FORM 2
THE PATENTS ACT, 1970
(39 of 1970)
&
THE PATENTS RULES, 2003
COMPLETE SPECIFICATION
(See section 10, rule 13)
1. Title of the invention: A LAMINATE OF MULTILAYER FILMS AND PROCESS
THEREOF
2. Applicant(s)
NAME NATIONALITY ADDRESS
EPL LIMITED Indian Top Floor, Times Tower, Kamala
City, Senapati Bapat Marg, Lower
Parel, Mumbai 400013, India
3. Preamble to the description
COMPLETE SPECIFICATION
The following specification particularly describes the invention and the manner in which it
is to be performed.
1
2
FIELD OF INVENTION
[0001] The subject matter disclosed herein relates to the field of packaging materials
and in particular, relates to chemically resistant laminate for use in the manufacturing
of packaging materials.
BACKGROUND OF THE INVENTION5
[0002] The packaging industry has emerged as one of the fastest growing sectors in
the world economy. There are various packaging materials available in the market,
such as glass, cardboard, paper, and metal, but plastic and polyethylene packaging
material remain among the most commonly used material. Tubes are one of the well-
established packaging formats used in any packing industry. The industry started with,10
aluminum tubes, then moved to aluminum barrier layer tubes (ABL), but over the years
it has migrated to laminated plastic barrier layer tubes (PBL), due to its enhanced
functionalities and for sustainability reasons.
[0003] Certain segments like cosmetics packaging, though are migrating from ABL to
PBL for sustainability reason, the metallic luster has been in demand due to the15
aesthetics. To have a metallic feel and look, the metallization on polymeric film has
been utilized. However, the metallic interface is the weakest aspect of the laminate
since there is weak bonding at the metallic interface, especially when you have
aggressive products which can penetrate and delaminate at the metallic interface.
[0004] US20060222796A1 discloses a multilayer structure comprising a metallized20
film, an ethylene/alkyl acrylate copolymers composition as an extrusion layer to
improve the adhesion to the metal film. US10150275B2 discloses a multilayer structure
comprising a skin layer of an ethylene/olefin copolymer to improve the adhesion of
metallization to the skin layer. Though there have been attempts to improve the
adhesion strength at the metallized interface, there has been a challenge to retain the25
adhesion especially when the filled products inside can be aggressive and migrate to
delaminate the metallic interface.
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SUMMARY OF THE INVENTION
[0005] In a first aspect of the present disclosure, there is provided a laminate
comprising: a) a multilayer outer film comprising a first barrier layer and polyolefin
layer on both sides of the first barrier layer; and b) a multilayer middle film comprising
a second barrier layer and polyolefin layer on both sides of the second barrier layer,5
wherein (i) the polyolefin layer of the multilayer outer film towards the multilayer
middle film, or (ii) the polyolefin layer of the multilayer middle film towards the
multilayer outer film, or both (i) and (ii), is metallized with a metal selected from
aluminum, nickel, chromium, or combinations thereof.
[0006] In a second aspect of the present disclosure, there is provided a process for10
preparing the laminate comprising: a) a multilayer outer film comprising a first barrier
layer and polyolefin layer on both sides of the first barrier layer; and b) a multilayer
middle film comprising a second barrier layer and polyolefin layer on both sides of the
second barrier layer, wherein (i) the polyolefin layer of the multilayer outer film
towards the multilayer middle film, or (ii) the polyolefin layer of the multilayer middle15
film towards the multilayer outer film, or both (i) and (ii), is metallized with a metal
selected from aluminum, nickel, chromium, or combinations thereof, the process
comprising: extrusion lamination of the multilayer outer film and the multilayer middle
film; and optionally, further laminating with a sealant film.
[0007] In a third aspect of the present disclosure, there is provided an article20
comprising the laminate comprising: a) a multilayer outer film comprising a first
barrier layer and polyolefin layer on both sides of the first barrier layer; and b) a
multilayer middle film comprising a second barrier layer and polyolefin layer on both
sides of the second barrier layer, (i) the polyolefin layer of the multilayer outer film
towards the multilayer middle film, or (ii) the polyolefin layer of the multilayer middle25
film towards the multilayer outer film, or both (i) and (ii), is metallized with a metal
selected from aluminum, nickel, chromium, or combinations thereof.
