EP2969539A1 - Mehrschichtiger wärmeschrumpfbarer polymerfilm mit gas- und wasserdampfbarrierewirkung - Google Patents
Mehrschichtiger wärmeschrumpfbarer polymerfilm mit gas- und wasserdampfbarrierewirkungInfo
- Publication number
- EP2969539A1 EP2969539A1 EP13722116.4A EP13722116A EP2969539A1 EP 2969539 A1 EP2969539 A1 EP 2969539A1 EP 13722116 A EP13722116 A EP 13722116A EP 2969539 A1 EP2969539 A1 EP 2969539A1
- Authority
- EP
- European Patent Office
- Prior art keywords
- ethylene
- adhesive polymer
- layer
- evoh
- polyamide
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Withdrawn
Links
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
- B32B7/00—Layered products characterised by the relation between layers; Layered products characterised by the relative orientation of features between layers, or by the relative values of a measurable parameter between layers, i.e. products comprising layers having different physical, chemical or physicochemical properties; Layered products characterised by the interconnection of layers
- B32B7/04—Interconnection of layers
- B32B7/12—Interconnection of layers using interposed adhesives or interposed materials with bonding properties
-
- 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
- B32B27/18—Layered products comprising a layer of synthetic resin characterised by the use of special additives
-
- 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
-
- 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
- B32B27/34—Layered products comprising a layer of synthetic resin comprising polyamides
-
- 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
- B32B2307/514—Oriented
- B32B2307/518—Oriented bi-axially
-
- 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
- B32B2307/724—Permeability to gases, adsorption
- B32B2307/7242—Non-permeable
- B32B2307/7246—Water vapor 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
- B32B2439/40—Closed containers
- B32B2439/46—Bags
-
- 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
Definitions
- the present invention concerns a heat-shrinking, multilayer polymeric film - wherein the individual layers are co-extruded from a single annular extrusion head, having multiple input ports, and then simultaneously biaxi- ally stretched - which shows an improved barrier effect to gases and water- vapour and a reduced elastic module, is stable to delamination, has an increased low-temperature heat-shrinking and, finally, shows the opportunity to use a wider selection of PA and EVOH polymers to manufacture it.
- the invention relates to a film of this type used for the manufacturing of bags or films for the packaging of perishable foods, which hence require to be highly gas-proof - in particular to 0 2 - and water-vapour-proof.
- Such films are manufactured in the form of planar films, to be used on machines of the flow pack type or the like, or of tubular films to be transformed into bags, or of small-diameter tubular films for the transformation into bags which are heat-sealable or closable through clips at the ends thereof.
- FIG. 1 A possible diagram of a plant for the manufacturing of multilayer film is shown, for illustration purposes only, in the attached fig. 1.
- the main steps of the process are schematically shown, namely:
- step 1 extrusion of the multilayer film
- step 2 forming of a first bubble of multilayer film
- step 3 forming of a second bubble of multilayer film and bidimen- sional stretching of the same;
- step 4 thermal stabilisation of the multilayer film
- step 5 winding onto the reel of the finished film.
- extrusion step 1 a plurality of screw extruders (A-I) is provided, one for each of the different plastic materials which make up the individual layers of the multilayer film.
- Each one of the outlets of such extruders is connected to a respective one of a plurality of annular and concentric extrusion channels, formed in an extrusion head to which the molten materials are supplied.
- step 2 immediately downstream of the extrusion head a first cylindrical bubble of multilayer film is formed, which is simultaneously cooled by cold water nebulization.
- the film thus formed is gathered in a planar shape, i.e. folded on itself, between a pair of rollers arranged in the lower area of the plant and then brought back through the upper area of the plant.
- Step 3 for bidirectional stretching, occurs by forming a second bubble of multilayer film which goes through a primary infrared oven where it is heated up to the stretching temperature.
