C2171
FORM - 2
THE PATENTS ACT, 1970
(39 of 1970)
&
The Patents Rules, 2006
PROVISIONAL SPECIFICATION
(See Section 10 and Rule 13)
A FILM FOR MAKING FLEXIBLE PACKS AND PROCESS FOR MAKING THE FILM
HINDUSTAN UNILEVER LIMITED, a company incorporated under
the Indian Companies Act, 1913 and having its registered office
at 165/166, Backbay Reclamation, Mumbai -400 020, Maharashtra, India
The following specification describes the invention

FIELD OF INVENTION
The present invention relates to a film for use in packaging, and more particularly to a film for making form-fill-seal pouches.
The invention has been developed primarily for use with detergent compositions, and will be described hereinafter with reference to this application. However, it will be appreciated that the invention is not limited to this particular field of use.
BACKGROUND AND RELATED ART
Any discussion of the prior art throughout the specification should in no way be considered as an admission that such prior art is widely known or forms part of the common general knowledge in the field.
Form-fill-seal pouches are very commonly used for packaging consumer goods such as detergent powders, detergent cakes, shampoos, cosmetic compositions and biscuits. Such pouches are used for packaging small quantity of fluid materials such as shampoos and cosmetic compositions, and also to pack bulk quantity of e.g. detergent compositions. These pouches may be 3-seal pouches or 4-seal pouches; which are also frequently provided with gussets. Such pouches are also known in the art as bags or sachets.
Consumer acceptance of many commercial products is not only related to their performance, but also to the aesthetics associated therewith, such as colour, perfume and packaging.


Many consumer products have a typical perfume or aroma, which many of the times, is the unique selling proposition of the products. This is true for several cosmetics and detergent products. Odorant additives e.g. perfume or fragrance components therefore form an important aspect of the success of such commercial products.
When such products are packaged, the consumer generally experiences the perfume or the aroma for the first time, only when the package is opened. If a new fragrance is to be introduced, the consumer would usually prefer to test the odorant i.e. smell the product before purchasing. It has been found desirable to provide the consumer, an indication of the perfume or aroma of the product, before using the product, and some methods have been adopted in the past to do so. Such methods include the use of perfume strips along with the package, and the inclusion of the aroma in the head-space (free-space) of the package, so that the consumer experiences this aroma in the form of a blast, when the package is opened. However, it is desirable to enable the buyer to experience the perfume or aroma of the product without destructively opening the package. Some attempts have been carried out in the past, to do so.
WO 2005/105587 (Unilever) describes a package containing an odorant composition where the package has an outlet for discharge of the product and another olfactory outlet for facilitating release of odorant components from the composition to provide multiple consumers with means for repeated olfactory testing of the composition before purchase; while preventing or at least minimising egress of non-volatile components of the composition.


Similar attempts have also been carried out in the field of flexible packages.
US2007/0014993 (Kenneth Joseph Longmoore) describes scented multilayer films in which an aromatic substance is present in the adhesive layer between the multiple films and the films have a differential degree of permeability to the aroma. The aroma may then permeate inwards or outwards depending upon the permeability characteristics of the films. It may be seen that such multilayer films when used, may result in packages in which the aroma may migrate inwards towards the product to augment its' aroma. On the other hand, when the aroma migrates outward of the package, it is quite likely that a large part of the aroma would be lost in transit and storage, due to continuous and uncontrolled release of aroma.
GB 218062 (Acrathane Products Limited) describes perfumed laminate for making flexible packages. In this case, the multilayer film has a surface-coating of a varnish that includes encapsulates of a perfume, which can be broken or ruptured when the consumer rubs his fingers against the surface, whereby the aroma gets transferred to his finger tips, by which the consumer can readily "test" the perfume. Consumer products packaged in flexible bags have to be transported to depots/godowns, where they are stored for long periods. From there, these packaged products are transported to retail outlets. This transportation and storage cycle may cause damage to the packages; and especially in case where the surface of the laminate is coated with a perfumed composition. The present inventors have found that such coated laminates are relatively less


