FIELD OF INVENTION

The present invention relates to a cost-effective flexible packaging for UHT treated milk/flowable products and, more particularly, relates to a cost-effective flexible packaging for UHT treated milk/ flowable products involving EVOH (Ethylene Vinyl Alcohol) by way of a selective co-extruded multi-layer EVOH (Ethylene Vinyl Alcohol) and PE (Polyethylene) flexible film based package combination adapted for high radiation barrier through the use of opacifiers in select films and for high impact resistance and desired shelf life of aseptically filled UHT treated milk/ flowable products to keep it acceptable for a minimum period of about 70 days at ambient temperature. The present invention also relates to packaged UHT treated milk/ flowable products packed aseptically in flexible pouches made with specially and selectively developed co-extruded multi-layer EVOH and PE flexible films, which would enable maintaining the UHT treated milk/ flowable products acceptable for a minimum period of about 70 days at ambient temperature while retaining the desired quality characteristics like taste, flavour, colour and appearance fit for consumption and as commercially available without the need for cost-extensive multi-layer flexible pouches or cartons made of PE, cardboard (paper) and aluminium (Al). More particularly, the present invention relates to the development of a suitable packaging material made of multi-layers preferably selective 5- or 7- layers films from co-extruded EVOH and PE with high radiation barriers and high impact resistance, which would be adapted for use in aseptic packaging of UHT treated milk/ flowable products to enable maintaining desired safe and hygienic quality for a minimum period of about 70 days at ambient temperature. The present invention, also specifically relates to packing UHT treated milk/ flowable products aseptically in form fill seal flexible pillow shaped pouches made of selective film combinations obtained of co-extruded multi-layer EVOH and PE flexible films, which would enable obtaining the much desired cost-effective packaging of UHT treated milk/flowable products with a shelf life for a minimum period of about 70 days at ambient temperature.

BACKGROUND ART

UHT processing and aseptic filling technology is one of the most extensively exploited methods of preservation of milk and certain flowable milk products, which involves pumping milk to a heat exchanger, heating at very high temperature for few seconds, holding for fixed duration in holding tube, cooling followed by packaging in a neat and sterile containers aseptically to give longer shelf life to milk or flowable milk products at ambient temperature.

The extent of storage period varies based on the type and composition of packaging films used. The concept of UHT processing and aseptic filling of milk/flowable milk products has been successfully adapted in dairy industry because of its inherent advantages related to elimination of the post processing cost of refrigerated storage and distribution besides producing milk with longer shelf life and convenience of use.

Milk and milk products are largely perishable product that requires to be delivered to the consumers in a safe condition and manner without deterioration in quality. Pasteurization of milk has several limitations in terms of chilled distribution, shorter shelf life and extent of distribution. Of the approximately 25 per cent of total milk processed in India today, more than 98 per cent is in the pasteurised segment and less than 1 per cent in UHT category because of relatively high cost. Long life milk/flowable milk products obtained by UHT treatment is today's reality with the advent of high heating plants and aseptic packaging systems. The commercial can fill systems and form-fill-seal system for carton or pouches filling marked the beginning the era of aseptic processing of liquid milk/flowable milk products.

In aseptic pouch packing technology, the film and the product filing path are sterilised using hydrogen peroxide (30-35% soln) such as to sterilise the co-extruded, multi-layered barrier film with high oxygen, UV radiation and moisture barrier properties. The triple sterilization principle employed in the design of the machine ensures that film is thoroughly washed and sterilised before it reaches the filling point. The filling is made in machine in sterile atmosphere to avoid recontamination, thus aseptically packing the UHT milk/flowable milk products.

The UHT treated milk/flowable milk products when packed aseptically in barrier packages provide an extended shelf life at ambient temperature. To achieve the longer shelf life, the product is usually treated at UHT plant, i.e. it is heated at 135-142°C for a brief period (2-4 seconds) and then rapidly cooled to room temperature followed by aseptic filling in barrier packages. This results in eliminating all the spoilage causing microorganisms and harmful bacteria for human consumption without loosing the nutritional value of the product, quality and making it safe and sterile to stay at room temperature.

It is known in the art that the presently used packaging materials for UHT milk essentially involve laminate film and flexible film of multi-layer paper, plastics and aluminium foil, all of which are cost-extensive and usually make such desired safe and hygienic storage of UHT treated milk cost-extensive and not a ready solution. Such packaging material works smoothly and reliably on the aseptic carton or pouch filling machines widely being used in the world market. In particular, the material used in making carton or flexible pouches are polyethylene-coated paper-board; in aseptic versions an aluminium foil lamina is normally incorporated into as a barrier layer. Pre-formed cartons or pre-cut, single-piece blanks pre-creased ready for forming into a container are also used for the container with a gable top and these, however, generally are more expensive. The other method of making a carton available is to form a tube from a reel of material, seam it longitudinally, fill with sterile milk and then make transverse seals in an a sterile environment as currently being followed by many industries. Alternatively, the tube is cut into lengths, which are formed into cartons or pouches before filling and sealing. Plastic sachets are usually pillow-shaped and made of low density polyethylene film.

UHT treated milk/ flowable products packed aseptically in PE, Paper and Al based pouches and carton are widely available in the present market, which ensures a shelf of even upto 6 months at room temperature. One of the major disadvantages associated with this barrier packaging material is comparatively the higher packaging material cost, very few supplier of the packaging material and machines, high maintenance cost of the packaging machine as well as limitations to handle multiple SKU in a single machine. Hence, the development and use of some barrier film in form of multi-layer flexible films involving special barrier film co-extruded with some PE based material for use in aseptic packing of UHT treated milk/ flowable milk products should have a great commercial importance to the dairy industry.

As technical requirement, the packaging material for UHT treated milk/flowable products requires better barrier properties like barrier towards UV radiation, migration of oxygen, moisture, flavour and aroma to survive this long shelf life without affecting the quality of milk/ flowable milk products. Instead of using HDPE mono-layer containers, carton packs with polyethylene coating is selected, in some cases, on account of better barrier properties. The carton is usually available in 1 litre size, mostly available in present market. To meet the weekly requirement, each of the 1 litre cartons packing is collated with shrink packing as per the present trade practice. HDPE multi-layer containers can also meet the barrier properties for UHT milk/ flowable products and therefore can be used. However, the cost of packaging material and distribution cost would be the selection criteria for these two types of packaging.

Conversely, flexible pouches made from LDPE/LLDPE for pasteurized milk has been currently in use in the Indian dairy industry. There is also another type of milk called sterilized milk, wherein milk is heated at 120-124 °C for 15-18 minutes. For the sterilized milk, packaging requires to withstand the heat treatment. Due to complete sterile packing, such packaging does not need barrier properties, although the sterilised milk is expected to give a shelf life of about 9 months compared to 6 to 8 months for UHT milk/ flowable milk products. While glass bottles can be used for sterilized milk, they are not chosen because of overall higher cost and the hassle of recovering them for consumers for multi-usage. PET (Polyethylene teripthalate) containers are often selected for value added milk products because of their aesthetic values. However, they cannot be used for UHT milk/flowable products due to inadequate barrier properties. Polyethylene, whether it is HDPE for rigid container or LDPE as coating to the carton or as film for the flexible packaging are the most chosen material for milk packaging, which is being widely used by the industry.

