NZ626181B - Heat shrinkable film - Google Patents
Heat shrinkable filmInfo
- Publication number
- NZ626181B NZ626181B NZ626181A NZ62618114A NZ626181B NZ 626181 B NZ626181 B NZ 626181B NZ 626181 A NZ626181 A NZ 626181A NZ 62618114 A NZ62618114 A NZ 62618114A NZ 626181 B NZ626181 B NZ 626181B
- Authority
- NZ
- New Zealand
- Prior art keywords
- film
- layer
- ethylene
- inner layer
- ionomer
- Prior art date
Links
- 229920001577 copolymer Polymers 0.000 claims abstract description 24
- 239000000463 material Substances 0.000 claims abstract description 22
- 239000005977 Ethylene Substances 0.000 claims abstract description 17
- VGGSQFUCUMXWEO-UHFFFAOYSA-N ethene Chemical compound C=C VGGSQFUCUMXWEO-UHFFFAOYSA-N 0.000 claims abstract description 17
- 239000004711 α-olefin Substances 0.000 claims abstract description 15
- 229920000554 ionomer Polymers 0.000 claims abstract description 14
- 239000002253 acid Substances 0.000 claims abstract description 12
- 229920001200 poly(ethylene-vinyl acetate) Polymers 0.000 claims abstract description 12
- 229920000089 Cyclic olefin copolymer Polymers 0.000 claims abstract description 11
- 238000007654 immersion Methods 0.000 claims abstract description 11
- 239000001301 oxygen Substances 0.000 claims abstract description 11
- MYMOFIZGZYHOMD-UHFFFAOYSA-N oxygen Chemical compound O=O MYMOFIZGZYHOMD-UHFFFAOYSA-N 0.000 claims abstract description 11
- 229910052760 oxygen Inorganic materials 0.000 claims abstract description 11
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims abstract description 8
- 229910052751 metal Inorganic materials 0.000 claims abstract description 5
- 239000002184 metal Substances 0.000 claims abstract description 5
- 239000000203 mixture Substances 0.000 claims description 8
- 150000002500 ions Chemical class 0.000 claims description 6
- 229920001328 Polyvinylidene chloride Polymers 0.000 claims description 5
- 239000005033 polyvinylidene chloride Substances 0.000 claims description 5
- 229920000219 Ethylene vinyl alcohol Polymers 0.000 claims description 4
- 239000004715 ethylene vinyl alcohol Substances 0.000 claims description 4
- FKNQFGJONOIPTF-UHFFFAOYSA-N sodium cation Chemical compound [Na+] FKNQFGJONOIPTF-UHFFFAOYSA-N 0.000 claims description 2
- 230000005591 charge neutralization Effects 0.000 claims 1
- 230000001264 neutralization Effects 0.000 claims 1
- 238000006386 neutralization reaction Methods 0.000 claims 1
- 229920000642 polymer Polymers 0.000 description 9
- 238000007789 sealing Methods 0.000 description 8
- 235000013305 food Nutrition 0.000 description 7
- 238000000034 method Methods 0.000 description 7
- 239000005038 ethylene vinyl acetate Substances 0.000 description 6
- 238000005259 measurement Methods 0.000 description 6
- 239000000654 additive Substances 0.000 description 5
- 238000004806 packaging method and process Methods 0.000 description 5
- 229920001519 homopolymer Polymers 0.000 description 4
- PPBRXRYQALVLMV-UHFFFAOYSA-N styrene Chemical compound C=CC1=CC=CC=C1 PPBRXRYQALVLMV-UHFFFAOYSA-N 0.000 description 4
- OSGAYBCDTDRGGQ-UHFFFAOYSA-L Calcium sulfate Chemical compound [Ca+2].[O-]S([O-])(=O)=O OSGAYBCDTDRGGQ-UHFFFAOYSA-L 0.000 description 3
- 239000004698 Polyethylene (PE) Substances 0.000 description 3
- 229910052925 anhydrite Inorganic materials 0.000 description 3
- 239000003795 chemical substances by application Substances 0.000 description 3
- 239000004707 linear low-density polyethylene Substances 0.000 description 3
- 235000013372 meat Nutrition 0.000 description 3
- 239000000178 monomer Substances 0.000 description 3
- -1 polyethylene Polymers 0.000 description 3
- 229920000573 polyethylene Polymers 0.000 description 3
- 229920003313 Bynel® Polymers 0.000 description 2
- 239000004952 Polyamide Substances 0.000 description 2
- 229920001748 Polybutylene Polymers 0.000 description 2
- NIXOWILDQLNWCW-UHFFFAOYSA-N acrylic acid Chemical compound OC(=O)C=C NIXOWILDQLNWCW-UHFFFAOYSA-N 0.000 description 2
