FORM-2
THE PATENTS ACT, 1970
(39 of 1970)
& THE PATENTS RULES, 2003
COMPLETE SPECIFICATION
(See section 10 and rule 13)
SPIN PACK DEVICE
(a) ADITYA BIRLA SCIENCE AND TECHNOLOGY CO. LIMITED
an Indian Company of Aditya Birla Centre, 2nd Floor, C Wing, S. K. Ahire Marg, Worli, Mumbai 400 025.
Maharashtra, India; and
(b) GRASIM INDUSTRIES LIMITED
an Indian Company
of Birlagram, Nagda 456 331, Madhya Pradesh, India.
THE FOLLOWING SPECIFICATION PARTICULARLY DESCRIBES THE INVENTION AND THE MANNER IN WHICH IT IS TO BE PERFORMED.

FIELD OF THE INVENTION
The present invention relates to spinning methods and apparatus.
In particular, the present invention relates to a spin pack device for converting a polymer suspension into filament.
BACKGROUND
Spinning is a process in which natural and synthetic fibers are twisted together to form yarn. The yarn is then processed to form fabric. Further, the fabric is processed to form textiles. Textiles are typically formed by various processes such as weaving, knitting, crocheting, knotting, pressing fibers together and the like. The spinning process is typically performed in various ways, such as hand spinning process, machine spinning process, solvent spinning process and the like. The hand spinning process is performed by using various apparatus such as a spindle, a distaff, a spinning wheel and the like. The machine spinning process is performed by various machines such as a spinning jenny, a spinning frame, a spinning wheel, textile machine and the like. There are four types of spinning known in the art namely wet spinning, dry spinning, melt spinning and gel spinning. The solvent spinning processes are adapted to form filaments from a molten polymer. This invention particularly relates to the field of solvent spinning.
Some methods and apparatus for solvent spinning have been disclosed in the prior art.

For instance, Indian Patent No. 189773 discloses a process for manufacturing cellulose solution for spinning fibers and films. The process includes steps of introducing cellulose material into an aqueous solution of tertiary amine oxide to prepare a suspension. Further, the suspension is subjected to high shear equipment heating under reduced pressure.
Again, U.S. Patent Nos. 4,144,080 and 4,246,221 disclose processes for preparation of amine oxide solution by extruding ground tertiary amine oxide solution and cellulose. Also, these patents disclose a method for producing fiber by spinning the solution through fine orifices in air, orienting the fiber by mechanical stretching and regenerating the cellulose from the solution bay for allowing the spun fibers to pass through a bath of a non-solvent.
Further, US Patent Application 2005/0087900 and International patent publication number WO 2005/010246 disclose a spin pack device for manufacturing non-woven multi component filaments of thermoplastic polymers. The spin pack device includes a series of distributor plates and has a very complex design, is difficult to assemble, and is difficult to use.
Furthermore, Indian Patent No. 229630 discloses a process of manufacturing cellulose non-woven web. In this process filaments are passed through a funnel immediately after spinning. The funnel randomizes as well as attenuates the filaments. The filaments are then collected on a belt to form a uniform web. The web is then consolidated by a hydraulic entanglement mechanism.

All the above methods and apparatus disclosed in the prior art have numerous limitations when applied to solvent spinning. For example, in these methods and apparatus, heating of the spinneret is not uniform. Further, the distribution of polymer provided by these methods and apparatus is unsatisfactory. Also, the fiber produced by these methods and apparatus is of a relatively poor quality.
There is thus felt a need for a spinning apparatus that overcomes the disadvantages of prior art including non uniform heating of the spin pack device, poor distribution of polymer and manufactured fiber being of poor quality. Moreover, there is a need for a spinning apparatus that provides all these benefits in a setup that is easy to use and assemble.
OBJECTS OF THE INVENTION
An object of this invention is to provide a spin pack device that provides uniform heating.
Another object of this invention is to provide a spin pack device that provides uniform distribution of polymer across the spinning area.
Yet another object of this invention is to provide a spin pack device that can manufacture high quality fibers.
Still another object of this invention is to provide a spin pack that is simple and user friendly.