fit for the rigorous cycle of transportation and storage, where the perfumed layer gets abraded and/or damaged to a substantial extent, before reaching the shops.
Therefore, there is a need of a film having perfumed surface for use in packaging, which is better adapted for the rigors of transportation and storage.
OBJECTS OF THE INVENTION
It is an object of the present invention to overcome or ameliorate at least some of the disadvantages of the prior art.
It is an object of the present invention to provide a film for use in packaging, in which the perfume is capable of better retention during storage and transportation.
The present inventors have found that the above mentioned objects can be achieved when a coat of primer is present between the film, and the surface-coating having encapsulates of odorous material.
SUMMARY OF THE INVENTION
According to the first aspect of the present invention there is provided a film for use in packaging, comprising a surface-coating that includes shear sensitive encapsulates of odorous material, wherein a coat of primer is present between the film, and the surface-coating.


According to the second aspect of the invention there is provided a process for making a film for use in packaging according to the first aspect, comprising the steps of:
(i) applying a coat of primer to said film;
(ii) drying said coat;
(ii) applying a surface-coating that includes shear sensitive encapsulates of odorous material over said coat of step (ii); and
(iv) drying said surface coating.
According to the third aspect of the present invention there is provided use of a film according to the first aspect in packaging.
According to the fourth aspect of the present invention there is provided a package comprising a film according to the first aspect of the invention.
The invention will now be explained in detail in the following detailed description.
DETAILED DESCRIPTION
The film
The invention relates to a film for use in packaging, comprising a surface-coating that includes shear sensitive encapsulates of odorous material, wherein a coat of primer is present between the film and the surface-coating. It is preferred that the thickness of the film is from 30 microns to 300 microns. More preferred thickness of the film is from 50 microns to 150 microns. It is further preferred that the film has a printed surface. While the printed surface of the


film may be coated with the coat of primer and the surface-coating in accordance with the invention; it is preferred that the coat of primer and the surface-coating are on the opposite side of the printed surface. The film may be made of a single plastic such as Polyester (Polyethyleneterepthalate) or Polyethylene. It is preferred that the film is a laminate of plurality of plastic films. The laminate preferably comprises a layer of Polyethyleneterepthalate, Biaxially Oriented Polypropylene, Nylon or Metalised films; and a layer of Polyethylene or Polypropylene. It is preferred that the thickness of the layer of Polyethyleneterepthalate is from 8 microns to 12 microns. It is preferred that the thickness of the layer of Polyethylene is from 20 microns to 200 microns. The laminate may further be metallized or may have holographic patterns.
The Primer
It is preferred that the primer is a solvent-based varnish. The thickness of the coat of primer is preferably from 0.5 g/m2 to 1.5 g/m2, more preferably from 0.75 g/m2 to 1.25 g/m2, and further more preferably from 0.9 g/m2 to 1.1 g/m2. It is preferred that the binder (i.e. the film forming material or the resin) of the solvent-based varnish is selected from acrylic, polyester, alkyd, polyurethane, epoxy or melamine resins. The more preferred binder is polyester.
The Surface-Coating
It is preferred that the surface-coating is of a water-based varnish. It is preferred that the thickness of the surface-coating is from 1.75 g/m2 to 3.5 g/m2, preferably from 2.0 g/m2 to 2.75 g/m2, and more preferably from 2.25 g/m2 to 2.5 g/m2. Preferred binder of the water-based varnish is selected


