Claims:Claims:
1)A sustainable recyclable Plastic Barrier Multilayer sheet or barrier films (7 or 9 or 11 layer) producing plastic barrier multilayer tubes (PBML Tubes) comprising of:
a polyethylene-based film having a density of 0.905 to 1.15 gms/ cm3, wherein: the first layer comprises a polyolefin film layer which may be a monolayer film or a multilayer film, and the outside of the first layer may optionally be printed by a surface printing; furthermore; the first layer may comprise a blend of one or more types of material selected from LDPE (low density polyethylene); a co-extruded MDPE (Medium density polyethylene) layer; a co-extruded LLDPE (Linear low-density polyethylene) layer; a co-extruded HDPE (High Density Poly Ethylene) layer; a co-extruded PP (Polypropylene) layer and Metallocene Polymers/Blend/Tie Resins/Barrier Resins such as EVOH, Nylon, Both, etc.
wherein the said thickness of recyclable Plastic Barrier Multilayer sheet /Tube Laminate ranges from 150 micron to 600 micron.
2. The sustainable recyclable Plastic Barrier Multilayer sheet or barrier films for producing plastic barrier multilayer tubes (PBML Tubes)as claimed in claim 1, wherein the said thickness of natural layer is 40 micron to 160 micron and the thickness of coloured layer ranges from 50 micron to 200 micron.
3. The sustainable recyclable Plastic Barrier Multilayer sheet or barrier films for producing plastic barrier multilayer tubes (PBML Tubes)as claimed in claim 1, wherein the said thickness of Barrier layer ranges from 6.0 micron to 24 micron and the thickness of Tie layer ranges from 7.0 micron to 28 micron and the thickness of special layers ranges from 50 micron to 200 micron.
4. The sustainable recyclable Plastic Barrier Multilayer sheet or barrier films for producing plastic barrier multilayer tubes (PBML Tubes)as claimed in claim 1, wherein the said density range of the barrier sheet is 0.905 to 1.15 gms/ cm3.
5. The sustainable recyclable Plastic Barrier Multilayer sheet or barrier films for producing plastic barrier multilayer tubes (PBML Tubes)as claimed in claim 1, wherein the said Natural Layer weighs in the range of 36 gms/sqm to 150 gms/sqm.
6. The sustainable recyclable Plastic Barrier Multilayer sheet or barrier films for producing plastic barrier multilayer tubes (PBML Tubes)as claimed in claim 1, wherein the said Coloured Layer weighs in the range of 47 gms/sqm to 192 gms/sqm.
7. The sustainable recyclable Plastic Barrier Multilayer sheet or barrier films for producing plastic barrier multilayer tubes (PBML Tubes)as claimed in claim 1, wherein the said Barrier Layers weighs in the range of 7.0 gms/sqm to 28 gms/sqm.
8. The sustainable recyclable Plastic Barrier Multilayer sheet or barrier films for producing plastic barrier multilayer tubes (PBML Tubes)as claimed in claim 1, wherein the said tie Layer weighs in the range of 6.5 gms/sqm to 26 gms/sqm.
9. The sustainable recyclable Plastic Barrier Multilayer sheet or barrier films for producing plastic barrier multilayer tubes (PBML Tubes)as claimed in claim 1, wherein the said special Layers weighs in the range of 44 gms/sqm to 176 gms/sqm.
10. The sustainable recyclable Plastic Barrier Multilayer sheet or barrier films for producing plastic barrier multilayer tubes (PBML Tubes) as claimed in claim 1, wherein the said multilayered flexible barrier sheet is 5 layered, 6 layered, 7 layered, 8 layered, 9 layered, 10 layered, 11 layered.
11. The method of forming multi-layer flexible barrier sheet for producing plastic barrier multilayer tubes (PBML Tubes) comprising the steps of;
a. Metalizing/ non-metalizing atleast one of the surfaces of a core polymer layer;
b. priming the metalized/ non-metalized surface of the core polymer layer with a primer;
c. extruding the primed surface of the core polymer layer with polyolefin and/or co-polymer of polyolefin; and
d. Co-extruding first heat sealable layer over the extrusion layer.
