EP3687789A1

EP3687789A1 - A multi-layer laminate

Info

Publication number: EP3687789A1
Application number: EP18792546.6A
Authority: EP
Inventors: Suresh Gupta; Marzban THANEVALA
Original assignee: Huhtamaki PPL Ltd
Current assignee: Huhtamaki PPL Ltd
Priority date: 2017-09-21
Filing date: 2018-09-21
Publication date: 2020-08-05
Also published as: WO2019058396A1

Abstract

The invention relates to a multi-layer laminate comprising: a laminate comprising at least two films, at least one of the film being a first non-oriented sealant film; and a second non-oriented sealant film selectively bonded to the first non-oriented sealant film of the laminate in pre- determined areas. The invention also relates to a process for forming the multi-layer laminate. The invention further relates to a bag comprising at-least two panels, each panel being a laminate comprising at least two films, at least one of the film being a first non-oriented sealant film; and second non-oriented sealant films, each second non-oriented sealant film provided adjacent to the first non-oriented sealant film in the laminate of each panel, each second non- oriented sealant films sealed along at least three edges with each other and the corresponding edges of each first non-oriented film and to a process of making the bag.

Description

TITLE OF THE INVENTION

A Multi-Layer Laminate

FIELD OF THE INVENTION

[001] The invention relates to a laminate, more particularly to a multi-layer laminate for flexible package and process for production thereof.

DEFINITIONS

The technical terms used in accordance with the present disclosure include but are not limited to the following:

NON-ORIENTED SEALANT FILM: A film manufactured using polyolefin resins, stretched mono-directionally and capable of sealing to itself. 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, drop test performance of flexible packaging is equally important.

[003] Drop test or drop test performance in the packaging industry context means a test to evaluate strength or impact resistance of a packaging. Generally, drop tests simulate shipping or handling environment during which the packaging may be subjected to all kinds of impacts. The packaging under test is dropped or weight is dropped on the packaging from a given height to see how the packaging holds itself and/or its contents. Depending upon outcome of the drop-test, structure and/or material of the packaging may be altered/modified so as to improve the durability/strength/impact resistance of the packaging.

[004] A common solution to improve drop test performance or durability/strength/impact resistance of the package, is to increase the thickness of the sealant layer used in multi-layer packaging material. However, increased sealant layer thickness does not necessarily produce the desired result. In fact, in several cases it actually deteriorates the drop test performance as thick sealant film tends to be very stiff.

[005] An alternate solution has been to use nylon films along with the sealant layers to improve the "mechanical barrier" of the laminate and hence improve the drop test performance. However, the additional nylon layer increases the cost of the package.

[006] In view of the above, there is a need for a laminate for flexible packaging overcoming the aforementioned problems.

SUMMARY OF THE INVENTION

[007] In one aspect, the invention provides a multi-layer laminate comprising of:

a laminate comprising at least two films, at least one of the film being a first non-oriented sealant film; and

a second non-oriented sealant film selectively bonded to the first non-oriented sealant film of the laminate in pre-determined areas.

[008] In another aspect, the invention provides a process for forming a multi-layer laminate comprising the steps of

providing a laminate comprising at least two films, at least one of the film being a first non- oriented sealant film;

providing a second non-oriented sealant film;

selectively bonding the first non-oriented sealant film of the laminate with the second non- oriented sealant film at pre-determined areas. [009] In yet another aspect, the invention provides a process for forming a bag comprising the steps of

providing a laminate of at least two films, at least one of the film being a first non-oriented sealant film, the laminate having a first area and a second area;

splitting the first area and the second area of the laminate;

providing a second non-oriented sealant film for each of the first area and the second area of the laminate respectively;

aligning each second non-oriented sealant film with the first non-oriented sealant film of the first area and the second area respectively;

selectively bonding each second non-oriented film with the first non-oriented film of the first area and the second area to form a first panel and a second panel; and

bonding the first panel and the second panel along the edges with each-other.

[010] In another aspect, the invention provides a bag comprising:

at-least two panels, each panel being a laminate comprising at least two films, at least one of the film being a first non-oriented sealant film; and second non-oriented sealant films, each second non-oriented sealant film provided adjacent to the first non-oriented sealant film in the laminate of each panel, each second non-oriented sealant films sealed along at least three edges with each other and the corresponding edges of each first non-oriented film. BRIEF DESCRIPTION OF THE DRAWINGS

[011] 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 the roll of the multi-layer laminate with bonded and non-bonded area in accordance with an embodiment.

Figure 2 shows the bag with the laminate and the second non-oriented layer in accordance with an embodiment.

