DESC:FORM 2

THE PATENTS ACT, 1970

(39 of 1970)

&

THE PATENT RULES, 2003

COMPLETE SPECIFICATION

[See Section 10 and Rule 13]

TITLE:

“AN ULTRA-HIGH BARRIER CAST POLYPROPYLENE FILM AND A METHOD OF PREPARATION THEREOF”

APPLICANT:

JPFL FILMS PVT. LTD.
A company incorporated under the Indian Companies Act, 1956
having address at
Mundhegaon, Taluka-Igatpuri, Dist.-Nashik, Pin Code – 422403,
Maharashtra, India

PREAMBLE TO THE DESCRIPTION:
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 the field of cast polypropylene (CPP) films. More particularly, the present invention relates to an ultra-high barrier metallized cast polypropylene film and a method of preparation thereof, having application in the packaging industry related to food, drug, cosmetics etc.

BACKGROUND OF THE INVENTION
Cast polypropylene (CPP) film, unlike bi-directionally oriented polypropylene film, is a non-oriented polypropylene film produced by a cast extrusion process. It is widely used in the flexible packaging industry for applications such as bakery, fresh produce, stationery items, textile, cosmetics, medicines, food and beverages industry. Due to its un-oriented manufacturing process, it is resistant to impact and low temperatures. CPP has become popular in many traditional flexible packaging applications owing to its high gloss, better heat resistance, and these CPP when metallized provide excellent barrier properties.
US7794845B2 discloses about a multilayer polypropylene film comprising, a base layer A, at least one skin layer B adhered to said base layer A and a metal layer M deposited on the surface of said skin layer, wherein said skin layer B comprises a propylene copolymer containing 3% to 6% by weight of C4-C10 alpha-olefin units, said propylene copolymer having a xylene soluble fraction at 23°C, vicat softening temperature higher than 135°C and an indentation value according to the vicat test method lower than or equal to 0.05 mm at 120°C.
WO2010/039375A1 discloses about film composition that provides a novel film, comprising: a first layer comprising at least one of polypropylene, polypropylene with cavitating agent, and mono-oriented high-density polyethylene; the first layer has a density in the range of 0.2 to 0.96gm/cm3 and a thickness in the range of about 0.5-80 microns. The film has tear strength from 79 to 197 gf/cm; oxygen transmission rate from 0 to 2.10 cm3/m2/24 hours at 23°C and 0% relative humidity; water transmission rate of less than about 1.00 g/m2/24 hours at 38°C. This citation discloses about the film with seven layers.
EP1885558B1 discloses about co-extruded multilayer barrier film having at least one film ply of ethylene-vinyl alcohol copolymer, method of producing it and its use. However, the mechanical properties of the disclosed multilayer film were largely determined by a biaxially oriented film for which a crystallizable polyolefin is used as a film-forming polymer.
CN107351500 discloses a kind of production method of high-barrier, high surface tension cast polypropylene metallized films. The cited document discloses about composition of the CPP aluminized film, which is a seven layered film.
IN375284 discloses about multilayer metallized cast polypropylene film, comprising: a) a metallizable skin layer comprising a polyolefin and an antiblock; b) a middle core layer comprising a homopolymer PP resin and a stiffener; and c) a sealant layer comprising a copolymer and an antiblock. The cited document discloses about the high range values for water vapour transmittance rate.
In these packaging applications, ethylene vinyl alcohol copolymer (EVOH) is commonly used in the form of a thin layer, together with thicker layers of less expensive structural materials. EVOH resins are used as relatively thin components of multilayer structures and the major parts of the structures are bounded to the EVOH layer by adhesive layers.
However, EVOH exhibits very poor drawability that is the ability to be stretched or deformed uniformly at a temperature below its melting point. This induces cracks, discontinuity or thinning in the EVOH layer. As a result, stretched or deformed multilayer structures that include a layer of EVOH resin, exhibit inferior barrier properties. Moreover, EVOH cannot be formed at the relatively lower temperatures required for the thermoforming of many common structural materials without rupturing the EVOH layer, resulting in a loss of overall barrier performance.
Another limitation of the existing cast polypropylene films that are used in packaging industry is that, when a film suitable for a packaging material is used alone as a packaging container or packaging material, the packaging process is completed through various processes such as printing or attaching a graphic to a film, or shape-processing such as a container or a packet. As a result of these processes, the gas barrier properties of the film are deteriorated or greatly reduced.
Therefore, there is a need to provide an improved material to overcome the above mentioned problems.

