FIELD OF THE INVENTION:
The present invention relates to a printed metallised biaxially oriented polypropylene (BOPP), and cast polypropylene (CPP) substrate film that exhibits improved adhesion, folding, bending and sealable properties.
BACKGROUND OF THE INVENTION:
Printed film structures of polyethylene (PE), polypropylene (PP), biaxially oriented polypropylene or polyethylene terephthalate have been disclosed in the prior art.
EP1361171 (B1) discloses a plastic film, for packaging rectangular objects such as stock cubes, comprising a base film (preferably metallised on one side) consisting of biaxially oriented polypropylene film or polyethylene terephthalate film with printing (preferably on the metallised layer) and an outer layer of heat-sealing varnish in the appropriate places.
DE19948286B4 discloses a plastic foil for packaging cube-shaped products, consists of polyolefin, as polyethylene (PE) or polypropylene (PP), at least one side of which is metallised, and on one side with a sealant coating preferably (heat sealing) is provided. Ink is applied to the plastic film with a lacquer coat.
DE10021687A1 discloses a plastic foil for packaging cube-shaped products consists of polyolefin, as polyethylene (PE) or polypropylene (PP), at least one side of which is provided with an adhesive or sealing layer. Under this adhesive substance a colour printing is provided which is additionally provided with an overprint varnish. In addition or instead of the colour print, the plastic film is metallized on one side.
NZ525610A discloses a biaxially oriented polypropylene or PET metallised film suitable for packaging three dimensional objects, such as soup cubes.
While the existing printed and heat sealed polyolefin, oriented polypropylene, and PET metallized films fold and bend at the edges and angles to pack the shaped objects, however the ends of the folded films easily gets disturbed during transportation and handling, and do not stay in the folded position, hence allowing the packed shaped object get contaminated, and sacrifices consumer satisfaction. This problem often requires the folded film ends to be closed with an adhesive, or by

sealing the open ends with an adhesive tape.
Another problem with the existing printed and heat sealed polyolefin, oriented polypropylene, and PET metallized films is that during storage or transportation, the films in the stack stick to each other, and hence compromising the workability of the films, and increasing the wastage that adds to the cost.
Therefore, the present invention eliminates the above problems by replacing the one component primer with a two-component primer-hardener system, and printing the metallised substrate film with a nitrocellulose based ink.
The present invention relates to a printed metallised biaxially oriented polypropylene (BOPP), and cast polypropylene (CPP) substrate film which uses a two-component primer-hardener system, printing the metallised substrate film with a nitrocellulose based ink, providing a nitrocellulose based overcoat over the printed nitrocellulose based ink. The printed and overcoat applied film is then heat-sealed with a heat-seal lacquer. The printed structure exhibits improved adhesion, folding, bending and sealable properties.
The printed structure exhibits improved adhesion, folding/ bending and sealable properties.
OBJECTS OF THE INVENTION:
The principal objective of the present invention is to provide a printed film structure on biaxially oriented polypropylene (BOPP) or cast polypropylene (CPP) which exhibits improved adhesion, folding/ bending and sealable properties.
Another objective of the present invention is to provide said films that do not stick to each other in the stack during storage or transportation.
A further objective of the present invention is to provide said films, where after packaging the shaped objects; the open ends of the films stay in place appropriately without getting opened up during transportation and handling.
Other objectives, features and advantages will become apparent to those skilled in

the art from the detailed description and the appended claims.
SUMMARY OF THE INVENTION:
The present invention relates to a printed metallised biaxially oriented polypropylene (BOPP) or cast polypropylene (CPP) film which exhibits improved adhesion, folding/ bending and sealable properties.
The biaxially oriented polypropylene (BOPP) or cast polypropylene (CPP) film is metallised on one side.
The printed film uses a two-component primer-hardener system to be applied on the metallised side of the BOPP or CPP substrate film.
A nitrocellulose based ink is provided to print the desired pattern on the printed polymeric film with the two-component primer-hardener system.
A nitrocellulose based overcoat is provided over the printed ink to improve the gloss, and scuff resistance.
The printed and overcoat applied film is then heat-sealed with a heat-seal lacquer.
The printed structure exhibits improved adhesion, folding/ bending and sealable properties.
BRIEF DESCRIPTION OF THE DRAWINGS:
Fig. 1. A cross-section view of a coated BOPP or CPP printed film structure
DETAILED DESCRIPTION OF THE INVENTION:
The preferred embodiments of the present invention will be described in detail with the following disclosure and examples. The foregoing general description and the following detailed description are provided to illustrate only some embodiments of the present invention and not to limit the scope of the present invention. The invention is capable of other embodiments and can be carried out or practiced in various other ways.