4
[0008] These and other features, aspects, and advantages of the present subject matter
will be better understood with reference to the following description. This summary is
provided to introduce a selection of concepts in a simplified form. This summary is not
intended to identify key features or essential features of the claimed subject matter.
BRIEF DESCRIPTION OF DRAWINGS5
[0009] The detailed description is described with reference to the accompanying
figures. In the figures, the left-most digit(s) of a reference number identifies the figure
in which the reference number first appears. The same numbers are used throughout
the drawings to reference like features and components.
[0010] Figure 1 illustrates the cross section of the overall laminate of the present10
disclosure with outer film, middle film and an extrusion layer, in accordance with an
implementation of the present disclosure.
[0011] Figure 2 illustrates the cross section of the overall laminate of the present
disclosure with outer film, middle film, an extrusion layer and a sealant film, in
accordance with an implementation of the present disclosure.15
[0012] Figure 3 illustrates the layered structure of the laminate of the present
disclosure depicting the multilayered outer film, in accordance with an implementation
of the present disclosure.
[0013] Figure 4 illustrates the layered structure of the laminate of the present disclosure
depicting the multilayered middle film, in accordance with an implementation of the20
present disclosure.
DETAILED DESCRIPTION OF THE INVENTION
[0014] Those skilled in the art will be aware that the present disclosure is subject to
variations and modifications other than those specifically described. It is to be
understood that the present disclosure includes all such variations and modifications.25
The disclosure also includes all such steps, features, compositions, and compounds
referred to or indicated in this specification, individually or collectively, and any and
all combinations of any or more of such steps or features.
5
Definitions
[0015] For convenience, before further description of the present disclosure, certain
terms employed in the specification, and examples are delineated here. These
definitions should be read in the light of the remainder of the disclosure and understood
as by a person of skill in the art. The terms used herein have the meanings recognized5
and known to those of skill in the art, however, for convenience and completeness,
particular terms and their meanings are set forth below.
[0016] The articles “a”, “an” and “the” are used to refer to one or to more than one
(i.e., to at least one) of the grammatical object of the article.
[0017] The terms “comprise” and “comprising” are used in the inclusive, open sense,10
meaning that additional elements may be included. It is not intended to be construed as
“consists of only”.
[0018] Throughout this specification, unless the context requires otherwise the word
“comprise”, and variations such as “comprises” and “comprising”, will be understood
to imply the inclusion of a stated element or step or group of element or steps but not15
the exclusion of any other element or step or group of element or steps.
[0019] The term “including” is used to mean “including but not limited to”.
“Including” and “including but not limited to” are used interchangeably.
[0020] The term “at least one” used herein refers to one or more and thus, includes
individual components as well as mixtures/combinations.20
[0021] The term “laminate” used herein refers to a wall between the packaged product
and the surrounding environment comprising at least two films. The laminate may be
molded to various shaped articles, such as packaging tubes, cans, containers, or rolled
bodies for the packaging of products/materials. In the present disclosure, the laminate
is highly chemical resistant such that when in contact with aggressive chemicals or the25
environment, the laminate is stable and does not degrade or delaminate.
[0022] The phrase “polyolefin” refers to a polymer of olefin may be polyethylene
having a density in the range 0.910 to 0.965 g/cm3. The term polyolefin as used herein
6
refers to any polyethylene having density in the range of 0.910 to 0.965 g/cm3, wherein
the polyethylene may include high density polyethylene, medium density polyethylene,
low density polyethylene, linear low-density polyethylene, modified polyethylene(s),
such as metal-modified polyethylene, chemically modified polyethylene, and the like.
[0023] The phrases “high-density polyethylene”, “medium-density polyethylene”,5
“low-density polyethylene”, and “linear low-density polyethylene” as used herein refer
to polyethylene having densities well known to the person skilled in the art.
[0024] The term “multilayer outer film” refers to a film comprising multiple layers of
polyolefin and a first barrier layer, with polyolefin on either side of the first barrier
layer. The first barrier layer is sandwiched by the polyolefin layers in the presence of10
a tie layer. And these multilayer form the outer film of the laminate.
[0025] The term “multilayer middle film” refers to a film comprising multiple layers
of polyolefin and a second barrier layer, with polyolefin on either side of the second
barrier layer, which forms the middle film of the laminate. In the multilayer middle
film, the polyolefin layers are sandwiched with the second barrier layer in the presence15
of a tie layer. The middle film itself may act as the product contact layer.