- the desired bidimensional stretching action is imparted to the film through a suitable adjustment, on the one hand, of the speed difference between the pairs of supply rollers (primary speed) and the gathering ones (stretch drawing speed), upstream and downstream, respectively, of the second bubble of multilayer film and, on the other hand, of the diameter difference between the first bubble and the second bubble.
- a third bubble of multilayer film is formed which goes through a stabilisation oven where the film is heated up to a temperature sufficient to obtain the stabilisation of the residual tensions found in the same.
- step 5 the finished multilayer film is gathered onto reels, son after any cutting and trimming operations.
- Heat-shrinking films made of polymer plastic materials with barrier effect to gases and water-vapour have been known for a long time, as well as the use of such films for the packaging of perishable foods.
- PVDC polyvinylidene chloride
- EVA ethylene vinyl acetate
- LLDPE linear low-density polyethylene
- ionomeric resins or mixtures of the above-said polymers.
- polyvinylidene chloride is manufactured as multilayer film comprising - in addition to the intermediate PVDC layer - a layer on the side of the multilayer film intended to build the wrapper inside (referred to as “inner layer” in the following for simplicity's sake) having features of sealability and a layer on the side of the multilayer film intended to build the outside of the wrapper (referred to as “outer layer” in the following for simplicity's sake) acting as mechanical protection of the PVDC from abrasions and mechanical breaks.
- the composite multilayer structure described above is also reticulated, usually through exposure of the film to a high-energy electron flow.
- the known PVDC-based multilayer film has high values of gas and water-vapour barrier in addition to good heat shrinking; however, it is not devoid of drawbacks and in particular it has limits both during manufacturing and during application, as it is highlighted in the following.
- barrier-effect films for the packaging of food products, are hence lately taking ever growing shares of applications and of the market some other non-chlorinated polymers, alternative to PVDC and having good gas-barrier features, such as ethylene-vinyl alcohol (EVOH) copolymers, said copolymers being the ones most used for this purpose, and some types of polyamides (PA) which, in addition to the well-known mechanical strength qualities, also have low values of gas transmission in the absence of water-vapour.
- EVOH ethylene-vinyl alcohol
- PA polyamides
- barrier polymers alternative to PVDC are sensitive to the action of water-vapour, which causes a reduction of the gas-barrier features thereof.
- the barrier-effect polymers replacing PVDC must be protected from moisture penetration into the film by introducing in the film structure one or more water- vapour-proof layers, consisting for example of polyole- fins (polyethylene or polypropylene), which protect from the contact with water-vapour the layer/s having oxygen barrier features.
- water- vapour-proof layers consisting for example of polyole- fins (polyethylene or polypropylene), which protect from the contact with water-vapour the layer/s having oxygen barrier features.
- EP 1513683 discloses a multilayer film comprising six or seven layers wherein the layers responsible for the gas-barrier effect consist of two or three layers, PA/EVOH or PA/EVOH/PA, respectively, with which they are associated, towards the inner side of the multilayer film, a water- vapour-barrier layer consisting of polyolefins, preferably polyethylene (PE), by interposition of a first intermediate bonding layer and a final PA layer, in this case too with the arrangement in between of an intermediate bonding layer.
- PE polyethylene
- EP 2351644 discloses a multilayer film comprising nine layers, the central gas-barrier pack of which consists of three PA/EVOH/PA lay- ers wherein the PA layers can be made of PA 6, or 66, 6.66, 11, 12 or alternatively they can be made of a mixture of each one of these types of PA with EVOH, or with polyvinyl alcohol (PVAL) or with MXD6.
- This central pack is flanked on both sides by water-vapour-barrier layers consisting of poly- olefins, preferably polyethylene (PE), by interposition of intermediate bonding layers.
- PE polyethylene
- a final layer of polyethylene terephthalate (PET) is arranged on the outer side of the film, in this case too by interposition of an intermediate bonding layer, for the purpose of imparting the multilayer film mechanical strength as well as brightness and transparency features.