Date: 16/11/2021 Applicant
Rajshree Polypack ltd
Agent of the applicant
Pallavi Unmesh deshmukh
, Description:FORM 2
THE PATENTS ACT, 1970
(39 OF 1970)
&
THE PATENTS RULES, 2003
(SEE SEC 10 AND RULE 13)
COMPLETE SPECIFICATION
“Plastic Barrier Multilayer sheet or films for plastic barrier multilayer Tubes (PBML) and process for preparation thereof”

Rajshree Polypack ltd , Indian applicant having place of business at Lodha Supremus, Unit No 503/504, Road No 22, Wagale Estate, Thane (West) – 400604

The following specification particularly describes the invention and the manner in which it is to be performed.

FIELD OF THE INVENTION:
The present invention relates to multi-layer flexible sheet to be used for containers, tubes etc. for packaging and dispensing paste, Gel and Cream type products. More particularly, the present invention relates to a sustainable, recyclable, extruded Plastic Barrier Multilayer sheet or barrier films (7 or 9 or 11 layer) used for producing plastic barrier multilayer tubes (PBML Tubes) for packaging of toothpaste, creams, shampoos, ointments, paste, lotions, etc.
BACKGROUND OF THE INVENTION:
Tube packagings, for example for the packaging of toiletries, such as toothpaste, or also for the packaging of foodstuffs, are usually formed from a tubular tube body and a closure component joined therewith. The above-mentioned tube laminate films are usually used to produce the tubular tube body.
Metal foils/Sheets have long been used for manufacturing containers and tubes for packaging and dispensing various products, including paste, Gel and Cream type products. Such containers and tubes have frequently been made from a single metal slugs . However, containers and tubes made from metal slugs have several disadvantages compared to containers made of laminated tubes or plastic tubes . Metal tubes tend to dent and deform more readily, crack with a moderate amount of flexure, often react with the filled product and they are more expensive.
Paper tubes serve many industries. Examples include shipping, packaging, and pulp and paper, as well as food processing, automotive manufacturing, mechanics, material handling, construction, textile, art, healthcare and horticulture.
Paper tube and cores have drawbacks compared to similar products made from metals, plastic or glass:
• Not Waterproof – Unlike plastics, glass and metals paper tubes can absorb water and moisture in damp environments.
• Dimensional Stability – The absorption of moisture or release of moisture can cause dimensional changes and distortion or warping.
• Lower Strength – Paper tubes and cores are not as strong as high strength metal, fiberglass or engineered plastics.
• Dust / Tearing – Cutting edges can generate dust. Paper can fray or tear over time.
• Chew-out - Core ends can experience "chew-out" after extended use and high loads.
• Non-transparent – Customers cannot see through the paper tube container and view the product unless a window is added to the container.
More recently, a large share of the tube market has been taken by flexible sheet structure materials having a multiplicity of polymeric layers. Typically, such tubes have an inner heat sealable layer, an outer heat sealable layer, and a barrier layer interposed there between. Additional layers may be used in conventional structures to provide other properties or qualities.
Plastic tubes form an integral part of the packaging industry as they are used to enhance the shelf-life of packaged goods and create a unique product identity. Lamination is the process of combining two or more flexible materials. This combined Product is called laminate. Laminate helps in keeping materials filled inside it as good as new for many years, increasing durability as well as presuming the Colour, protect them from smudges, fingerprints and other type of damage. Laminated Tubes are used for packaging in various sectors like oral care, food, cosmetics, pharmaceuticals, and also for other industrial applications. The oral care industry contributes to 70% of production of laminated tubes.
More recently, a large share of the tube market has been taken by flexible sheet structure materials having a multiplicity of polymeric layers. Typically, such tubes have an inner heat sealable layer, an outer heat sealable layer, and a barrier layer interposed there between. Additional layers may be used in conventional structures to provide other properties or qualities.
The laminated tubes thus made are of two types, viz. Aluminum Barrier Laminates (ABL) tubes that have an aluminum foil barrier, which provides superior light, air and moisture barrier along with reduced flavor absorption. The second type of laminated tubes is Plastic Barrier Laminates (PBL) tubes that possess structures that are a good option for packaging with a need to maintain its form and shape. It presents a more cosmetic look and is environmental friendly. Special barriers can be provided such as Ethylene Vinyl Alcohol Polymer (EVOH), Nylon to offer a strong chemical resistance. Standard material is offered in white or natural (clear) but specialty custom colors can also be developed.
