepared is called "Dough". The dough prepared by above process is then weighed and spread uniformly in a die. The dough is then pressed with punch in the die with 15 kg/sq. cm pressure. The temperature of die is kept 120°C The heating is carried out for 12 minutes at iiie same temperature and pressure mentioned above. After 12 minutes, the sample is taken out of the die. Post curing of rings is carried out at 120°C for 2 hours. Machining and grinding of sample is done to get the desired size. Packing rings for suspension system were made by using the same dough. The mould for the packing ring was made by using stainless steel with a mirror finish surface. 13-mm thick packing rings having 254-mm outer diameter and 120 mm inner diameter were fabricated as mentioned above. The material developed by using above composition and process yields f ollowing results SN. Properties Values .54 i Density(g/cc) ii Compressive Strength 6 (proof load), tonnes iii Water absorption % (Max). 0.86 iv Resistance to Boiling water 1.06 a) Water Absorption %, (Max) Example 3 Following ingredients were taken Weight percentage Ingredients 1. Jute Fibre (fibre length less than 5mm) 20% 2 FRP Machining Waste (contains fines as well as glass fibre of length 15mm) 5% Commercial grade Unsaturated Polyester 45% 3' containing 2 % of resin methyl ethyl ketone peroxide MEK peroxide (Additive /hardener) 4. Red mud paniculate filler (particle size less than 45micron) 25% 5- Commercial grade Calcium Carbonate powder 5% Lignocellulosic jute fibre cut to the size ( approximately 5mm long) in a fibre cutting machine. The jute fibre obtained after cutting is then mixed with the FRF machining waste, red mud powder and Calcium Carbonate in the above proportion. Then approximately half of this mixture is taken in a mechanical mixer and unsaturated polyester resin containing 2% hardener is added to the above mixture and mixed thoroughly in a mechanical/sigma mixer. The remaining mix of jute fibre, redmud, calcium carbonte and FRP waste is then added in a small quantity in few steps until it is totally consumed in the above resin mixture. The mixture finally prepared is called "Dough". The dough prepared by above process is then weighed and spread uniformly in a mould. The dough is then pressed with punch in the die with 25 kg/sq. cm pressure. The temperature of mould is kept 130°C. The heating is carried out for 10 minutes at the same temperature and pressure mentioned above. After 10 minutes, the sample is taken out of the mould. Post curing of rings is carried out at 120°C for 2 hours. Machining and grinding of sample is done to get the desired size. Packing rings for suspension system were made by using the same dough. The mould/die for the packing ring was made by using stainless steel with a mirror finish surface. 13-mm thick packing rings having 254-mm outer diameter and 120 mm inner diameter were fabricated as mentioned above. The material developed by using above composition and process yields following results SN. Properties Values i Density (gm/cc) 1.68 ii Compressive Strength 6 (proof load), tonnes iii Water absorption %, (Max.) 0.25 iv Resistant to Boiling water a) Water Absorbed %, (Max) 0.71 b) Increase in thickness % 1.0 These examples clearly indicate that the material produced by this composition is superior to the wood as well as fibre reinforced thermosetting materials. The water retention is very low as compared to 30% of wood. Consequently, the dimensional stability at different conditions would be superior. The composition prepared is not a mere admixture resulting in mere aggregation but is a synergistic mixture resulting in improved mechanical properties as can be seen above explained. Advantages 1. This invention provides a better product as compared to existing materials in this class of materials. The cost of material for packing rings / pads is low as compared to existing high cost wooden and UHMWPE rings. 2. One of the ingredient of this composition "FRP Waste" will be utilized into a value-added product. 3. This process is fast as compared to the sintering process of UHMWPE. We claim : 1. A process for making improved packing material which comprises mixing lignocellulosic fibre 10 to 60 wt %, thermosetting resin 8 to 60 wt %, fibre reinforced polymer (FRP) waste 5 to 50 wt %, participate filler 0 - 40 %, additive 0.5 to 3wt% in a mixer having blades rotating at a speed of 8 - 200 rpm, for the time ranging from 15 minutes to 100 minutes to obtain a homogeneous dough, transferring the dough to a preheated metallic moulds maintained at a temperature in the range of 100 to 140°C, i* subjecting the said mould to a pressure in the range of 10 - 1000 kgf/cm for a period in the range of 5 minutes to 50 minutes, post cured the article so obtained in an oven at a temperature in the range of 80 to 120°C for a period in the range of 1 hour to 24 hours, and thereafter allowing the moulded item to cool at room temperature , 2. A process as claimed in claim 1, wherein the lignocellulosic fibre is selected from sisal, jute, sun hemp and banana or a mixture of two fibres in the ratio of 0.1-10. 3. A process as claimed in claims 1 &2, wherein the thermosetting polymer used is selected from phenol formaldehyde, imsaturated polyester, epoxy resin, polyamides, melamine formaldehyde and polyurethane resin systems. 4. A process as claimed in claims 1 to 3 wherein the FRP waste useful in this composition is obtained from the waste generated during machining, polishing, cutting, and fabrication of FRP items such as insulation boxes, printed circuit board, sheets, blocks, insulators, covers, frames etc. and may be preferably used in the size ranging from powder to fibres up to 25 mm length and/or the pieces of FRP upto 1 cm3 volume which can be separated from the bulk waste by screening, hand sorting, gravity separation method. 5. A process as claimed in claims 1 to 4, wherein the particulate filler is selected from red mud, fly ash, saw dust, silica, Calcium carbonate and talc or a mixture of two fillers in a ratio of 0.1 to 10. 6. A Procees as claimed in claims 1 to 5, wherein the additive used is selected from benzoyl peroxide, methyl ethyl ketone (MEK) peroxide, and preferably used in the range of 2 to 3% of resin with or without accel erator selected from cobalt naphthanate or alkyl mercaptans in the range 0 to 1.5% of resin. 7. A process for making improved packing materials substantially as herein described with reference to the examples.

Documents:

1197-del-2001-abstract.pdf

1197-del-2001-claims.pdf

1197-del-2001-correspondence-others.pdf

1197-del-2001-correspondence-po.pdf

1197-del-2001-description (complete).pdf

1197-del-2001-form-1.pdf

1197-del-2001-form-18.pdf

1197-del-2001-form-2.pdf

1197-del-2001-form-3.pdf