Thermoplastic multi-layer packaging film and bags made therefrom.
Abstract
A THERMOPLASTIC MULTI-PACKAGING FILM IS DISCLOSED THAT INCLUDES AN EXTERNAL POLYMER LAYER, A CENTRAL LAYER THAT ACTS AS OXYGEN BARRIER AND AN INTERNAL THERMAL SEALING LAYER THE THERMAL SEALING LAYER INCLUDES AN ETHYLENE / ALPHA COPOLYMER © OLEFINA HAS 4 TO 8 CARBON ATOMS PER MOLECULA AND ITS CONTENT IN THE COPYLIMERO OSCILA OF XAY% BY WEIGHT WHERE XF 0.5 NC B 8 EYF 1.25 NC B15 , WHERE NC IS THE NUMBER OF CARBON ATOMS IN THE ALPHA © OLEFINA. THE COPOLIMERO OF THE THERMAL SEALING COAT HAS A DENSITY LESS THAN 920 KG / M3. THIS INVENTION APPLIES TO FILMS AND PACKAGING BAGS FOR COLD SEALING.
Term
Term ended
Expired 29 September 2006, 20 years ago.
- Priority
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11 claims: 1 independent, 10 dependent
- 1REIVINDICACIONES 1. Un míetodo para mejorar las propiedades de sellado en frío en receptíaculos obtenidos de película de embalaje termoplíastica de muíltiples capas, que se caracteriza porque tiene una capa de polímero exterior, opcionalmente una capa de barrera de oxígeno, y tiene una capa de sello tíermico interior que comprende un copolímero de etileno con x a y % en peso, basado en el copolímero, de una alfaolefina con 4 a 8 atomos de carbono por molecula, en donde x = 0,5 n C + 8,e y + 1,25 n C + 15 siendo n C el numero de aítomos de carbono en la alfa-olefina, teniendo dicho copolímero una densidad inferior a 920 kg/m 3 .
- 2Un míetodo, de conformidad con la reivindicacioín 1, caracterizado porque la capa de sellado por calor comprende un copolímero de etileno y 12 a 20% en peso, basado en el copolímero, de un alfa-olefina con 4 a 8 íatomos de carbono.
- 3Un míetodo, de conformidad con la reivindicaciíon 1, caracterizado porque la capa de sellado tíermico, comprende un copolímero de etileno y 10 a 20% en peso, basado en el copolímero, de buteno (1), teniendo dicho copolímero una densidad de menos de 915 kg/m 3 .
- 4Un míetodo de conformidad con la reivindicaciíon 1, caracterizado porque la capa de sellado tíermico comprende un copolímero de etileno y 12 a 25% en peso, basado en el copolímero, de octeno (1), teniendo dicho copolímero una densidad inferior a 920 kg/m 3 .
- 5Un míetodo, de conformidad con cualquiera de las reivindicaciones 1 a 5, caracterizado porque la capa de sellado tíermico comprende adicionalmente hasta el 50% en peso, basado en la composiciíon de la capa de un copolímero que es compatible con dicho copolímero de etileno/alfa-olefina y se elige del grupo que comprende polietileno lineal de baja densidad (LLDPE), polietileno lineal de alta densidad (LHDPE), polietileno de baja densidad (LDPE), etileno/acetato de vinilo (EVA), EVA modificado por aícido, polipropileno, copolímeros de etileno/propileno, ioníomeros y copolímeros de etileno/alquilacrilato con 1 a 8 íatomos de C en el radical alquílico respectivo.
- 6Un míetodo de conformidad con la reivindicaciíon 5, caracterizado porque dicho polímero compatible con dicho copolímero de etileno/alfa-olefina es un copolímero de etileno/etilacrilato y etilenbutilacrilato.
- 7Un míetodo seguín cualquiera de las reivindicaciones 1 a 6, caracterizado porque la capa de polímero externa es de un polímero elegido del grupo que comprende un copolímero de etileno y 10 a 25% en peso, basado en el copolímero, de una alfa-olefina con 4 a 8 íatomos de carbono, teniendo dicho copolímero una densidad inferior a 920 kg/m 3 , EVA, poliamida y resinas ionomíericas.
- 8Un míetodo, seguín cualquiera de las reivindicaciones 1 a 7, caracterizado porque la capa de barrera de oxígeno comprende un polímero elegido del grupo que comprende cloruro de polivinilideno (PVDC) y copolímeros de etileno/acetato de vinilo hidrolizados (EVOH).
- 9Un míetodo, seguín cualquiera de las reivindicaciones 1 a 8, caracterizado porque se interpone una capa de adhesivo y/o una capa promotora de adhesiíon entre dichas otras capas.
