Description:FIELD OF THE INVENTION

The present invention relates to a packaging laminate and process for preparation thereof, wherein said packaging laminate is easy to tear, has excellent barrier properties, and mechanically strong enough for convenient handling.

BACKGROUND OF THE INVENTION

Packaging laminates have been used for many years for packaging such as liquid food, snacks, drugs, medical devices, and the like. Packaging laminate is often used to retain and seal products for shipping and storage till they are consumed or used by the end user. In the packaging industry, there is yet no ideal single material that can provide all the desired properties and meet all the requirements, thus, packaging laminates generally comprise two or more layers with each made up of different materials and these are laminated together to form laminates. A problem encountered in the developments of laminates has been that each different polymer has its unique set of rheological properties related to the heating and stretching conditions.

The present invention is in particular concerned with packaging laminates in the field of medicinal drug products such as tablets, capsules etc., medical devices such as syringes, women hygiene and contraception field such as sanitary napkins, tampons, condoms and the like.

US 6846532 B1 relates to a pouch having at least one sheet comprising a laminate comprising: a polyester outer layer; a polypropylene inner layer; and a first solvent less aliphatic polyurethane laminating adhesive applied to at least one layer of an adjacent pair of layers of said laminate to bond together said adjacent layers of said laminate, said laminating adhesive including exfoliated clay platelets forming a functional barrier to the passage of gases through the at least one sheet; and the pouch including a storage space substantially enclosed by said at least one sheet.
WO2015181281A1 relates to a packaging material for a packaging container for liquid or semi-liquid food, comprising a decor layer which on one side of the layer has a bulk layer having a density of less than 700 kg/m3 and foamed cellulose of at least 25% thickness of the bulk layer, which on the side opposite the decor layer has a barrier layer, which on the side opposite the bulk layer has a heat-sealable layer.

WO 1996/029262A1 relates to a package for condoms comprising an upper and a lower generally flat part sealed to each other along their edges, defining a cavity for the condom there between, characterised in that the package has the general appearance and dimensions, except for the thickness, that both the upper and lower parts are made of rigid plastic material, that at least one of the upper and lower parts is provided with at least one weakening arranged reaching from one of the edges in a pair of opposite edges on said part essentially in the direction of the centre of said part.

WO 2018/225521A1 relates to an easy-open laminated film used for bonding resin-based nonwoven fabrics, one surface layer is a heat seal layer that adheres to the resin nonwoven fabric, and the other surface layer is a surface layer, on the heat seal layer, an intermediate layer containing an ethylene resin having a melt flow rate at 190 °C. of 5 to 50 g/10 min and a butene resin as resin components is laminated, The content of the ethylene resin in the resin component contained in the intermediate layer is 50 to 80% by mass, and the content of the butene resin is 20 to 50% by mass. Easily openable laminated film.

Despite the advantages of the packaging laminates, there are particular problems in connection with the storage, distribution and handling of products or articles in the field of medicines, medical devices, women hygiene and contraception field. Typically, the laminate must protect the product from being damaged. The package must be absolutely tight to be able to keep the product sterile. The package must also be designed so that the risk for unintentional opening of the package is minimized. The existing laminates can sometimes face major drawbacks such as difficulty in opening. In the field of medicines, medical devices, women hygiene and contraception, the package should be easy to open. Additionally, the unpacking must be possible to make in a safe way so that the product is not damaged or dropped during this operation. Further, the package must offer a good security against tampering. It should preferably be possible for the consumer at the moment of its use to indicate that the product has not been tampered with. The existing packaging laminates comprise inner most layer that is heat sealable and require high temperatures for sealing that is deleterious for such sensitive products or articles. Further, packaging laminates must have good barrier property against ingress of moisture and gases.

OBJECT OF THE INVENTION

The present invention is focussed on providing a solution to problems with existing laminates and development of a cost effective packaging laminate which is easy to tear and open, and mechanically strong enough for convenient handling.