[0026] The term “first barrier layer” and “second barrier layer” refer to layer providing
barrier properties to the film or the laminate. The first barrier layer and the second
barrier layer comprise a member independently selected from ethylene vinyl alcohol,
polyamides, polyvinyl alcohol, ceramic coatings, polyethylene terephthalate, or20
combinations thereof. The first barrier layer and the second barrier layer may comprise
same member or different member selected from ethylene vinyl alcohol, polyamides,
polyvinyl alcohol, ceramic coatings, polyethylene terephthalate, or combinations
thereof. The first barrier layer and the second barrier layer of the present disclosure
provides dual barrier property to the laminate thereby providing improved chemical25
resistance to the laminate, especially at the metallized interface
[0027] The term “extrusion layer” refers to a layer of polymer of ethylene or copolymer
of polyethylene comprising ethylene with acrylic acid or maleic anhydride.
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[0028] The term “tie layer” refers to a layer which binds any two layers having
dissimilar polarity in a film. In the present disclosure, the tie layer binds polyolefin
layer with barrier layer and the tie layer comprises polymeric adhesive selected from
the group consisting of maleated polyethylene, anhydride grafted ethylene/1-butene
copolymer, anhydride grafted ethylene/1-hexene copolymer, anhydride grafted5
polypropylene, anhydride grafted propylene ethylene copolymer, ethylene vinyl
acetate copolymer, ethylene methyl acrylate copolymer, anhydride grafted ethylene/1-
octene copolymer, and combinations thereof. The term “anhydride grafted (ethylene/1-
hexene copolymer, polypropylene, propylene ethylene copolymer) refers to anhydride
grafted ethylene/1-hexene copolymer, anhydride grafted polypropylene, and anhydride10
grafted propylene ethylene copolymer
[0029] The term “sealant film” used herein refers to a multilayer polyolefin. The
polyolefin can be polyethylene. In an embodiment, the sealant film is laminated to the
middle film and is generally the innermost layer of packaging and will be the product
contact layer.15
[0030] The term “an article” used herein refers to any packaging material made from
the laminate of the present disclosure which includes but not limited to packaging
pouch, packaging tube, cans, containers, rolled bodies, laminated tubes widely used for
packaging chemicals, cosmetic material, toothpaste, and other viscous food products.
[0031] The term “lamination” used herein refers to a process in which two or more20
films are joined together by an extrusion layer extruded in film shape and / or adhesive
lamination. The extrusion layer thus acts as a bonding agent.
[0032] The term “tandem lamination” used herein refers to a process in which two or
more films are joined together in the presence of a bonding material using a tandem
laminator. The films per se could be multilayer film produced through blown film25
process or cast film process.
[0033] The term “metallized” refers to metal incorporation in the specific layer of the
laminate. Metallized-PE refers to metallization of the polyolefin layer of multilayer
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middle film which is towards the multilayer outer film. Metallized-PE also refers to the
metallization of the top polyolefin layer of the multilayer middle film. PE-metallized
refers to metallization of polyolefin layer of the multilayer outer film which is towards
the multilayer middle film. PE-metallized also refers to metallization of bottom
polyolefin layer of the multilayer outer film. Metallized is carried out by chemical or5
physical vapor deposition of the metals on the polyethylene layer. The metallized-PE
or PE-metallized provides the laminate the lustrous appearance which is significant for
commercial purpose of the laminate.
