CLIAMS:1. An apparatus for stretching polymer pre-laminates; said apparatus comprising the following components:
i. at least one spool holder assembly adapted to hold at least one feed spool and at least one product spool;
ii. optionally, at least one feeding assembly;
iii. optionally, at least one slitter assembly comprising at least one blade;
iv. at least three godets arranged in a pre-determined manner;
v. at least one heat convention unit;
vi. optionally, at least one winder; and
vii. optionally, at least one idle roll.
2. The apparatus as claimed in claim 1, wherein said godets are arranged to form at least one of the ‘W’ or ‘V’ shape letters such that the path of drawing resulting out of the arrangement forms an angle ranging from 30° to 90° between two consecutive godets in the horizontal direction.
3. The apparatus as claimed in claim 1, wherein the stretching is carried out from the operative front to the operative back direction.
4. The apparatus as claimed in claim 1, wherein the stretching is carried out from the operative back to the operative front direction.
5. The apparatus as claimed in claim 1, further comprising at least one individual controller adapted to regulate at least one parameter selected from the group consisting of temperature of the heat convection unit(s), temperature of the godets and speed of the godets.
6. The apparatus as claimed in claim 1, further comprising at least one main control unit adapted to display the temperature and speed controlled by the individual controller(s).
7. The apparatus as claimed in claim 1, being insulated by at least one insulating material to minimize heat loss.
8. A process for stretching polymer pre-laminates by using the apparatus as claimed in claim 1.
9. The process as claimed in claim 8, being single step stretching.
10. The process as claimed in claim 8, being multiple step stretching. ,TagSPECI:FIELD
The present disclosure relates to an apparatus and a process for stretching of polymers.

BACKGROUND
Polymers, upon extrusion are stretched to obtain laminates with exceptional mechanical and optical properties which increase their industrial applicability. The stretching of polymer pre-laminates is typically longitudinal, or stretching along the width or incremental stretching.

Longitudinal stretching orients the polymer chains in the longitudinal direction by passing the polymer pre-laminates through a series of nip rollers. Stretching along the width can be achieved by griping the side edge of the continuously running pre-laminate(s) in the longitudinally direction. Incremental stretching is achieved by passing the pre-laminate(s) between a pair of cylindrical rollers, such that either of the rollers has a plurality of projections on its surface and a plurality of corresponding recesses on the surface of another roller. The projections on the rollers engage in discrete portions of the pre-laminates at the stage of rolling and this produces stretching in multiple directions.

The conventional processes and machines used for the longitudinal stretching of polymer pre-laminates are associated with certain disadvantages such as complications arising out of use of suction, contraction of pre-laminate(s) in a transverse direction and use of complex and non-flexible machinery.

The present disclosure envisages an apparatus and a process for longitudinal stretching of polymer pre-laminates which mitigates the drawbacks associated with conventional means.

OBJECTS
Some of the objects of the present disclosure, which at least one embodiment is able to achieve, are discussed herein below.
It is an object of the present disclosure to provide an apparatus for stretching of polymer pre-laminates.
It is another object of the present disclosure to provide an apparatus for stretching of polymer pre-laminates which is non-complex and flexible.
It is still another object of the present disclosure to provide a process for stretching of polymer pre-laminates.
It is yet another object of the present disclosure to ameliorate one or more problems of the prior art or to at least provide a useful alternative.
Other objects and advantages of the present disclosure will be more apparent from the following description which is not intended to limit the scope of the present disclosure.

SUMMARY
The present disclosure provides an apparatus for stretching polymer pre-laminates which includes at least one spool holder assembly; optionally, at least one feeding assembly; optionally, at least one slitter assembly comprising at least one blade; at least three godets arranged in a pre-determined fashion; at least one heat convention unit; optionally, at least one winder and optionally, at least one idle roll. The present disclosure further provides a process for stretching the polymer pre-laminates by means of the afore-stated apparatus.