Laminate tubes are a hybrid of aluminum tubes and plastic tubes. They efficiently protect contents thanks to many overlaid layers, one of which is the barrier layer. Both longitudinal edges of the laminate tube are welded together and constitute the body which is then sealed to the tube shoulder.
Minimum one barrier layer is provided to protect the content of the packaging from external environmental influences, in particular from oxygen and water vapour which can cause an undesirably rapid deterioration or an undesirably rapid spoiling of the packaging content. The barrier layer is also used to prevent components of the packaging content (aromas, water vapour, etc.) from being able to escape from the packaging.
The barrier against leakage of volatile substances from tube contents and against oxidation of tube contents is formed from aluminum foil, which is also the carrier of laminated layers of plastic material. This barrier feature gives an advantage to the laminate tubes over plastic tubes that do not possess such a feature. A plastic barrier provides protection against leakage of volatile substances from tube contents and against oxidation of tube contents. The advantage of laminate tubes include the shape memory- the tube resumes its original shape after it is squeezed. Tubes can be also manufactured as transparent and fully recyclable.
Barrier films are impervious packaging solutions, usually made up of single or multiple layers of flexible films, the material of which depends on the area of application. Barrier films are also coated on either side by different lacquers/resins to obtain desired results.
The effectiveness of a barrier film was earlier measured in terms of its ability to prevent the ingress of oxygen, carbon dioxide and moisture. However, in recent times protection against migration of mineral oil and UV light is also considered important. This impervious nature allows barrier films to protect products such as food from the loss of nutrients and functional properties such as taste, aroma, texture and color.
The barrier films that are manufactured are used in duplex or triplex laminate structures.
In typical manufacturing processes, a tenter frame is used to stretch the molten film in both machine and cross directions. The biaxial orientation of the film aids in reducing stretching, puncturing and tearing of the film.
Layers of a non-polymeric nature, such as paper and thin metal foils, may also be included in these sheet materials to provide specialized performance functions. It is known, for example, to provide a layer of thin aluminum foil as a high quality barrier layer and luster. When foil is used, it is common practice to use a highly adherent polymer to adhere the foil to its adjacent layers.
However, Aluminum foil layer is considered as foreign material in the plastic multilayer and therefore not eco-friendly. On the other hand, commonly available metalized such as film base laminate Polyester, Polypropylene, polyamide, polyethylene consists of usage of pre-metalized polyester or polypropylene film and, sandwiching and laminating metalized film with inner and outer thermoplastic film such as low density polyethylene, linear low density polyethylene, co-polymer of ethylene. However, these metalized film base laminate gets delaminated at metal and film interface thereby having problems in stability.

One of the prior art means is disclosed in patent no. US 5296170 in which Method for improving the internal surface of seamless tube of multi-layer plastics film laminate is disclosed. The present invention provides a method for improving the internal surface of a gas-barrier, optionally heat shrinkable, multi-layer plastics film laminate in the form of a seamless tube having the innermost layer of olefin resin, the method comprising applying corona discharge employing at least two pairs of electrodes to the innermost layer from the outside of the tube having a gas sealed therein and pressed to a flat state avoiding the contact of opposed surface areas of innermost olefin resin layer with each other, said two pairs of electrodes being arranged such that one electrode of each pair is in contact with the outermost layer of the tube and the other of the same pair out of contact therewith while one electrode of one pair is kept in contact with the outermost layer of the tube with which one electrode of another pair is kept out of contact on the same side of the tube, so that the wetting tension of the innermost layer surface is increased to at least 35 dyne/cm by the corona discharge treatment.
Another one prior art means is disclosed in patent no. PCT/TH2016/000103 in which Aluminium barrier laminate and barrier liner at shoulder for container is disclosed.