- 239000005043 ethylene-methyl acrylate Substances 0.000 description 2
- 229920000092 linear low density polyethylene Polymers 0.000 description 2
- 229920001684 low density polyethylene Polymers 0.000 description 2
- 239000004702 low-density polyethylene Substances 0.000 description 2
- CERQOIWHTDAKMF-UHFFFAOYSA-N methacrylic acid Chemical compound CC(=C)C(O)=O CERQOIWHTDAKMF-UHFFFAOYSA-N 0.000 description 2
- 229920002647 polyamide Polymers 0.000 description 2
- 239000011528 polyamide (building material) Substances 0.000 description 2
- 229920000098 polyolefin Polymers 0.000 description 2
- 229920005989 resin Polymers 0.000 description 2
- 239000011347 resin Substances 0.000 description 2
- 229920001862 ultra low molecular weight polyethylene Polymers 0.000 description 2
- LGXVIGDEPROXKC-UHFFFAOYSA-N 1,1-Dichloroethene Chemical compound ClC(Cl)=C LGXVIGDEPROXKC-UHFFFAOYSA-N 0.000 description 1
- LIKMAJRDDDTEIG-UHFFFAOYSA-N 1-Hexene Chemical compound CCCCC=C LIKMAJRDDDTEIG-UHFFFAOYSA-N 0.000 description 1
- KWKAKUADMBZCLK-UHFFFAOYSA-N 1-Octene Chemical compound CCCCCCC=C KWKAKUADMBZCLK-UHFFFAOYSA-N 0.000 description 1
- VXNZUUAINFGPBY-UHFFFAOYSA-N 1-butene Chemical compound CCC=C VXNZUUAINFGPBY-UHFFFAOYSA-N 0.000 description 1
- JTXMVXSTHSMVQF-UHFFFAOYSA-N 2-acetyloxyethyl acetate Chemical compound CC(=O)OCCOC(C)=O JTXMVXSTHSMVQF-UHFFFAOYSA-N 0.000 description 1
- KUDUQBURMYMBIJ-UHFFFAOYSA-N 2-prop-2-enoyloxyethyl prop-2-enoate Chemical compound C=CC(=O)OCCOC(=O)C=C KUDUQBURMYMBIJ-UHFFFAOYSA-N 0.000 description 1
- MTJGVAJYTOXFJH-UHFFFAOYSA-N 3-aminonaphthalene-1,5-disulfonic acid Chemical compound C1=CC=C(S(O)(=O)=O)C2=CC(N)=CC(S(O)(=O)=O)=C21 MTJGVAJYTOXFJH-UHFFFAOYSA-N 0.000 description 1
- 101710034857 ATIC Proteins 0.000 description 1
- 229920002126 Acrylic acid copolymer Polymers 0.000 description 1
- MTAZNLWOLGHBHU-UHFFFAOYSA-N Butadiene-styrene rubber Chemical compound C=CC=C.C=CC1=CC=CC=C1 MTAZNLWOLGHBHU-UHFFFAOYSA-N 0.000 description 1
- 239000004594 Masterbatch (MB) Substances 0.000 description 1
- 239000006057 Non-nutritive feed additive Substances 0.000 description 1
- 229920000034 Plastomer Polymers 0.000 description 1
- 239000004793 Polystyrene Substances 0.000 description 1
- 241000216735 Satsuma dwarf virus Species 0.000 description 1
- 239000002174 Styrene-butadiene Substances 0.000 description 1
- 239000004708 Very-low-density polyethylene Substances 0.000 description 1
- 229920001567 Vinyl ester Polymers 0.000 description 1
- 125000005250 alkyl acrylate group Chemical group 0.000 description 1
- 230000001143 conditioned Effects 0.000 description 1
- 238000010276 construction Methods 0.000 description 1
- VOLSCWDWGMWXGO-UHFFFAOYSA-N cyclobuten-1-yl acetate Chemical compound CC(=O)OC1=CCC1 VOLSCWDWGMWXGO-UHFFFAOYSA-N 0.000 description 1
- 230000001627 detrimental Effects 0.000 description 1
- 229920001971 elastomer Polymers 0.000 description 1
- 239000000806 elastomer Substances 0.000 description 1
- XSMJZKTTXZAXHD-UHFFFAOYSA-N ethene;2-methylprop-2-enoic acid Chemical compound C=C.CC(=C)C(O)=O XSMJZKTTXZAXHD-UHFFFAOYSA-N 0.000 description 1
- QHZOMAXECYYXGP-UHFFFAOYSA-N ethene;prop-2-enoic acid Chemical compound C=C.OC(=O)C=C QHZOMAXECYYXGP-UHFFFAOYSA-N 0.000 description 1
- BXOUVIIITJXIKB-UHFFFAOYSA-N ethene;styrene Chemical compound C=C.C=CC1=CC=CC=C1 BXOUVIIITJXIKB-UHFFFAOYSA-N 0.000 description 1
- 230000005251 gamma ray Effects 0.000 description 1
- 239000007789 gas Substances 0.000 description 1
- 239000004700 high-density polyethylene Substances 0.000 description 1
- 239000007788 liquid Substances 0.000 description 1
- WHXSMMKQMYFTQS-UHFFFAOYSA-N lithium Chemical compound [Li] WHXSMMKQMYFTQS-UHFFFAOYSA-N 0.000 description 1
- 229910052744 lithium Inorganic materials 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 239000004701 medium-density polyethylene Substances 0.000 description 1
- 150000002734 metacrylic acid derivatives Chemical class 0.000 description 1