There is, however, a need in the art for providing UHT treated milk/ flowable products in aseptic packages, particularly in cost-effective flexible pouches to meet the demands of the today's consumers'. Importantly thus, if it is possible to package cost effectively UHT treated milk/flowable products, the same would ensure, apart from wholesomeness, that it would be cheaper in cost, convenience with desired advantages of long shelf life of UHT milk/flowable milk products at ambient temperatures. Thus, if such a flexible package for UHT treated milk/ flowable products can be obtained the advantage would be cost-effective extended shelf life of UHT milk/ milk products at ambient temperature and avoid the need for cost-extensive PE/AI/Paper based carton or flexible pouch packaging. It would also avoid the cold chain during distribution, storage and at the point of sale reducing the logistic costs. Thus a suitable flexible pouch with suitable barrier properties for UHT milk/flowable products will offer tremendous cost saving in the packing material and investment in packaging machinery. Such selective pouch packs if possible for UHT treated milk/flowable products will be easy to recycle, thus will be eco-friendly in comparison to the Al based carton or flexible pouch packaging presently being used.

However, the above prevailing state of the art of UHT milk/ flowable products packaging clearly reveal its limitations till date to avoid the need for cost-extensive packaging materials to render it storage stable by imparting suitable barrier properties and impact resistant which suggest the complexity involved in obtaining any form of cost-effective storage packaging of UHT treated milk /flowable products due to the special and peculiar requirements for maintaining effective shelf life particularly of UHT treated milk amidst other flowable products.

OBJECTS OF THE INVENTION

It is thus the basic object of the present invention to provide a EVOH (Ethylene Vinyl Alcohol) based multi-layer select combination of flexible films involving adequate levels of opacifiers that would be capable of providing a selective and cost-effective barrier for UHT treated milk/flowable products towards anyone or more of UV radiation, migration of oxygen, flavour and aroma and moisture.

Another object of the present invention is to provide for flexible package involving EVOH (Ethylene Vinyl Alcohol) based multi-layer select combination of flexible films which would enable packaging cost effectively UHT treated milk/flowable products which would ensure, apart from maintaining wholesomeness, convenience of desired advantages of long shelf life of UHT milk/flowable products of at least about 70 days at ambient temperatures to the ultimate consumers.

Further object of the present invention is directed to provide for flexible package involving EVOH (Ethylene Vinyl Alcohol) based multi-layer select combination of flexible films which would favour cost-effective packaging with desired extended shelf life of atleast about 70 days of UHT treated milk/flowable products at ambient temperature without the need for cost-extensive PE/AI/paper based carton or flexible pouch packaging presently in use.

A further object of the present invention is directed to selective packaging involving EVOH (Ethylene Vinyl Alcohol) based multi-layer select combination of flexible films for UHT treated milk and like products filled aseptically which would avoid the cold chain during distribution, storage and at the point of sale reducing the logistic costs.

Yet further object of the present invention is directed to selective flexible pouches involving EVOH (Ethylene Vinyl Alcohol) based multi-layer select combination of flexible films with suitable barrier properties and selective thickness of the multi-layer select combination of flexible films including resistance towards UV radiation, migration of oxygen, flavour and aroma and moisture for UHT treated milk/flowable milk products which would offer tremendous cost saving in the packing material and investment in packaging machinery.

Another object of the present invention is directed to selective pouch pack involving EVOH (Ethylene Vinyl Alcohol) based multi-layer select combination of flexible films for UHT treated milk/milk products which apart from the desired shelf life would be easy to recycle, thus will be eco-friendly in comparison to the PE/AI/Paper based carton or flexible pouch packaging presently being used.

SUMMARY OF THE INVENTION

Thus according to the basic aspect of the present invention there is provided a multi-layer flexible film for packaging UHT treated milk/ flowable products comprising EVOH (Ethylene Vinyl Alcohol) based film co-extruded with selective combinations of PE films wherein the said EVOH film layer as the barrier layer has a thickness of 5-15 micron with a total film thickness of at least about 60 to 150 micron said selective combinations of PE films alongwith said EVOH providing for opacity level of atleast 70% for said film for desired preservation of said UHT treated milk/ flowable products.

It has been surprisingly found by way of the present invention that it is possible to arrest the deterioration of UHT treated milk/flowable products for atleast 70 days at ambient temperature by providing desired barrier characteristics and impact resistance involving the above disclosed cost-effective select combination of flexible films comprising EVOH co-extruded with PE films incorporating adequate levels of opacifiers as radiation barriers in selected film layers which is thus found to provide the much desired solution for a cost-effective packaging of UHT treated milk/flowable products to maintain desired shelf life of at least 70 days at ambient temperatures also having desired impact resistant characteristics. It has been a surprisingly special finding of the present advancement that combination of the properties of barriers to oxygen transmission and the prevention of penetration of damaging and penetrative radiation significantly prevents deterioration of the desired quality characteristics of UHT treated milk/flowable products and extends the desired shelf-life of the products to 120 days or even more.

In the above multi-layer flexible film for packaging UHT treated milk/ flowable products as above said selective combinations of PE films alongwith said EVOH are selected from PE (polyethylene) comprising LDPE (low density polyethylene), and LLDPE (linear low density polyethylene) and combinations thereof.

In accordance with a preferred aspect of the invention there is provided a multi-layer flexible film for packaging UHT treated milk/ flowable products as above wherein said combinations of PE films alongwith said EVOH comprise selective 7-layers comprising of [(LDPE+LLDPE)+(LDPE+LLDPE)+TIE+EVOH+TIE+LDPE+ (LDPE+ LLDPE)] from the outside to inside of the package, adapted to keep the UTH milk with the desired quality characteristics like taste, flavour, colour and appearance fit for consumption, for a minimum period of about 90 days.

In accordance with another preferred aspect of the invention there is provided a multi-layer flexible film for packaging UHT treated milk/ flowable products as above wherein said combinations of PE films alongwith said EVOH comprise selective 5-layers comprising of [(LDPE+LLDPE)+TIE+EVOH+TIE+(LDPE+LLDPE)] layers from the outside to inside of the package, adapted to keep the UTH milk with the desired quality characteristics like taste, flavour, colour and appearance fit for consumption for a minimum period of about 70 days.

Importantly, in the above disclosed multi-layer flexible film for packaging UHT treated milk/ flowable products as above said EVOH as the barrier layer has a thickness of at least 5-15 micron with a total film thickness of at least about 70 to 150 micron for said 7 layer film and at least about 60 microns-150 micron for said 5 layer film.

According to a further aspect of the advancement in the multi-layer flexible film for packaging UHT treated milk/ flowable products as above said selective combinations of PE films alongwith said EVOH in relation to said basic EVOH barrier layer is selectively provided such as to favour said desired film opacity of atleast 70% preferably atleast 80% with said EVOH as the barrier layer having a thickness in the range of 5 microns to 15 microns preferably 10 micron thick.