Unless otherwise specified, all the technical and scientific terms used herein have the same meaning as is generally understood by a person skilled in the art pertaining to the present invention. All the patents published patent applications referred to throughout the entire disclosure herein, unless specified otherwise, are incorporated by reference in their entirety.
Definitions of terms used in this specification:
The term "polyurethane", "PU", "urethane polymer", as used herein refers to a thermoplastic polymer which can be made crosslinkable (or thermosettable) and which is produced by the reaction of a polyisocyanate (i.e., an organic compound containing at least two isocyanate (-N=C=0) groups per molecule) and a polyol. The polymeric reaction product contains repeating urethane linkages (or carbamate ester linkages) of the structure:
H O I II HM-C—O—
When such linkages are present in a polymer, it is classified as polyurethane herein.
Polyisocyanates also react with amines (that is, compounds which contain at least one primary or secondary amino
-NH2 or -NH I
R1
group per molecule (where Ri is typically an alkyl, aryl, or like hydrocarbonaceous radical) in a similar fashion to produce a polymeric reaction product that contains urea linkages:
H O H
I II I
-W-C—N —
Polymers containing both urethane and urea linkages are known as polyurethane ureas and such polyurethane polymers can be used as starting polymers in the practice of this invention.

Either the starting polyisocyanate or the starting polyol can itself have an internal polymeric structure. Examples of suitable structures include polyethers, polyesters, polyalkyls, polydimethylsiloxanes, and the like. Commonly used isocyanates in polyurethane synthesis include toluene dissocyanate (TDI) and methylene bis (p-phenyl isocyanate) or 4,4'-dimethylmethane diisocyanate (MDI) although many other isocyanates are available. Commonly used polyols include polyester and polyethers.
A polyurethane polymer can contain various functional (i.e., reactive) groups, such as one or more groups selected from the class consisting of isocyanato, hydroxyl and amino (particularly primary or secondary amino). Such functional groups are characteristically associated with polyurethane polymers. However, in addition to, or apart from, such functional groups, a polyurethane polymer can also contain other functional groups such as carboxyl groups, sulfonic acid groups, and the like, as those skilled in the art will appreciate.
A chemical compound with two or more hydroxyl (-OH) groups is known as a "polyol" in this disclosure. A polyol with exactly two -OH groups is a "diol". Similarly a polyol with just three -OH groups is a "triol".
A chemical compound that comprises at least two ester (R-CO-OR) linkages in the same linear chain of atoms is known in this disclosure as a "polyester". A chemical compound that includes both multiple ester linkages and multiple -OH functional groups is known in the present disclosure as a "polyester polyol".
A chemical compound that comprises at least two ether (R-O-R) linkages in the same linear chain of atoms is known in this disclosure as a "polyether". A chemical compound that includes both multiple ether linkages and multiple -OH functional groups is known in the present disclosure as a "polyether polyol".
The present invention relates to a printed metallised biaxially oriented polypropylene (BOPP) or cast polypropylene (CPP) film which exhibits improved adhesion, folding/ bending and sealable properties.
The biaxially oriented polypropylene (BOPP) or cast polypropylene (CPP) film is metallised on one side.

The printed film uses a two-component primer-hardener system to be applied on the metallised side of the BOPP or CPP substrate film.
A nitrocellulose based ink is provided to print the desired pattern on the printed polymeric film with the two-component primer-hardener system.
A nitrocellulose based overcoat is provided over the printed ink to improve the gloss, and scuff resistance.
The printed and overcoat applied film is then heat-sealed with a heat-seal lacquer.
The printed structure exhibits improved adhesion, folding/ bending and sealable properties.
The two-component primer-hardener system includes a polyol based primer system PMA036 (2K Primer) mixed with an isocyanate based hardener PMA037 (2K Hardener), both of which are manufactured by Yansefu® Inks and Coatings Pvt. Ltd. India.
The nitrocellulose based Ink is SARJO®FOIL ink manufactured by Yansefu® Inks and Coatings Pvt. Ltd. India.
The nitrocellulose based overcoat varnish is SARJO®FILM Plus Gloss OPM (SRJFILMPLE004) manufactured by Yansefu® Inks and Coatings Pvt. Ltd. India.
The heat seal lacquer (HSL) is polyurethane based SARJO®FILM Plus (SRJFILMPLE005) manufactured by Yansefu® Inks and Coatings Pvt. Ltd. India.
The process of manufacturing the printed polymeric film
As shown in Fig. 1 the printed polymeric film (1) comprises a film substrate (2) of biaxially oriented polypropylene (BOPP) or cast polypropylene (CPP). The film substrate (2) is metallised (3) on one side. The side of the metallisation (3) that faces away from the film substrate (2) is applied with a two-component primer-hardener system (4). A nitrocellulose based ink is printed (5) over the two-component primer-