- 150000002739 metals Chemical class 0.000 description 1
- CERQOIWHTDAKMF-UHFFFAOYSA-M methacrylate Chemical compound CC(=C)C([O-])=O CERQOIWHTDAKMF-UHFFFAOYSA-M 0.000 description 1
- 230000003287 optical Effects 0.000 description 1
- 229920000728 polyester Polymers 0.000 description 1
- 238000010094 polymer processing Methods 0.000 description 1
- 238000006116 polymerization reaction Methods 0.000 description 1
- 229920002223 polystyrene Polymers 0.000 description 1
- QQONPFPTGQHPMA-UHFFFAOYSA-N propene Chemical compound CC=C QQONPFPTGQHPMA-UHFFFAOYSA-N 0.000 description 1
- 229920005653 propylene-ethylene copolymer Polymers 0.000 description 1
- KEAYESYHFKHZAL-UHFFFAOYSA-N sodium Chemical compound [Na] KEAYESYHFKHZAL-UHFFFAOYSA-N 0.000 description 1
- 229910052708 sodium Inorganic materials 0.000 description 1
- 239000011734 sodium Substances 0.000 description 1
- 239000011115 styrene butadiene Substances 0.000 description 1
- 229920003048 styrene butadiene rubber Polymers 0.000 description 1
- 229920001935 styrene-ethylene-butadiene-styrene Polymers 0.000 description 1
- 229920001169 thermoplastic Polymers 0.000 description 1
- 239000004416 thermosoftening plastic Substances 0.000 description 1
- 231100000756 time-weighted average Toxicity 0.000 description 1
- 238000004642 transportation engineering Methods 0.000 description 1
- 229920001866 very low density polyethylene Polymers 0.000 description 1
- XTXRWKRVRITETP-UHFFFAOYSA-N vinyl acetate Chemical compound CC(=O)OC=C XTXRWKRVRITETP-UHFFFAOYSA-N 0.000 description 1
- BZHJMEDXRYGGRV-UHFFFAOYSA-N vinyl chloride Chemical compound ClC=C BZHJMEDXRYGGRV-UHFFFAOYSA-N 0.000 description 1
- HCHKCACWOHOZIP-UHFFFAOYSA-N zinc Chemical compound [Zn] HCHKCACWOHOZIP-UHFFFAOYSA-N 0.000 description 1
- 229910052725 zinc Inorganic materials 0.000 description 1
- 239000011701 zinc Substances 0.000 description 1
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B32—LAYERED PRODUCTS
- B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
- B32B2270/00—Resin or rubber layer containing a blend of at least two different polymers
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B32—LAYERED PRODUCTS
- B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
- B32B2307/00—Properties of the layers or laminate
- B32B2307/50—Properties of the layers or laminate having particular mechanical properties
- B32B2307/58—Cuttability
- B32B2307/581—Resistant to cut
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B32—LAYERED PRODUCTS
- B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
- B32B2307/00—Properties of the layers or laminate
- B32B2307/70—Other properties
- B32B2307/724—Permeability to gases, adsorption
- B32B2307/7242—Non-permeable
- B32B2307/7244—Oxygen barrier
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B32—LAYERED PRODUCTS
- B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
- B32B2307/00—Properties of the layers or laminate
- B32B2307/70—Other properties
- B32B2307/732—Dimensional properties
- B32B2307/734—Dimensional stability
- B32B2307/736—Shrinkable
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B32—LAYERED PRODUCTS
- B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
- B32B2439/00—Containers; Receptacles
- B32B2439/70—Food packaging
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B32—LAYERED PRODUCTS
- B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
- B32B27/00—Layered products comprising a layer of synthetic resin
- B32B27/06—Layered products comprising a layer of synthetic resin as the main or only constituent of a layer, which is next to another layer of the same or of a different material
- B32B27/08—Layered products comprising a layer of synthetic resin as the main or only constituent of a layer, which is next to another layer of the same or of a different material of synthetic resin
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B32—LAYERED PRODUCTS
- B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
