A PROCESS FOR RECYCLING POLYCARBONATE MATERIAL, FOR REUSE IN MANUFACTURING OPTICAL MEDIA AND AN APPARATUS
THEREFOR
FIELD OF THE INVENTION
The present invention in general, relates to a process for recycling polycarbonate material for reuse in manufacturing optical media and an apparatus therefor,and in particular, to an automated technology for recycling polycarbonate material, for reuse in manufacturing optical media, such as CDs/DVDRs.
BACKGROUND OF THE INVENTION
It is traditionally known that manufacturing optical media such as CDs/ DVDRs involves consumption of substantial volume of polycarbonate material. This has resulted in cropping up of manufacturing cost of optical media, due to high cost of such polycarbonate material. Furthermore, use of such substantial volume of polycarbonate material, leads to usual environmental hazards as well.
Accordingly, over the years, attempts are on for recycling of the polycarbonate material for re-use in manufacturing optical media. However, no reliable automated process for recycling polycarbonate material, could be designed and the processes in vogue, are mainly batch manual processes. These batch manual processes have some vital disadvantages, like limiting the quality of the final product, inconsistency in the production line and huge time consumption. Furthermore, these processes have not been able to recycle, substantial volume of polycarbonate material for reuse in manufacturing optical media such as CDs/DVDRs. Other residual factors like high cost of polycarbonate material and degradation of environment due to littering of scrap, have further aggravated the problems.

Accordingly, there was a long felt need to design an automated process for recycling polycarbonate material in the field of optical media and an apparatus therefor, to ensure recycling of substantial volume of polycarbonate material without compromising with the quality of the final product, whereby, a reduction in the net cost for procuring polycarbonate material would be achieved and consequently, environmental degradation would be reduced.
The present invention achieves the aforesaid need and overcomes the various disadvantages as narrated aforesaid.
All throughout the specification including the claims the invention has been described, with reference to optical media , for the sake of understanding and is not limited to it and it includes CDR, DVDR, HD DVD & BD R/RE and the like, unless specifically mentioned to that effect.
OBJECTS OF THE INVENTION
It is a principal object of the present invention, to provide an automated process for recycling polycarbonate material, for reuse in manufacturing optical media without compromising with the quality of the final product, thereby ensuring a reduction in the net cost for procuring polycarbonate material and reduction in environmental degradation.
It is a further object of the present invention to provide an apparatus for carrying out an automated process for recycling polycarbonate material for reuse in manufacturing optical media, without compromising with the quality of the end product, thereby ensuring a reduction in the net cost for procuring polycarbonate material and reduction in environmental degradation.

It is yet another object of the present invention, to provide a high speed automatic process for recycling polycarbonate material, for reuse in manufacturing optical media.
It is a further object of the present invention to provide an automatic process for recycling polycarbonate material, for reuse in manufacturing optical media whereby, reliability of quality of the final product, is ensured at low cost.
How the foregoing objects of the invention are achieved and the other aspects of the invention, will be clear from the following description, which is purely for the sake of understanding and not by way of any sort of limitation. SUMMARY OF THE INVENTION
Accordingly, the present invention provides an automated process for recycling polycarbonate material , for reuse in manufacturing optical media and also for ensuring reliability of quality of the final product at low cost, reduction in the net cost for procuring polycarbonate material and reduction in environmental degradation said process including, passing the optical media scrap such as CD/DVDR scrap through a feeder, separating the magnetic and non-ferrous material, grinding the remaining material, passing the grinded material through a floatation process in a floatation unit, for floating out the lighter material and for decanting the heavy material, passing the left over polycarbonate material, from the floatation unit to a chemical washing unit for chemical washing for a requisite time at a desired rpm, followed by hot washing the resultant polycarbonate solid to remove any traces of lacquer and chemicals and thereafter cold washing the resultant polycarbonate solid to solidify and remove lacquer if any, followed by centrifuging and heat drying said polycarbonate material to reduce the percentage of moisture, thereby obtaining clean dry polycarbonate flakes for further use in optical media manufacturing process. In accordance with preferred embodiments of the process of the invention : -said lighter material includes paper, paint flakes and silver dust while the