The laminate according to this invention comprises: a first layer which is a polyethylene-based film having a density of 0.90-0.96 g/cc, wherein: the first layer comprises a polyolefin film layer which may be a monolayer film or a multilayer film, and the outside of the first layer may optionally be printed by a surface printing; furthermore; the first layer may comprise a blend of one or more types of material selected from low density polyethylene, or linear low density polyethylene, or high density polyethylene; and the first layer preferably has a thickness in the range of 50-100 microns; a second layer which is a polyethylene-based film having a melting temperature of less than 240°C, wherein the second layer is a polyethylene film having a density of 0.85-0.94 g/cc, and the second layer preferably has a thickness in the range of 18-25 microns; a third layer which is low density polyethylene to provide high adhesion, wherein: a high interlayer adhesive is preferably selected from acid copolymers which is selected from ethylene acrylic acid (EAA) copolymers, ethylene vinyl acetate, ethylene methacrylic acid, maleic anhydride copolymers, or mixture thereof; and the third layer preferably has a thickness in the range of 18-25 microns;
a fourth layer having an aluminium barrier film, wherein the fourth layer has a thickness of 7-20 microns, preferably in the range of 7-12 microns, and more preferably in the range of 8-9 microns;
a fifth layer having low density polyethylene to provide high interlayer adhesion, wherein: a high interlayer adhesive is preferably selected from acid copolymers which is selected from ethylene acrylic acid (EAA) copolymers, ethylene vinyl acetate, ethylene methacrylic acid, maleic anhydride copolymers, or mixture thereof; and the fifth layer preferably has a thickness in the range of 18-25 microns; a sixth layer having a polyethylene-based film with a melting temperature of less than 240°
C, wherein the sixth layer is a polyethylene film having a density of 0.85-0.94 g/cc, and the sixth layer preferably has a thickness in the range of 18-25 microns; and
a seventh layer having a polyethylene-based film with a sealing property which is a monolayer film, a multilayer film, preferably a 3-layer film, 5-layer blown film, or a blend of 90% to 99% of polyolefin and 1% to 10% of polyolefin plastomer; and the seventh layer preferably has a thickness in the range of 40-100 microns.

Another one prior art means is disclosed in US12/741,713 as Multi-layer flexible sheet and method thereof. The present invention provides a method for manufacturing a multilayer flexible sheet and a multilayer flexible sheet. The present invention provides a method for manufacturing a multilayer flexible sheet and a multilayer flexible sheet. The method for manufacturing a multilayer sheet comprises steps of metalizing atleast one of the surfaces of a core polymer layer; priming the metalized surface of the core polymer layer with a primer; extrusion laminating the primed surface of the core polymer layer with polyolefin and/or co-polymer of polyolefin; and co-extruding first heat sealable layer over the extrusion laminated layer.
The method of the present invention may comprise further steps of priming of non-metalized or polymer side of the core layer of the multilayer sheet and extrusion coating with an outer layer. Alternatively the method may comprise priming non-metalized or polymer side of the core layer of the multilayer sheet and extrusion coating with an outer layer before the priming of the metalized layer of the core layer.
In general, a multilayer polymer sheet of the present invention atleast comprises a core layer having one of the polymer sides plasma treated, a metal layer deposited on the plasma treated side of the core layer, a primer layer applied on the metalized surface of the core layer, an extrusion polymer lamination layer of polyolefin and/or co-polymer of polyolefin and a heat sealable layer on the extrusion polymer lamination layer.
The tubes find in the market are not more lustrous as surface gloss of these presently available multi-layer metal sheets used for tubes for packaging and dispensing the product.
So there is a need for a sustainable, recyclable extruded Plastic Barrier Multilayer sheet or barrier films (7 or 9 or 11 layer) used for producing plastic barrier multilayer tubes (PBML Tubes) for packaging of toothpaste, creams, shampoos, ointments, paste, lotions, etc.

OBJECTS OF THE INVENTION:
The main object of the present invention is to provide a sustainable, recyclable extruded Plastic Barrier Multilayer sheet or barrier films (7 or 9 or 11 layer) used for producing plastic barrier multilayer tubes (PBML Tubes) for packaging of toothpaste, creams, shampoos, ointments, paste, lotions, etc.
Another object of the present invention is to provide an extruded sustainable, recyclable Plastic Barrier Multilayer sheet or barrier films (7 or 9 or 11 layer) with improved Puncture strength, good heat sealing properties, excellent bounce back property.
