WO2013156849A1

WO2013156849A1 - A laminate for producing flexible pouch for storing water

Info

Publication number: WO2013156849A1
Application number: PCT/IB2013/000745
Authority: WO
Inventors: Anand Sarkar; Partha MAITI; Amjad Ali
Original assignee: Nourishco Beverages Ltd.; Mount Everest Mineral Water Limited
Priority date: 2012-04-21
Filing date: 2013-04-22
Publication date: 2013-10-24

Abstract

The present invention relates to a pouch made of a laminate for storing liquid wherein, the said laminate comprising one or more layers of polymeric material being adhered to each other in presence of adhesive comprising essentially iso-nitrile and hydroxyl group, wherein the said pouch characterized by improved barrier properties particularly water vapor transmission rate (W.V.T.R) in the range of 22 to 40 gm/m²/day and oxygen transmission rate (O.T.R) in the range of 70 to 100 cc/m²/day and shelf life enhanced by 5-15 times then commercial pouch.

Description

"A LAMINATE FOR PRODUCING FLEXIBLE POUCH FOR STORING

WATER" FIELD OF INVENTION

The present invention relates to a pouch made of laminate for storing liquid and a process for preparing the same. The flexible pouch have extended shelf life for the stored content therein and comprising a sealing jaw for enabling convenience for use with an easy tear and a spout to drink.

BACKGROUND AND PRIOR ART OF THE INVENTION

It is known that the laminate flexible pouches are available in the market for storing the various drinkable liquids or food products. However, the pouches known in the art for storing the water produces offensive odour within one or two days, due to exposure of sunlight having ultraviolet radiation. Various scientific researches reveals that such exposure of drinking water with sunlight having UV radiation leads to generation of primary amine (such as i.e. primary amino amine (PAA)) which develop carcinogenic effect in the drinking water. Research further reveals that sunlight contains component of ultraviolet rays such as UV A and UV B and visible lights followed by Infrared. It is also known that UV-B is far more harmful than UV A and in presence of high temperature and humidity, it may enhance the action of degradation of polymer by UV exposure. UV-A and UV-B set up various reactions in laminates, plastics, coatings, lacquers and adhesives, cleaving crystal chains, breaking up covalent bonds, distorting polar bond and reorienting Van Der Wall 's forces, as well as setting up reactions between the degraded molecules, anti- oxidants, slip additives, anti-block agents and the product components, which leads to harmful chemicals inside the product stored therein. Therefore, the products stored in such pouches are harmful for consumption.

It has been observed that in the domestic and international market, more particularly for developing countries such water pouches do not have any protection from direct sunlight exposure. Therefore, such water pouches produces offensive odour in the water within one or two days. In view of the above-said challenges and mass requirement of safe and hygienic water to the people of in the developing countries, the applicant of the present invention come out with an improved laminate structure for producing flexible pouches for storing water or mineral fortified water or non-ozonated drinking water or immunity water or other drinkable liquid, without affecting the original content filled therein.

The applicants addressing the grave need of large mass for getting safe and packaged drinking or immunity water in flexible pouch. However, the specific Go-to-market execution need of the packaging format is under trial and process.

However, due to failure of the earlier laminate to withstand the market conditions, the applicants of the present invention develop an improved flexible pouch for liquid such as nutrient fortified drinking / immunity water.

A string of ingredients for base polymer, adhesives and barrier additives has been brought into the current commercially competent laminate structure. This laminate is manufactured using the best technological procedures for stability, consistency and conformance to stringent quality and logistic requirements across the world.

The new laminate structure in the present disclosure is a completely turnaround from the conventional methods and has taken a distinctively new process and construct of laminated flexible pouches with smart graphics. Thus, the development o f such flexible pouch for nutrient fortified water with extended shelf life is a long pending requirement. In addition to, the present disclosure provides the said flexible pouches in multicolour, printable and highly decorative, with a premium finish.

OBJECTIVES OF THE PRESENT INVENTION

The primary objective o f the present invention is to provide a laminate structure for producing flexible pouch for storing liquid such as water or nutrient fortified water or non-ozonated drinking water or immunity water or other drinkable liquid, without affecting the original content filled therein.