heavier material includes sand, mud and dust.
-said grinding comprises, dry grinding the material and passing the material so
grinded, through blower and cyclone separator for flowing out a part of the dust,
paper, silver dusts and so on prior to introducing the grinded material to floatation
unit.
-said grinding comprises wet grinding.
- in said chemical washing unit, solvent is pumped from the bottom to create
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vertical agitation, to make the silver flakes and dust float out, above the
polycarbonate material and the solution is filtered and re-pumped back into the
the said chemical washing unit.
-said hot washing, is done at a temperature of around 9O°C.
-the vapors emanating from the chemicals during the washing is cooled down by
condensing.
-the polycarbonate spent solvent is collected into a distillation unit, where the
recovery of solvent is done and thereafter, caustic component and die part are
separated from the residual material by neutralization and the water recovered
is recirculated back into the system for running of the process in general and
particularly for undertaking the washing operations.
The present invention also provides an apparatus for carrying out an automated
process for recycling polycarbonate material , for reuse in manufacturing optical
media and also for ensuring reliability of quality of the final product at low cost,
reduction in the net cost for procuring polycarbonate material and reduction in
environmental degradation, said apparatus having all operatively connected
units including feeding means for passing the optical media scrap such as
CD/DVDR scrap , magnetic means for separating the magnetic material and
metallic separator means for separating non-ferrous material, grinder means for
grinding the remaining material, a floatation unit for passing the grinded material
there through for carrying out floatation process for floating out the lighter
material and for decanting the heavy material, a chemical washing unit for

passing there through the left over polycarbonate material, from the floatation
unit for chemical washing for a requisite time at a desired rpm, a hot washing
unit for hot washing the resultant polycarbonate solid to remove any traces of
lacquer and chemicals and a cold washing unit for cold washing the resultant
polycarbonate material to solidify and remove lacquer if any, and a centrifuging
unit and hot drying unit for centrifuging and hot drying said polycarbonate
material to reduce the percentage of moisture, and obtain clean dry
polycarbonate flakes for further use in optical media manufacturing process.
In accordance with preferred embodiments of the apparatus of the invention :
-conveyors are provided for carrying the polycarbonate material to be recycled
from one unit to another and said floatation unit is equipped with perforated
holes at the bottom for settling of heavy solids such as sand, mud, dust and so
on to the bottom most compartment.
-said chemical washing unit is designed to optimize mixing time, usage of
chemicals, water and power.
-said chemical washing unit is specially designed with respect to the behaviour
of die, solvents, lacquor, paint, ink and other chemicals and said unit is provided
with top mounted geared motor with necessary mixing propellers/anchors.
-said chemical washing unit is provided with a condenser to cool down the
vapors emanating from the chemicals during the wash and a water cooling
jacket is also provided all around the body of the chemical washing unit.
-said apparatus comprises means to reject the material, if found unsuitable, due
to presence of too much non-ferrous material, and also means to generate beep
noise, in the event of detection of too much non-ferrous material, for manual
checking,
BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS
The nature and scope of the present invention, will be better understood from the
accompanying drawings, which are by way of' illustration of some preferred
embodiments and not by way of any sort of limitation. In the accompanying

drawings :
FIG 1 illustrates of a preferred embodiment of the apparatus, in accordance
with the present invention.
FIG 2 illustrates a schematic representation of the flow of the process, in
accordance with a preferred embodiment, of the present invention.
BRIEF DESCRIPTION OF THE INVENTION
The following describes some preferred embodiments of the present invention,
which are purely for the sake of understanding the performance of the invention,
and not by way of any sort of limitation.
Fig 1 illustrates, the various components of the apparatus, in accordance with the
invention.
Fig 2 illustrates the various stages, involved in the process for recycling
polycarbonate material for reuse in manufacturing optical media.
First and in the foremost, the CD/DVD scrap is fed in to the Hopper. From here,
the conveyor picks up the material and moves forward. Heap Breakers" are
provided to control the flow of the input. As shown in Fig 2, electro Magnets are
provided, to take out the ferrous parts. The CDs/DVDs pass through metal
detector, where non ferrous metals are detected, if found. Options are there to
reject the material, if found unsuitable, due to presence of too much non-ferrous
material. Alternatively, options are there to generate beep noise, in the event of
detection of too much non-ferrous material, for manual checking.
Thereafter, the accepted material passes to the grinder. Options are also
available for either wet grinding, or dry grinding. If wet grinding is done, the
ground material falls directly into the floating tank. If dry grinding is done, then
the ground material is sent through blower and cyclone separator and thereafter,
such material is made to fall into floating tank. The advantage in dry grinding is
that, some part of the dust, paper, silver dusts etc. will be flown out. However,
dry grinding, hampers the life of the blades.
When the polycarbonate falls into the floating tank, the lighter materials such as