SUMMARY OF THE INVENTION
In accordance with the present invention, there is provided a spin pack device for continuous spinning of polymer to form filament for producing high quality fiber, the device comprising:
• a polymer supply pipe provided with an inlet and an outlet, the inlet being adapted to receive polymer;
• a first heating system adapted to uniformly heat the polymer supply pipe;
• a top plate adapted to receive polymer from the outlet;
• a polymer distribution channel configured with spaced apart holes thereon, the channel being adapted to co-operate with the top plate, the polymer distribution channel being further adapted to provide the polymer with a predetermined depth inside the top plate after distribution;
• a plurality of first set of heating channels adapted to co-operate with the top plate;
• a bottom plate adapted to receive the distributed polymer from the polymer distribution channel;
• a plurality of second set of heating channels adapted to co-operate with the bottom plate;
• a second heating system adapted to uniformly heat the first set of heating channels and the second set of heating channels;
• a distributor plate with a plurality of holes configured thereon, the distributor plate adapted to co-operate with the bottom plate, the distributor plate defining a spinning area;

• a filter media adapted to remove any obstruction in the flow of polymer, the filter media being further adapted to provide a back pressure on the polymer to facilitate uniform spreading of the polymer on the spinning area; and
• a spinneret with a plurality of holes configured thereon, the spinneret adapted to co-operate with the distributor plate and extrude the polymer through the holes of the spinneret to form filament.
Preferably, in accordance with this invention, the outlet is adapted to have a diameter such that it can cater to an area corresponding to 15-20 times its diameter in a cross direction and 2-3 times its diameter in a machine direction while traversing a height equal to its diameter.
Additionally, in accordance with the present invention, the polymer distribution channel is adapted to have a length to width ratio ranging from 30:1 to 40:1.
Typically, in accordance with this invention, the diameter of the plurality of holes on the distributor plate is in the ratio of 0.1 to 0.3 times the width of the spinning area, when the length to width ratio of the spinning area is 30 to 60.
Typically, in accordance with this invention, the spinning area has a length to width ratio of 30:1 to 40:1 with a spinning hole density of 30 to 60 holes per square centimeter.
Preferably, in accordance with this invention, the filter media is adapted to provide the back pressure in the range of 5 to 15 bar.

Typically, in accordance with this invention, the first heating system and the second heating system include a network of hot water pipes.
Preferably, in accordance with this invention, the first heating system is adapted to provide a counter flow of water to the flow of polymer in the polymer supply pipe.
Additionally, in accordance with this invention, water inlets of the first heating system are provided near the outlet of the polymer supply pipe and water outlet of the first heating system is provided near the inlet of the polymer supply pipe.
Typically, in accordance with this invention, the diameter of the first set of heating channels is l/3rd the thickness of the top plate and the diameter of the second set of heating channels is 1/4th the thickness of the bottom plate.
Furthermore, in accordance with this invention, the ratio of distance of the first and second set of heating channels from the top plate and the bottom plate respectively to an external surface of the device is in the range of ½ to ¼.
Preferably, in accordance with this invention, water from the first and second heating system flows through the first and second set of heating channels in less than 1.5 seconds the change in temperature of water flowing from the first and second heating system through the first and second set of heating channels is less than 0.3 deg. Celsius.

In accordance with the present invention, there is provided a method for continuous spinning of a polymer to form filament for producing fiber, the method comprising the steps of:
• receiving polymer through an inlet of a polymer supply pipe;
• uniformly heating the polymer supply pipe by a first heating system;
• receiving polymer from an outlet of the polymer supply pipe on a top plate;
• uniformly distributing polymer through a polymer distribution channel to attain a predetermined depth;
• receiving the distributed polymer on a distributor plate associated with a bottom plate;
• uniformly heating the top plate and the bottom plate by a second heating system via a plurality of heating channels associated with the top plate and the bottom plate;
• providing a back pressure on the polymer to facilitate uniform spreading of the polymer;
• extruding polymer through holes of a spinneret to form filament;
• regenerating and processing the filaments; and
• producing staple fiber or non woven web.
BRIEF DESCRIPTION OF ACCOMPANYING DRAWINGS
The invention will now be described in relation to the accompanying drawings, in which:
FIGURE 1 illustrates an elevation view of an assembly of a spin pack device in accordance with an embodiment of the present invention;