Yet another objective of the invention is to provide a composition of laminate structure for producing flexible pouch. Yet another objective of the invention is to provide a method for preparation of laminate structure for flexible pouch.

Yet another objective of the invention is to provide a method for preparation of multilayer laminate structure for flexible pouch.

Yet another objective of the invention is to provide an economic, commercially and viable solution to producing flexible pouch for storing water.

SUMMARY OF THE INVE TION

The present invention relates to a pouch made of a laminate for storing liquid wherein, the said laminate comprising one or more layers of polymeric material being adhered to each other in presence of adhesive comprising essentially iso-cyanate and hydroxy! group, wherein the said pouch characterized by improved barrier properties. The laminate structure for producing flexible pouches having enhanced printability or graphics. The said flexible pouches are used for storing water or mineral forti fied water or non-ozonated drinking water or immunity water or other drinkable liquid, without affecting the original content filled therein. The said flexible pouch having extended shelf for the stored content therein and comprising a sealing jaw for enabling convenience for use with an easy tear and a spout to drink. BRIEF DESCRIPTION OF FIGURES

FIGURE 1 shows comparison of different laminates for UV transmission data. It indicates the performance of different laminates according to present invention.

FIGURE 2 shows comparison of different laminates for water extraction analysis.

FIGURE 3 exhibit comparative UV transmission analysis of non-conventional laminate. It indicates the performance of transparent sample and blue sample.

FIGURE 4 shows the new unique water pouch laminate structure

FIGURE 5 shows UV-vis Spectra of Pure LDPE Film and 5% UVABLOCK 75 Film.

It indicates the performance of UV block 75 in film segment as per prior art.

FIGURE 6 shows sensory evaluation data by expert benched panel.

FIGURE 7shows day field test qualification of different laminate structures.

FIGURE 8 shows test of different laminate structures in artificial weather and different instrument. FIGURE 9 shows work flow and inter-relation of processes for flexible laminate according to the present invention.

FIGURE 10 indicates manufacturing flow chart of flexible pouch according to the present invention.

BRIEF DESCRIPTION OF ANNEXURES

Anncxurc 1 shows the results of low retained solvent in commercial sample printed by ^{^}LIOVAL UE^" .

Anncxurc 2 shows the benefits of alteration to "LIOVAL UE" according to the present invention.

Anncxurc 3 shows the GC analysis of laminated sample printed with "LIOVAL UE^"' ,

DETAIL DESCRIPTION OF THE INVENTION

While the invention is susceptible to various modifications and alternative forms, specific aspect thereof has been shown by way of example and graphs and will be described in detail below. It should be understood, however that it is not intended to limit the invention to the particular forms disclosed, but on the contrary, the invention is to cover al l modi fications, equivalents, and alternative falling within the spirit and the scope of the invention.

The Applicants would like to mention that the examples are mentioned to show only those specific details that are pertinent to understanding the aspects of the present invention so as not to obscure the disclosure with details that will be readily apparent to those of ordinary skill in the art having benefit of the description herein.

The terms "comprises", "comprising", or any other variations thereof, are intended to cover a non-exclusive inclusion, such that a process that comprises a list of components does not include only those components but may include other components not expressly listed or inherent to such process.

In the following detailed description of the aspects of the invention, reference is made to the accompanying drawings and graphs that form part hereof and in which are shown by way of illustration specific aspects in which the invention may be practiced. The aspects are described in sufficient details to enable those skilled in the art to practice the invention, and it is to be understood that other aspects may be utilized and that charges may be made without departing from the scope of the present invention. The following description is, therefore, not to be taken in a limiting sense, and the scope of the present invention.

Accordingly, the present invention relates to a pouch made of a laminate for storing liquid such as water or nutrient fortified water or non-ozonated drinking water or immunity water or other drinkable liquid wherein, the said laminate comprising one or more layers of polymeric material being adhered to each other in presence of adhesive comprising essentially iso-cyanate and hydroxyl group, wherein the said pouch characterized by improved barrier properties.

In one embodiment of the invention polymeric material is selected from matt polyester film and polyolefin film or combination thereof wherein, said film comprising additives, stabi lizers or colorants.

In another embodiment of the invention matt polyester film is either both side untreated or one side corona treated or one side chemical treated.