BRIEF DESCRIPTION OF THE DRAWING
The non-limiting drawing stated herein below represents one embodiment of the subject matter of the present disclosure.
Figure 1 illustrates the apparatus for stretching of polymer pre-laminates in accordance with the present disclosure.

DETAILED DESCRIPTION
In accordance with one aspect, the present disclosure provides an apparatus for the stretching of polymers or polymer pre-laminates to obtain polymer laminates. Polymer pre-laminates may be described as the sheets or films obtained as a result of extrusion or roller compaction of polymers. Polymer laminates obtained after stretching bear exceptional mechanical and optical properties which increase their industrial applicability. The polymers that can be stretched by using the apparatus and process of the present disclosure include but are not limited to polyamides, polyesters, linear polyesters and polyolefins of different varieties. In one embodiment, the apparatus and process of the present disclosure are applicable for longitudinal stretching.
The apparatus (Figure 1) described in the present disclosure includes but is not limited to at least one spool holder assembly, at least one feeding assembly, optionally, at least one slitter assembly comprising at least one blade, at least three godets arranged in a pre-determined fashion, at least one heat convention unit, optionally, at least one winder and optionally, at least one idle roll. The components of the apparatus are arranged at pre-determined distances and angles with respect to each other and are made from materials commonly in the knowledge of a person skilled in the art.
The spool holder assembly of the present disclosure has the function of holding feed spool(s) before stretching and product spool(s) after the process of stretching is complete. The feeding assembly facilitates the conveying of the feed spool to one of the godets. The apparatus is also optionally equipped with a slitter to slit a wide pre-laminate into multiple pre-laminates of smaller width. The slitter or the slitting unit is arranged just before the stretching zone.
The present apparatus comprises at least three godets arranged in a pre-determined fashion to facilitate the stretching. The speed of the different godets can be varied in any segment and any combination of godets can be used as a feed roller or as a winding roller. Typically, the godets are arranged in such a way so as to form at least one shape of the letters ‘W’ or ‘V’. The path of drawing those results out of this arrangement is such that it forms an angle ranging from 30 to 90° between two consecutive godets in the horizontal direction. This characteristic arrangement has been clearly demonstrated in Figure 1. Such an arrangement facilitates single step stretching as well as multiple step stretching.
The apparatus also includes at least one heat convection unit which is placed between two consecutive godets. The heat convection unit(s) or the non-contact heat convection unit, supplies heat to facilitate the stretching of the pre-laminates. The heat convection unit in one embodiment is a hot plate chamber. Typically, the hot plate chamber is constituted with open and closed door system. The present apparatus can be used for hot stretching or cold stretching or a combination of both. The apparatus further comprises at least one individual controller adapted to vary, control and monitor the temperature of the heat convection unit and the speed of the godets. The readings of these controlled parameters are displayed by at least one main control unit.
The apparatus is fully insulated by at least one insulating material to reduce the loss of heat which can affect the quality of the final product. The apparatus of the present disclosure may be used in a laboratory, in a pilot plant, on a semi-commercial or commercial scale. In one embodiment, the stretching is mostly suitable for pre-laminates of thermoplastic material. The apparatus is different from conventional stretching units in design which provides it with versatility in the stretching operations. For instance, any of the godets may be used as a feed roller or as a winding roller. The stretching can be done from front to back or back to front direction. The process of stretching can be carried out in solid state below the melt temperature.
The present application further optionally includes at least one winder and at least one idle roll.
In accordance with another aspect, the present disclosure provides a process for stretching polymer pre-laminates by means of the apparatus described herein above. The process of the present disclosure will be more apparent from the example provided herein below.
The present disclosure will now be discussed in the light of the following non-limiting embodiments:
Example 1:
80 g of ultra high molecular weight polyethylene (UHMWPE) was processed to form pre-laminates by two roller mills at 125 ºC. The total length, width and thickness of pre-laminates were found to be 17.4 m, 46 mm and 0.09 mm respectively. The pre-laminates were subsequently stretched by means of the apparatus of the present disclosure, three times.
The first stretching was done by utilizing the godets G1, G2, G3 and the hot plate P1 (Figure 1). The godets G3 and G2 worked as feed and winding rollers whose temperature was kept at room temperature (RT). The stretching was mainly done in between godets G1 and G2 in a hot condition by keeping the temperature of G1 at 136ºC and P1 at 144ºC. To obtain stretched laminates, the speed of the godets G1, G2 G3 were kept 4 RPM, 4.91 RPM, and 15 RPM in increasing order respectively. After the first stretching, the length of tape was increased from 17.4 m to 67.86 m in which the stretching ratio was obtained around four.
The second stretching was carried out by utilizing the godets G1 to G4 and hot plates P1 to P3 whose temperatures were kept RT, 140ºC, 146ºC, 142 ºC and 155ºC, 160ºC, 165ºC respectively. The godet G1 was used as the feed roller in the second stretching. The stretching was carried out in a hot condition by keeping the speed of godet G1 to G4 at 3.3 RPM, 4.61 RPM, 5 RPM and 7.1 RPM respectively. The length of the tape was increased up to 139 m after the second stretching and the stretching ratio was obtained around eight.
The third stretching was carried out by keeping the same drawing path and almost the same condition of speed and temperature as the second stretching. The final length after the third stretching was achieved up to 225.6 m with a stretching ratio around 13. 5. The width and thickness were found to reduce, about 16 mm and 0.015 mm after third stretching, respectively.
The advantage of the present apparatus was that it gave uniform length and thickness. The tensile strength and tensile modulus of the laminate after third stretching was found in the range of 2.1-2.2 GPa and 98-119 GPa which was much higher than the un-stretched pre-laminate.
The embodiments herein and the various features and advantageous details thereof are explained with reference to the non-limiting embodiments in the description. Descriptions of well-known components and processing techniques are omitted so as to not unnecessarily obscure the embodiments herein. The examples used herein are intended merely to facilitate an understanding of ways in which the embodiments herein may be practiced and to further enable those of skill in the art to practice the embodiments herein. Accordingly, the examples should not be construed as limiting the scope of the embodiments herein.