The packaging laminate of the present invention provides excellent barrier mechanism against ingress of external moisture and gases that have deleterious effect on the quality, long term stability, and shelf-life of the product.

The packaging laminate of the present invention does not require high temperatures for sealing. Further, the packaging laminate of the present invention minimizes the risk from unintentional opening of the package, keep the product safe, tamper proof, and protected from physical damage.

SUMMARY OF THE INVENTION

In one aspect, the present invention provides a packaging laminate comprising:
i) a first layer which is an outer labelling layer comprising a polymer;
ii) a second layer comprising a polymer by way of extrusion;
iii) a third layer of a metal foil; and
iv) a fourth sealing layer.

In another aspect, the present invention provides a packaging laminate comprising:
i) a first layer comprising a polymer selected from polypropylene, polyethylene terephthalate, and polyethylene naphthalate;
ii) a second layer comprising a polymer selected from extruded polyethylene or polypropylene;
iii) a third layer of aluminium foil; and
iv) a fourth sealing layer comprising:
(a) a film composite comprising two or more layers made up of low density polyethylene, linear low density polyethylene, medium density polyethylene, high density polyethylene, polyolefinic plastomers, metallocene grade polyethylene, or combinations thereof; or
(b) a blend of one or more of low density polyethylene, linear low density polyethylene, medium density polyethylene, high density polyethylene, polyolefin plastomers, and metallocene grade polyethylene.

In another aspect, the present invention provides a laminate comprising:
i) a first layer of polyethylene terephthalate, wherein the thickness of the first layer is 10-30 microns;
ii) a second layer of extruded polyethylene, wherein the thickness of the second layer is 5-30 microns;
iii) a third layer of aluminium foil having a thickness of 5-15 microns; and
iv) a fourth sealing layer comprising a film composite comprising a layer of low density polyethylene, a layer of linear low density polyethylene, a layer of high density polyethylene, a layer of polyolefin plastomer, and a layer of metallocene grade polyethylene, wherein the thickness of the fourth layer is 10-50 microns.

In another aspect, the present invention provides a method for preparation of packaging laminate, comprising the steps of:
i) preparing a first layer comprising a polymer selected from polypropylene, polyethylene terephthalate, and polyethylene naphthalate;
ii) providing a second layer of polyethylene or polypropylene by way of extrusion;
iii) preparing a third layer of aluminium foil;
iv) joining together the outer layer of step (i) with the third layer step (iii) with the layer of step (ii) there-between by performing a step selected from co-extrusion, extrusion lamination or lamination;
v) joining together layer of step iv) with adhesion layer;
vi) preparing multi layered film composite of low density polyethylene, linear low density polyethylene, high density polyethylene, polyolefin plastomer, and metallocene grade polyethylene; and
vii) laminating the layer generated in step (vi) with the film prepared in step (v) by performing solvent based lamination and obtaining the laminate.

According to one more aspect, the packaging laminates of the present invention find application in the packaging of medicinal drug products such as tablets, capsules etc., medical devices such as syringes etc., women hygiene and contraception field such as sanitary napkins, tampons, condoms etc. It has particular relevance to the packaging of condoms.

DETAILED DESCRIPTION OF THE INVENTION

The packaging laminate which constitutes the present invention is shown in the accompanying figures and drawings.

Figures and Drawings:
Fig. 1: Layers of packaging laminate of the present invention
Fig. 2: 2D-Structure of packaging laminate of the present invention

The present invention provides a cost effective packaging laminate which is easy to tear and open, provides excellent barrier mechanism. Moreover, it does not require high temperatures for sealing.

Referring to the drawings, the packaging laminate of the present invention is made up of four layers as shown in Fig. 1 and Fig. 2. The packaging laminate comprises a first layer (1) which is an outer labelling layer, a second layer (2) comprising a polymer by way of extrusion, a third layer (3) of a metal foil, a layer or coat of adhesive (4), and a fourth sealing layer (5).