OBJECT OF THE INVENTION
The main object of the present invention is to provide an ultra-high barrier cast polypropylene film and a method of preparation thereof.
Another object of the present invention is to provide an ultra-high barrier cast polypropylene film having an ultra-high oxygen and moisture barrier properties for packaging of commodities such as food, drugs, cosmetics and related products.
Yet another object of the present invention is to provide an ultra-high barrier cast polypropylene film with high surface tension, seal strength and haze properties.
Yet another object of the present invention is to provide an ultra-high barrier cast polypropylene film that increases the shelf life of the packed items by suppressing degradation or deterioration of the packed item and hence, have extended storage period.
Still another object of the present invention is to provide an ultra-high barrier cast polypropylene film that is cheaper and more efficient.

SUMMARY OF THE INVENTION
The present invention relates to an ultra-high barrier multilayer cast polypropylene film and a method of preparation thereof.
In an embodiment, the present invention provides an ultra-high barrier multilayer cast polypropylene film comprising of an untreated layer (11); a plurality of tie layers (12); a main layer or a core layer (13); and a treated layer (14, 15).
The ultra-high barrier cast polypropylene film (20) is a metallized ultra-high barrier cast polypropylene film, the untreated layer (11) includes a heat seal layer (11), the plurality of tie layers (12) includes a first tie layer between the heat seal layer (11) and the main layer (13) and a second tie layer between the main layer (13) and the treated layer (14); and the treated layer (14) is metallized by maintaining optical density in a range of 2.6-2.7 to form a metallized layer (15).
The ultra-high barrier cast polypropylene film (20) of the present invention is prepared by five-layer technology.
The present invention relates to an ultra-high barrier metallized cast polypropylene film with a modified EVOH layer, exhibiting excellent water and oxygen barrier properties, seal strength and haze properties.
The above objects and advantages of the present invention will become apparent from the hereinafter set forth brief description of the drawings, detailed description of the invention, and claims appended herewith.