Another object of the present invention is to provide an extruded sustainable, recyclable Plastic Barrier Multilayer sheet or barrier films (7 or 9 or 11 layer) having excellent Flavor Retention, excellent barrier Property, better Printability and better Bond Strength.
Another object of the present invention is to provide an extruded sustainable, recyclable Plastic Barrier Multilayer sheet or barrier films (7 or 9 or 11 layer) with high permeability resistance (moist, oxygen, nitrogen, carbon dioxide) allows increasing significantly the retention period of a product.
Yet another object of the present invention is to provide an environment friendly, extruded sustainable, recyclable Plastic Barrier Multilayer sheet or barrier films (7 or 9 or 11 layer) for producing plastic barrier multilayer tubes (PBML Tubes) with transparency and gloss of the film and sealability; use materials providing a tight seam even under high temperature and high strength films resistant to disruption, tearing and puncture to provide a reliable package.
SUMMARY OF THE INVENTION:
Accordingly, a sustainable, recyclable extruded Plastic Barrier Multilayer sheet or barrier films (7 or 9 or 11 layer) for producing plastic barrier multilayer tubes (PBML Tubes) for packaging of toothpaste, creams, shampoos, ointments, paste, lotions, etc.is disclosed. An extruded Plastic Barrier Multilayer sheet or barrier films (7 or 9 or 11 layer)comprising: a polyethylene-based film having a density of 0.905 to 1.15 gms/ cm3, wherein: the first layer comprises a polyolefin film layer which may be a monolayer film or a multilayer film, and the outside of the first layer may optionally be printed by a surface printing; furthermore; the first layer may comprise a blend of one or more types of material selected from LDPE (low density polyethylene); a co-extruded MDPE (Medium density polyethylene) layer; a co-extruded LLDPE (Linear low-density polyethylene) layer; a co-extruded HDPE (High Density Poly Ethylene) layer; a co-extruded PP (Polypropylene) layer and Metallocene Polymers/Blend/Tie Resins/Barrier Resins such as EVOH, Nylon, Both, etc.
DESCRIPTION OF THE DRAWINGS:
Fig 1 is the extruded Plastic Barrier Multilayer sheet or barrier films (7 or 9 or 11 layer) for producing plastic barrier multilayer tubes (PBML Tubes) for packaging of toothpaste, creams, shampoos, ointments, paste, lotions, etc.
DETAILED DESCRIPTION OF THE INVENTION WITH RESPECT TO DRAWINGS:
The foregoing objects of the present invention are accomplished and the problems and shortcomings associated with the prior art, techniques and approaches are overcome by the present invention as described below in the preferred embodiments. The invention will now be described in detail in connection with certain preferred and optional embodiments, so that various aspects thereof may be more fully understood and appreciated.
The present invention provides an extruded, sustainable recyclable Plastic Barrier Multilayer sheet or barrier films (7 or 9 or 11 layer) to be used for producing plastic barrier multilayer tubes (PBML Tubes).The sustainable recyclable Plastic Barrier Multilayer sheet or barrier films (7 or 9 or 11 layer) film comprises at least one plastics layer and also comprises at least one barrier layer. The present invention is a multilayer or 7 layer 0r 9 layer or 11 layer. Barrier sheet is made using Cast Extrusion line, in which the different polymers are melted in Extruders & thus extrude molten polymer mass, which is then pushed through Manifold & Die to extrude Sheet/Film in molten form. This molten form sheet/film is immediately cooled on Chill Roll to freeze at lower temperature.
Similarly other Extruders extrude polymers granules/resins & form molten sheet/film through Die. All these different molten sheets/films are fused in the Die itself at high temperature to extrude single Sheet comprising 7 or 9 or 11 layers.
In the Cast Film process, the molten polymer is usually extruded through a slot die onto an internally cooled chill roll and then passes through a series of rollers which will determine the nature and properties of the cast film including thickness. The resin is first melted by subjecting it to heat and pressure inside the barrel of an extruder and finally forcing the melt through a narrow slit in a die. The slit may be either a straight line or a circle. The resulting thin film has either the form of a multilayer sheet (cast film) or a tube. As the film comes out of the die, it is cooled and then rolled up on a core.