In yet another embodiment of the invention thickness of matt polyester film is in the range of 6 to 20 microns, more preferably in the range of 10 to 15 microns.

In yet another embodiment of the invention polyolefin film is linear low density poly ethylene (LLDPE) or low density poly ethylene (LDPE) or combination thereof.

In yet another embodiment of the invention the thickness of polyolefin film is in the range of 15 to 80 microns, more preferably in the range of 40 to 65 microns.

In yet another embodiment of the invention one or. more layers of polymeric material are adhered by adhesive material (7a) and / Or, extrusion process (7b).

In yet another embodiment of the invention wherein adhesive material (7a) is solvent free. And the extrusion process (7b) is of polyethylene or, polyoleifin

In yet another embodiment of the invention wherein adhesive material is selected such as main component is hydroxyl terminated group (-OH- group) and cross-linker is iso- nitrile terminated group (NCO- group).

In yet another embodiment of the invention wherein adhesive material main component and crosslinker is in the ratio of 10: 1 to 10: 8

In yet another embodiment of the invention wherein combination of UV A Block 25 additives are used along with UV A Block 75 and equivalent UV stabilizer. In yet another embodiment of the invention wherein UV Block 25 additives are in the range of 20 % to 80%.

In yet another embodiment of the invention wherein said pouch having 22 to 40 gm/m2/day 70 to 100 cc/ m2/day, more preferably WVTR in the range of 20 to 35 gm/m2/day & OTR in the range o f 65 to 95 cc/ m2/day. The inertness to UV exposure of the pouch is in the range of 10 to 100 MJ/m2 and seal strength of 2.5 kg/25mm.

Second aspect of the invention relates to a process for preparing the laminate for producing pouch. The process for preparing the laminate comprises the steps of:

(i) extruding first base film of matt polyester either both side untreated or one side corona treated or one side chemical treated having thickness in the range of 15 μ to 80 μ, more preferably in the range of 40 μ to 65μ, essentially having anti slip additives and UVA25 & UVA75;

(ii) printing with ink composition wherein, said ink composition is free from Toluene and MEK solvent;

(iii) curing the base film thus obtained in step (ii) at temperature in the range of 80°C to 1 50°C for a time period of 30 to 60 seconds;

(iv) applying adhesive on the surface of the base film as produced in step (iii);

(v) extruding second polyolefin and adhering the same on the surface of the first base film as obtained in step (iv);

(vi) curing film as obtained in step (v) for at least 8 to 1 4 days in order to produce a laminate.

Third aspect of the invention relates to a process for manufacturing pouch made of a laminate by connecting the laminate into pouch, where the laminates are sealed at the edges in order to obtain desired pouch, which is capable to store drinking water or mineral fortified water or non-ozonated drinking water or immunity water or other drinkable liquid, without affecting the original content filled therein. The said method comprising the steps of;

i) extruding first base fi lm of matt polyester either both side untreated or one side corona treated or one side chemical treated having thickness in the range of 6 μ to 20 μ, more preferably in the range of 40 μ lo 65μ, essentially having anti slip additives and UVA25 & UVA75 ;

(ii) printing with ink composition wherein, said ink composition is free from Toluene and ME solvent;

(iii) curing the base film thus obtained in step (ii) at temperature in the range of 80°C to 150°C for a time period of 30 to 60 seconds;

(vi) curing film as obtained in step (v) for at least 8 to 10 days in order to produce a laminate;

(vii) slitting of laminate as obtained in step (vi);

(viii) sealing edges of the laminate as produced in step (vii) in order to obtain desired size pouch;

(ix) Packaging of water, mineral fortified water, or similar drinks, beverages in the pouch

The present invention comprises of a matt polyester film is a base film of the laminate structure, which may be uniaxial or biaxial oriented matt polyester film can be either one side corona-treated -or one side chemical treated or both side untreated. The thickness of matt polyester film may be in the range of 6 μ to 20 μ, more preferably in the range of 10 μ to 15μ. The corona treated polyester film provides improved adhesion with inks and adhesives.

Another layer of laminate is a polyolefin film, which is extruded by using polyolefin selected from LLDPE.

Another component of the laminate is the adhesive material. A solvent free adhesive wherein, main component is OH-terminated and cross-linker is NCO- terminated is used for the present invention. The ratio of OH group to NCO group is in the range of 100: 60 to 100: 70. Mixing of both the components can be done'either by auto mixer or by mechanical mixing (hand mixing).