- 10Un míetodo, de conformidad con cualquiera de las reivindicaciones 1 a 9, caracterizado porque por lo menos la capa de sellado tíermico se ha reticulado por irradiaciíon.
- 11Un míetodo, de conformidad con la reivindicaciíon 10, caracterizado porque la capa de barrera de oxígeno comprende EVOH y porque se irradia la totalidad de la película multicapa.
Independent claims11
180 paragraphs in 5 sections, as filed
DESCRIPTION
The invention relates to thermoplastic multi-layer packaging films and bags or sacks of these obtained. In particular, this invention relates to films and bags that have thermal shrinkage and heat seal properties that provide good resistance to sealing even through contamination such as fat or blood, and which may allow the application of higher shrinkage temperatures due to their resistance to sealing at high temperatures.
Shrinkable and heat sealable thermoplastic films have been used in the packaging of non-food and food products such as meat, cheese, poultry and the like. Many attempts have been made to combine good shrinkage properties with satisfactory sealability and good seal resistance to ambient temperature and higher temperatures but there is still room for improvement.
A known laminated film of U.S. Patent No. 3,741,253 comprises a core layer and a vinylidene chloride copolymer between a layer and a crosslinked ethylene-vinyl acetate copolymer used as a sealant and an external layer of ethylene copolymer vinyl acetate that is not crosslinked. The ethylene-vinyl acetate copolymer has improved properties over the previously used polyethylene, especially when it has been crosslinked by irradiation.
As described in U.S. Patent No.<sup>°</sup> 4,064,296 the core layer may also comprise a copolymer of ethylene-hydrolyzed vinyl acetate. It has similar oxygen barrier properties such as vinylidene chloride copolymers and offers the advantage that it can radiate without discoloration.
Certain advantages have been obtained with the use of an ionomeric resin as a sealant layer. It results in superior sealing resistance at elevated temperatures thus allowing higher shrinkage temperatures. However, its resistance to sealing the cold is not entirely satisfactory. This last property is important in the processes of modern automatic bag packaging where the seals are subjected to substantial efforts when the bags are opened and loaded with the item to be packaged.
More recently, low density linear polyethylenes have been found commercially and have also been proposed for packaging applications. Currently, linear density polyethylenes called linear are copolymers of ethylene and varying amounts of higher alpha-olefins with, for example, 5 to 10 carbon atoms per molecule (US Pat.<sup>°</sup> 4,076,698) or 3 to 8 carbon atoms per molecule (European Patent Application Published 120503). Depending on their density, these materials are referred to as linear low density polyethylene (LLDPE) or very low density polyethylene (VLDPE), the separating line being at a density of about 0.910g / cmb. Some VLDPE properties have been described in Plastics Technology, September 1984, page 113 and October 1984, page 13, as well as in the company's brochure published in February 1984 and DSM in the Netherlands and entitled “Stamilex PE”. Its properties are said to be a unique combination between those of ordinary polyethylene and polyolephane rubbers. Its sealability and its compatibility with other polymers have been cited.
It is an object of the present invention to provide a multilayer laminated packaging film and bags obtained therefrom that have shrinkage characteristics on the materials used in the past. This means that at a given temperature the percentage shrinkage (the measure between the shrinkage in the longitudinal and transverse direction) must be higher and the maximum tolerated shrinkage temperature must also be higher. The maximum shrink temperature is dependent on the resistance to sealing at elevated temperatures.
It is another object of this invention to provide a packaging material with improved strength in sealing strength and therefore a reduced risk of breakage when the balls obtained from the film material are used in automatic loading processes.
It is still another object of the present invention to provide a packing material that provides reliable seals even when there is contamination. Especially in meat packing it often happens that sealed areas become contaminated with fat and blood, both of which tend to damage the seal between the sealing layers used so far.
Finally and mainly it is an object of this invention to provide a material that combines the above advantages, that is, improved shrinkage, increased shrinkage temperature.
003 111 maximum, good cold sealing resistance and sealability against contamination.
It has been found that the aforementioned objects are obtained with the present invention, which is directed to a thermoplastic multilayer packaging film comprising at least one outer polymer layer, an internal tandem sealing layer and optionally a barrier layer of oxygen between said inner layer and said outer layer, and that is characterized in that the thermal sealing layer comprises an ethylene copolymer and x% by weight, based on copolymer, of an alpha-olefin with 4 to 8 carbon atoms, whereby x = 0.5 nC + 8ey = 1.25nC + 15 where nC is the number of carbon atoms in the alpha-olefin, said copolymer having a lower density at 950 kg / cmb.