FIGURE 2 (a) illustrates an elevation view of a top plate of the spin pack device of FIGURE 1;
FIGURE 2 (b) illustrates a plan view of the top plate of FIGURE 1;
FIGURE 3 illustrates a bottom plate of the spin pack device of FIGURE 1;
FIGURE 4 (a) illustrates a polymer distributor plate of the spin pack device ofFIGUREl;and
FIGURE 4(b) illustrates an enlarged view of an encircled area of the polymer distributor plate marked in FIGURE 4 (a).
DETAILED DESCRIPTION OF THE ACCOMPANYING DRAWINGS
The invention will now be described with reference to the embodiments shown in the accompanying drawings. The embodiments do not limit the scope and ambit of the invention. The description relates purely to the exemplary preferred embodiments of the invention and its suggested applications.
The diagrams and the description hereto are merely illustrative and only exemplify the invention and in no way limit the scope thereof.
An essential component of a spinning machine is the spin pack. The main function of the spin pack is to receive the liquefied polymer, filter it, distribute it and extrude the polymer to form filaments. The spinning systems known in the art are plagued by drawbacks including non-uniform

heating of the spin pack and non uniform distribution of the polymer across the spinning area resulting in a low quality fiber.
The main components of a spin pack device 1 in accordance with the present invention, as illustrated in FIGURE 1 to FIGURE 4b are referenced generally as given below:
polymer supply pipe 2; top plate 4; bottom plate 6; and polymer distributor plate 8.
Referring to FIGURE 1 to FIGURE 4b, a spin pack device 1 for continuous spinning of a suspension of cellulose in tertiary amine oxide is depicted. First, a cellulose suspension is produced from cellulose and water. A tertiary amine oxide is fed as a solvent to the cellulose suspension, thus producing a cellulose solution, hereinafter referred to as a polymer. The device in accordance with the present invention provides uniform distribution of polymer along the machine direction as well as cross direction. The filaments, thus produced, can be processed to produce staple fiber as well as uniform non woven web. The device also maintains uniform temperature throughout the holes of the spinneret fixed inside the device. Also there is a network of hot water piping which ensures uniform temperature across the spin pack.
FIGURE 1 illustrates an elevation view of an assembly of the spin pack device 1 in accordance with an embodiment of the present invention. The

spin pack device 1 comprises four main sections namely the polymer supply pipe 2, the top plate 4, the bottom plate 6 and the distributor plate 8.
The polymer enters the spin pack device 1 though the supply pipe 2 from where it enters the top plate 4. The polymer supply pipe 2 has an inlet portion and an outlet portion. The outlet portion has a diameter such that it can cater to an area corresponding to 15-20 times its diameter in a cross direction and 2-3 times its diameter in the machine direction while traversing a height equal to its diameter. The polymer supply pipe 2 thus distributes the polymer inside the top plate 4 which provides the polymer with the depth required for the polymer to spread. In one embodiment of the present invention, the length to width ratio of polymer distribution area ranges from 30 to 40:1. The top plate 4 includes a plurality of heating channels and a polymer distribution channel.
From the top plate 4, the polymer enters the bottom plate 6, where there is a distributor plate 8 followed by the filter media (not specifically indicated) and the spinneret (not specifically indicated). The bottom plate 6 further includes a plurality of entry sections for the heating channels. The distributor plate 8 includes a plurality of holes configured thereon. The diameter of the plurality of holes is in the ratio of 0.1-0.3 times the width of a spinning area, when the length to width ratio of the spinning area is 30 to 60.
In one embodiment of the present invention, the spinning area has a length to width ratio of 30:1 to 40:1 with spinning hole-density of 30-60 holes per square centimeters.