hardener system. The ink print (5) is provided with an overcoat (6), and then on the overcoat, a polyurethane based heat sealing lacquer (7) is pattern coated at an elevated temperature.
The biaxially oriented polypropylene (BOPP) or cast polypropylene (CPP) used for the film substrate (2) has a thickness of about 10 to 70 u, more preferably 15 to 40 u, and most preferably 20 to 35 u.
The shaped object to be packaged by the printed polymeric film is selected from a three-dimensionally shaped article such as a cuboid shaped article, a spherical article, a cubical article.
Examples:
The present disclosure will now be explained in further detail by the following examples. These examples are illustrative of certain embodiments of the invention without being limited to the specific examples given here.
Example 1.
A biaxially oriented polypropylene (BOPP) film substrate is metallised on one side. The side of the metallisation that faces away from the film substrate is applied with a two-component primer-hardener system. A nitrocellulose based ink is printed over the two-component primer-hardener system. The ink print is provided with an overcoat, followed by a polyurethane based heat sealing lacquer is pattern coated on the overcoat at an elevated temperature.
Example 2.
A cast polypropylene (CPP) film substrate is metallised on one side. The side of the metallisation that faces away from the film substrate is applied with a two-component primer-hardener system. A nitrocellulose based ink is printed over the two-component primer-hardener system. The ink print is provided with an overcoat, followed by a polyurethane based heat sealing lacquer is pattern coated on the overcoat at an elevated temperature.

Example 3.
The two component primer-hardener system for applying to a metallised biaxially oriented polypropylene (BOPP) or a metallised cast polypropylene (CPP) polymeric film substrate as discussed in Examples 1 and 2 includes a polyol based primer system PMA036 (2K Primer) mixed with an isocyanate based hardener PMA037 (2K Hardener), both of which are manufactured by Yansefu Inks and Coatings Pvt. Ltd. India.
While various aspects and embodiments have been disclosed herein, other aspects, embodiments and uses of the invention will be apparent to those skilled in the art. It is intended that the specification and examples be considered as exemplary only, with the true scope and spirit of the invention being indicated by the following claims.

CLAIMS We claim:
1. A printed polymeric film for packaging a shaped object comprising: a metallised film substrate, wherein said metallised film substrate is coated with a two-component primer-hardener system on the metallised side, wherein the two-component primer-hardener system coated side of the metallised film is printed with a nitrocellulose based ink to achieve a desired pattern, wherein an overcoat is applied on the ink printing, and a heat seal of a heat sealing lacquer is provided on the overcoat at an elevated temperature.
2. The printed polymeric film according to claim 1, wherein the metallised film substrate is made of a biaxially oriented polypropylene (BOPP) or a cast polypropylene (CPP) that is metallised on one side.
3. The two-component primer-hardener system composition according to claim 1, is a two component polyurethane system.
4. The printed polymeric film according to claim 1, wherein the polymeric overcoat is a nitrocellulose based overcoat.
5. The printed polymeric film according to claim 1, wherein the heat sealing lacquer is polyurethane based heat sealing lacquer.
6. The printed polymeric film according to any one of the preceding claims, wherein the film substrate has a thickness of about 10 to 70 u, more preferably 15 to 40 u and most preferably 20 to 35 u.
7. The printed polymeric film for packaging a shaped object according to claim 1, wherein the shaped object is selected from a three-dimensionally shaped article such as a cuboid shaped article, a spherical article, a cubical article.

8. A two-component primer-hardener system composition for applying to a metallised biaxially oriented polypropylene (BOPP) or a metallised cast polypropylene (CPP) polymeric film substrate, which in turn is printed for packaging a shaped object comprising: a two-component polyurethane system.
9. The two-component primer-hardener system composition applied metallised biaxially oriented polypropylene (BOPP) or a metallised cast polypropylene (CPP) polymeric film according to claim 8, wherein a nitrocellulose based ink is printed over the two-component primer-hardener system, an overcoat is applied on the ink printing, and a heat seal of a heat sealing lacquer is provided on the overcoat at an elevated temperature.
10. The two-component primer-hardener system composition applied metallised biaxially oriented polypropylene (BOPP) or a metallised cast polypropylene (CPP) polymeric film according to claim 8, wherein the polymeric overcoat is a nitrocellulose based overcoat; and the heat sealing lacquer is polyurethane based heat sealing lacquer.