BRIEF DESCRIPTION OF THE DRAWINGS
An understanding of the ultra-high barrier cast polypropylene film and the method of preparation thereof of the present invention may be obtained by reference to the following drawings:
Figure 1 is a pictorial representation of the different layers of the non-metallized ultra-high barrier cast polypropylene film (10), according to the present invention.
Figure 2 is a pictorial representation of the different layers of the metallized ultra-high barrier cast polypropylene film (20), according to the present invention
DETAILED DESCRIPTION OF THE INVENTION
The present invention will now be described hereinafter with reference to the accompanying drawings in which a preferred embodiment of the invention is shown. This invention may, however, be embodied in many different forms and should not be construed as being limited to the embodiment set forth herein. Rather, the embodiment is provided so that this disclosure will be thorough, and will fully convey the scope of the invention to those skilled in the art.
The present invention now will be described hereinafter with reference to the detailed description, in which some, but not all embodiments of the invention are indicated. Indeed, the invention may be embodied in many different forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided so that this disclosure will satisfy applicable legal requirements. Like numbers refer to like elements throughout. The present invention is described fully herein with non-limiting embodiments and exemplary experimentation.
The present invention relates to an ultra-high barrier multilayer cast polypropylene film and a method of preparation thereof.
In a preferred embodiment, the present invention provides an ultra-high barrier cast polypropylene film ( 20), comprising of: an untreated layer (11); a plurality of tie layers (12); a main layer or a core layer (13); and a treated layer (14, 15); wherein, the ultra-high barrier cast polypropylene film (20) is a metallized ultra-high barrier cast polypropylene film; the untreated layer (11) includes a heat seal layer (11); the plurality of tie layers (12) includes a first tie layer between the heat seal layer (11) and the main layer (13) and a second tie layer between said main layer (13) and the treated layer (14); and the treated layer (14) is metallized by maintaining optical density in a range of 2.6-2.7 to form a metallized layer (15)..
Here, the heat seal layer (11) is made up of 90-94 % of copolymer, 1-4% additive A and 4-9% additive B, the treated layer (14) is made up of an aqueous dispersion of ethylene/vinyl alcohol-based copolymer and the aqueous dispersion of ethylene/vinyl alcohol-based copolymer is a combination of ethylene/vinyl alcohol-based copolymer in the form of particles with an ethylene content of 15-65 mole percent with a degree of saponification in a range of 75-80 mole percent and a base-neutralized ethylene/a,e-unsaturated carboxylic acid-based copolymer. Further, the plurality of tie layers (12) is made up of 90-100% copolymer and 0-10% propylene based elastomer, the core layer (13) is made up of 100% homopolymer and the metallized layer (15) is made up of a metal that includes aluminium or gold. In addition, the film is having thickness in a range of 18-25 µ with GSM in range of 23-24 gm/m2, possesses haze percentage in a range of 4.5-6.4% and gloss in a range of 70-80 GU, has seal initiation temperature (SIT) in a range of 105-120°C and seal strength in a range of 1220-1400 g/25 mm, oxygen transmittance rate (OTR) in a range of 0.087-1.5 cc/m2/day and water vapour transmittance rate (WVTR) in a range of 0.10-1.5 g/m2/day.
In another embodiment, the present invention provides a method for preparation of an ultra-high barrier metallized cast polypropylene film with five-layer technology.
Referring to Figure 1, a pictorial representation of the different layers of the non-metallized ultra-high barrier cast polypropylene film (10), is depicted. The non-metallized ultra-high barrier cast polypropylene film (10) comprises of an Extruder A (a heat seal layer, 11), an Extruder B (a core layer, 13), an Extruder D (a treated layer, 14), a first tie layer (12) between heat seal layer and core layer, and a second tie layer (12) between the core layer and the treated layer, (14).
Referring to Figure 2, a pictorial representation of the different layers of the metallized ultra-high barrier cast polypropylene film (20), is depicted. The metallized ultra-high barrier cast polypropylene film (20) comprises of an Extruder A (a heat seal layer, 11), an Extruder B (a core layer, 13), an Extruder D (atreated layer, 14), a first tie layer (12) between heat seal layer (11).and core layer (13), a second tie layer (12) between the core layer (13).and the treated layer (14), and a metallized layer (15).
EXAMPLE 1
For Experimentation Data
Materials and method
Extruder A (Heat seal layer, 11)
The heat seal layer is a skin layer and is prepared in a manner to achieve properties such as seal strength, coefficient of friction (COF) and barrier properties of film. The heat seal layer is made up of 1-4% CONSLIP201PP/AVER11SC, 4-9% High ADD 2C01A/ABVT22NSC/ABVT22SC, 90-94% Basel Adsyl 6064 /Borough RD 368 / ADSYL 7572. Adsyl resins are propylene plus ethylene and butene based random copolymers and terpolymers with high comonomer ratios that deliver improved sealing properties. Adsyl resins provide low seal initiation temperatures (SIT), high hot tack, good optics, breathability, high speed processing, printability, and in metallization applications. Adsyl resins are employed in food and beverage, tobacco and industrial packaging. Melt flow rate is 230°C/2.16 kg, 5.5 g/10min, density is 0.9 g/cm3, SIT is 105°C
Extruder B (Main layer or core layer, 13)
The core layer comprises of polypropylene such as Homopolymer. The properties such as strength and haze gloss of the prepared film depend on homopolymer. Materials employed for core layer are selected from homopolymer or Reliance H0 34 SG/H0 70 SG properties.
Extruder C (Tie layer, 12)
The first tie layer is between heat seal layer and core layer. Second tie layer is between core layer and barrier layer. The tie layers act as adhesive layers that makes homopolymer layer (core layer) compatible with sealing layer or barrier layer.
Extruder D (Treated or Barrier layer, 14)
The treated barrier layer is a skin layer that is made of special materials that enhance the properties of CPP film.
Metallization
Metallization is performed by physical vapour deposition process. Aluminum/gold is the main metal for deposition; however other metals like chromium or nickel are also employed. Metals are heated, dissolved under vacuum and concentrates on cold polymer films, which is unwinded next to metal vapor source. Such coatings do not fade over time. The prepared films are essentially impassable by oxygen and moisture. However, when the packaging made with metal foil are subjected to repeated handling and manipulation that are frequent with cartooning, manufacturing, consumer handling and shelf stocking in retail environment, pinholes are developed that results into permeable packaging. The metallized films have a shiny silvery surface like the aluminum foil.
The coating provided also shrinks the ability of the films to expose to oxygen, light, and water. The features of the prepared film stay, such as high toughness, the capacity to preserve heat, and low density at lower cost when compared to aluminum foil. The coating provides metalized films numerous benefits over aluminum foil laminate and aluminum foil. Metalized film is substitute for aluminum foil laminate.
Experiment 1: Composition of the ultra-high barrier CPP film (20)
Table 1 depicts the composition of layers of an ultra-high barrier CPP film. The ultra-high barrier CPP film comprises of different layers as given below:
In coextrusion layer A (11), untreated layer is made up of Conslip 201PP 1-5%, high ADD 2C01A dosing (5-8%), and 85-95% copolymer grade ADSYL 6064 or Adsyl 3C 30 FC or Adsyl 5C 30 or RD 367 from Borough for compatible.
The main or core layer B (13) is made up of homopolymer grade Reliance HO34 SG/H070 SG or P 201PP 95-100%.
The tie layer (12) or adhesive layer C, known as intermediate tie layer was made up of a combination with copolymer BONDYRAM–4108/S K Functional-Orevac 825 OE (90-100%) or Exxon Mobil VISTAMAX 3980 (0-10%); and in coextrusion layer D (14), treated layer (barrier layer) was made up of an aqueous ethylene/vinyl alcohol-based copolymer dispersion, which comprises of: (a) ethylene/vinyl alcohol-based copolymer in the form of particles with an ethylene content of 15-65 mole percent with a degree of saponification in range of not lower than 75-80 mole percent and (b) a base-neutralized ethylene/a,e-unsaturated carboxylic acid-based copolymer.