from one or more of acrylic emulsions, polysaccharides, gums, water-borne polyesters or water-borne alkyds. The preferred binder is acrylic emulsion. It is preferred that the encapsulates are made of gelatinous material, more preferably gelatin. Preferred size of the encapsulates is from 10 microns to 40 microns; more preferably from 10 microns to 25 microns, and more preferably from 15 microns to 17 microns.
The term "odorous material" means a perfume, scent, aroma or flavour. It is preferred that the odorous material is a perfume. While it is preferred that the odorous material, which is included in the surface-coating is the same as the perfume/aroma of the product in the pack, the two may be different.
Process for making the film
According to another aspect, the present invention provides a process of making a film for use in packaging comprising the steps of:
(i) applying a coat of primer to said film;
(ii) drying said coat;
(iii) applying a surface-coating that includes shear sensitive encapsulates of odorous material over said coat of step (ii); and
(iv) drying said surface coating.
In a preferred aspect, the surface-coating is applied by rotogravure, flexo-printing, screen-printing or offset printing. It is further preferred that the surface-coating is applied by use of engraved Anilox rollers. In a preferred aspect, the coat of primer is applied by rotogravure or


flexo-printing. It is preferred that the viscosity of the solvent-based varnish is from 15 seconds to 25 seconds, as measured by B4 cup at 30 °C. It is preferred that the solids-content of the solvent-based varnish is from 23 % to 27 % by weight. The solvent of the solvent-based varnish is selected from benzene, toluene, xylene, ethyl acetate, acetone, methyl ethyl ketone or a mixture thereof. Ethyl acetate is particularly preferred.
When the film is printed, the process of coating of the film may be off-line or in-line. In off-line process, the film is transferred from the printing station to the coating station. In the case of in-line coating, the printed film is reversed by a process known as "web-reversal" (web and film are equivalent terms), wherein the printed side is reversed to expose the non-printed side, which can be coated with the primer and surface-coating. It is particularly preferred that the primer and the surface-coating are applied on the opposite side of the printed surface by reversing the film in-line, after printing.
It is preferred that the viscosity of the water-based varnish is from 15 seconds to 25 seconds, as measured by B4 cup at 30 °C. It is preferred that the solids content of the water-based varnish is from 36% to 40% by weight.
Preferably, the encapsulates of gelatinous material contain 12% to 25% by weight odorous material, more preferably 15% to 20%. It is preferred that the water-based varnish contains 17% to 30% by weight encapsulates of gelatinous material, and more preferably from 20% to 25%.


A typical process of coating of films is described below as an example; which forms a non-limiting embodiment of the process and the film, according to the invention.
Materials used for the process are as per table-1 below.
Table-1

Film is a laminate 12 micron PET/adhesive/12 micron metallised PET/adhesive/70 micron PE (Ex. Starflex Company, Thailand)
Primer Gravure Polyester Primer, Product Code RL70670, Ex. Polymer Printing Inks, Gujarat, India. Solids content - 25±2% by weight Viscosity (B4 cup at 30 °C) - 20±5 seconds Solvent - Ethyl acetate Binder - Polyester
Surface Coating W/B fragrance coating, Product Code RL79660,Ex. Polymer Printing Inks, Gujarat, India.Solids content - 38+2% by weightViscosity (B4 cup at 30 °C) - 20±5 secondsSolvent - WaterBinder - Acrylic emulsion20% by weight gelatine-based encapsulatescontaining 12% by weight perfume
Note: PET means Polyethyleneterepthalate PE means Polyethylene
Process for making the film according to the invention
The laminate was printed by gravure or flexography printing process. The maximum number of colours could be 8. The laminate was drawn out of jumbo rolls and was passed through various printing stations, each time followed by a drier. After printing 8 colours, the film was reversed on the printing machine itself, immediately before entering the 9th station and a thin coating of primer (0.5-0.6 g/m2) was


applied on the outer side of the laminate with in-line registration with the design on the laminate by gravure coating through chemically/electromechanically etched cylinders. After application of the coat of primer, the coat was dried instantly from 70 °C to 80 °C. Thereafter, the surface-coating of water-based varnish (2 to 3 gsm) was applied on the primer coated laminate on the 10th station of the printing machine immediately passing it through either an extended drier or a drier with heavy air exhaust. The coating cylinders for the surface-coating are designed and engraved in such a way that they have higher cell depth and can handle heavy coating weights of the varnish with relatively large encapsulate size (25-40 microns). The printing machine is also set such that it could handle a heavy coating weight of primer and surface coating, which are perfectly registered one on top of the other and in perfect registration with the print on the other side of the film.
It is preferred that the area of the coat of primer is kept slightly larger than the area of the surface-coating to ensure that the latter does not go outside the periphery of the coat of primer.
The perfume is reinforced without altering the hedonics for strength in the notes so that it could be used for such coating application through gravure/ flexography route.
In general, once the polyester film is printed, it is cured for some period of time, generally 24 to 48 hours, before starting the lamination process. The number of films in the