The foregoing description of the specific embodiments will so fully reveal the general nature of the embodiments herein that others can, by applying current knowledge, readily modify and/or adapt for various applications such specific embodiments without departing from the generic concept, and, therefore, such adaptations and modifications should and are intended to be comprehended within the meaning and range of equivalents of the disclosed embodiments. It is to be understood that the phraseology or terminology employed herein is for the purpose of description and not of limitation. Therefore, while the embodiments herein have been described in terms of preferred embodiments, those skilled in the art will recognize that the embodiments herein can be practiced with modification within the spirit and scope of the embodiments as described herein.

TECHNICAL ADVANTAGES AND ECONOMIC SIGNIFICANCE
• The apparatus of the present disclosure has highly flexibility in the stretching operation
• Stretching can be done by using any set of godets and heat convection units at any combination of heat and speed.
• The apparatus is applicable for is also applicable for single or multiple steps stretching.

Throughout this specification the word “comprise”, or variations such as “comprises” or “comprising”, will be understood to imply the inclusion of a stated element, integer or step, or group of elements, integers or steps, but not the exclusion of any other element, integer or step, or group of elements, integers or steps.
The use of the expression “at least” or “at least one” suggests the use of one or more elements or ingredients or quantities, as the use may be in the embodiment of the invention to achieve one or more of the desired objects or results.
The numerical values given for various physical parameters, dimensions and quantities are only approximate values and it is envisaged that the values higher than the numerical value assigned to the physical parameters, dimensions and quantities fall within the scope of the invention and the claims unless there is a statement in the specification to the contrary.

While certain embodiments of the inventions have been described, these embodiments have been presented by way of example only, and are not intended to limit the scope of the inventions. Variations or modifications in the process or compound or formulation or combination of this invention, within the scope of the invention, may occur to those skilled in the art upon reviewing the disclosure herein. Such variations or modifications are well within the spirit of this invention. The accompanying claims and their equivalents are intended to cover such forms or modifications as would fall within the scope and spirit of the invention.