DESCRIPTION OF THE INVENTION

[012] The present invention is directed towards a multi-layer laminate and process of production thereof and also a process for making a bag and the bag made therefrom, wherein the bag or pouch made from the multilayer laminate has enhanced drop test performance or durability/strength/impact resistance.

[013] In one aspect, the present invention provides a multi-layer laminate as shown in fig 1 comprising a laminate (la) comprising at least two films, at least one of the film being a first non-oriented sealant film; and

a second non-oriented sealant film (lb) selectively bonded to the first non-oriented sealant film of the laminate in pre-determined areas. The selective bonding of the first and second non- oriented sealant films results in bonded areas (lc) and non-bonded areas (Id) between the non- oriented films, the non-bonded areas allowing the non-oriented films to extend under pressure conditions, thereby absorbing shock that the laminate may experience on a fall. In this regard, the non-bonded areas leave the non-oriented films loose, and the loose film by virtue of being an extensible film bears the shock during impact or drop test.

[014] In an embodiment of the invention, the first non-oriented sealant film of the laminate is a sealable film and can be selected from, but not limited to, polyolefin film family (Poly ethylene films and/or Polypropylene films) or its co-polymers, PA (Poly amide film) or co-extruded film therefrom.

[015] The second non-oriented film is a sealable film and can be selected from, but not limited to, polyolefin film family (Poly ethylene films and/or Polypropylene films or its co-polymers). [016] The non-oriented sealant films can also be a co-extruded film like PE/tie/PA/Tie/PE, PP/PA/Tie/PE, other barrier films etc. Typically non-oriented sealant films are of higher thickness than the other non-sealable films and are used most commonly for lamination of films to impart thickness, stiffness and sealability to laminates.

[017] In an embodiment, the other film of the laminate is a non-sealable film and can be selected from any of, but not limited to, PET (Poly ethylene terepthalate), BOPP (Bi axially oriented poly propylene), OPA (oriented poly amide film, also called Nylon), Oriented Poly Ethylene, cast polypropylene etc. This film may be a printable film which can be printed on reverse or surface of the film by using a variety of printing processes like rotogravure, flexographic, offset, screen, digital printing process etc.

[018] Alternatively, the other film of the laminate may be unprinted as well, thereby resulting in an overall unprinted laminate.

[019] In an embodiment of the invention, this other film of the laminate may be used to impart thickness as well as barrier properties to the package.

[020] Generally, it is also understood that this laminate can be made using various multilayer combinations of oriented and non-oriented films and other barrier layers like metallised films, vacuum metallised polyethylene terepthalte (Metpet), vacuum metallised bi axially oriented polypropylene film (metbopp), vacuum metallised nylon and aluminium foils, metallised cpp etc. Basically the multi-layer laminate is designed to ensure that the product being packed inside the formed package is shelf stable and consumer safe over its intended shelf life.

[021] Typically, the first and second non-oriented sealant films can have a thickness of approximately 20 - 160 microns and 20 - 120 microns respectively or vice-versa. These are indicative parameters; actual usage will vary upon various other factors and is to be designed accordingly. [022] The invention also relates to a process for forming a multi-layer laminate comprising the steps of

providing a second non-oriented sealant film;

selectively bonding the first non-oriented sealant film of the laminate with the second non- oriented sealant film at pre-determined areas. The selective bonding results in forming bonded areas and non-bonded areas between the non-oriented films, the non-bonded areas allowing the non-oriented films to extend/elongate under pressure conditions, thereby absorbing shock that the laminate may experience. The laminate may also comprise a multilayer combination of oriented and non-oriented films wherein barrier layers like metallised films (typically but not limited to vacuum metallised polyethylene terepthalte (Metpet), vacuum metallised bi axially oriented polypropylene film (metbopp), vacuum metallised nylon etc), aluminium foils (typically within the thickness range of 5 mic to 40 mic), and other such barrier layers used commonly in the flexible packaging industry are sandwiched in between the outer printable, non-sealable oriented films and inner sealable non-oriented films.

[023] In an embodiment of the invention, the selective bonding comprises using adhesive or sealing in pre-determined areas of the first non-oriented layer i.e. a sealant layer of the laminate to the second non-oriented layer. While heat sealing is the more commonly used method, other sealing mechanisms such as cold sealing, ultrasonic sealing, impulse sealing and all other such methods can also be used for sealing the laminate.

[024] Typically, the laminate comprising at least two films is passed through an adhesive applicator, wherein adhesive is applied only in select, pre-determined areas on the first non- oriented sealant film of the laminate. This laminate is then passed on to a lamination station. The lamination station also receives the second non-oriented sealant film. The laminate layer with selectively applied adhesive and the second non-oriented layer are superposed and bonded together by passing them through an assembly of nip rollers. The selective lamination between the outer laminate layer and the second non-oriented sealant film can be performed under heat and/or pressure. The outer laminate with adhesive is bonded with the second non-oriented sealant film only in areas where adhesive is present. The multi-layer laminate exits the nip rollers as a laminate of the outer laminate layer selectively bonded with the second non-oriented sealant film i.e. the outer laminate layer is bonded to the second non-oriented sealant film only in selected areas to obtain a selectively bonded film.