Yet further aspect of the advancement provides a multi-layer flexible film for packaging UHT treated milk/ flowable products as above adapted for heat induced sealing and conversion into packages selected from pouch, bag favouring barrier to the inner content from anyone or more of UV radiation, migration of oxygen, flavour and aroma and moisture.

According to a further aspect the multi-layer flexible film for packaging UHT treated milk/ flowable products as above is selectively adapted for packaging, transporting, and storage of UHT treated milk under normal temperature conditions for at least about 70-120 days in the complete absence of any specialised low temperature conditions.

Another aspect of the present advancement provides that a multi-layer flexible film for packaging UHT treated milk/ flowable products as above have sufficient strength such as not to burst/tear open either from the body or the seal during transit, handling and storage or even when dropped from a height of upto 3 meter to release the contents therein.

According to yet another aspect of the present invention there is provided a multi-layer flexible film for packaging UHT treated milk/ flowable products as above comprising TIE layer involving ethylene acrylic acid or any suitable bonding material either as individual material or combinations thereof.

According to yet further preferred aspect of the present invention there is provided a multi¬layer flexible film for packaging UHT treated milk/ flowable products as above comprising:

1st layer - a natural printable layer of PE comprising a blend of LDPE and LLDPE and constitutes a thickness of at least about 15 micron to 35 micron, more preferably about 25 micron;

2nd layer - an adjacent layer having opacifiers comprising a blend of LDPE and LLDPE adapted for at least about 70% opacity wherein the said layer constitutes a thickness of at least about 10 micron to 25 micron, more preferably about 18 micron;

3rd layer - a tie layer involving ethylene acrylic acid or a suitable bonding material either as individual material or a combination of different materials wherein the said layer constitutes with a thickness of at least about 5 micron to 10 micron, more preferably about 7 micron;

4th layer - a layer involving EVOH and having a thickness of at least 5 micron to 15 micron, more preferably about 10 micron,;

5th layer - a tie layer involving ethylene acrylic acid or a suitable bonding material either as individual material or a combination of different materials wherein the said layer constitutes a thickness of at least about 5 micron to 10 micron, more preferably about 7 micron;

6th layer - a layer of LDPE involving opacifiers for at least about 70% opacity to the film wherein the said layer constitutes a thickness of at least about 10 micron to 25 micron, more preferably about 18 micron;

7th layer - a natural heat induced sealable layer of PE comprising a blend of LDPE and LLDPE in the desired ratio, adapted to be sealed so as to form a bag, pouch, etc wherein the said layer constitutes a thickness of at least about 20 micron to 30 micron, more preferably about 25 micron.

According to yet further aspect of the present advancement there is provided a multi-layer flexible film for packaging UHT treated milk/ flowable products as above comprising:

1st layer - a printable layer of PE comprising a blend of LDPE and LLDPE and opacifiers adopted for atleast about 70 % opacity wherein the said layer constitutes a thickness of at least about 15 micron to 35 micron, more preferably about 25 micron;

2nd layer - an adjacent layer having opacifiers comprising a blend of LDPE and LLDPE adapted for at least about 70% opacity wherein the said layer constitutes a thickness of at least about 10 micron to 25 micron, more preferably about 18 micron;

3rd layer - a tie layer involving ethylene acrylic acid or a suitable bonding material either as individual material or a combination of different materials wherein the said layer constitutes with a thickness of at least about 5 micron to 10 micron, more preferably about 7 micron;

4th layer - a layer involving EVOH and having a thickness of at least 5 micron to 15 micron, more preferably about 10 micron,;

5th layer - a tie layer involving ethylene acrylic acid or a suitable bonding material either as individual material or a combination of different materials wherein the said layer constitutes a thickness of at least about 5 micron to 10 micron, more preferably about 7 micron;

6th layer - a layer of LDPE involving opacifiers for at least about 70% opacity to the film wherein the said layer constitutes a thickness of at least about 10 micron to 25 micron, more preferably about 18 micron;

7th layer - a natural heat induced sealable layer of PE comprising a blend of LDPE and LLDPE in the desired ratio, adapted to be sealed so as to form a bag, pouch, etc wherein the said layer constitutes a thickness of at least about 20 to 30 micron, more preferably about 25 micron.

According to yet further preferred aspect of the present invention there is provided a multi¬layer flexible film for packaging UHT treated milk/ flowable products as above comprising PE and involving 5 layers comprises

1st layer - a layer of PE having opacifier comprising either LDPE or a blend of LDPE and LLDPE for least about 70% opacity wherein the said layer constitutes a thickness of at least about 20 micron to 60 micron, more preferably about 43 micron;

2nd layer - a tie layer comprising ethylene acrylic acid or a suitable bonding material either as individual material or a combination of different materials wherein the said layer constitutes with a thickness of at least about 5 micron to 10 micron, more preferably about 7 micron;

3rd layer - a layer made from EVOH and having a thickness of at least 10 micron wherein the said layer constitutes with a thickness of at least about 5 micron to 15 micron, more preferably about 10 micron;

4th layer - a tie layer comprising ethylene acrylic acid or a suitable bonding material either as individual material or a combination of different materials wherein the said layer constitutes with a thickness of at least about 5 micron to 10 micron, more preferably about 7 micron;

5th layer - a heat seal inducible layer of PE having opacifier comprising either LDPE or a blend of LDPE and LLDPE, adapted to be sealed to form a bag, pouch, etc wherein the said layer constitutes with a thickness of at least about 25 micron to 55 micron, more preferably about 43 micron;

Yet further aspect of the present invention is directed to a process for the manufacture of a multi-layer flexible film for packaging UHT treated milk/ flowable products as above comprising the steps of co-extruding said select combination of EVOH layer on both the sides with polyolefin material based layer comprising PE using an additional tie layer and obtaining therefrom said multi-layer flexible film.

Another aspect of the invention provides that in the above process said PE layers are selectively provided comprising either LDPE and/or a blend of LDPE and LLDPE and wherein said tie layer is provided involving ethylene acrylic acid or any suitable bonding material either as individual material or a combinations thereof.

DETAILED DESCRIPTION OF THE INVENTION

Thus according to the basic aspect of the present invention there is provided a cost-effective multi-layer flexible packaging for UHT treated milk/flowable products thereof comprising select combination of EVOH co-extruded with PE films involving adequate levels of opacifiers in such films thus providing a selective effective barrier towards anyone or more of UV radiation, migration of oxygen, flavour and aroma and moisture.

Importantly, the select multi-layer EVOH coextruded with PE film of the invention involving adequate levels of opacifiers is found to be cost-effective and selectively special for use in aseptic packing of UHT treated milk/flowable products to keep it acceptable for a minimum period of 70 days at ambient temperature while retaining the desired quality characteristics of milk like taste, flavour, colour and appearance acceptable and fit for consumption even after desired storage in such multi-layered EVOH co-extruded PE films.