The laminate layers are individually selected from the group consisting of polyolefinic or polyalkene polymers or copolymers, a polyamide, a polyester, a polyvinylidene chloride, a polyvinyl alcohol, or co-polymers thereof. Preferably, polyolefinic polymers including but not limited to low density polyethylene (LDPE), high-density polyethylene (HDPE), medium-density polyethylene (MDPE), linear low- density polyethylene (LLDPE), very low-density polyethylene (VLDPE), ultra-low-density polyethylene (ULDPE), or polyolefinic polymers manufactured by using metallocene catalysts such as metallocene polyethylene (mPE), and blends thereof.

A “polyolefin” or “polyalkene” is a polymer produced from a simple olefin of the formula C2H2n as a monomer.

A “polyethylene” is a polyolefin produced by polymerizing the monomer ethylene.

A “copolymer” or “heteropolymer” is a polymer of two or more monomeric species.

A “high density polyethylene” or “HDPE” is an ethylene polymer having a density of more than 0.941 g/cm3.

A “low density polyethylene” or “LDPE” is a polyethylene homopolymer having a density from 0.910 to 0.935 g/cm3. LDPE is also known as branched or heterogeneously branched polyethylene because of the relatively large number of long chain branches extending from the main polymer backbone.

A “linear low density polyethylene” or “LLDPE” refer to a polyethylene copolymer having a density from 0.89 g/cm3. LLDPE is linear and does not substantially contain long-chain branching, and generally has a narrower molecular weight distribution than conventional LDPE. The traditional “linear low density polyethylene” (LLDPE) can be produced with conventional Ziegler-Natta catalysts.

An “mPE” is polyethylenes produced by metallocene catalysts in gas phase reactors and/or with metallocene catalysts in slurry reactors and/or with any of the haftocene catalysts in solution reactors. These are new generation polyethylene (PE), also called Linear Metallocenes.

According to one embodiment, the outer labelling layer, i.e., the first layer of laminate comprises of polymer selected from polypropylene (PP), polyethylene terephthalate (PET), and polyethylene naphthalate (PEN). optionally adapted for printing and ink anchorage. It is disposed in by lamination on the second layer of laminate. The thickness of this outer labelling layer may be about 5 to 30 microns. Preferably, the thickness of this outer labelling layer is 5-20 microns and most preferably, it is 10-15 microns, depending upon the type of packaging required.

In another embodiment, the second layer comprises of polymer selected from polypropylene (PP), polyethylene (PE) by way of extrusion. In other words, the second layer comprises of extrusion grade polyethylene or polypropylene. This layer is disposed in by lamination over the inner barrier layer which is the third layer composed of aluminium foil by performing a step selected from co-extrusion, extrusion lamination or lamination. The said layer acts as a tie layer. The thickness of this second layer may vary from 5 to 30 microns, depending on the type of packaging required; preferably 5 to 20 microns and most preferable 10-20 microns.

In another embodiment, the third layer is made up of metal foil, preferably Aluminium (Al) foil. This layer acts as a barrier to ingress of moisture and oxygen. This layer further provides mechanical strength for convenient handling and protection against physical damage by sharp objects. This layer by its very presence ensures excellent dimensional stability and consistent barrier property. The thickness of this third layer of aluminium foil may vary from 5 to 15 microns, depending on the type of packaging required; preferably 5 to 10 microns. The metallised film are flexible and are difficult to tear. Aluminium foil alone can be easy to tear but sealability issues with aluminium foil make it less preferable. In some embodiments, the third layer, i.e., barrier layer has adhesive on the side opposite or is joined with an adhesive layer. In some embodiments, the laminate comprises a layer of adhesive in between the third layer and the fourth layer or third layer is coated with an adhesive.

Adhesives may be selected from polyurethane adhesives, vinyl acetate homopolymers, vinyl ester/acrylic copolymers, oligomers having relatively high molecular weight, epoxy adhesives.

