A mono-layer sheet and a laminate therefrom FIELD OF THE INVENTION

[001] The invention relates to a monolayer sheet and a laminate therefrom. The invention also relates to a process and system for production thereof.

BACKGROUND OF THE INVENTION

[002] Flexible packaging solutions find application in beverage, food, consumer packaged goods, personal care products, etc, and with rising consumer needs and requirements, flexible packaging solutions continue to evolve. While, barrier properties, durability, etc remain essential requirements for flexible packaging solutions, aesthetic appeal of flexible packaging is equally important.

[003] To improve aesthetic appeal/ attractiveness of the flexible packaging, a combination of colors, graphics, words etc are applied to the packaging. To further enhance aesthetic appeal, a. holographic or a metallized sheet is used in conjunction with a printed / unprinted sheet rendering a metallic or holographic effect to the entire sheet.

[004] Holographic effect on the packaging also acts as an anti-counterfeit measure. However, usage of overall holography/metallization is quite prevalent in the industry and is widely used, and over time it has become fairly common and can also be easily copied, leading to brand security getting compromised.

[005] In view of the above, there is a need for a packaging overcoming the aforementioned problems, SUMMARY OF THE INVENTION

[006] In one aspect, the present invention provides a monolayer sheet, comprising one or more pre-determined areas with a metal layer applied/deposited thereon, the metal layer adheres with the sheet in pre-determined areas imparting a metallic effect to the pre-determined areas of the sheet.

[007] In one another aspect, the present invention provides a system for forming a monolayer sheet, the system comprising a first material source for providing a base sheet; an applicator for applying a bonding medium on the base sheet, the applicator having an engraved pattern for holding bonding medium such that bonding medium is applied/transferred to the base sheet in pre-determined areas corresponding to the engraved pattern of the applicator; a second material source for providing a metallized sheet; a lamination station having a pair of nip rollers, the base sheet with bonding medium in pre-determined areas is superposed and bonded with the metallized sheet by passing the sheets through the nip rollers to obtain a laminate of base sheet and selectively bonded metallized sheet; and a delamination station having a first roller for receiving the base sheet and a second roller for receiving the metallized sheet, the operation of the roller causes the metallized sheet to separate from the base sheet whereby a metal layer from the metallized sheet transfers and adheres with the sheet imparting a metallic effect to the predetermined area of the sheet.

[008] In one another aspect, the present invention provides a process for forming a monolayer sheet, the process comprising the steps of providing a base sheet and a metallized sheet; applying bonding medium to one or more pre-determined areas of the base sheet; bonding the metallized sheet with the base sheet in the pre-determined areas applied with bonding medium; and separating the metallized sheet from the base sheet such that a metal layer from the metallized sheet is transferred to the pre-determined areas of the base sheet, thereby imparting a metallic effect to the pre-determined areas of the base sheet. BRIEF DESCRIPTION OF THE DRAWINGS

Reference will be made to embodiments of the invention, examples of which may be illustrated in accompanying figures. These figures are intended to be illustrative, not limiting. Although the invention is generally described in context of these embodiments, it should be understood that it is not intended to limit the scope of the invention to these particular embodiments.

Figure 1 shows a mono-layer sheet in accordance with an embodiment of the invention. Figure 2 shows a system for forming a mono-layer sheet in accordance with an embodiment of the invention.

Figure 3 shows a bonding medium application station in accordance with an embodiment of the invention.

Figure 4 shows a delaminating station in accordance with an embodiment of the invention.

Figure 5 shows a flow diagram of a process for forming a mono-layer sheet in accordance with an embodiment of the invention.

DETAILED DESCRIPTION OF THE INVENTION

[009] The present invention is directed towards a laminate having a metallic or holographic effect in predetermined areas imparting an aesthetic appeal to the laminate. The metallic or holographic effect in predetermined/selected areas also provides anti-counterfeit feature to the laminate.