- PET polyethylene terephthalate
- Materials alternative to PET for the outer layer of the multilayer film are disclosed in EP-2351645 (Kuhne).
- the direct PA/EVOH coupling is made possible due to the natural adhesion shown by these two materials, at least partly compatible with each other, and in general it is sufficient for the various applications even after the simultaneous stretching in both directions. According to the prior art, such direct coupling is desirable in order to avoid resorting to the use of intermediate bonding layers consisting of adhesive polymers.
- the present invention has faced the problem of supplying a gas-barrier and water-vapour-barrier multilayer film which have improved physical and mechanical features with respect to known films, in particular as concerns the central layer pack of the film responsible for the barrier effect, which pack - as seen above - consists of two or three layers, PA/EVOH or PA/EVOH/PA, respectively, directly coupled with each other without the arrangement of intermediate bonding layers.
- a further problem faced by the present invention is then that of allowing a widening of the range of PA and EVOH polymers which can be used for making the multilayer film, comprising therein also the ones which, due to the different attitude to stretching thereof, have not been used as yet.
- fig. 1 shows schematically a plant for the production of a multilayer film according to the present invention
- fig. 2A is an enlarged-scale section view of a three-layer film according to the present invention wherein the stresses between adjacent layers during the stretching step are schematically shown;
- fig. 2B is a view similar to fig. 2A of a 5-layer film according to the present invention.
- Tg vitreous transition temperature
- this phenomenon is schematically shown in a strongly enlarged scale, in fig. 2A for a 3-layer film : PA (A), intermediate bonding layer (B), EVOH (C), and in fig. 2B the similar phenomenon is shown for a 5-layer film : PA (A), intermediate bonding layer (B), EVOH (C), intermediate bonding layer (D), PA (E), wherein the greatest stretching stress Fl or F3 in the PA layers with respect to the stretching stress F2 in the EVOH layer, is gradually absorbed in compensating layers B and D, as shown in the details enclosed in a circle in a further enlarged scale, hence without de- termining the above-described drawbacks in the multilayer film.
- the compensating adhesive polymers which make up the intermediate bonding layers are based on polyolefins polymers added with adhesive components and notoriously polyolefins build a layer resistant to water- vapour; - more persistent barrier effect to oxygen, due to the fact that, as a result of the water-vapour protection offered by the intermediate bonding layers, EVOH preserves its features of oxygen-barrier over time;
- the compensating adhesive polymers building the intermediate layers may be oriented at low temperatures and have a higher stretching or blow-up ratio (BUR) than that of any other polymer generally used in barrier structures.
- BUR blow-up ratio
- the multilayer film of the present invention has unchanged gloss and haze features compared to prior art films, regardless of the thicknesses used for the intermediate layers.
- the adhesion of the different layers making up the multilayer film of the present invention has been assessed following an internal method which comprises two steps.
- film samples measuring 10 x 10 cm are dipped for 60 seconds in a bath containing a suitable diathermic oil, the temperature of which is changed in subsequent 10°C steps between +80°C and +110°C.
- the samples must be at least 4, taken in different areas along the circumference of the tubular film.
- a quality judgement is expressed on layer separability: the layers separate or not, intermediate conditions being also possible wherein layer separation occurs only following the application of a mechanical stress which can be assessed from a quality point of view or through a dynamometer, with respect to a reference sample.
- the second step of the test provides the assessment of the residual adhesion force between the layers according to the standard method ASTM D1876.
- This second step of the test provides cutting 2 test pieces 10 mm wide from the previously dipped samples, on which samples a beginning of layer separation is evident.
- One test piece must be taken longitudinally (machine direction) and the other in a crosswise direction. To the effects of film use, and hence of the assessment according to this test, it is unimportant between which layers said separation occurs.
- the separated edges of the test piece are arranged between the clamps of a dynamometer provided with loading cell with scale bottom ⁇ 500 g. Clamp distance: 20 mm. Crossbar speed : 50 cm/min. The average force developed is measured and the ratio thereof in respect of the width of the test piece is reported value in g/cm.