It has been surprisingly found by way of the present invention that it is possible to arrest the deterioration of UHT treated milk/flowable products for atleast 70 days at ambient temperature by providing desired barrier characteristics and impact resistance involving the above disclosed cost-effective select combination of flexible films comprising EVOH co-extruded with PE films incorporating adequate levels of opacifiers as radiation barriers in selected film layers which is found to provide the much desired solution for a cost-effective packaging of UHT treated milk/flowable products to maintain desired shelf life of at least 70 days at ambient temperatures also having desired impact resistant characteristics. It has been a surprisingly special finding of the present invention that combination of the properties of barriers to oxygen transmission and the prevention of penetration of damaging and penetrative radiation significantly prevents deterioration of the desired quality characteristics of UHT treated milk/flowable products and extends the desired shelf-life of the products to 120 days or even more.

According to a preferred aspect of the present invention the same is directed to development of a cost-effective and selectively special flexible packaging for UHT treated milk/ flowable products thereof comprising 7-layer film combination of EVOH coextruded with PE films involving adequate levels of opacifiers involving at least about 5 micron to 15 micron EVOH layer, more preferably about 10 micron, with a total film thickness of at least about 70 to 150 micron, more preferably at least about 110 micron, and involving the selective 7-layers comprising of [(LDPE+LLDPE)+(LDPE+LLDPE)+TIE+EVOH+TIE+LDPE+ (LDPE+ LLDPE)], found specially suitable for use in aseptic packing of UHT treated milk/flowable products to keep it acceptable for a period of minimum 120 days at ambient temperature while preserving the desired quality characteristics suitable for consumption as regular UHT milk/ flowable products commercially available.

In the above discussed cost-effective and selectively special 5-or 7-layer EVOH co-extruded PE films, preferably there is provided a flexible poly films with suitable opacifier incorporated to the extent of minimum 70%, preferably about 80% and more preferably about 90%.

The special 7-layer EVOH coextruded with PE films according to the invention is comprised to provide for a flexible poly film with suitable opacifier selectively of:
1st Layer - a natural layer which is a blend of LDPE and LLDPE in the desired ratio wherein the said layer constitutes with a thickness of at least about 15 micron to 35 micron, more preferably about 25 micron

2nd layer - a layer which is a blend of LDPE and LLDPE added with suitable opacifier to give an at least about 70% opacity wherein the said layer constitutes with a thickness of at least about 10 micron to 25 micron, more preferably about 18 micron

3rd layer - a tie layer made of ethylene acrylic acid or a suitable bonding material either as individual material or a combination of different materials wherein the said layer constitutes with a thickness of at least about 5 micron to 10 micron, more preferably about 7 micron

4th layer - a layer made from EVOH and having a thickness of at least 5 micron to 15 micron, more preferably about 10 micron, to provide sufficient barrier properties against one or more of UV radiation, oxygen transmission, water vapour transmission, etc
5th layer - a tie layer made of ethylene acrylic acid or a suitable bonding material either as individual material or a combination of different materials wherein the said layer constitutes with a thickness of at least about 5 micron to 10 micron, more preferably about 7 micron

6th layer - a layer of LDPE with addition of suitable opacifier to give an at least about 70% opacity to the film wherein the said layer constitutes with a thickness of at least about 10 micron to 25 micron, more preferably about 18 micron

7th layer - a natural layer which is a blend of LDPE and LLDPE in the desired ratio, adapted to be sealed by heat induced sealing process so as to form a bag, pouch, etc wherein the said layer constitutes with a thickness of at least about 20 micron to 30 micron, more preferably about 25 micron

The above 7-layer EVOH coextruded PE films is also selectively provided to favour the 1st layer suitable for printing on its surface with said 2nd and 6th layers involving an addition of suitable opacifier to give desired sufficient opacity of at least about 70%.

Advantageously, it has also been found by way of the present invention that the selective addition of suitable opacifier such as in the 2nd and 6th layer is found to advantageously facilitate the desired barrier characteristics viz. opacity of the flexible package of the invention.

According to yet another preferred feature of the present invention there is provided for development of a cost-effective and selectively special flexible packaging for UHT treated milk/ flowable products comprising of a 5-layer film combination of EVOH coextruded with PE films comprising of at least about 5 micron to 15 micron EVOH layer, more preferably at least about 10 micron, with a total minimum film thickness of at least about 60 micron to 150 micron, more preferably at least about 110 micron, and involving the selective 5-layers comprising of [(LDPE+LLDPE)+TIE+EVOH+TIE+(LDPE+LLDPE)], found specially suitable for use in aseptic packing of UHT treated milk/flowable milk products to keep it acceptable for a minimum period of at least about 120 days while preserving the preferred quality attributes fit for consumption and mostly similar to regular UHT milk commercially available in market.

The special flexible package film combination of EVOH co-extruded with PE films according to the invention is comprised to provide for a flexible poly films with suitable opacifier selectively of:

1st layer - a layer which is a blend of LDPE and LLDPE added with suitable opacifier to give an at least about 70% opacity wherein the said layer constitutes with a thickness of at least about 20 micron to 60 micron, more preferably about 43 micron

2nd layer - a tie layer made of ethylene acrylic acid or a suitable bonding material either as individual material or a combination of different materials wherein the said layer constitutes with a thickness of at least about 5 micron to 10 micron, more preferably about 7 micron

3rd layer - a layer made from EVOH and having a thickness of at least 10 micron to provide sufficient barrier properties against one or more of UV radiation, oxygen transmission, water vapour transmission, etc wherein the said layer constitutes with a thickness of at least about 5 micron to 15 micron, more preferably about 10 micron

4th layer - a tie layer made of ethylene acrylic acid or a suitable bonding material either as individual material or a combination of different materials wherein the said layer constitutes with a thickness of at least about 5 micron to 10 micron, more preferably about 7 micron

5th layer - a layer of LDPE or blend of LDPE and LLDPE with addition of suitable opacifier, adapted to be sealed by heat induced sealing process so as to form a bag, pouch, etc wherein the said layer constitutes with a thickness of at least about 25 micron to 55 micron, more preferably about 43 micron

In the above special 5-layer EVOH coextruded with PE films of the invention the 1st and 5th layers also includes additional suitable opacifier to result in at least about 70% opacity and adapted for printing on either of its surfaces.

Advantageously, it has also been found by way of the present invention that the addition of suitable opacifier such as in the 1st and 5th layers are found to advantageously facilitate the desired barrier characteristics viz. opacity of the flexible package of the invention.

According to yet another preferred aspect of the present invention there is provided a packaged UHT treated milk/flowable products which are packed aseptically in flexible pouches made with said specially selective co-extruded either 5- or 7- layer EVOH with PE flexible films, adapted to be maintained acceptable for a minimum period of at least about 70 days at ambient temperature while maintaining the desired quality traits like taste, flavour, colour and appearance suitable for consumption and commercially available.

According to another preferred aspect of the present invention there is provided pillow shaped pouch packages for aseptic packing of UHT treated milk/flowable products, involving selectively special EVOH co-extruded with PE films, with application of suitable opacifier, in form of pillow shaped pouches comprising of a at least 5 micron to 15 micron EVOH layer, more preferably about 10 micron, with a total minimum film thickness of about 60 micron to 150 micron and 70 micron to 150 micron, respectively more preferably about 110 micron, which serves surprising and unexpectedly special as a cost-effective multi-layered package combination adapted for maintaining for a minimum period of 120 days and suitable for consumption the regular UHT milk/flowable products commercially available.