[010] Figure 1 shows a mono-layer sheet 100 in accordance with an embodiment of the invention. The mono-layer sheet has one or more pre-determined areas 102 with a metal layer applied/deposited thereon. Accordingly, the sheet will now have areas with metallic layer 102 and areas without metallic layer 104. The metallic layer adheres with the sheet in pre-determined areas imparting a metallic effect to the pre-determined areas of the sheet. The mono-layer sheet thus has a metallic or shiny or lustrous or glazed effect in the pre-determined areas. In an embodiment, the metallic layer can be applied on any face of the mono-layer sheet depending upon the type of sheet. In this regard, the mono-layer sheet has a first face and a second face. For an opaque sheet, the metallic layer may be applied on the first face in one or more predetermined regions such that the metal layer adheres with the sheet and imparts a metallic effect to the first face of the sheet. The first face of the sheet thus has a metallic or shiny or lustrous or glazed effect in the pre-determined areas. Alternately, if the sheet is a transparent sheet, the metal layer can be bonded to the first face of the sheet, wherein the metal layer adheres with the sheet and imparts a metallic effect to the second face of the sheet in areas corresponding/inline with the pre-determined areas of the first face of the sheet. The second face of the sheet thus has a metallic or shiny or lustrous or glazed effect in the corresponding areas. The pre-determined areas are selected as per design and/or aesthetic to be rendered to the mono-layer sheet. In this regard, the predetermined area is a shape or a pattern or a text present on the monolayer sheet [Oi l] The mono-layer sheet is a base sheet selected from a plastic film or a non-plastic film. The plastic film can be selected from but not limited to, a polyethylene terephthalate (PET) film, a biaxially oriented polypropylene (BOPP) film, a cast polypropylene (CPP) film, a poly ethylene (PE) film, a poly vinyl chloride (PVC) film, a nylon film, a pearlised BOPP film, a metallized PET film, a metallized CPP film, a white CPP film, a biaxially oriented nylon film, etc. The non-plastic film can be selected from aluminum foil, paper. The mono-layer sheet has a first face and a second face. The first face and the second face are opposite faces of the sheet. The mono-layer sheet may have printed areas or non-printed areas or colored areas or transparent areas or translucent areas or opaque areas on the sheet, and any of such areas can be predetermined or selected to have the metallic effect. For example, a red colored area of the sheet may be selected, whereby the metal layer is applied to pre-determined areas in red colored area only. The metal layer adheres to the pre-determined area and imparts a metallic effect to the red colored area i.e. a metallic red color will appear in the pre-determined area. In an embodiment, the metal layer imparting the metallic effect is from a metallized sheet. Further, the metallic effect can be a plain metallic effect or a patterned metallic effect. The plain metallic effect is from a metal layer of a plain metallized sheet, and the patterned metallic effect is from a metal layer of a holographic metallized sheet. The metallized sheets can be selected from any of, but not limited to polyethylene terephthalate (PET), biaxially oriented Polypropylene (BOPP), cast polypropylene (CPP) film families.

[012] In an embodiment, the mono-layer sheet with the metallic effect can be bonded with another sheet to form a laminate. In this regard, additional layers of paper, aluminum or other plastic films can be added to the laminate depending on the product technical requirements.

[013] Figure 2 shows a system for forming a laminate 200 in accordance with an embodiment of the invention. The system comprising a first material supply source 210, a second material supply source 220, a bonding medium application station 230, a dryer 240, and a lamination station 250.

[014] The first material supply source is preferably a roll or a web of a first sheet. The first sheet is a base sheet selected from a plastic film or a non-plastic film. The plastic film can be selected from but not limited to, a polyethylene terephthalate (PET) film, a biaxially oriented polypropylene (BOPP) film, a cast polypropylene (CPP) film, a poly ethylene (PE) film, a poly vinyl chloride (PVC) film, a nylon film, a pearlised BOPP film, a metallized PET film, a metallized CPP film, a white CPP film, a biaxially oriented nylon film, etc. The non-plastic film can be selected from aluminum foil, paper. All kinds of transparent and white opaque sheets used in flexible packaging can be the first material supply source. In an embodiment of the invention, the first sheet is a printed sheet which is printed on reverse or surface of the sheet by using a variety of printing processes like rotogravure, flexographic, offset, digital printing process etc. Alternately, the first sheet can be an unprinted sheet, in which case the first sheet can be straight away taken as a primary source.

[015] The second material supply source is preferably a roll or a web of a second sheet. In an embodiment of the invention, the second sheet is a metallized sheet. The metallized sheet can be selected from any of, but not limited to metallized polyethylene terephthalate (MPET), metallized biaxially oriented Polypropylene (MBOPP), metallized cast polypropylene (MCPP) film families.

[016] The first sheet from the first material supply source is unwound and passed though the bonding medium application station where bonding medium is applied to the first sheet to obtain a first sheet with bonding medium. The bonding medium is an adhesive selected from a water based adhesive, solvent-based adhesive, solvent-less adhesive or any such types of adhesive. The application station shown in figure 1 includes an applicator 232, a counter roller 234 and a reservoir 236.