- B32B27/00—Layered products comprising a layer of synthetic resin
- B32B27/28—Layered products comprising a layer of synthetic resin comprising synthetic resins not wholly covered by any one of the sub-groups B32B27/30 - B32B27/42
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B32—LAYERED PRODUCTS
- B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
- B32B27/00—Layered products comprising a layer of synthetic resin
- B32B27/30—Layered products comprising a layer of synthetic resin comprising vinyl (co)polymers; comprising acrylic (co)polymers
- B32B27/304—Layered products comprising a layer of synthetic resin comprising vinyl (co)polymers; comprising acrylic (co)polymers comprising vinyl halide (co)polymers, e.g. PVC, PVDC, PVF, PVDF
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B32—LAYERED PRODUCTS
- B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
- B32B27/00—Layered products comprising a layer of synthetic resin
- B32B27/30—Layered products comprising a layer of synthetic resin comprising vinyl (co)polymers; comprising acrylic (co)polymers
- B32B27/306—Layered products comprising a layer of synthetic resin comprising vinyl (co)polymers; comprising acrylic (co)polymers comprising vinyl acetate or vinyl alcohol (co)polymers
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B32—LAYERED PRODUCTS
- B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
- B32B27/00—Layered products comprising a layer of synthetic resin
- B32B27/32—Layered products comprising a layer of synthetic resin comprising polyolefins
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
- C08J2331/00—Characterised by the use of copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and at least one being terminated by an acyloxy radical of a saturated carboxylic acid, or carbonic acid, or of a haloformic acid
- C08J2331/02—Characterised by the use of omopolymers or copolymers of esters of monocarboxylic acids
- C08J2331/04—Homopolymers or copolymers of vinyl acetate
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
- C08J5/00—Manufacture of articles or shaped materials containing macromolecular substances
- C08J5/18—Manufacture of films or sheets
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
- Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
- Y10T428/00—Stock material or miscellaneous articles
- Y10T428/31504—Composite [nonstructural laminate]
- Y10T428/31855—Of addition polymer from unsaturated monomers
- Y10T428/31909—Next to second addition polymer from unsaturated monomers
- Y10T428/31913—Monoolefin polymer
Abstract
Disclosed herein are heat shrinkable multilayer films whose puncture resistance is increased by at least 100% by immersion in hot water 90°C for 4 seconds in a way that the thickness of the film before and after immersion has a maximum difference of 3%, the film comprising: - an outer layer comprising an ionomer which is an ethylene-acid copolymer neutralised by a metal with acid content of at least 15% per weight; - an intermediate layer which comprises EVA: - an inner layer comprising an ethylene alpha olefin copolymer with density less than 0.905 g/cc; and - an oxygen barrier material layer. ing an ionomer which is an ethylene-acid copolymer neutralised by a metal with acid content of at least 15% per weight; - an intermediate layer which comprises EVA: - an inner layer comprising an ethylene alpha olefin copolymer with density less than 0.905 g/cc; and - an oxygen barrier material layer.
Description
HEAT SHRINKABLE FILM
The present invention refers to a multilayer heat shrinkable film characterized by a
combination of desirable properties, such as high shrinkage, good optical properties,
excellent sealability and puncture resistance. The invention further is directed to a
method of producing said film. The invention is further ed to the use of said film
or bags and pouches made therefrom for packaging goods as for example food
products.