The cost-effective EVOH co-extruded with PE multi-layer flexible films of the present invention suitable for use in aseptic packing of UHT treated milk/flowable products comprising a multi-layer select combination of films involving adequate levels of opacifiers is thus selective and surprising for the development of special said either 5- or 7-layer EVOH coextruded PE films, with application of suitable opacifier, comprising of at least 10 micron EVOH layer with a total film thickness of at least about 110 micron comprising of said [(LDPE+LLDPE) + (LDPE+LLDPE)+TIE+ EVOH+TIE+LDPE+(LDPE+LLDPE)] and [(LDPE+LLDPE)+TIE+EVOH+TIE+(LDPE+ LLDPE)], respectively, which can be used for aseptic packing of UHT treated milk/flowable products to keep it acceptable for a minimum period of about 120 days, respectively while retaining the desired quality attributes fit for consumption and as that of regular UHT milk commercially available.

Importantly, extensive studies by way of the present invention have also shown that the pillow pouch made from flexible films comprising EVOH of desired thickness only when co-extruded with selective PE films and adhesive material involving adequate levels of opacifiers in accordance with the present advancement could provide for the desired cost-effective flexible packaging with substantially the same barrier to the UHT treated milk/flowable products as could be obtained only involving high costs involving flexible pouches and carton made of PE, cardboard (paper) and aluminium presently available in market place. The pillow pouches formed from the selective flexible films provided for surprisingly good barrier against anyone or more of required UV radiation, oxygen, flavour and aroma as well as moisture and thus the UHT treated milk/flowable products packed in such selective packaging material is found acceptable for a minimum period of at least about 70 days of storage at room temperature as demonstrated by sensory evaluation and analysis of several physico-chemical parameters like peroxide value, level free fatty acids (FFA), Hunter Colour value, etc. The effectiveness of the selective flexible films combination of the present invention as a selective barrier to the migration of particularly oxygen and UV/ visible radiation permits a significant cost-effective alternative manner of extension of the shelf life of UHT treated milk/flowable products aseptically packed in pouches obtained therefrom and would enable the much required replacement of pouches or cartons made of PE, cardboard (paper) and aluminium or even other expensive co-extruded multi-layer flexible films with resultant significant economic savings in packaging cost.

The invention is illustrated in greater detail in relation to the following non-limiting exemplary illustrations:

Example I:

A trial was run with 3-layer co-extruded films consisting of PE/PE/PE made of blended polyethylene of LDPE and LLDPE in aseptic filling of UHT milk. It failed to achieve a shelf life more than 21 days at room temperature. After 21 days of storage, milk developed some typical flavour characterized with some objectionable cabbagey and cardboard type flavour with a note of oxidized smell as well as some bitter taste. This was attributed to the lack of •required barrier properties of the films, particularly towards the migration of UV radiation, oxygen transmission, etc in comparison to the present 5- and 7- layer films. Even the fat extracted from the samples showed a peroxide value of more than 0.1 milli eqv./lOOO g fat, which showed a higher degree of oxidative degradation of fat. Even majority of the pouches made thereof and filled with 500 and 1000 ml milk failed to withstand the impact while dropped from a height more than 1.8 meter because of the poor impact resistance compared to the 5- and 7-layer films claimed in the present invention.

Based on the findings of the study aforesaid, further trials were conducted to improve the barrier properties as well as impact resistance of the films. With the aim of achieving so, the efficacy of the films made by increasing the number of layers of polyethylene (PE) made of either LDPE or blend of LDPE and LLDPE as well as inserting a barrier layer of PA (Polyamide/Nylon), EVOH, PVDC, PETP, etc. Accordingly, trials were made with a number of flexible films made of more than 3-layer of PE. Therefore, the efforts were further conducted using 5- and 7- layer co-extruded films, where a barrier layer made either of PA (Polyamide)/Nylon or EVOH or PVDC (polyvinylidene chloride) or PETP (Polyethylene terephthlate) or PVDC coated PVC was inserted along with another layer PE made either of LDPE alone or blend of LDPE and LLDPE being used in increasing the number of layer in the films to achieve desired barrier properties, sealing strength and impact resistance. The trials were run with several films made inserting a single barrier layer (viz. PA or EVOH or PVDC or PETP or PVDC coated PVC) individually, which was co-extruded either with LDPE or blend of LDPE and LLDPE, or inserting a single barrier layer (viz. PA or EVOH or PVDC or PETP or PVDC coated PVC) individually, which was co-extruded either with LDPE or blend of LDPE and LLDPE along with another additional layer of PE made of either LDPE or a blend of LDPE and LLDPE. Out of these several films tried as above under the present invention, the 5-layer films consisting of LDPE + LLDPE/TIE/EVOH/TIE/LPDE+LLDP and 7-layer films consisting of LDPE + LLDPE/LDPE+ LLDPE/TIE/EVOH/TIE/LDPE/LPDE+LLDP only achieved the desired results in terms of i) ability to keep UHT milk acceptable with a minimum shelf life of 90 days and 120 days for 5- and 7-layer films, respectively while retaining all the sensory traits like colour and appearance, taste and flavour acceptable and suitable for consumption like commercial UHT milk packed in carton or flexible pouches made of PE (polyethylene), cardboard (paper) and aluminium (Al), ii) keeping minimum changes in physico-chemical quality like pH, peroxide value, HMF (hydroxyl methyl furfural), Hunter colour value, etc, iii) resistance to impact while dropped from a height of 1.8 meters for filled 500 ml and 1000 ml milk pack and iv) barrier properties like OTR (Oxygen Transmission Rate) value maximum of 4.06 cc/m2-day, impact resistance like bursting strength of more than 250 kg/cm2, impact resistance of minimum of 145 g and tensile elongation of more than 450 % at break, etc. This confirmed the fact that there has been some special and unexpected benefit attributes which flow from the above the 5-layer films comprising of LDPE + LLDPE/TIE/EVOH/TIE/LPDE+LLDP and 7-layer films comprising of LDPE + LLDPE/LDPE+ LLDPE/TIE/EVOH/TIE/LDPE/LPDE+LLDP films in accordance with the present advancement which cannot be achieved involving same combinations but with other barrier materials such as PVDC or PETP or PVDC coated PVC in place of EVOH.

Unlike 3-layer films made of either LDPE or blends of LDPE+LLDPE, 5- and 7-layer films made of a barrier layer other than EVOH and LDPE alone, the present 5- and 7 layer films consisting of LDPE + LLDPE/TIE/EVOH/TIE/LPDE+LLDP and LDPE +LLDPE/LDPE+LDPE/TIE/EVOH/TIE/LDPE/LPDE+LLDP, respectively, wherein incorporation of EVOH as barrier layer as well as additional PE layer in form of suitable blends of LDPE and LLDPE was made, performed well in all the aspects compared to the other films tried. It is thus a selective and surprising by the way that use of 5- and 7-layer films with the structure and composition described hereabove was found successful in achieving the desired functions required for use in aseptic packaging of UHT milk.