Metallization layer (outer layer, 15): The outer layer is a metallized layer deposited with metal having optical density (OD) of 2.6 to 2.7. The metal aluminum (Al) is deposited by physical vapour deposition.

Table 1: Composition of layers of an ultra-high barrier CPP film (20)
Layer Materials Dosing % Microns Division
Co-Ex-A- UT CONSLIP201PP/AVER11SC 1 4.5
High ADD 2C01A/ABVT22NSC/ABVT22SC 5
Basel Adsyl 6064 SIT - 105/Borough RD 368- SIT-115/ADSYL 7572 94
Ex-B Reliance H0 34 SG/ H0 70 SG 100 13.0
Ex-C BONDYRAM - 4108/ S K Functional -Orevac 825 OE/BONDYRAM TL1235/ADMER QF 500 T 90 3.0
Exxon Mobil VISTAMAX 3980/EXCEED 3518 CB 10
Co-Ex-D- UT Kuraray EVALG156B 100 4.5
Total 25.0

Result Analysis
The ultra-high barrier CPP film exhibits the thickness in range of 18 µ and 25 µ with GSM in range of 23-24 gm/m2; haze percentage in range of 4.5-6.4%; gloss in range of 70-80 GU; seal initiation temperature (SIT) in range of 102-105°C; seal strength in range of 1220-1400 g/25mm; oxygen transmittance rate (OTR) in range of 0.5-1.5 cc/m2/day and water vapour transmittance rate (WVTR) in range of 0.5-1.5 g/m2/day.
Table 2: Values for OD, WVTR and OTR of the ultra-high barrier CPP film
OD WVTR
(38°C & 90% RH) OTR
(25°C & 0% RH)
2.60-2.71 0.5-1.5 0.5-1.5