Generally, the packaging of food items by means of a heat shrinkable bag comprises
the following steps
1. Putting the food item inside the bag and removing the air (vacuumising) With
the help of a vacuum .
2. Sealing of the open end of the bag.
3. g the vacuum pack in a heat shrinking media such as hot water under a
temperature that ensures the shrink of the pack (eg 90°C).
4. The pack is ready and is characterized by appealing appearance and long shelf
life because .Of-theabsenswtstygen-
These films need high shrink properties and good optics to ensure an excellent
appearance and ent ility so that there is no entrance of oxygen to the pack
as this would be detrimental for the shelf life of the food.
In some cases, Where the food is stored in frozen conditions for example, there is the
possibility to use a non gas r film. The other characteristics remain the same.
Packaging films with the above properties are well known in the art.
A problem that is often found in the art is that during the packaging process there is
too much abuse of the packed bags by the production and transportation process.
rr'r:JCL
“ ‘
10013093 1 9_2.docx
Therefore it is common to have punctured bags that result in lowering the s
yield and increasing the process scrap.
A further problem encountered in the art is the exudation of meat liquids in the
internal bag area. This makes the bag look messy and unattractive to the consumer.
A further problem is the need for high heat shrinkage of the bag at temperatures lower
than 90°C. Such temperatures (eg 80-85°C) are often used as 90°C are mes
considered too much for fresh meat packing.
nce to any prior art in the specification is not, and should not be taken as, an
acknowledgment, or any form of suggestion, that this prior art forms part of the
common general knowledge in New Zealand or any other iction or that this prior
art could reasonably be expected to be ascertained, understood and regarded as
relevant by a person skilled in the art.
As used herein, except where the context requires otherwise, the term "comprise" and
variations of the term, such as "comprising", "comprises" and "comprised", are not
intended to exclude other additives, components, integers or steps.
SUMMARY OF THE INVENTION
In one aspect of the ion there is provided a heat shrinkable film whose puncture
resistance is increased by at least 100% by immersion in hot water at 90°C for 4
seconds in a way that the thickness of the film before and after ion has a
maximum difference of 3%, the film comprising: an outer layer, an intermediate layer,
and an inner lay, where the outer layer surface of the film ses an outer layer
comprising an ionomer, with an acid content of at least 15 weight%, and the inner
layer comprises at least one ethylene alpha olefin copolymer with a density less than
0.905 g/cc; wherein the ionomer is an ethylene—acid copolymer neutralised by a metal;
wherein the film ses an oxygen barrier material layer; and wherein the
intermediate layer comprises EVA.
Thus ageously provides a heat shrinkable film with the following desirable
attributes:
1000659385
1. Heat shrinkage at 85°C is at least 40% in at least one of each of machine and
transverse directions where the shrinkage is measured ing to ASTM D
2732.
2. High puncture resistance which increases by immersing the material in hot
water bath by at least 100%.
3. Very good optics
Thus, in one or more embodiments the heat shrinkable film has one or more of the
attributes above.
Definitions:
In this application the following definitions are used:
The term “film” refers to a flat or r flexible structure of thermoplastic material.
The term “heat shrinkable” refers to a film that shrinks at least 10% in at least one of
the longitudinal and transverse directions (TD) when heated at 90°C for 4 s.
The shrinkability is measured according to ASTM D 2732.
The phrase “longitudinal direction” or “machine direction” herein abbreviated “MD”
refers to a direction along the length of the film.
The phrase “outer layer” refers to the film layer which comes in immediate contact
with the outside environment (atmosphere).
The phrase “inner layer” refers to the film layer that comes in direct contact with the
product . This is also called “sealing layer” as this layer must be hermetically
sealed in order to protect the product from ingress of air.
The phrase “intermediate layer” refers to any layer of the film that is neither outer nor
inner layer. A film may comprise more than one intermediate layers.
1000659385
As used , the term “homopolymer” refers to a polymer resulting from
rization of a single monomer.
As used herein, the term “copolymer” refers to a polymer resulting from
polymerization of at least two different rs.
As used herein, the term “polymer” includes both above types.
As used herein the term “polyethylene” identifies polymers consisting essentially of
the ethylene repeating unit. The ones that have a density more than 0.940 are called
high density polyethylene (HDPE), the ones that are have less than 0.940 are low
density polyethylene (LDPE).