Yet another component is UV Block additives, which are selected from UVABLOC 25 1 03025- or UVABLOCK 25 103075-K or combination thereof. The ink used herein is free from volatile and pungent smelling Toluene and ME solvents. Looking at multiple sensitivity of low boiling solvent the entire water pouch laminate development was restricted to Multi-purpose ester/alcohol based gravure laminate ink.

The base film of polyester matt film comprising antislip additives and UV additives.

In yet another embodiment of the invention wherein said lamintae having 22 to 40 gm/m²/day 70 to 100 cc/ m²/day, & OTR in the range of 70 to 100 cc/ m2/day. ^'[^'he inertness to UV exposure of the pouch is in the range of 10 to 100 MJ/m², bond strength of laminate {(,g/ l 5 mm ( l OOmm/min speed) } : 130 (min) Pet to Poly with Pet break.

Yet another aspect of the invention is to provide ink composition and method for printing by the ink composition on the said flexible pouch.

Yet another embodiment of the invention is to improve printing quality by modi fying ink composition, which is free from free from Toluene and MEK solvent. It is possible to obtain different colour ink.

Another aspect of the present invention relates to an adhesive used for sealing of the flexible pouches. One of the most critical components in the laminate is the adhesive as Primary Aromatic Amine (PAA) migrates in to water / moisture caused by uncured Iso-cyanates in the Solvent Free Adhesives.The specific grade of adhesive based on technical parameters such as chemistry of the adhesive, short curing time, lower PAA migration post curing were analyzed. The adhesive system comprises of main component OH-terminated and cross-linker is NCO-terminated and therefore, some precautions are needed for machine trials such as never mix adhesive before complete machine and substrate setting on the machine is done.

The novel laminate structure, developed for producing flexible pouches having enhanced printability or graphics. The flexible pouches are used for storing water or mineral fortified water or non-ozonated drinking water or immunity water or other drinkable liquid, without affecting the original content filled therein. The flexible pouch have extended shelf for the stored content therein and comprising a sealing jaw for enabling convenience for use with an easy tear and a spout to drink. The present invention provides a multilayer laminate specification developed and offered for product packaging compatibility of non ozonated drinking / immunity water in flexible pouches. This is an economic and commercially viable solution to cater source of mass hydration at an affordable price and convenient on the go usage. The present invention also relates to UV block additives used for producing the flexible water pouches and its characteristics. A laminate structure has been developed that can be inert to direct UV exposure up to an extent > 100 MJ/m2. Both simulated laboratory tests and field qualifications were made as per Atlas protocol. UVA BLOCK 25 1 03025-K and UVA BLOCK 25 103075-K were used in the laminate. UVA BLOCK 25 is primarily designed for protecting the contents inside a transparent packaging film from UV or visible light. In the use for the UV protection of polyolefins, the let-down ratio is between 2 and 3%. UVABLOCK 75 has been developed as a UV barrier, which contains an e fficient UV absorbing additive for flexible packaging. The use-level of UVABLOCK 75 depends on various factors such as exposure time, climatic conditions and film thickness. In the use for the LiV protection o f polyolefins, the typical let down ratio is between 2 and 5%.

The technical characteristics for film production such as layer ratio, BUR (blow up ratio), Extruder type for homogenization of the polymers were done based on design of the Poly recipe.

The trapped solvent testing was done according to ASTM G 1 5 1 -09 standards by a simple test using Chromatograph equipment. Exposed the blue sample to UV radiation at 22 °C using 366 nm UV radiation lamp for 72 hrs and then tried analyzing the water that was wrapped inside the folded laminate. The GC plot when examined did not show any traces of any solvent (Figure 2).

Further, it was critical that the laminate be exposed to the 340 nm UV radiation with lamp at 60°C as per ASTM test to simulate this solvent migration.