structure of laminate depends upon the barrier properties reguired in order to protect the product for particular time period under extreme atmospheric conditions. The lamination can be done either by adhesive lamination or extrusion lamination depending upon reguirements.
Once the laminate is manufactured, it is generally cured for another 24 to 48 hours. After the curing process, the film roll which generally has a high width, is cut into smaller rolls as per requirement.
The coated film so produced was subjected to the following tests to check its suitability for the rigors of transportation and storage.
Scotch Tape Test
A special grade of self-adhesive tape (MAGIC® tape of 3M) is used to measure the adhesion of any coating to the surface on which it rests. The tape is brought against the coated surface, adhered properly and pulled to separate from the coated surface. This pull, soft or hard as the case may be, gives a fair qualitative estimate of the extent of adhesion of the coating to the surface. Results of this scotch tape tests performed on various films made in accordance with the invention; and one comparative example, are compiled in table-2 below.


Table-2

Sample No. Primerthickness in g/m2 Surface coating in g/m2 Observation
1 0.91 2.5 Passes
2 0.91 2.2 Passes
3 0.86 5.5 Passes
4 0.79 3.4 Passes
5 Nil 2.9 Lifting of the coating was observed
Thus, it may be readily seen that the application of primer is essential for adhesion of the surface-coating.
Scuff-proofness test
This is a test that helps in determining the adhesion of the surface-coating to the film, and the strength of the surface-coating to survive external mechanical abuses, under application of load. In this test the coated side of a film is continuously rotationally rubbed against another coated side of the film under a static load. Tests were performed with varying thickness of the coats of primer and the surface-coating as mentioned in table-2 above. This test was performed at 27+1 °C, and 65±2 Relative Humidity. Results have been compiled and presented in Table-3 below.


Table-3

Sample no. No of revolutions / rubs Observation Perfume
1 20 No Scuffing Intact
40 No Scuffing Intact
60 No Scuffing Intact
80 No Scuffing Intact
120 No Scuffing Intact
2 20 No Scuffing Intact
40 No Scuffing Intact
60 No Scuffing Intact
3 20 No Scuffing Intact
40 No Scuffing Intact
60 No Scuffing Intact
80 No Scuffing Intact
100 No Scuffing Intact
120 No Scuffing Intact
4 20 No Scuffing Intact
40 No Scuffing Intact
60 No Scuffing Intact
80 No Scuffing Intact
5 20 No Scuffing observed Intact
40 More Scuffing observed Not intact
60 More Scuffing observed Not intact
Thus it may be readily seen that laminate without primer does not withstand Scuff-proofness test, and the coating gets relatively easily scratched, at the same time, the perfume does not remain intact. The perfume assessment was done by a panel of expert perfumers.
It will be appreciated that the illustrated examples, provide for a film for making flexible packs, in which the perfume is capable of better retention during storage and transportation.


The film could be used for packaging perfumed consumer goods such as detergent powders, shampoos and cosmetic creams in flexible packs, which include form-fill-seal pouches, or could be used as soap wrappers. In these cases, the film itself is used as a packaging material. Alternatively, the film according to the invention could also be used to coat paper-board based cartons by processes well known in the art; which may be used for packaging purposes, e.g. cartons for toothpaste tubes. Further, the film according to the invention may also be used to prepare collapsible tubes, such as tubes for toothpaste and creams, and in these cases, the thickness of the film may be appropriately selected by persons skilled in the art.
Although the invention has been described with reference to specific embodiments, it will be appreciated by those skilled in the art that the invention may be embodied in many other forms.