EXAMPLE II:

Under this example it was selectively found that the degree of oxidative changes and discolouration because of the browning as well as storage related flavour defects along with decreasing sensory score for UHT milk packed in the flexible pouches during storage period was directly related to the thickness of barrier layer viz. EVOH layer used. The trials also demonstrated that the resistance of the pillow pouches made of this flexible films towards impact as measured by Drop Test, Bursting Strength, puncture resistance as well as tensile elongation required for packing of UHT milk to result in sufficient strength for packaging, stacking, storage and transportation without any damage of the pouches like seal leakage, rupture, etc because of the pressure.

It was observed that the flexible pouches made of 7-layer EVOH based films comprising selective 5 micron - 15 micron thickness of EVOH layer with a total film thickness of 70 -150 micron as well as 5-layer EVOH films consisting of 5 micron - 15 micron EVOH layer with a total film thickness of 60 -150 micron performed well in all the aspects including i) ensuring UHT milk with a with a minimum shelf life of 70 days for 5- and 7-layer films, ii) ensuring minimum storage related changes in physico-chemical quality and iii) resistance to impact. Beyond this limit of EVOH layer and total film thickness, the films were found to poorly perform either in achieving the minimum shelf life and impact resistance of the packages or in machineability of film, film brittleness, ease and strength of sealing, etc. Further trials revealed that flexible pouches while made of 7-layer EVOH films consisting of 10 micron EVOH layer with a total film thickness of 110 micron as well as 5-layer EVOH films consisting of 10 micron EVOH layer with a total film thickness of 110 micron was observed optimum in achieving the results in all the above aspects as compared to the pouches made of 7-layer EVOH films consisting of 15 micron EVOH layer with a total film thickness of 150 micron as well as 5-layer EVOH films consisting of 15 micron EVOH layer with a total film thickness of 150 micron.

EXAMPLE III:
Trials were conducted to explore the effects on the alteration of positional sequence of PE layers on 1st, 2nd, 6th and 7th made either of LDPE or a blend of LDPE and LLDPE were also studied for 7-layer films. The 7-layer films (LDPE+LLDPE /LDPE+ LLDPE / TIE/EVOH/TIE/LDPE/LDPE+LLDPE) with 2nd and 6th layer made of blend of LDPE+LLDPE added with white masterbatch and LDPE added with black pigment, respectively under the present invention did not show in any significant variation in demonstrating its ability to achieve the target characteristics either in achieving shelf life, product quality even when the 2nd layer and 6th layer of the film (LDPE+LLDPE /LDPE/ TIE/EVOH/TIE/LDPE+LLDPE/LDPE+LLDPE) were of made of LDPE with white masterbatch and blend of LDPE+LLDPE with addition of black pigment, respectively. However it produce some changes in film characteristics like film machineability, strength and ease of sealing, bursting strength, impact resistance, puncture resistance, tensile elongation, etc. While considering the overall effects more especially in terms of impact resistance, seal strength and tensile elongation, the 7-layer film consisting of LDPE+LLDPE /LDPE+ LLDPE / TIE/EVOH/TIE/LDPE/LDPE+LLDPE in this positional sequence comparatively produced the better results in desired film characteristics.

It is important to note however, that there is no possibility in altering the position of EVOH layer with PE layer because EVOH layer is co-extruded both sides with PE layer (LDPE or blend of LDPE+LLDPE) using TIE layer, which is made of made of Ethylene acrylic acid or a suitable bonding material either as individual material or a combination of different materials.

EXAMPLE IV:
The 5-layer film under the present invention consists of LDPE + LLDPE/TIE/EVOH/TIE/LDPE+LLDPE beginning from out side towards the inner with a PE layer made of blend of LDPE and LLDPE on outer and inner most layer added with white masterbatch and black pigment, respectively. The 5-layer EVOH films of the present invention comprises of 5 micron - 15 micron thick EVOH layer with a total film thickness of 60 -150 micron. More specifically, it is consisting of 10 micron EVOH layer with a total film thickness of 110 micron, which was also found to be optimum in achieving the target results compared to the pouches made of 5-layer EVOH films consisting of 15 micron EVOH layer with a total film thickness of 150 micron.

There is, therefore, no possibility in alteration of positional sequence of PE layer made of blend of LDPE+LLDPE on 1st and 5th layer. Even There is no possibility in altering the position of EVOH layer with PE layer because EVOH layer is co-extruded both sides with PE layer (LDPE or blend of LDPE+LLDPE) using TIE layer, which is made of made of Ethylene acrylic acid or a suitable bonding material either as individual material or a combination of different materials.

EXAMPLE V:

With increasing number of PE layers from 5 to 7 as well as concomitant increase in total film thickness, keeping quality of UHT milk as well as the impact resistance of the films were found to improve significantly. The 5-layer films consisting of LDPE + LLDPE/TIE/EVOH/TIE/LPDE+LLDP with minimum of 5 micron EVOH layer with a total minimum film thickness of 60 micron was found quite satisfactory to keep UHT milk acceptable atleast for a period of 70 days with a maximum FFA and peroxide value of 0.1% and 0.09 milli eqv./lOOO g fat, respectively as well as show a good resistance towards impacts and seal strength while 500 and 1000 ml filled pouches were dropped from a height of upto 1.8 meter. Conversely, the 7-layer films comprising of LDPE + LLDPE/LDPE+ LLDPE/TIE/EVOH/TIE/LDPE/LPDE+LLDP with minimum 5 micron EVOH layer with a total minimum film thickness of 70 micron performed comparatively better than that of 5-layer films. The 7-layer films was even observed to extend the shelf life of UHT milk atleast for a period of 90 days with a maximum FFA and peroxide value of 0.08% and 0.07 milli eqv./lOOO g fat, respectively. It also exhibited moderately better resistance towards impacts and seal strength while the filled pouches were dropped from a height of upto 2.2 meter.

EXAMPLE VI:

The effects of optional alteration of 7-layer film made of LDPE+LLDPE /LDPE+ LLDPE / TIE/EVOH/TIE/LDPE/LDPE+LLDPE was also investigated on the keeping quality of UHT milk and other film characteristics.

The trial covered the following different films:

Film-A: LDPE+LLDPE /LDPE+ LLDPE / TIE/EVOH/TIE/LDPE/LDPE+LLDPE Film-B: LDPE+LLDPE /LDPE+ LLDPE/LDPE / TIE/EVOH/TIE/LDPE+LLDPE Film-C: LDPE+LLDPE /LDPE+ LLDPE/LDPE+LLDPE / TIE/EVOH/TIE/LDPE Film-D: LDPE+LLDPE/ TIE/EVOH/TIE/LDPE/LDPE+LLDPE/LDPE+LLDPE Film-E: LDPE+LLDPE/ TIE/EVOH/TIE/LDPE+LLDPE/LDPE+LLDPE/LDPE

Instead of positional alteration in case of the 5-layer film made of LDPE + LLDPE/TIE/EVOH/TIE/LDPE+LLDPE, change of PE layer of the 1st and the 5th layer was also investigated on the keeping quality of UHT milk and other film characteristics. The trial covered the following different films: Film-F: LDPE + LLDPE/TIE/EVOH/TIE/LDPE+LLDPE Film-G: LDPE /TIE/EVOH/TIE/LPDE Film-H: LDPE+LDPE /TIE/EVOH/TIE/LPDE Film-I: LDPE /TIE/EVOH/TIE/LDPE+LLDPE

It was found that even the positional alteration of the selective layers of the EVOH layer and PE layers identified by way of the present advancement in different 7-layer films under the study (Film A to Film E) did not produce any significant changes to the extent of keeping quality and storage related physico-chemical properties. However, film A (LDPE+LLDPE/LDPE+LLDPE/TIE/EVOH/TIE/LDPE/LDPE+LLDPE) demonstrated comparatively better performance in seal strength, puncture resistance as well as resistance towards impacts. Almost all pouches made of film A even did not rupture against impact while dropped from a maximum height of 2.2 meter. Even it provided maximum ease of machineability, maximum run in machine, etc alike the others.