In this invention, the multilayer barrier structure comprises at least 3 or more layers in total as follows: an outer LDPE (low density polyethylene); a co-extruded MDPE (Medium density polyethylene) layer; a co-extruded LLDPE (Linear low-density polyethylene) layer; a co-extruded HDPE (High Density Poly Ethylene) layer; a co-extruded PP (Polypropylene) layer and Metallocene Polymers/Blend/Tie Resins/Barrier Resins such as EVOH, Nylon, Both, etc.
In one embodiment, the sustainable recyclable Plastic Barrier Multilayer sheet or barrier films (7 or 9 or 11 layer) according to this invention comprises:
a first layer which is a polyethylene-based film having a density of 0.905 to 1.15 gms/ cm3, wherein: the first layer comprises a polyolefin film layer which may be a monolayer film or a multilayer film, and the outside of the first layer may optionally be printed by a surface printing; furthermore; the first layer may comprise a blend of one or more types of material selected from LDPE (low density polyethylene); a co-extruded MDPE (Medium density polyethylene) layer; a co-extruded LLDPE (Linear low-density polyethylene) layer; a co-extruded HDPE (High Density Poly Ethylene) layer; a co-extruded PP (Polypropylene) layer and Metallocene Polymers/Blend/Tie Resins/Barrier Resins such as EVOH, Nylon, Both, etc.
Outer Surface made from LDPE (low density polyethylene) /MDPE (Medium density polyethylene)/LLDPE (Linear low-density polyethylene)/HDPE (High Density Poly Ethylene)/PP (Polypropylene) /Metallocene Polymers/Blend/Tie Resins/Barrier Resins such as EVOH, Nylon, Both, etc.
Total thickness of sustainable recyclable Plastic Barrier Multilayer sheet or barrier films (7 or 9 or 11 layer) /Tube ranges from 150 micron to 600 micron. The thickness of natural layer is 40 micron to 160 micron. The thickness of coloured layer ranges from 50 micron to 200 micron. The thickness of Barrier layer ranges from 6.0 micron to 24 micron. The thickness of Tie layer ranges from 7.0 micron to 28 micron. The thickness of special layers ranges from 50 micron to 200 micron.
Combination of natural layer, colored layer, barrier layer, tie layer and special layers are used. The density range of the present invention is 0.905 to 1.15 gms/ cm3.
The weight percentage of each layer is as follows:
Natural Layer - Minimum 36 gms/sqm – maximum 150 gms/sqm
Coloured Layer - Minimum 47 gms/sqm – maximum 192 gms/sqm
Barrier Layers- Minimum 7.0 gms/sqm – maximum 28 gms/sqm
Tie Layer - Minimum 6.5 gms/sqm – maximum 26 gms/sqm
Special Layers – Minimum 44 gms/sqm – maximum 176 gms/sqm

The Extruded Sheet can be made of 11 layers/10 layers/9 layers/8 Layer/7 Layers/6 Layers/5 Layers/4 layers. The combinations depend upon the characteristics & application.

In another embodiment, the method of forming multi-layer flexible barrier sheet for producing plastic barrier multilayer tubes (PBML Tubes) comprising the steps of;
a. Metalizing/ non-metalizing atleast one of the surfaces of a core polymer layer;
b. priming the metalized/ non-metalized surface of the core polymer layer with a primer;
c. extruding the primed surface of the core polymer layer with polyolefin and/or co-polymer of polyolefin; and
d. Co-extruding first heat sealable layer over the extrusion laminated layer.
Advantages of the invention:
These multilayer sheets/films are used to make sustainable recyclable Plastic Barrier Multilayer sheet or barrier films (7 or 9 or 11 layer) used for producing plastic barrier multilayer tubes (PBML Tubes), first it is being slit to required size & then printed to desired design & colours. This printed sheet/film reel is then loaded on Tube making machine, in which the body is first formed by using high frequency technique to seal the both sides of tube laminate & form cylinder/tube, this cylinder is then cut to required size, which is further loaded on tube heading machine to form shoulders & fuse the tube body. The present invention is sustainable, recyclable, environment friendly extruded Plastic Barrier Multilayer sheet.