paper, paint flakes etc. floats out and polycarbonate sinks. Comparatively, heavy solids such as sand, mud, dust etc. sinks further, through the perforated holes provided in the floating tank, to the bottom most compartment. The polycarbonate lying in the floating tank is conveyed through screw conveyor from the floating tank to the next operation, namely chemical wash. The chemical wash tank is specially designed, with respect to the behaviour of die, solvents, lacquor, paint, ink and other chemicals. Necessary care is taken while designing, to optimize mixing time, usage of chemicals, water and power. This tank is provided with top mounted geared motor with necessary mixing propellers/anchors. Condenser is provided to cool down the vapors emanating from the chemicals during the wash. Apart from this, water cooling jacket is also provided all around the body. Facility also exists for re-circulation of chemicals. The chemical wash tank is provided with a conical bottom, provided with pneumatically operated Knife edge valve.
The material is nicely mixed in the chemical wash tank for a requisite period of time at 48/60 rpm. At the same time, the solvent is pumped into the tank from the bottom to create vertical agitation. This makes the silver flakes and dust to float out, above the polycarbonate material. The solution is filtered and re-pumped back into the tank.
After the said time of mixing, the knife edge valve opens automatically and the . solid material is conveyed through a screw conveyor to hot wash tank and thereafter, the liquid is sent for distillation. In hot wash tank, the material is washed at a temperature of around 9O°C, mainly to remove the traces of any lacquer and chemicals. Thereafter, the material is washed "on line" with cold water, to solidify and remove lacquer, if found any. The material is sent through centrifuge to spin out the water and also pass through hot blown air, to reduce the percentage of moisture below 1% level. Cleaned, dry polycarbonate flakes are sent for further processing, for use in the manufacturing process of optical media. While washing, the polycarbonate spent solvent is collected into a

distillation unit, where the recovery of solvent is done. After the recovery, the residual material will consist the following, in liquid form.
A) Water.
B) Caustic component.
C) Die part
Separation of die and caustic can be done by neutralizing this liquid, to separate out the die in its process. It can be disposed off in a tanker. The estimated quantity of output is 60 KL/month. The water is recirculated back into the system for running of the process in general and particularly for undertaking the washing operation.
The present invention has been described with reference to some drawings and preferred embodiments, purely for the sake of understanding and not by way of any limitation and the present invention includes all legitimate developments within the scope of what has been described hereinbefore and what has been claimed hereinafter.

WE CLAIM
1.An automated process for recycling polycarbonate material , for reuse in manufacturing optical media and also for ensuring reliability of quality of the final product at low cost, reduction in the net cost for procuring polycarbonate material and reduction in environmental degradation said process including, passing the optical media scrap such as CD/DVDR scrap through a feeder, separating the magnetic and non-ferrous material , grinding the remaining material, passing the grinded material through a floatation process in a floatation unit , for floating out the lighter material and for decanting the heavy material, passing the left over polycarbonate material, from the floatation unit to a chemical washing unit for chemical washing for a requisite time at a desired rpm, followed by hot washing the resultant polycarbonate solid to remove any traces of lacquer and chemicals and thereafter cold washing the resultant polycarbonate solid to solidify and remove lacquer if any, followed by centrifuging and heat dpying said polycarbonate material to reduce the percentage of moisture, thereby obtaining clean dry polycarbonate flakes for further use in optical media manufacturing process.
2.The automated process for recycling polycarbonate material for reuse in manufacturing optical media as claimed in claim 1, wherein said lighter material includes paper, paint flakes and silver dust while the heavier material includes sand, mud and dust.
3.The automated process for recycling polycarbonate material for reuse in manufacturing optical media as claimed in any preceding claim, wherein said grinding comprises, dry grinding the material and passing the material so grinded, through blower and cyclone separator for flowing out a part of the dust, paper, silver dusts and so on prior to introducing the grinded material to floatation unit.