The above data was generated as:

a) Sample of water from blue laminate, which was exposed to UV radiation

b) Sample of plain water before testing laminate, control 1 c) Sample of plain water after testing blue laminate, control 2 to see if anything got desorbed in the GC column

d) Sample of UV exposed blue laminate by itself tested like AA in a vial at 150°C for 30 min

RESULTS

Simulated and Field tests were successfully conducted and quali fication demonstrated in indoor laboratories of international repute and government accreditation as well as at the outdoor field testing under different climatic conditions (with extended exposure to UV- A and UV-B light of varied wavelength and energy, elevated temperature of 45 to 60 degree Celsius and relative humidity higher than 60 %):

Flexible laminated pouches exposed to and abused under extreme climatic and UV radiation conditions were tested for sensory evaluation by an expert bench of quali fied sensory panel. Confirmatory acid tests were conducted to qualify for repeatability and reproducibility of quality and logistic requirements of the flexible water pouch for packaging drinking / immunity water fortified with minerals. Hence, a unique laminate structure which can seal forti fied drinking / immunity water and resistant to UV exposure is produced.

The current commercially approved 12-50 micro base film has flexible characteristics and offers a matt surface finish for high definition graphics for excellence in aesthetic and shelf-appeal. Reverse printing is possible on this new laminate structure by using E and Toluene free ink thereby preventing imparting of any odour. Aliphatic solvent less adhesive of reputed and chemically stable / inert grade - EX 7660 or EX 7910 is used in conjunction with 50μ special Polymer base film. The entire string / chain of stabilized and tested ingredients were used in a total unconventional processing method to extrude and finally produce a laminated film of unique properties for packaging fortified mineral drinking / immunity water.

This packaging format is a new structure and stands out unique and unparallel for packaging of drinking / immunity water fortified with minerals which would function as provider of hydration of mass at an affordable price, easy reach for lighter logistic benefits and convenience to drink water from a pouch tlirough a sprout without any spillage / wastage thus cherishing value for money for the common man.

ADVANTAGES OF THE INVENTIONS

The major features of the present laminate structure are as follows.

• Matt Polyester base film to cut down UV charge penetrating the pouch and creating a greenhouse environment.

• Toluene and ME free ink with no residual solvent was used, eventually reproducing high pixel graphics with bare minimum ink coverage (< 0.6 gsm) for surface printing and aesthetic appeal.

• Aromatic adhesive compounds were replaced with aliphatic compounds thereby retaining low PA A profile.

• The thickness o f the sealant poly film was tinkered by 25% to ensure lower migration levels in the much sensory sensitive drinking / immunity water.

• The laminate structure increased dosage of UV additives in single layer against earlier 3 layers thereby saving upon material.

• UVA block 25 was supported with addition of UVA block 75 which was a totally new and non-conventional concept in the regular lamination process for flexible packaging.

• Change of organic slip additive to inorganic slip in poly to avoid migration / leeching of salts / ions into water.

• Conventional barrier compounds like "Smell Free" was totally withdrawn against earlier conventional usage in all layers of the laminate construct.

• Base poly Film for the flexible laminate was extruded using only LLDPE (non migratory / non-slip grade) replacing the regular LDPE (migratory and conventional slip base) was avoided for prevention from migratory additives.

• Produced flexible pouches having enhanced printability and graphics.

• Pouch achieved in an economical, practical, and facile manner. Anncxurc \ shows the results of low retained solvent in commercial sam printed by "UO 'VALUE .

Anncxurc 2 shows the benefits of alteration to ^{^}LIOVALUE' according to the present invention.

Non

Toluene and MEK

For White^' For Color

EAC 50 -

IPA 12 -

N-ProOH 3 10(15)

N-ProAc 34 (35) 85

PGM 1 (0) 5(0)

MEK 0 0

Toluene 0 0

Total 100 100

Annexurc3 shows the GC analysis of laminated sample printed with LIOVALUI ^{' '}.