- Example 2 Polyolefin
- Table 3 The types and trade names of the raw materials used to manufacture the multilayer film according to Example 1 are reported below in Table 2, compared against those of the similar structure of comparison Example 3, while the type of plant used and the work conditions of the extrusion process are reported in Table 3.
- Table 4 The characteristic properties of the multilayer films obtained according to this Example are finally reported in Table 4.
- the thickness percentage of the adhesive polymer layers arranged in between the PA and EVOH layers according to the present invention is preferably comprised between 10% and 40%. From the description and from the Examples reported above it appears clearly how the multilayer film of the present invention has fully reached the set objects: as a matter of fact, such multilayer film shows substantial improvements of its mechanical and physical properties, in particular as regards stability to layer separation, reduction of the elastic module, reduction of the transmission of water-vapour and of oxygen and increase of the shrinking at lower temperature.
Landscapes
- Laminated Bodies (AREA)
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
PCT/IT2013/000074 WO2014141308A1 (en) | 2013-03-13 | 2013-03-13 | Heat-shrinking multi-layer polymeric film with barrier effect to gases and water-vapour |
Publications (1)
Publication Number | Publication Date |
---|---|
EP2969539A1 true EP2969539A1 (de) | 2016-01-20 |
Family
ID=48428571
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
EP13722116.4A Withdrawn EP2969539A1 (de) | 2013-03-13 | 2013-03-13 | Mehrschichtiger wärmeschrumpfbarer polymerfilm mit gas- und wasserdampfbarrierewirkung |
Country Status (3)
Country | Link |
---|---|
EP (1) | EP2969539A1 (de) |
RU (1) | RU2015143118A (de) |
WO (1) | WO2014141308A1 (de) |
Family Cites Families (8)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US6531198B2 (en) * | 1993-06-24 | 2003-03-11 | Pechiney Emballage Flexible Europe | Heat shrinkable barrier bags with anti block additives |
US6503549B1 (en) * | 1998-09-30 | 2003-01-07 | Cryovac, Inc. | Polyester tray package with lidding film having glycol-modified copolyester sealant layer |
ATE326506T1 (de) * | 1999-02-18 | 2006-06-15 | Cryovac Inc | Mehrlagiger, orientierter, hitzeschrumpfbarer thermoplastischer film |
DE10227580A1 (de) | 2002-06-20 | 2004-01-08 | Kuhne Anlagenbau Gmbh | Mehrschichtige flächen- oder schlauchförmige Nahrungsmittelhülle oder -folie |
US7125929B2 (en) * | 2004-05-11 | 2006-10-24 | Equistar Chemicals, Lp | Adhesive composition having improved clarity for coextruded barrier films |
US20070172614A1 (en) | 2005-12-30 | 2007-07-26 | I-Hwa Lee | Heat shrinkable multilayer film and tube with improved adhesion after orientation |
DE202006020148U1 (de) | 2006-08-07 | 2007-12-06 | Kuhne Anlagenbau Gmbh | Mehrschichtige flächen- oder schlauchförmige Nahrungsmittelhülle oder -folie |
US20090035594A1 (en) | 2007-08-01 | 2009-02-05 | Lee Chun D | Rheology-modified grafts and adhesive blends |
-
2013
- 2013-03-13 RU RU2015143118A patent/RU2015143118A/ru not_active Application Discontinuation
- 2013-03-13 WO PCT/IT2013/000074 patent/WO2014141308A1/en active Application Filing
- 2013-03-13 EP EP13722116.4A patent/EP2969539A1/de not_active Withdrawn
Non-Patent Citations (2)
Title |
---|
None * |
See also references of WO2014141308A1 * |
Also Published As
Publication number | Publication date |
---|---|
RU2015143118A (ru) | 2017-04-19 |
WO2014141308A1 (en) | 2014-09-18 |
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