The filter media provides a back pressure in the range of 5 to 15 bar. The back pressure provided by the filter media facilitates uniform spreading of the polymer across the spinning width of the spinneret. The spinneret includes a plurality of holes configured thereon. The polymer is extruded through the holes in the spinneret to form filament. The filament is regenerated and processed to produce staple fiber or non woven web.
The pair of heating systems is adapted to provide uniform heating of the spin pack device 1 during spinning operation. A first heating system provides uniform heating of the polymer supply pipe 2 and a second heating system provides uniform heating of the top plate 4 and the bottom plate 6. Each of the heating systems includes a network of hot water channels that ensure uniform temperature across the spin pack device 1. Further, the first heating system and the second heating system are kept separate from each other to provide an additional control over the spinning conditions.
The heating system of the polymer supply pipe 2 provides a counter flow of water with water inlets near the polymer outlet and a water outlet near polymer inlet point. The diameter of the jacket pipeline is kept at 1.5-3 times that of the polymer supply pipe 2.
As shown in FIGURES 2a, 2b and 3, the heating system for the top plate 4 and the bottom plate 6 includes water channels. The diameter of the water channels is l/3rd to 1/4th of the thickness of the top plate 4 and the bottom plate 6. The ratio of distance of the water flow channels from the polymer flow area and distance from the water flow channel to the external surface of the spin pack is in the range of 1/2 to 1/4. This ensures better heat absorption in the spinning zone, improves the distribution of heat in the spinning area

and reduces heat loss to the atmosphere. The heating system of the present invention is adapted to maintain uniform temperature throughout the plurality of holes of the spinneret.
In conventional spin packs, heating is provided to the polymer along its path, where as in the spin pack device 1 in accordance with the present invention heating is provided in such a way that it controls the temperature of the spinneret directly. Water enters the bottom plate 6 as referenced by C in FIGURE 3. The water inlet channels are spaced such that residence time or the average time of water inside the spin pack is less than 1.5 seconds. Then the water passes through the channel and passes out of the plate through an outlet (not shown). The water then moves into the top plate 4 through corresponding holes as shown in FIGURE 2. Again the water passes through channel in the top plate and passes out through an outlet.
The residence time inside the spin pack is very short as it has to cover a maximum distance of 270-350 mm operatively. The temperature change of water during steady state operation is less than 0.3 deg G.
Example 1
12.5% cellulose suspension in tertiary amine oxide was fed at the rate of 0.07 grams/hole/min through a rectangular spinneret. The rectangular spinneret had 29 rows of 75 micron diameter holes placed inside the said spin pack. The said spin pack provided steady, fault free spinning for a period of 26 hours across the full length of the spin pack.
Summarizing the process as follows:
• the polymer supply pipe 2 supplies polymer to the top plate 4;

• the polymer flows from the top plate 4 to the distributor plate 8 followed by the filter media and the spinneret;
• the assembly of filter media provides a back pressure in the range of 5 to 15 bar to facilitate uniform spreading of the polymer across spinning width of the spinneret;
• the polymer is extruded through the spinneret to form filaments;
• the filaments are regenerated and processed; and
• the filaments, thus produced, are processed to produce staple fiber or uniform non-woven web.
Although the device and the method described herein above refer to spinning of suspension of cellulose in tertiary amine oxide, it can be applied to any polymer and is not restricted by the specific suspension referred herein above.
TECHNICAL ADVANCEMENTS
The technical advancements offered by the present invention include the realization of:
• a spin pack device that provides uniform heating;
• a spin pack device that provides uniform distribution of polymer across the spinning area;
• a spin pack device that can manufacture high quality fibers; and
• a spin pack that is simple and user friendly.

The numerical values given for various physical parameters, dimensions and quantities are such that they envisage values higher or lower than the numerical value assigned to the physical parameters, dimensions and quantities fall within the scope of the invention unless there is a statement in the specification to the contrary.
Wherever a range of values is specified, a value up to 10% below and above the lowest and highest numerical value respectively, of the specified range, is included in the scope of the invention.
While considerable emphasis has been placed herein on the particular features of this invention, it will be appreciated that various modifications can be made, and that many changes can be made in the preferred embodiment without departing from the principles of the invention. These and other modifications in the nature of the invention or the preferred embodiments will be apparent to those skilled in the art from the disclosure herein, whereby it is to be distinctly understood that the foregoing descriptive matter is to be interpreted merely as illustrative of the invention and not as a limitation.