In another embodiment, the fourth layer or the innermost layer of the laminate of the present invention is a multilayer film composite comprising separate layers or is a blend of one or more of polymers selected from low density polyethylene (LDPE), linear low density polyethylene (LLDPE) from Octene C8, Hexene C6 and Butene C4, of varying densities from high (up to 0.941 g/cm3) to very low (0.905 g/cm3), medium density polyethylene (MDPE), high density polyethylene (HDPE), polyolefin plastomer such as AFFINITY™ Polyolefin Plastomers, and metallocene grade polyethylene (mPE). In one of the preferred embodiments, the fourth layer is a multilayer film composite comprising separate layers of low density polyethylene (LDPE), linear low density polyethylene C4 (LLDPE C4), high density polyethylene (HDPE), AFFINITY™ Polyolefin Plastomers, and metallocene grade polyethylene. As the innermost layer comes in direct contact with the product, hence, the choice of polymers is very critical. The innermost layer of the multilayer film composite of fourth layer acts as a sealant layer that comes in direct contact with the product and the inner layer of the multilayer film composite assists in lamination binding when bound to the other layers of the laminate of the present invention. The thickness of the innermost layer of packaging material is between 10 -50 microns, preferably between 10- 30 microns, or between 15 -35 microns, and most preferably between 20-35 microns.

In comparison to the existing laminates such as surlyn based, the inner most layer of the present invention is disposed over the layer comprising of first outermost layer, second extrusion layer, and third barrier layer by performing solvent based lamination. The process of preparing laminate of present invention requires lower temperature and may be prepared by co-extrusion or lamination or extrusion-lamination, and irrespective of the process followed, the preparation of the film is a solvent based lamination process requiring lower heat. As the inner most layer is prepared using solvents hence, the cost of manufacture is substantially reduced as higher temperature maintenance is no more required.

In another embodiment, the present invention provides a laminate comprising:
i) a first layer comprising a polymer selected from polypropylene, polyethylene terephthalate, and polyethylene naphthalate;
ii) a second layer comprising a polymer selected from extruded polyethylene or polypropylene;
iii) a third layer of aluminium foil; and
iv) a fourth sealing layer comprising:
(a) a film composite comprising two or more layers made up of low density polyethylene, linear low density polyethylene, medium density polyethylene, high density polyethylene, polyolefinic plastomers, metallocene grade polyethylene, or combinations thereof; or
(b) a blend of one or more of low density polyethylene, linear low density polyethylene, medium density polyethylene, high density polyethylene, polyolefin plastomers, and metallocene grade polyethylene.

In some embodiments, the laminate comprises a layer of adhesive in between the third layer and the fourth layer or third layer is coated with an adhesive.

In another embodiment, the present invention provides a laminate comprising:
i) a first layer of polyethylene terephthalate, wherein the thickness of the first layer is 10-30 microns;
ii) a second layer of extruded polyethylene, wherein the thickness of the second layer is 5-30 microns;
iii) a third layer of aluminium foil having a thickness of 5-15 microns; and
iv) a fourth sealing layer comprising a film composite comprising a layer of low density polyethylene, a layer of linear low density polyethylene, a layer of high density polyethylene, a layer of polyolefin plastomer, and a layer of metallocene grade polyethylene, wherein the thickness of the fourth layer is 10-50 microns.

In another embodiment, the present invention provides a method for preparation of packaging laminate, comprising the steps of:
i) preparing a first layer comprising a polymer selected from polypropylene, polyethylene terephthalate, and polyethylene naphthalate;
ii) providing a second layer of polyethylene or polypropylene by way of extrusion;
iii) preparing a third layer of aluminium foil;
iv) joining together the outer layer of step (i) with the third layer step (iii) with the layer of step (ii) there-between by performing a step selected from co-extrusion, extrusion lamination or lamination;
v) joining together layer of step iv) with adhesion layer;
vi) preparing multi layered film composite of low density polyethylene, linear low density polyethylene, high density polyethylene, polyolefin plastomer, and metallocene grade polyethylene; and
vii) laminating the layer generated in step (vi) with the film prepared in step (v) by performing solvent based lamination and obtaining the laminate.