[025] Another embodiment of the invention relates to a bag as shown in Figure 2. The bag according to the invention comprises at- least two panels (2a and 2b), each panel being a combination of a laminate (2c) comprising at least two films, at least one of the film being a first non-oriented sealant film; and a second non-oriented sealant film (2d), each second non-oriented sealant film provided adjacent to the first non-oriented sealant film in the laminate (2c) of each panel, each second non-oriented sealant films sealed along at least three edges with each-other and the corresponding edges of each first non-oriented film. The sealing along the edges may extend upto 2-15 mm inside the panels.

[026] In another embodiment, the invention relates to a process for forming the bag comprising the steps of providing a laminate of at least two films, at least one of the film being a first non- oriented sealant film, the laminate having a first area and a second area; splitting the first area and the second area of the laminate; providing a second non-oriented sealant film for each of the first area and the second area of the laminate respectively; aligning each second non-oriented film with the first area and the second area of the first non-oriented film respectively; selectively bonding each second non-oriented film with the first non-oriented film of the first area and the second area respectively to form a first panel and a second panel; and bonding the first panel and the second panel along at least three edges to form the bag.

[027] The necessary barrier layers used commonly in the flexible packaging industry may be sandwiched in between the outer non-sealable oriented film and inner sealable non-oriented film. Such a configuration provides a bag-in-bag effect to the bag formed which enhances the drop- test performance of the bag.

[028] In an embodiment of the invention, the selective bonding to form the first and second panel and the bonding of the first and second panels with each other is simultaneous. In another embodiment, the bonding of the first panel and the second panel along its edges extends upto 2- 15 mm inside the panels.

EXAMPLES

The following experimental examples are illustrative of the invention but not limitative of the scope thereof:

[029] Secant modulus is used for measuring the stiffness of a plastic material. The higher the value of secant modulus, the stiffer the material. Therefore, for a material to stretch and absorb shock, it should have a low value of secant modulus. The test of secant modulus-2% is done where a tangent to the straight line portion of the curve of stress to strain graph is drawn and then it is offset by 2%. The material is stretched at a constant speed till it breaks, and the distance the jaws travelled is recorded. The elongation percentage is the ratio of the length of the material just before breaking to the initial length of the material. The test was done to compare the stretching properties of 60 micron white opaque Polyethylene (PE) to a laminate of 12 Micron Polyethylene Terephthalate (PET) and 60 micron Polyethylene. This experiment was done by stretching the film in machine direction (MD) as well as transverse direction(TD). The table below illustrates that the non-oriented film elongates much more in both the directions as compared to the laminate. Alternatively, this is to test the secant modulus - 2% which indicates that non-oriented film is less stiff compared to combination of oriented and non-oriented film thereby providing improved drop test performance.

COMPARATIVE TESTI NG

[030] A comparison of the elongation values of a laminate made from PET and polyethylene to that of a polyethylene film by itself as illustrated by the following data. Secant modulus-2% test was done for illustrating the elongation of the laminate and Polyethylene film. The higher elongation values of non-oriented sealant film Polyethylene filmallows them to extend / elongate under pressure conditions thus helping in better drop test performance.

Example 1

[031] The drop test performance of a 1 kg tomato ketchup pouch was done. A pouch (A) was made using only the outer laminate i.e. 12 Micron PET/ 9 Micron Aluminum Foil/ 15 Micron Biaxially Oriented Nylon / 30 Micron Both Side Treated Cast Polypropylene without presence of the selectively bonded second non oriented film. Another pouch (B) was made using outer laminate alongwith presence of the selectively bonded second non oriented film i.e. a laminate of 12 Micron PET/ 9 Micron Aluminum Foil/ 15 Micron Biaxially Oriented Nylon / 30 Micron Both Side Treated Cast Polypropylene, selectively bonded to a layer of 90 Micron Cast polypropylene. Both pouches (A) and (B) were filled with 1 kg tomato ketchup and sealed and dropped from a height of 1.5 metres. The pouch B passed 18 drops whereas the pouch A failed after only 5 drops.