We Claim:
1. A spin pack device for continuous spinning of polymer to form filament for producing high quality fiber, said device comprising:
• a polymer supply pipe provided with an inlet and an outlet, said inlet being adapted to receive polymer;
• a first heating system adapted to uniformly heat said polymer supply pipe;
• a top plate adapted to receive polymer from said outlet;
• a polymer distribution channel configured with spaced apart holes thereon, said channel being adapted to co-operate with said top plate, said polymer distribution channel being further adapted to provide the polymer with a predetermined depth inside said top plate after distribution;
• a plurality of first set of heating channels adapted to co-operate with said top plate;
• a bottom plate adapted to receive the distributed polymer from said polymer distribution channel;
• a plurality of second set of heating channels adapted to co-operate with said bottom plate;
• a second heating system adapted to uniformly heat said first set of heating channels and said second set of heating channels;
• a distributor plate with a plurality of holes configured thereon, said distributor plate adapted to co-operate with said bottom plate, said distributor plate defining a spinning area;

• a filter media adapted to remove any obstruction in the flow of polymer, said filter media being further adapted to provide a back pressure on the polymer to facilitate uniform spreading of the polymer on said spinning area; and
• a spinneret with a plurality of holes configured thereon, said spinneret adapted to co-operate with said distributor plate and extrude the polymer through said holes of said spinneret to form filament.

2. The spin pack device as claimed in claim 1, wherein said outlet is adapted to have a diameter such that it can cater to an area corresponding to 15-20 times its diameter in a cross direction and 2-3 times its diameter in a machine direction while traversing a height equal to its diameter.
3. The spin pack device as claimed in claim 1, wherein said polymer distribution channel is adapted to have a length to width ratio ranging rrom30:l to 40:1.
4. The spin pack device as claimed in claim 1, wherein the diameter of the plurality of holes on said distributor plate is in the ratio of 0.1 to 0.3 times the width of the spinning area, when the length to width ratio of the spinning area is 30 to 60.
5. The spin pack device as claimed in claim 1, wherein the spinning area has a length to width ratio of 30:1 to 40:1 with a spinning hole density of 30 to 60 holes per square centimeter.

6. The spin pack device as claimed in claim 1, wherein said filter media is adapted to provide said back pressure in the range of 5 to 15 bar.
7. The spin pack device as claimed in claim 1, wherein said first heating system and said second heating system include a network of hot water pipes.
8. The spin pack device as claimed in claim 1, wherein said first heating system is adapted to provide a counter flow of water to the flow of polymer in said polymer supply pipe.
9. The spin pack device as claimed in claim 1, wherein water inlets of said first heating system are provided near said outlet of said polymer supply pipe and water outlet of said first heating system is provided near said inlet of said polymer supply pipe.
10. The spin pack device as claimed in claim 1, wherein the diameter of said first set of heating channels is l/3rd the thickness of said top plate.
11. The spin pack device as claimed in claim 1, wherein the diameter of said second set of heating channels is 1/4th the thickness of said bottom plate.
12. The spin pack device as claimed in claim 1, wherein the ratio of distance of the first and second set of heating channels from said top plate and said bottom plate respectively to an external surface of said device is in the range of ½ to ¼.

13. The spin pack device as claimed in claim 1, wherein water from said first and second heating system flows through said first and second set of heating channels in less than 1.5 seconds.
14. The spin pack device as claimed in claim 1, wherein the change in temperature of water flowing from said first and second heating system through said first and second set of heating channels is less than 0.3 deg. Celsius.
15. A method for continuous spinning of a polymer to form filament for producing fiber,
said method comprising the steps of:
• receiving polymer through an inlet of a polymer supply pipe;
• uniformly heating said polymer supply pipe by a first heating system;
• receiving polymer from an outlet of said polymer supply pipe on a top plate;
• uniformly distributing polymer through a polymer distribution channel to attain a predetermined depth;
• receiving the distributed polymer on a distributor plate associated with a bottom plate;
• uniformly heating said top plate and said bottom plate by a second heating system via a plurality of heating channels associated with said top plate and said bottom plate;
• providing a back pressure on the polymer to facilitate uniform spreading of the polymer;

• extruding polymer through holes of a spinneret to form filament;
• regenerating and processing said filaments; and
• producing staple fiber or non woven web.