[017] The applicator is a cylinder configured to rotate around a central axis for applying bonding medium to the first sheet passing through the bonding medium application station.

[018] The counter roller positioned adjacent to the applicator ensures sufficient contact is maintained between the first sheet and the applicator.

[019] In an embodiment of the invention, the applicator is provided with one or more engraved patterns on its circumference. In this regard the engraved pattern is representative of a design or a shape or a text corresponding to the design / shape / text where a layer from the second sheet is to be transfered.

[020] The applicator as can be seen in the figure is positioned such that at-least a portion of circumference of the applicator is in contact with the reservoir. As the applicator rotates, the circumference of the applicator including the engraved pattern picks-up bonding medium from the reservoir. The bonding medium is an adhesive selected from a water based adhesive, solvent- based adhesive, solvent-less adhesive or any such types of adhesive. As the first sheet is passed through the applicator, bonding medium is applied to the first sheet in areas corresponding to the engraved pattern of the applicator. Accordingly, the first sheet with bonding medium will have bonding medium applied in selected/predetermined areas. [021] Furthermore, a doctor blade is provided adjacent to the applicator to remove excess bonding medium picked up by the applicator.

[022] Figure 3 shows a bonding medium application station 300 in accordance with an embodiment of the invention. The bonding medium application station shown in figure 3 includes a transfer roller 302, an applicator 304, a counter roller 306 and a reservoir 308.

[023] The transfer roller is an anilox cylinder configured to rotate around a central axis in the reservoir containing bonding medium. The transfer roller as can be seen in figure 2 is positioned such that at-least a portion of circumference of the transfer roller is in contact with the reservoir. As the transfer roller rotates, the circumference of the transfer roller picks-up bonding medium from the reservoir. Furthermore, a doctor blade is provided adjacent to the transfer roller to remove excess bonding medium picked up by the applicator.

[024] The applicator is provided adjacent to the transfer roller. The applicator is a plate comprising of plurality of image areas along its circumference. Each plate has one or more image areas - protruding pattern. In this regard, the protruding pattern is representative of a design or a shape or text corresponding to the design / shape / text where the layer of the second sheet is to be transferred. While figure 2 and 3 illustrate a set up for bonding medium application station, various other set ups including an applicator with protruding patterns as discussed hereinbefore are well within the scope of the invention.

[025] The counter roller is provided adjacent to the applicator and ensures sufficient contact is maintained between the first sheet and the applicator. As the applicator rotates, the circumference of the plate including the protruding pattern applies bonding medium to the first sheet in areas corresponding to the protruding pattern of the cylinder. Accordingly, the first sheet with bonding medium will have bonding medium applied in selected/predetermined areas.

[026] The first sheet with bonding medium (from the bonding medium application station) is then directed/passed to a lamination station. As shown in figure 1, the first sheet with bonding medium is first passed through the dryer before passing to the lamination station. The lamination station also receives the second sheet from the second material supply source. The first sheet with bonding medium and the second sheet are superposed and bonded together by passing them through an assembly of nip rollers 252. The lamination between the first and second sheets can be performed under heat and/or pressure. In this regard, the first sheet with bonding medium is bonded with the second sheet only in areas where bonding medium is present. The sheets exit the nip rollers as a laminate of first sheet and selectively bonded second sheet i.e. the metallic or holographic sheet is bonded to the first sheet only in selected areas to obtain a selectively bonded sheet.

[027] The selectively bonded sheet is thereafter taken to a delaminating station 400 shown in figure 4. At the delamination station, the first sheet and the second sheet (from first and second supply source) are separated to obtain a final sheet. The delamination station as shown in the figure comprises a pair of conveyor rollers 410, a first roller 420 and a second roller 430. The conveyor rollers are spaced apart from each other for allowing the selectively bonded sheet to pass through. The selectively bonded sheet coming out of the pair of rollers is thereafter separated manually or automatically by pulling the first sheet and the second sheet apart, and thereafter leading end of both the sheets are placed on the rollers 420 and 430 respectively. The rollers are operated and the sheets separated - final sheet and the second sheet are wound on the rollers. Separation from the second sheet results in transfer of a layer from the second sheet to the first sheet i.e. metal layer of the second sheet onto the printed or unprinted first sheet in selected areas. The final sheet is thus a printed or unprinted sheet with selected areas of metal layer or holographic metal layer transferred onto it from the second sheet. If the second sheet is a plain metallized sheet, the metallized sheet will impart a metallic effect to the final sheet, and if the second sheet is a patterned metallized sheet, the metallized sheet will impart a holographic effect to the final sheet in selected areas. The final laminate does not include the second sheet and only the layer i.e. metal or holographic metal layer from its surface is transferred in selective areas of the first printed or imprinted sheet. The final sheet is wound on first roller 420 and the second sheet is wound on second roller 430.