Experiment 2
Table 3 depicts another composition of layers of an ultra-high barrier CPP film. The ultra-high barrier CPP film (20) comprises of different layers as given below:
The coextrusion layer A is an untreated layer, and was made up of additive “A” (High Add 2C01 4-9%), additive “B” (Conslip 201PP 1-4%), and copolymer Borough RD 368 90-94%.
The main or core layer B was made up of homopolymer grade Reliance HO34 SG/H070 SG or P201PP 95-100%.
The tie layer or adhesive layer C was made up of a combination with copolymer BONDYRAM–4108 or S K Functional Orevac 825 OE (90-100%) or/and Exxon Mobil VISTAMAX 3980 (0-10%) and the coextrusion layer D was made up of an aqueous ethylene/vinyl alcohol-based copolymer dispersion, which comprises of: (a) ethylene/vinyl alcohol-based copolymer in the form of particles with an ethylene content of 15-65 mole percent with a degree of saponification in range 75-80 mole percent and (b) a base-neutralized ethylene/a, ß-unsaturated carboxylic acid-based copolymer.
Metallization layer (Outer layer): The outer layer is a metallized layer deposited with metal having optical density (OD) in a range of 2.6 to 2.7. The metal aluminum (Al) is deposited by physical vapour deposition.
Table 3: Composition of layers of an ultra-high barrier CPP film (20)
Layer Materials Dosing % Microns Division
Co-Ex-A- UT CONSLIP201PP/AVER11SC 1 4.5
High ADD 2C01A/ABVT22NSC/ABVT22SC 5
Basel Adsyl 6064 SIT - 105/Borough RD 368- SIT-115/ADSYL 7572 94
Ex-B Reliance H0 34 SG/ H0 70 SG 100 13.0
Ex-C BONDYRAM - 4108/ S K Functional -Orevac 825 OE/BONDYRAM TL1235/ADMER QF 500 T 100 3.0
Co-Ex-D- UT Kuraray EVALG156B 100 4.5
Total 25.0

Results: Physical properties of an ultra-high barrier CPP film
Table 4 depicts the oxygen transmittance rate (OTR) and water vapour transmittance rate (WVTR) properties of an ultra-high barrier CPP film. Table 5 depicts the physical properties properties of an ultra-high barrier CPP film. The ultra-high barrier CPP film exhibits the thickness in range of 18 µ and 25 µ with GSM in range of 23-24 gm/m2; haze percentage in range of 4.5-6.4%; gloss in range of 70-80 GU; seal initiation temperature (SIT) in range of 105-120°C; seal strength in range of 1220-1400 g/25 mm; oxygen transmittance rate (OTR) in range of 0.087-0.5 cc/m2/day and water vapour transmittance rate (WVTR) in range of 0.18-0.5 g/m2/day.
Table 4: Values for OD, WVTR and OTR of the ultra-high barrier CPP film
OD WVTR
(38°C & 90% RH) OTR
(23°C & 0%RH)
2.60-2.71 0.18-0.5 0.087-0.5

Table 5: Physical properties of prepared CPP film
S. No. Properties Unit Experiment 2
1 Thickness µ 25.2
2 GSM gm/m² 23.07
3 Density gm/cc 0.91
4 Treatment Inside 33
Outside -
5 Haze % 4.5-6.4
6 Gloss 45° 74.3-79.2
7 C.O.F. Tr/tr 0.229/1.195
Tr/TM 0.315/0.224
Ut/Ut 0.092/0.671
Ut/M 0.224/0.208
8 Tensile Strength MD Kg/cm² 300
TD 150
9 Elongation MD % 258
TD 355
10 SIT 2 bar / 1 sec. (200 gm Load) 114°C 480