[0034] The term “ILBS” refers to Inter Layer Bond Strength as per ASTM F 904-16
This test measures the bond strength (or) ply adhesion of laminates made from flexible10
materials such as cellulose, paper, plastic film, and foil. This includes laminates made
by various processes: adhesive laminates, extrusion coatings, extrusion laminates, and
coextrusion. The ILBS value of metallized surface with its adjacent layer (namely PE
layer) through an acid copolymer is measured to reflect the improvement of the
invention.15
[0035] Ratios, concentrations, amounts, and other numerical data may be presented
herein in a range format. It is to be understood that such range format is used merely
for convenience and brevity and should be interpreted flexibly to include not only the
numerical values explicitly recited as the limits of the range, but also to include all the
individual numerical values or sub-ranges encompassed within that range as if each20
numerical value and sub-range is explicitly recited. For example, a thickness range of
50 μm to 200 μm should be interpreted to include not only the explicitly recited limits
of 50 μm to 200 μm, but also to include sub-ranges, such as 65 μm to 150 μm, 70 μm
to 200 μm, and so forth, as well as individual amounts, including fractional amounts,
within the specified ranges, such as 65.2 μm, 140.6 μm, and 161.3 μm, for example.25
[0036] As discussed in the background, there have been various efforts in the recent
past to design a laminate or a packaging material to withstand harsh environmental
conditions. There have been reports in which the barrier effect had been increased
9
either by inclusion of multiple barrier layers or by increasing thickness of the barrier
layer to improve the barrier property of the laminate, however, that resulted in the
increased thickness of the laminate, as against the desired thickness of the laminate or
the packaging material. Hence it is essential to maintain the thickness at the same time
improve the barrier property of the laminate. Also, the metallic appearance is a5
significantly important aspect of these laminates from the commercial point of view
and hence there is a need for a laminate that provides a perfect balance of all the
parameters mentioned above. It is therefore an object of the invention to provide a
laminate with an improved metallized layer adhesion in spite of aggressive product that
is filled inside. This objective is achieved by protecting the metallized interface with10
high barrier layers to provide laminate with higher chemical resistance. Accordingly,
the present disclosure provides a laminate with multilayer outer film, a multilayer
middle film, and an optional multilayered sealant film. The multilayered outer film
comprises a first barrier layer sandwiched by polyethylene layers with optional
metallization of the polyethylene layer facing the middle film. The multilayered middle15
film comprises a second barrier layer sandwiched by polyethylene layers with optional
metallization of the polyethylene layer facing the outer film. The thickness of the first
barrier layer in the outer film and the thickness of the second barrier layer in the middle
film is designed in such a way, it possesses high barrier properties on the inside as well
as on the outside without an increase in the thickness of the laminate. The barrier layer20
and the polyethylene layers are held together by a tie layer. And the outer film and the
middle film are laminated through an extrusion layer. The sealant film comprising
multiple layers of polyethylene is tandem laminated with outer and middle film. Thus,
the presence of a barrier layer in the outer film and middle film provides dual barrier
property and the laminate exhibits high chemical resistance protecting the metallized25
interface. Metallization of polyethylene either in the outer film or in the middle film
helps in preserving the gleaming look of the laminate. The metallic interface is
protected on either side by the barrier layer.
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[0037] Unless defined otherwise, all technical and scientific terms used herein have
the same meaning as commonly understood by one of ordinary skill in the art to which
this disclosure belongs. Although any methods and materials similar or equivalent to
those described herein can be used in the practice or testing of the disclosure, the
preferred methods, and materials are now described. All publications mentioned herein5
are incorporated herein by reference.
[0038] The present disclosure is not to be limited in scope by the specific embodiments
described herein, which are intended for the purposes of exemplification only.
Functionally-equivalent products, compositions, and methods are clearly within the
scope of the disclosure, as described herein.10
[0039] In an embodiment of the present disclosure, there is provided a laminate
comprising: a) a multilayer outer film comprising a first barrier layer and polyolefin
layer on both sides of the first barrier layer; and b) a multilayer middle film comprising
a second barrier layer and polyolefin layer on both sides of the second barrier layer,
wherein (i) the polyolefin layer of the multilayer outer film towards the multilayer15
middle film, or (ii) the polyolefin layer of multilayer middle film towards the multilayer
outer film, or both (i) and (ii), is metallized with a metal selected from aluminum,
nickel, chromium, or combinations thereof.
[0040] In an embodiment of the present disclosure, there is provided a laminate
comprising: a) a multilayer outer film comprising a first barrier layer and polyolefin20
layer on both sides of the first barrier layer; and b) a multilayer middle film comprising
a second barrier layer and polyolefin layer on both sides of the second barrier layer,
wherein the polyolefin layer of the multilayer outer film towards the multilayer middle
film, (or) the polyolefin layer of multilayer middle film towards the multilayer outer
film, (or) the polyolefin layer of the multilayer outer film towards the multilayer middle25
film and the polyolefin layer of multilayer middle film towards the multilayer outer
film, is metallized with a metal selected from aluminum, nickel, chromium, or
combinations thereof.