[028] The final sheet with partial areas of metal or holography on it is thereafter laminated to a sealant film typically, but not limited to, polyethylene, cast Poly Propylene, bi-axially oriented poly propylene, metallized bi-axially oriented poly propylene film, metalized cast poly propylene etc to obtain a final laminate specification. Also, additional layers of paper, aluminum or other plastic films can be added to the laminate depending on the product technical requirements. This final laminate is wound on a roll for storage and/or shipment.

[029] Further, the system includes electronically or mechanically controlled drives for each of the stages illustrated through figure 2 to 4. These drives help in ensuring exact circumferential and lateral superimposition (registration) of the sheets from the first and second supply source.

[030] Figure 5 shows a process for forming a laminate. The process may be carried out on the system discussed hereinbefore. The process begins at step 5A where a first sheet is provided. The first sheet is a base sheet selected from a plastic film or a non-plastic film. The plastic film can be selected from but not limited to, a polyethylene terephthalate (PET) film, a biaxially oriented polypropylene (BOPP) film, a cast polypropylene (CPP) film, a poly ethylene (PE) film, a poly vinyl chloride (PVC) film, a nylon film, a pearlised BOPP film, a metallized PET film, a metallized CPP film, a white CPP film, a biaxially oriented nylon film, etc. The non-plastic film can be selected from aluminum foil, paper. All kinds of transparent and white opaque films used in flexible packaging can be the first material supply source. In an embodiment of the invention, the first sheet is a printed sheet which is printed on reverse or surface of the sheet by using a variety of printing processes like rotogravure, flexographic, offset, digital printing process etc. Alternately, the first sheet can be an unprinted sheet, in which case the first sheet can be straight away taken as a primary source.

[031] At step 5B, bonding medium is applied to the first sheet to obtain a first sheet with bonding medium, wherein bonding medium is applied in selected/predetermined areas. The bonding medium is an adhesive selected from a water based adhesive, solvent-based adhesive, solvent-less adhesive or any such types of adhesive.

[032] At step 5C, a second sheet is provided. The second sheet is a metallized sheet. The metallized sheets can be selected from any of, but not limited to metallized polyethylene terephthalate (MPET), metallized biaxially oriented Polypropylene (MBOPP), metallized cast polypropylene (MCPP) film families. The process thereafter proceeds to step 5D.

[033] At step 5D, the first sheet is laminated with the second sheet, wherein the first sheet with bonding medium and the second sheet are superposed and bonded together. In this regard, the first sheet with bonding medium is bonded with the second sheet only in areas where bonding medium is present to obtain a selectively bonded sheet. The selectively bonded sheet obtained at step 5D is a laminate of first sheet and selectively bonded second sheet i.e. the metallic or holographic sheet is bonded to the printed sheet only in selected areas.

[034] The selectively bonded sheet obtained is thereafter delaminated at step 5E, wherein, the first sheet and the second sheet are separated to obtain a final sheet. Separation from the second sheet results in transfer of a layer from the second sheet onto the first sheet i.e. metal or holographic layer onto the printed or unprinted sheet in selected areas. The final sheet is thus a printed or unprinted sheet with selected areas of metal layer or holographic metal layer transferred onto it from the second sheet. If the second sheet is a metallized sheet, the metallized sheet will impart a metallic effect to the final sheet, and if the second sheet is a holographic sheet, the metallized sheet will impart a holographic metallic effect to the final sheet. The process further comprises the step of laminating the final sheet with a sealant film typically, but not limited to, polyethylene, cast poly propylene, bi-axially oriented poly propylene, metallized bi-axially oriented poly propylene film, metalized cast poly propylene etc to obtain a final laminate specification. This final laminate is wound on a roll for storage and/or shipment.

[035] Advantageously, the present invention provides a mono-layer sheet/ laminate with metallic or holographic metallic effect in predetermined/selected areas, which in addition to rendering aesthetic features to the mono-layer sheet/laminate also provides an anti-counterfeit feature to the laminate.

[036] While the present invention has been described with respect to certain embodiments, it will be apparent to those skilled in the art that various changes and modification may be made without departing from the scope of the invention as defined in the following claims.