In another embodiment, the packaging laminates are obtained by various methods for laminating layers together, such as extrusion lamination, wet or dry adhesive lamination, solvent based lamination, and may also be including various coating methods.

In yet another embodiment, the packaging laminate of the present invention can be used for preparing pouches, sachets, films, sheets and can be used for the products such as pharmaceuticals, cosmetics, personal care, food, and Non-alcoholic beverages. In particular, the packaging laminates of the present invention find application in the packaging of medicinal drug products such as tablets, capsules etc., medical devices such as syringes etc., women hygiene and contraception field such as sanitary napkins, tampons, condoms etc. It has particular relevance to the packaging of condoms.

The invention is now illustrated by the following examples and drawings which are not meant to limit the scope of the invention.

EXAMPLES

Example 1: Structure of Packaging laminate

Present invention laminate structure: 12 microns printed Polyethylene terephthalate / 12 microns extruded polyethylene / 9 microns Aluminium foil/ Solvent based adhesive / 30 microns multilayer composite of low density polyethylene, Linear Low Density Polyethylene C4, High Density Polyethylene, AFFINITYTM polyolefin plastomer, and metallocene grade polyethylene (Type B).

STABILITY STUDY:
To determine provisional shelf Life by Minimum studies test methods of foiled condoms in the laminate of present invention; using minimum ageing studies for Natural rubber male latex condom (square pack).

Sample Foiled with laminate of the present invention. There must be at least test 315 pieces Burst tested, 500 pieces Freedom from Hole and 50 pieces for seal integrity test. The test of the condom shall be carried out under Controlled Environment at Room temperature of (25 ± 5 °C). The condom of shall be 400 -700 mg/condom of silicon lubricant (including flavor) quantity used for foiling. After the stipulated oven conditioning period, remove the sample and keep the package at (25 ± 5 °C) until tested within 96 hours but not sooner than 12 hours after removal

Results:
Seal Integrity Test and Water Leakage Test:
Seal Integrity Test
Vacuum used 20±5 kPa for 1 minute; Repeated five times
Sample size Seal Integrity Failure Visual Observation
0 days 60 days 90 days 0 days 60 days 90 days
10 0 0 0 No defects No defects No defects
Water Leakage Test
Repeated five times
Sample size Leakage Test Failure Visual Observation
0 days 60 days 90 days 0 days 60 days 90 days
10 0 0 0 No leakage No leakage No leakage

Bursting Test
Bursting Test Sample size Observation Non-Complier
Accept Reject Found
Volume (L) 18.0 0 Day 315 36.3 10 11 2
Pressure(kPa) 1.0 Min. 1.79
Volume (L) 18.0 Min. 07 Days @70°C 315 30.5 10 11 3
Pressure (kPa) 1.0 min. 1.65
Volume (L) 18.0 Min. 90 Days@50°C 315 28.7 10 11 3
Pressure(kPa) 1.0 min. 1.61

Freedom from hole test:
Freedom from Hole Sample size Non-Complier
Accept Reject Found
0 Day 500 03 04 00
07 Days @70°C 500 03 04 00
90 Days@50°C 500 03 04 00

Odour test
Freedom from Hole Sample size Non-Complier
Accept Reject Found
0 Day 10 No any Foul Smell
07 Days @70°C 10 No any Foul Smell
90 Days@50°C 10 No any Foul Smell

Comparative laminate structure: 12 microns printed Polyethylene terephthalate / 15 microns extruded polyethylene / 9 microns metallized PET/ extrusion layer or Tie layer / 32 microns extruded surlyn.