11 HSS 120°C @ 2 bar , 1 sec. Gm/25mm 1220

Therefore, the present invention provides a high surface tension CPP metallized flexible plastic film having ultra-low permeability to gases and moisture which comprises a film substrate selected from the group consisting of polyolefin and barrier resin such as EVOH with fixed weight ratios.
Many modifications and other embodiment of the invention set forth herein will readily occur to one skilled in the art to which the invention pertain having the benefit of the teachings presented in the foregoing descriptions and the associated drawings. Therefore, it is to be understood that the invention is not to be limited to the specific embodiments disclosed and that modifications and other embodiments are intended to be included within the scope of the appended claims. Although specific terms are employed herein, they are used in a generic and descriptive sense only and not for purposes of limitation.
,CLAIMS:CLAIMS
We claim:
1. An ultra-high barrier cast polypropylene film (20), comprising of:
an untreated layer (11);
a plurality of tie layers (12);
a main layer or a core layer (13); and
a treated layer (14, 15);
wherein,
said ultra-high barrier cast polypropylene film (20) is a metallized ultra-high barrier cast polypropylene film;
said untreated layer (11) includes a heat seal layer (11);
said plurality of tie layers (12) includes a first tie layer between said heat seal layer (11) and said main layer (13) and a second tie layer between said main layer (13) and said treated layer (14); and
said treated layer (14) includes a metallized layer (15).

2. The ultra-high barrier cast polypropylene film (20) as claimed in claim 1, wherein said heat seal layer (11) is made up of 90-94% of copolymer, 1-4% additive A and 4-9% additive B.

3. The ultra-high barrier cast polypropylene film (20) as claimed in claim 1, wherein said treated layer (14) is made up of an aqueous dispersion of ethylene/vinyl alcohol-based copolymer.

4. The ultra-high barrier cast polypropylene film (10, 20) as claimed in claim 1, wherein said aqueous dispersion of ethylene/vinyl alcohol-based copolymer is a combination of ethylene/vinyl alcohol-based copolymer in the form of particles with an ethylene content of 15-65 mole percent with a degree of saponification in a range of 75-80 mole percent and a base-neutralized ethylene/a,ß-unsaturated carboxylic acid-based copolymer.

5. The ultra-high barrier cast polypropylene film (20) as claimed in claim 1, wherein said plurality of tie layers (12) is made up of 90-100% copolymer and 0-10% propylene based elastomer.

6. The ultra-high barrier cast polypropylene film (20) as claimed in claim 1, wherein said core layer (13) is made up of 100% homopolymer.

7. The ultra-high barrier cast polypropylene film (20) as claimed in claim 1, wherein metallization is performed on said treated layer (14) by physical vapour deposition of a metal having optical density (OD) on a range of 2.6-2.7 to obtain said metallized layer (15).

8. The ultra-high barrier cast polypropylene film (20) as claimed in claim 1, wherein said metallized layer (15) is made up of metal that includes aluminium or gold.

9. The ultra-high barrier cast polypropylene film (20) as claimed in claim 1, wherein said film is having thickness in a range of 18-25 µ with GSM in range of 23-24 gm/m2.

10. The ultra-high barrier cast polypropylene film (20) as claimed in claim 1, wherein said film possesses haze percentage in a range of 4.5-6.4% and gloss in a range of 70-80 GU.

11. The ultra-high barrier cast polypropylene film (20) as claimed in claim 1, wherein said film is having seal initiation temperature (SIT) in a range of 105-120°C and seal strength in a range of 1220-1400 g/25 mm.

12. The ultra-high barrier cast polypropylene film (20) as claimed in claim 1, wherein said film exhibits oxygen transmittance rate (OTR) in a range of 0.087-1.5 cc/m2/day.

13. The ultra-high barrier cast polypropylene film (20) as claimed in claim 1, wherein said film exhibits water vapour transmittance rate (WVTR) in a range of 0.10-1.50 g/m2/day.