Similarly for 5-layer film, it was observed that the film F (LDPE + LLDPE/TIE/EVOH/TIE/LDPE+LLDPE) relatively performed better in desired film characteristics viz. seal strength, impact resistance, film machineability, etc compared to others under the study.

The barrier property of the film is because of EVOH layer. In 5-layer film, the alteration of the positional sequence of EVOH layer is not possible. Because the 1st and 5th layer are PE layer and 2nd and 4th layer are TIE viz. adhesive layer, always required before and after EVOH layer. EVOH layer can't be 1st or 5th layer.

EXAMPLE VII:
Although various films covered in the present investigation both 7-layer (Film A to Film E) and 5-layer (Film F to Film I), achieved a minimum shelf life of 70 days pouches made of film A consisting of LDPE+LLDPE /LDPE+ LLDPE / TIE/EVOH/TIE/LDPE/LDPE+LLDPE as well as film F consisting of LDPE + LLDPE/TIE/EVOH/TIE/LDPE+LLDPE with the PE layer either as LDPE or as blend of LDPE+LLDPE in this selective positional sequence , as it was found, resulted in best functional properties over the others in terms of impact resistance and seal strength as measured by drop test and Transit trial. It was observed that almost cent percent of pouches made of Film A and film F passed dropped test from a height of 2.2 meter and 1.8 meter, respectively over the others resulting comparatively greater damages either in sealing damage or film rupture under the impact. Even the pouches made of film A and Film F experienced around 6% and 4% less damages in pouch, respectively on transit trial ac compared to the pouches made of other 7- and 5-layer films under the trials conducted.

EXAMPLE VIII:

It is also importantly found by way of the present trials that the 7th layer and 5th layer of 7- and 5-layer film when made of blend of LDPE and LLDPE, the same can be conveniently sealed by heat induced sealing process so as to form a bag, pouch, etc. Finally pouch format are chosen because of its advantages in terms of space consumption, ease of fitting in box, look and convenience in handling, resistance to withstand impacts during transport over other formats like bag, tube, etc.

EXAMPLE IX:

Barrier properties of the barrier layer as revealed in the trials of the present invention of selective thickness of 5 to 15 micron. It is also found by way of extensive trials that EVOH layer with a thickness of 7 micron gave a OTR rate of 4.06 cc/m2-day while a 10 micron thick layer gave a OTR value of 0.68 cc/m2-day. Based on such trials it was identified that a 7 micron barrier layer was preferred to preserve UHT treated milk, it is more preferred to the use a 10 micron thick barrier film which is found to give sufficient barrier such that it preserves the taste, aroma and colour of UHT treated milk to give a shelf life of atleast 120 days. Thickness greater than 15 microns was found to add to unnecessary costs and with not much added protection and hence was not required as evidenced by the trials.

Optical Properties:

Based on the trials conducted it was found that film in accordance with the present advancements with opacity level of more than 70 % was sufficient to preserve the UHT treated milk but it is preferred to have a film with opacity of minimum 80% which is sufficient to preserve the UHT treated milk against the harmful effects of radiation for a period of atleast 120 days. The results are provided hereunder:

Optical Properties: Total Film Thickness (110 microns)

Mechanical Properties:

It was further studied that the co-extruded film in accordance with the present advancement with a total thickness of 75 micron gave a Dart Impact strength of 145 g and a seal strength of 3.77 kgf/25mm. This strength of the film is sufficient to ensure the integrity of the pillow pouch containing the UHT treated milk. It was also found that the film with a total thickness of 110 micron gives a Dart Impact strength of 240g and a Seal Strength of 4.58 kgf/25mm. This is sufficient to ensure that the pillow pouch remains intact when dropped from a height of 3 m.

It is thus possible by way of the present advancement to provide for cost-effective flexible packaging for UHT treated milk/flowable products and, more particularly, to a cost-effective and selective co-extruded multi-layer EVOH (Ethylene Vinyl Alcohol) and PE (Polyethylene) flexible film based package combination involving adequate amount of opacifiers as radiation barriers in selective film layers adapted for desired shelf life of aseptically filled UHT treated milk/ flowable products thus keeping it acceptable for a minimum period of atleast about 70 days at ambient temperature together with high impact resistance . The present advancement would also enable packaged UHT treated milk/ flowable products/ milk based products packed aseptically in flexible pouches made with specially and selectively developed co-extruded multi-layer EVOH and PE flexible films, which would favour maintaining the UHT treated milk/ flowable products/ milk based products acceptable for a minimum period of about 70 days at ambient temperature while retaining the desired quality characteristics like taste, flavour, colour and appearance fit for consumption and as commercially required without the need for cost-extensive multi-layer flexible pouches or cartons made of PE, cardboard (paper) and aluminium (Al).

We Claim:

1. A multi-layer flexible film for packaging UHT treated milk/ flowable products comprising

EVOH (Ethylene Vinyl Alcohol) based multilayer film coextruded with selective combinations of PE films wherein the said EVOH film layer as the barrier layer has a thickness of 5 micron -15 micron with a total film thickness of at least about 60 to 150 micron said selective combinations of PE films alongwith said EVOH providing for opacity level of atleast 70% for said film for desired preservation of said UHT treated milk/ flowable products.

2. A multi-layer flexible film for packaging UHT treated milk/ flowable products as claimed in claim 1 wherein said selective combinations of PE films alongwith said EVOH are selected from PE (polyethylene) comprising LDPE (low density polyethylene), and LLDPE (linear low density polyethylene) and combinations thereof.

3. A multi-layer flexible film for packaging UHT treated milk/ flowable products as claimed in anyone of claims 1 and 2 wherein said combinations of PE films alongwith said EVOH comprise selective 7-layers comprising of [(LDPE+LLDPE) + (LDPE+LLDPE)+TIE+EVOH+TIE+LDPE+ (LDPE+ LLDPE)] from the outside to inside of the package , adapted to keep the UHT milk.with the desired quality characteristics like taste, flavour, colour and appearance fit for consumption. for a minimum period of 90 days.

4. A multi-layer flexible film for packaging UHT treated milk/ flowable products as claimed in anyone of claims 1 and 2 wherein said combinations of PE films alongwith said EVOH comprise selective 5-layers comprising of [(LDPE+LLDPE)+TIE+EVOH+TIE+(LDPE+LLDPE)] layers from the outside to inside of the package, adapted to keep the UHT milk. With the desired quality characteristics like taste, flavour, colour and appearance fit for consumption., for a minimum period of 70 days.