Residual Solvent (unit: mg/m2)

No. Sample IPA N- MEK Ethyl N- Toluen Total

description Prop Propyl e

Aceta

anol

te Acetat

e

A- Liovalue 0.13 0.01 0.10 0.12 0.09 0.04 0.49

black

A- Liovalue 0.05 0.01 0.05 0.14 0.02 0.05 0.32 (2) blue

A- Liovalue 0.12 0.01 0.07 0.34 0.03 0.05 0.62

(3) clear

A- Liovalue 0.09 0.01 0.05 0.23 0.02 0.04 0.44 (4) white

A- Liovalue 0.13 0.01 0.05 0.17 0.02 0.03 0.41

(5) blue

B- Sakata 0.07 0.04 0.14 0.01 0.04 0.30

white

B- Sakata 0.09 0.01 0.06 0.21 0.02 0.04 0.43

(2) clear

Claims

THE CLAIM:

1 . A pouch made of a laminate for storing liquid wherein, the said laminate comprising one or more layers of polymeric material being adhered to each other in presence of adhesive comprising essentially iso-nUrile and hydroxyl group, wherein the said pouch characterized by improved barrier properties particularly water vapor transmission rate (W.V.T.R) in the range of 22 to 40 gm/m²/day and oxygen transmission rate (O.T.R) in the range of 70 to 100 cc/ m²/day and shelf l ife enhanced by 5- 1 5 times then commercial pouch.

2. The pouch as claimed in claim 1 , wherein polymeric material is selected from matt polyester film and polyolefin fi lm or combination thereof wherein, said film comprising additives, stabilizers or colorants.

3. The pouch as claimed in claim 1 or 2, wherein the matt polyester film is either both side untreated or one side corona treated or one side chemical treated.

4. The pouch as claimed in claim I , 2 or 3, wherein thickness o f matt polyester film is in the range of 6 to 20 microns, more preferably in the range o f 10 to 1 5 microns.

5. The pouch as claimed in claim 1 or 2, wherein polyolefin film is linear low density poly ethylene (LLDPE) or low density poly ethylene (LDPE) or combination thereof.

6. The pouch as claimed in claim 1 , 2 or 5, wherein thickness of polyolefin film is in the range of 15 to 80 microns, more preferably in the range of 40 to 65 microns.

7. The pouch as claimed in claim 1 , wherein one or more layers of polymeric material are adhered by adhesive material (7a) and / Or, extrusion process (7b).

8. The pouch as claimed in claim 1 or 7, wherein adhesive material (7a) is solvent free. And the extrusion process (7b) is of polyethylene or, polyoleifin.

9. The pouch as claimed in claim 1 , 7 or 8, wherein adhesive material is selected such as main component is hydroxyl terminated group (-OH- group) and cross-linker is iso-nitrile terminated group (NCO- group).

10. The pouch as claimed in claim 9, wherein adhesive material main component and crosslinker is in the ratio of 10: 1 to 10: 8

1 1. The pouch as claimed in claim 1 , wherein combination o f UV A Block 25 additives are used along with UV A Block 75 and equivalent UV stabilizer.

12. The pouch as claimed in claim 1 or 1 1 , wherein UV Block 25 additives are in the range o f 20 % to 80%.

13. A process for preparing the laminate as claimed in claim 1 comprises the steps of:

(i) extruding first base film of matt polyester either both side untreated or one side corona treated or one side chemical treated having thickness in the range of of 1 5 μ to 80 μ, more preferably in the range of 40 μ to 65μ, essentially having anti slip additives and UVA25 & UVA75.

(iii) curing the base film thus obtained in step (ii) at temperature in the range of 80°C to 150°C for a time period of 30 to 60 seconds

(iv) applying adhesive on the surface of the base film as produced in step (hi);

(vi) curing film as obtained in step (v) for at least 8 to 10 days in order to produce a laminate.

14. A process for manufacturing pouch made of a laminate as claimed in 1 comprising the steps of;

(i) extruding first base film of matt polyester either both side untreated or one side corona treated- or one side chemical treated having thickness in the range of 6 μ to 20 μ, more preferably in the range of 40 μ to 65μ, essentially having anti slip additives and UVA25 & UVA75.

(iii ) curing the base film thus obtained in step (ii) at temperature in the range of 80°C to 1 50°C for a time period of 30 to 60 seconds;

(vii ) slitting of laminate as obtained in step (vi );

(viii ) sealing edges of the laminate as produced in step (vii);

(ix) Packaging of water, nutrient fortified water, or similar drinks, beverages etc.

15. The pouch as claimed in claim 1 , having WVTR in the range of 20 to 35 gm/m /day & OTR in the range of 65 to 95 cc/ nr/day.

16. The pouch as claimed in claim 1 , having inertness to UV exposure in the range of 10 to 100 MJ/m².