Test Parameter Specification Laminate of the invention Comparative laminate structure
(Type A) (Type B)
Dimension (Width mm) 120±0.5 120.5 120 120
Thickness(mm) 0.070 ± 0.010 0.069 0.067 0.068
Print Matter Should be clean & with legible letter Plain Foil No printing matter Plain Foil No printing matter Plain metallized PET No printing matter
Pin Hole Test < 150/M2 22 19 85
Bond Strength NLT 200 235 252 180
Grammage G/M2 85±5 87.07 86.52 95
Tear-ability Easy to tear Good Excellent Poor
Cutting Easy to separate Easy Very easy Difficult
Seal integrity All should pass ok ok ok
Temperature 115-140°C 135 138°C 115°C
Speed of machine 80±2 pcs/min. 80 80 80

Above data implies that laminate of the invention is better than comparative laminate. Further, out of the tested laminates of present invention laminate Type B is still better than laminate Type A.
, Claims:WE CLAIM:

Claim 1. A packaging laminate comprising:
i) a first layer which is an outer labelling layer comprising a polymer;
ii) a second layer comprising a polymer by way of extrusion;
iii) a third layer of a metal foil; and
iv) a fourth sealing layer.

Claim 2. The packaging laminate according to claim 1, wherein the first layer comprises a polymer selected from polypropylene, polyethylene terephthalate, and polyethylene naphthalate.

Claim 3. The packaging laminate according to claim 1, wherein the second layer comprises a polymer selected from extruded polyethylene or polypropylene.

Claim 4. The packaging laminate according to claim 1, wherein the third layer comprises aluminium foil.

Claim 5. The packaging laminate according to claim 1, wherein the fourth sealing layer comprises:
- a film composite comprising two or more layers made up of low density polyethylene, linear low density polyethylene, medium density polyethylene, high density polyethylene, polyolefinic plastomers, metallocene grade polyethylene, or combinations thereof; or
- a blend of one or more of low density polyethylene, linear low density polyethylene, medium density polyethylene, high density polyethylene, polyolefin plastomers, and metallocene grade polyethylene.

Claim 6. The packaging laminate according to claim 4, wherein the laminate further comprises a layer of adhesive in between the third layer and the fourth layer or third layer is coated with an adhesive.

Claim 7. The packaging laminate according to claim 1, wherein the packaging laminate comprises:
i) a first layer of polyethylene terephthalate, wherein the thickness of the first layer is 10-30 microns;
ii) a second layer of extruded polyethylene, wherein the thickness of the second layer is 5-30 microns;
iii) a third layer of aluminium foil having a thickness of 5-15 microns; and
iv) a fourth sealing layer comprising a film composite comprising a layer of low density polyethylene, a layer of linear low density polyethylene, a layer of high density polyethylene, a layer of polyolefin plastomer, and a layer of metallocene grade polyethylene, wherein the thickness of the fourth layer is 10-50 microns.

Claim 8. The packaging laminate according to claim 7, wherein the thickness of the first layer is 12 microns; the thickness of the second layer is 12 microns, thickness of the third layer of aluminium foil having a thickness of 9 microns; and the thickness of fourth sealing layer comprising a film composite is 30 microns.

Claim 9. A method for preparing a packaging laminate according to claim 1, the method for preparation of the packaging laminate, comprising the steps of:
i) preparing a first layer comprising a polymer selected from polypropylene, polyethylene terephthalate, and polyethylene naphthalate;
ii) providing a second layer of polyethylene or polypropylene by way of extrusion;
iii) preparing a third layer of aluminium foil;
iv) joining together the outer layer of step (i) with the third layer step (iii) with the layer of step (ii) there-between by performing a step selected from co-extrusion, extrusion lamination or lamination;
v) joining together layer of step iv) with adhesion layer;
vi) preparing multi layered film composite of low density polyethylene, linear low density polyethylene, high density polyethylene, polyolefin plastomer, and metallocene grade polyethylene; and
vii) laminating the layer generated in step (vi) with the film prepared in step (v) by performing solvent based lamination and obtaining the laminate.

Claim 10. The packaging laminate according to claim 1, wherein the packaging laminate is for packaging of medicinal drug products, medical devices, product for women hygiene and contraception, in particular condoms.

Dated this, 9th day of September, 2022 For Mankind Pharma Ltd.

Dr. Anil Kumar
Chief Scientific Officer