As used herein the phrase “ethylene alpha olefin mer” refers to polymers like
linear low density polyethylene (LLDPE), medium density polyethylene (MDPE),
very low y polyethylene (VLDPE), ultra low density polyethylene (ULDPE),
metallocene catalysed polymers and polyethylene plastomers and elastomers.
In these cases the alpha olefin can be propene, butene, hexene, octene etc as known in
the art.
As used herein the term “homogeneous ethylene alpha olefin copolymers” refer to
ethylene alpha olefin mers having a molecular weight distribution less than 2.7
as measured by GPC. Typical examples of these polymers are AFFINITY from DOW
or Exact from Exxon.
As used herein the phrase “styrene polymers” refers to styrene homopolymer such as
polystyrene and to e copolymers such as styrene-butadiene mers, styrene—
butadiene-styrene copolymers, styrene-isoprene-styrene copolymers, styrene-
ethylene-butadiene-styrene copolymers, ethylene—styrene mers and the like.
As used herein the phrase ”ethylene methacrylate copolymers” refers to copolymers
of ethylene and methacrylate monomer. The monomer content is less than 40%
weight.
1000659385
As used herein the phrase “ethylene vinyl acetate mer” refers to copolymers of
ethylene and vinyl acetate.
As used herein, the term EVOH refers to saponified products of ethylene Vinyl ester
copolymers. The ethylene content is typically in the range of 25 to 50% per mol.
As used herein the term PVDC refers to a Vinylidene chloride copolymer wherein a
major amount of the copolymer comprises Vinylidene chloride and a minor amount of
the copolymer comprises one or more monomers such as vinyl chloride and/or alkyl
acrylates and methacrylates.
As used herein the term polyamide refers to homopolymers and mers.
As used herein the term “ionomer” refers to ne-acid copolymers which have
been neutralized by metals such as sodium, zinc, lithium or others.
The acid used is usually methacrylic or acrylic acid.
As used herein the term “polybutylene” refers to butene—l homopolymers and
copolymers. Useful copolymers comprise ethylene mer units. Ethylene content should
be generally less than 50% per weight.
All ement methods mentioned herein are readily ble for the skilled
person. For example, they can be obtained from the American National Standards
Institute at: www.webstore.ansi.org
All percentages used are per weight unless stated otherwise.
DETAILED DESCRIPTION OF THE INVENTION
According to a first aspect, the invention is directed to a heat shrinkable film whose
re resistance is sed by at least 100% by immersion in hot water 90°C for
1 385
4 seconds in a way that the thickness of the film before and after immersion has
maximum difference of 3 %.
In a preferred embodiment, the film according to the invention comprises an outer
layer, an intermediate layer and an inner layer, Where the outer layer surface of the
film comprises an ionomer with acid t of at least 10 weight% and the inner
layer comprises an ethylene alpha olefin copolymer with density less than 0.905 g/cc.
According to a preferred version of the invention, the ionomer resin ses at least
15 % of methacrylic or acrylic acid.
According to a further preferred version of the invention the r resin is at least
% neutralized, more preferably at least 50% neutralized. In a further preferred
version the ionomer is neutralized with sodium cation.
According to a further preferred version, the outer layer comprises at least 90%
ionomer per weight, more preferably at least 95%.
According to a further preferred version the outer layer comprises less than (and up to)
5 Wt% of polybutylene. Above 5 wt% the material becomes difficult to stretch.
According to a further preferred version the outer layer comprises slip and/or
antiblock agents. Preferably the slip and antiblock agents are ed as a
masterbatch where the host polymer is ionomer or ethylene acrylic acid copolymer or
ethylene methacrylic acid mer.
In the film ing to the present invention, the inner heat sealing layer may
comprise a single polyolefin or a blend of different polyolefins. In a preferred version
ofthe structure, the sealing layer comprises at least one homogeneous efin.
In a further preferred version the sealing layer comprises a homogeneous ne
alpha olefin copolymer with a density of less than 0.905 g/cc.
1000659385
In a further preferred version the sealing layer comprises a homogeneous alpha olefin
mer with a density of less than 0.900 g/cc.
In a further version the inner layer comprises a blend of two ethylene alpha olefin
copolymers with a density of less than 0.905 g/cc
In another version of the invention the inner layer comprises a blend of two
homogeneous ethylene alpha olefin copolymers which have both densities less than
0.900 g/cc.
In a further preferred version of the invention the inner layer does not se EVA.
The reason is that addition of EVA deteriorates the resistance of the heat seal of the
bag during the shrink s. In another version the tage of the EVA in the
inner layer blend is less than 50% per weight, preferably less than 40%
per weight.