4.The automated process for recycling polycarbonate material for reuse in manufacturing optical media as claimed in any of claims 1 or 2 wherein said grinding comprises wet grinding.
5The automated process for recycling polycarbonate material for reuse in manufacturing optical media as claimed in any preceding claim wherein in said chemical washing unit, solvent is pumped from the bottom to create vertical agitation, to make the silver flakes and dust float out, above the polycarbonate material and the solution is filtered and re-pumped back into the the said chemical washing unit.
6.The automated process for recycling polycarbonate material for reuse in manufacturing optical media as claimed in any preceding claim wherein said hot washing, is done at a temperature of around 9O°C.
7.The automated process for recycling polycarbonate material for reuse in manufacturing optical media as claimed in any preceding claim wherein the vapors emanating from the chemicals during the washing is cooled down by condensing.
8.The automated process for recycling polycarbonate material for reuse in manufacturing optical media as claimed in any preceding claim wherein the polycarbonate spent solvent is collected into a distillation unit, where the recovery of solvent is done and thereafter, caustic component and die part are separated from the residual material by neutralization and the water recovered is recirculated back into the system for running of the process in general and particularly for undertaking the washing operations.

9.An apparatus for carrying out an automated process for recycling polycarbonate material, for reuse in manufacturing optical media and also for ensuring reliability of quality of the final product at low cost, reduction in the net cost for procuring polycarbonate material and reduction in environmental degradation, said apparatus having all operatively connected units including feeding means for passing the optical media scrap such as CD/DVDR scrap , magnetic means for separating the magnetic material and metallic separator means for separating non-ferrous material , grinder means for grinding the remaining material, a floatation unit for passing the grinded material there through for carrying out floatation process for floating out the lighter material and for decanting the heavy material, a chemical washing unit for passing there through the left over polycarbonate material, from the floatation unit for chemical washing for a requisite time at a desired rpm, a hot washing unit for hot washing the resultant polycarbonate solid to remove any traces of lacquer and chemicals and a cold washing unit for cold washing the resultant polycarbonate material to solidify and remove lacquer if any, and a centrifuging unit and heat drying unit for centrifuging and heat drying said polycarbonate material to reduce the percentage of moisture, and obtain clean dry polycarbonate flakes for further use in optical media manufacturing process.
10.The apparatus for carrying out an automated process for recycling polycarbonate material , for reuse in manufacturing optical media as claimed in claim 9 wherein conveyors are provided for carrying the polycarbonate material to be recycled from one unit to another and said floatation unit is equipped with perforated holes at the bottom for settling of heavy solids such as sand, mud, dust and so on to the bottom most compartment.
11.The apparatus for carrying out an automated process for recycling polycarbonate material, for reuse in manufacturing optical media as claimed in

claims 9 to 10 wherein said chemical washing unit is designed to optimize mixing time, usage of chemicals, water and power.
12The apparatus for carrying out an automated process for recycling polycarbonate material for reuse in manufacturing optical media as claimed in claim 11 wherein said chemical washing unit is specially designed with respect to the behaviour of die, solvents, lacquor, paint, ink and other chemicals and said unit is provided with top mounted geared motor with necessary mixing propellers/anchors.
13The apparatus for carrying out an automated process for recycling polycarbonate material for reuse in manufacturing optical media as claimed in any of claims 10 to 12 wherein said chemical washing unit is provided with a condenser to cool down the vapors emanating from the chemicals during the wash and a water cooling jacket is also provided all around the body of the chemical washing unit.
l4.TJie apparatus for carrying out an automated process for recycling polycarbonate material for reuse in manufacturing optical media as claimed in any preceding claim wherein said apparatus comprises means to reject the material, if found unsuitable, due to presence of too much non-ferrous material, and also means to generate beep noise, in the event of detection of too much non-ferrous material, for manual checking.