5. A multi-layer flexible film for packaging UHT treated milk/ flowable products as claimed in anyone of claims 3 or 4 wherein said EVOH as the barrier layer has a thickness of at least 5 micron -15 micron with a total film thickness of at least about 70 micron to 150 micron for said 7 layer film and at least about 60-150 micron for said 5 layer filtn.

6. A multi-layer flexible film for packaging UHT treated milk/ flowable products as claimed in anyone of claims 1 to 5 wherein said selective combinations of PE films alongwith said EVOH in relation to said basic EVOH barrier layer is selectively provided such as to favour said desired film opacity of atleast 70 % preferably atleast 80%

7. A multi-layer flexible film for packaging UHT treated milk/ flowable products as claimed in anyone of claims 1 to 6 wherein said selective combinations of PE films alongwith said EVOH in relation to said basic EVOH barrier layer is selectively provided such as to favour said desired film having a thickness in the range of 5 micron to 15 micron preferably 10 micron thick.

8. A multi-layer flexible film for packaging UHT treated milk/ flowable products as claimed in anyone of claims 1 to 7 adapted for heat induced sealing and conversion into packages selected from pouch, bag favouring barrier to the inner content from anyone or more of UV radiation, migration of oxygen, flavour and aroma and moisture.

9. A multi-layer flexible film for packaging UHT treated milk/ flowable products as claimed in anyone of claims 1 to 8 selectively adapted for packaging, transporting, and storage of UHT treated milk/flowable products under normal temperature conditions for at least 70 days preferably atleast about 90 days and more preferably atleast about 120 days in the complete absence of any specialised low temperature conditions.

10. A multi-layer flexible film for packaging UHT treated milk/ flowable products as claimed in anyone of claims 1 to 9 having sufficient strength such as not to burst/tear open either from the body or the seal during transit, handling and storage or even when dropped from a height of upto 3 meter to release the contents therein.

11. A multi-layer flexible film for packaging UHT treated milk/ flowable products as claimed in anyone of claims 1 to 10 comprising TIE layer involving ethylene acrylic acid or any suitable bonding material either as individual material or combinations thereof.

12. A multi-layer flexible film for packaging UHT treated milk/ flowable products as claimed in anyone of claims 1 to 11 comprising:

1st layer - a natural printable layer of PE comprising a blend of LDPE and LLDPE and constitutes a thickness of at least about 15 micron to 35 micron, more preferably about 25 micron;

2nd layer - an adjacent layer having opacifiers comprising a blend of LDPE and LLDPE adapted for at least about 70% opacity wherein the said layer constitutes a thickness of at least about 10 micron to 25 micron, more preferably about 18 micron;

3rd layer - a tie layer involving ethylene acrylic acid or a suitable bonding material either as individual material or a combination of different materials wherein the said layer constitutes with a thickness of at least about 5 micron to 10 micron, more preferably about 7 micron;

4th layer - a layer involving EVOH and having a thickness of at least 5 micron to 15 micron, more preferably about 10 micron,;

5th layer - a tie layer involving ethylene acrylic acid or a suitable bonding material either as individual material or a combination of different materials wherein the said layer constitutes a thickness of at least about 5 micron to 10 micron, more preferably about 7 micron;

6th layer - a layer of LDPE involving opacifiers for at least about 70% opacity to the film wherein the said layer constitutes a thickness of at least about 10 micron to 25 micron, more preferably about 18 micron;

7th layer - a natural heat induced sealable layer of PE comprising a blend of LDPE and LLDPE in the desired ratio, adapted to be sealed so as to form a bag, pouch, etc wherein the said layer constitutes a thickness of at least about 20 micron to 30 micron, more preferably about 25 micron.

13. A multi-layer flexible film for packaging UHT treated milk/ flowable products as claimed in anyone of claims 1 to 11 comprising:

1st layer - a printable layer of PE comprising a blend of LDPE and LLDPE and opacifiers adopted for atleast about 70 % opacity wherein the said layer constitutes a thickness of at least about 15 micron to 35 micron, more preferably about 25 micron;

2nd layer - an adjacent layer having opacifiers comprising a blend of LDPE and LLDPE adapted for at least about 70% opacity wherein the said layer constitutes a thickness of at least about 10 micron to 25 micron, more preferably about 18 micron;

3rd layer - a tie layer involving ethylene acrylic acid or a suitable bonding material either as individual material or a combination of different materials wherein the said layer constitutes with a thickness of at least about 5 micron to 10 micron, more preferably about 7 micron;

4th layer - a layer involving EVOH and having a thickness of at least 5 micron to 15 micron, more preferably about 10 micron,;

5th layer - a tie layer involving ethylene acrylic acid or a suitable bonding material either as individual material or a combination of different materials wherein the said layer constitutes a thickness of at least about 5 micron to 10 micron, more preferably about 7 micron;

6th layer - a layer of LDPE involving opacifiers for at least about 70% opacity to the film wherein the said layer constitutes a thickness of at least about 10 micron to 25 micron, more preferably about 18 micron;

7th layer - a natural heat induced sealable layer of PE comprising a blend of LDPE and LLDPE in the desired ratio, adapted to be sealed so as to form a bag, pouch, etc wherein the said layer constitutes a thickness of at least about 20 micron to 30 micron, more preferably about 25 micron.

14. A multi-layer flexible film for packaging UHT treated milk/ flowable products as claimed in anyone of claims 1 to 11 comprising:

1st layer - a layer of PE having opacifier comprising either LDPE or a blend of LDPE and LLDPE for least about 70% opacity wherein the said layer constitutes a thickness of at least about 20 micron to 60 micron, more preferably about 43 micron;

2nd layer - a tie layer comprising ethylene acrylic acid or a suitable bonding material either as individual material or a combination of different materials wherein the said layer constitutes with a thickness of at least about 5 micron to 10 micron, more preferably about 7 micron;

3rd layer - a layer made from EVOH and having a thickness of at least 10 micron wherein the said layer constitutes with a thickness of at least about 5 micron to 15 micron, more preferably about 10 micron;

4th layer - a tie layer comprising ethylene acrylic acid or a suitable bonding material either as individual material or a combination of different materials wherein the said layer constitutes with a thickness of at least about 5 micron to 10 micron, more preferably about 7 micron;

5th layer - a heat seal inducible layer of PE having opacifier comprising either LDPE or a blend of LDPE and LLDPE, adapted to be sealed to form a bag, pouch, etc wherein the said layer constitutes with a thickness of at least about 25 micron to 55 micron, more preferably about 43 micron;

15. A process for the manufacture of a multi-layer flexible film for packaging UHT treated milk/ flowable products as claimed in anyone of claims 1 to 14 comprising the steps of co-extruding said select combination of EVOH layer on both the sides with polyolefin material based layer comprising PE using an additional tie layer and obtaining therefrom said multi-layer flexible film.

16. A process as claimed in claim 15 wherein said PE layers are selectively provided comprising either LDPE and/or a blend of LDPE and LLDPE and wherein said tie layer is provided involving ethylene acrylic acid or any suitable bonding material either as individual material or combinations thereof.