Example 2

The drop test performance of a bag / pouch filled with 5Kg of epoxy sand was done. Bag (A) made with only outer laminate of a printed outer film and a sealant non oriented film, i.e. 12 Micron PET/130 Micron PE failed drop test on an average of 5 drops. Another bag (B) was made, according to an embodiment of the invention, from a laminate of 12 Micron PET/130 Micron PE and having a 80 micron PE selectively bonded to the 130 Micron PE film only along the edges thereby creating a bag-in-bag effect. The gussets were made from a laminate of 12 Micron PET/ 15 Micron Biaxially Oriented Nylon/ 130 Micron Polyethylene. 5Kg epoxy sand was filled in the inside chamber created by 80 micron PE film. The bag (B) was filled with 5Kg of epoxy sand, sealed and was dropped from a height of 1.5 meter. The bag (B) remained intact even after 20 drops, after which the test was stopped.

[032] Notwithstanding the result as given above as examples, the results on how many drops a bag/pouch will withstand depends on various factors such as but not limited to, the outer laminate structure, the thickness of inner interleaving film, the density of product being packed, the weight of product packed inside etc. The quantification of results is merely illustrative and is not to be taken as a guideline or have limiting effects. The concept of improving the drop test performance by using this invention is thus being proved.

[033] Advantageously, the present invention provides a multi-layer laminate, the laminate comprising at least one outer laminate layer selectively bonded to inner layer in predetermined areas so as to create at least one gap or space between the layers. This gap or space enables the package to bear shock burden during impacts or drop test. Moreover, the extensible, non- oriented inner layer of the package expands on impact of any kind and this also helps in enhanced impact resistance or drop test performance.

[034] The foregoing description of the invention has been set merely to illustrate the invention and is not intended to be limiting. Since the modifications of the disclosed embodiments incorporating the spirit and substance of the invention may occur to the person skilled in the art, the invention should be construed to include everything within the scope of the disclosure.

Claims

Claims:

1. A multi-layer laminate comprising of:

2. The multi-layer laminate as claimed in claim 1, wherein the first non-oriented sealant film has a thickness in the range of 20 - 160 micron.

3. The multi-layer laminate as claimed in claim 1, wherein the second non-oriented sealant film has a thickness in the range of 20-120 micron.

4. The multi-layer laminate as claimed in claim 1, wherein the first non-oriented sealant film is selected from polyolefin film family (Poly ethylene films and/or Polypropylene films) or its co-polymers, Poly amide film or co-extruded barrier film therefrom.

5. The multi-layer laminate as claimed in claim 1, wherein the second non-oriented sealant film is selected from polyolefin film family (Poly ethylene films and/or Polypropylene films or its co-polymers).

6. The multi-layer laminate as claimed in claim 1, wherein the laminate optionally comprises barrier layers.

7. The multi-layer laminate as claimed in claim 6, wherein the barrier layer is selected from metallised films, vacuum metallised polyethylene terepthalte (Metpet), vacuum metallised bi axially oriented polypropylene film (metbopp), vacuum metallised nylon and aluminium foils.

8. A process for forming a multi-layer laminate comprising the steps of

providing a second non-oriented sealant film;

selectively bonding the first non-oriented sealant film of the laminate with the second non- oriented sealant film at pre-determined areas.

9. The process as claimed in claim 8, wherein the selective bonding of the non-oriented sealant films comprises adhesive application or sealing at the predetermined areas.

10. The process as claimed in claim 9, wherein the sealing is by heat sealing, cold sealing, ultrasonic sealing or impulse sealing.

11. A process for forming a bag comprising the steps of

splitting the first area and the second area of the laminate;

aligning each second non-oriented sealant film with the first non-oriented sealant film of the first area and the second area respectively; selectively bonding each second non-oriented film with the first non-oriented film of the first area and the second area to form a first panel and a second panel; and

bonding the first panel and the second panel along the edges with each-other.

12. The process as claimed in claim 11, wherein the selective bonding to form the first and second panel and the bonding of the first and second panels with each other is simultaneous.

13. The process as claimed in claim 11, wherein the bonding of the first panel and the second panel along its edges extends upto 2-15 mm inside the panels.

14. A bag comprising:

at-least two panels, each panel being a laminate comprising at least two films, at least one of the film being a first non-oriented sealant film; and a second non-oriented sealant film, each second non-oriented sealant film provided adjacent to the first non-oriented sealant film in the laminate of each panel, each second non-oriented sealant films sealed along at least three edges with each other and the corresponding edges of each first non-oriented film.

15. The bag as claimed in claim 14, wherein the first non-oriented sealant film has a thickness in the range of 20 - 160 micron.

16. The bag as claimed in claim 14, wherein the second non-oriented sealant film has a thickness in the range of 20-100 micron.

17. The bag as claimed in claim 14, wherein the second non-oriented sealant film is selected from polyolefin film family (Poly ethylene films and/or Polypropylene films) or its copolymers.