In a preferred version of the invention, the multilayer film comprises an oxygen
barrier material, preferably PVDC, EVOH, polyamide or polyester.
Preferably the oxygen barrier material is located in an intermediate layer of the film.
In general PVDC is preferred as barrier material for the invention due to its
insensitiveness under high humidity conditions which are often encountered in meat
packing operations. EVOH can be used as well but is more sensitive to humidity
Between the sealing layer and the oxygen barrier layer, a tie layer could be used.
red als for this tie layer may be ethylene ester copolymers, such as
ethylene Vinyl acetate copolymers, ethylene methyl acrylate copolymers and other
materials well known in the art. A preferred version might include maleic ite
modified ethylene ester copolymers or maleic anhydrite d LLDPE.
cial trademarks are for example BYNEL® from Dupont and ADMER®
from Mitsui.
Between the outer and the barrier layer there may be another layer incorporating
a tie
layer. Preferred als for this tie layer may be ethylene ester copolymers, such
1000659385
ethylene vinyl acetate copolymers, ethylene methyl acrylate copolymers and other
als well known in the art. A preferred version might include maleic anhydrite
d ethylene ester copolymers or maleic anhydrite modified LLDPE.
cial arks are for example BYNEL® from Dupont and ADMER®
from Mitsui.
A further preferred option for the intermediate layers is a blend ofEVA and propylene
ethylene copolymer.
A preferred construction of the multilayer film is as follows
Outer layer — intermediate layer — barrier layer — intermediate layer — inner layer
Other preferred constructions are as s.
Outer layer — intermediate layer 1 — intermediate layer 2— barrier layer— intermediate
layer 3 — intermediate layer 4 — inner layer
Any of the layers described above may also include additives well known in the art
such as slip agents, antiblock, polymer processing aids, atic, antifog, acid
scavengers, odour scavengers and the like. A person skilled in the art may select the
right additives according to any particular needs.
The thickness of the film is preferably in the range 10 to 150 microns, more
preferably 20 to 120 microns. The thickness of the outer layer is preferably from 1 to
50 microns, more preferably 3 to 25 microns. The thickness of the inner layer is
preferably 5 to 100 microns, more preferably 10 to 60 microns.
In order the material to have a high shrinkability at 85°C, it is needed to be biaxially
oriented either by using the double bubble process or the tenter frame
process.
Both ses are well known in the art. The double bubble process is especially
preferred.
1000659385
In a further aspect of the invention the film or some layers of the film are irradiated. A
preferable method is e-beam or UV ion or gamma ray. Other methods are also
known in the art.
According to a further aspect, the present invention discloses a bag or pouch
comprising a film according to the present ion.
In a further aspect, the ion is directed to the use of the films or the bag or pouch
of the invention for packaging food. For example, the food item is put inside the bag
and the air is removed (vacuumising) with the help of a vacuum device. Subsequently,
the open end of the bag is sealed and the vacuum pack is placed in a heat shrinking
media such as hot water under a ature that ensures the shrink of the pack (eg
90°C). The pack than is ready and is characterized by appealing appearance and long
shelf life because of the absence of oxygen.
The present invention is now described by the following es:
EXAMPLES
A 5 layer film is produced in a double bubble (the double bubble method is described
in US 3,456,044) commercial line with the following recipe
Inner (sealing layer), 56% PH 40% P2+4% additives
Adjacent layer 70% E l +30%PP1
Barrier layer PVDC commercial grade
Adjacent layer 70% E2+30%PP1
Outer layer 95% 11+ 5% ADDITIVES
See table 1
1 000659385
The ess of the ure is 23/9/5/9/8 starting from the inner and going to the
outer layer.
TABLEl
~'fiWnB/Ianufacturer lfielt 4|Density MeltingpoT‘
Index g/cm3 C.
g/10 min
[H TWA jolimeriFCfi “E3 40.935 i93°c
E2 EVA PolimeriFDSO 0.4 0.938 ‘i
J88°C
PP1 PP copolymer Dow _l0.885
in —llonomer J
with DUPONT —l0.9 0.94 194°C
acid content
P1 AFFINITY Wow T71. 0.896 We
PF1140 |_
P2 TAFMER 4085 MITSUI I35 0.885 Less than 70°c_]
The inventive material is compared to an already existing product named TRF 55
which does not comprise ionomer in the outer layer.
Tests
1. Haze measurement. The haze measurement was done according to ASTM
D 1003.
2. Gloss measurement. This was done according to BS 2782.
3. age measurement done according to ASTM D 2732 at 85°C.
Puncture resistance test.
1000659385
re resistance is measured using a MECMESIN instrument
comprising a vertical stand VERSA TEST, a load cell AFG 100N, which
is mounted on the stand, and a digital height gauge MITUTOYO SDV
60B. A cylindrical shaft ending to a l indenter is attached to the
load cell. The er has an angle of 600 and a tip of 0.5mm in diameter.
The film is conditioned at 23°C and about 50%RH for at least 24 hours
prior to the measurement. Square samples of 8.5cmx8.5cm are prepared
and clamped on a 5cm diameter circular base. The indenter moves
perpendicular to the film and force is measured as the indenter comes into
contact with and ruptures the film. The speed of the indenter is set to
25mm/min. Maximum force needed to puncture the film is recorded. The
puncture force of a material is determined by ing the values
obtained for at least 5 samples of the material tested.
5. Puncture resistance test at restrained shrinkage sample.
In order to obtain an area of a film that has undergone restrained shrinkage, we use the
following procedure:
i) We take a 0 bag of the material under question.
ii) We measure the thickness of the material at an area about 80m below the
open end of
the bag.
iii) We put inside the bag a cylinder, which is 4cm high and has a diameter of 14 cm.
iv) We vacuum the package using a vacuum chamber and seal it about 2 cm from the
open end ofthe bag.
V) We place the package obtained in a shrink bath heated at a temperature of 90°C for 4
seconds.
Vi) After the shrinkage of the package, we open the bag, take the cylinder out and cut a
piece of the material at the same area where we had originally measured thickness.
The two ess measurements should be identical (so e ess difference
should be less than 3%), as the material has not been shrunk at this specific area,
since it has undergone restrained shrinkage.
TABLE 2
1000659385
GLOSS SHRINKAGE(M PUNCTURE RE
D/TD) RESISTANCE IN RESISTANCE IN
85C UNSHRUNK RESTRAINED
FILM SHRUNK FILM
Inventive 47/52
material
Therefore one can see that the inventive material is similar to TRF 55 in optics,
has much bigger shrinkability in 85°C conditions and presents an increase in
puncture at least 100% after ined shrinkage in pieces with same
thickness(difference of average esses before and after immersion in water is
less than 1%).
Thickness of the inventive film before immersion was 55.2 microns and after
immersion 55.5 microns whereas the thickness of TRF 55 before immersion was
56 microns while after immersion was 56.3 microns.
{ r"r‘ 31;":
I00 I 3093 l9_2.docx ;l”l._ "
THE
Claims (8)
- l. A heat shrinkable film whose puncture resistance is increased by at least 100% by ion in hot water at 90°C for 4 seconds in a way that the thickness of the film before and after immersion has a maximum difference of 3%, the film comprising: an outer layer, an intermediate layer, and 10 an inner layer, where the outer layer surface of the film comprises an ionomer with acid t of at least 15% per weight and the inner layer comprises an ethylene alpha olefin copolymer with density less than 0.905 g/cc; wherein the ionomer is an ethylene-acid copolymer neutralised by a metal; 15 wherein the film comprises an oxygen barrier material layer; and wherein the intermediate layer comprises EVA.
- 2. The film of claim 1, where the oxygen barrier material comprises PVDC. 20
- 3. The film of claim 1, where the oxygen barrier al comprises EVOH.
- 4. The film of any one of the preceding claims, where the ionomer is neutralized with a sodium cation. 25
- 5. The film of claim 4, where the neutralization ratio is at least 50%.
- 6. The film of any one of claims 1 to 5, where the inner layer comprises a blend of two ethylene alpha olefin copolymers with density less than 0.905 g/cc. 30
- 7. The film of any one of claims 1 to 5, where the inner layer comprises a blend oftwo ethylene alpha olefin copolymers with densities less than 0.900 g/cc.
- 8. The film of any one of claims 1 to 5, where the inner layer ses less than 50% per weight of EVA copolymer.
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
EP13172025.2 | 2013-06-14 | ||
EP13172025 | 2013-06-14 |
Publications (2)
Publication Number | Publication Date |
---|---|
NZ626181A NZ626181A (en) | 2016-01-29 |
NZ626181B true NZ626181B (en) | 2016-05-03 |
Family
ID=
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