Preferably, the thermal sealing layer comprises a copolymer of ethylene and 12 to 20% by weight, based on the copolymer, of an alpha-olefin with 4 to 8 carbon atoms.
Surprisingly, it has been found that both the thermal shrinkage properties and the cold seal resistance of the laminated packaging film depend on the comonomer content of the ethylene copolymer used as the sealant layer. In order to obtain the optimal results, the comonomer content must increase when guiding from C4-alpha-olefin (butene (1)) to C8-alpha-olefin (octene (1)). It is particularly surprising that the films of the present invention exhibit improved shrinkage properties both in irradiation (crosslinking) and non-irradiation conditions and that these properties, as well as the seal resistance, are a function of the low linear polyethylene comonomer content. and very low density.
When an ethylene and butene copolymer (1) is used, the comonomer content must be between 10 and 20% by weight, based on the copolymer. These copolymers have a density of less than 915 kg / cmb. When an ethylene and octene copolymer (1) is used, the comonomer content should be increased, preferably between 12 and 25% by weight, based on the copolymer. These copolymers have a density of less than 920 kg / cm<sup>3</sup>.
In accordance with the invention it is also possible to mix the ethylene / alpha-olefin copolymer with up to 50% by weight, based on the composition of the sealant layer, of a polymer that is compatible with said ethylene / alpha-olefin copolymer. This further polymer can be chosen, preferably from the group comprising linear low density polyethylene (LLDPE) with a density greater than 920 kg / mb, linear high density polyethylene (LHDPE), low density polyethylene (LDPE), acetate vinyl ethylene (EVA), acid modified EVA, polypropylene, ethylene / alkylacrylate copolymers in which the alkyl fraction has 1 to 8 atoms of C, in articular ethylene methyl acrylate (EMA), ethylene ether acrylate (EEA) and ethylene butyl acrylate (EBA).
The ethylene / alkyl acrylate copolymer that can be mixed with the ethylene / alpha-olefin in the heat seal layer may comprise 3 to 30% by weight of alkyl acrylate.
In accordance with one embodiment of the invention, the ethylene copolymer that forms the sealant layer can be crosslinked by irradiation in order to improve its shrinkage characteristics and mechanical properties. However, this cross-linking is not necessary since a very satisfactory packaging film is also obtained without irradiation. If polyvinylidene chloride is used as a nucleus layer providing an oxygen barrier, irradiation must take place before the lamination of the nucleus layer to the sealing layer that the PVDC can be damaged when exposed to high energy irradiation. The total multilayer film can be irradiated if the PVDC core layer is replaced by a layer of hydrolyzed ethylene vinyl acetate copolymer core (EVOH). Preferred core layers are PVDC and EVOH since they show remarkable oxygen barrier properties.
The films are normally oriented in the longitudinal and transverse direction to obtain the desired shrinkage properties. If a tubular film is produced by extrusion, the orientation can be carried out using the known air bubble method and subsequently stretching the film by means of a traccian. Alternatively, the orientation can be obtained by deep drawing a planar film.
The outer layer of the multilayer packaging film of the invention may be of the same ethylene copolymer as the sealant layer, that is an ethylene / alpha-olefin copolymer comprising 10 to 25% by weight, based on the copolymer, of an alpha-olefin with 4 to 8 carbon atoms, said copolymer having a density of less than 920 kg / m<sup>3</sup> of ethylene vinyl acetate and polyamides, and ionomeric resins. It can often be advantageous if an adhesive layer and / or adhesive promoting layer is interposed between said other layers.
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If bags of the film material are obtained, the film will normally be folded so that the folding forms the bottom of the bag after which both sides are sealed so that the side seals close both sides of the bag. Alternatively, a bag can be formed from a tubular film where the bottom of the bag is formed by a transverse seal through the flattened tube and the mouth is formed by cutting the tube at a preselected distance from said transverse seal. Pockets can be obtained by sealing two film sheets on three edges.
The illustration of the invention would be extended with reference to the examples that follow without implying limitation.
The following test methods were used to investigate the properties of the packaging films and to compare them with other materials.
A. Variable pressure heat rupture test (HPV)
This is a test to determine the seal quality of shrinkable materials at different temperatures. The method of this test consists of submerging total seal areas in hot water and after a predetermined residence time the pressure inside the bag is increased at a constant speed of approximately 25.4 mm of water per second until it fails the stamp.
The mm of water pressure were recorded, at the level at which the seal fails, and there are minimum specifications expressed in mm for each bag width. Against more high is the best number is the quality of the seal at this temperature.
B. Shrinkage percentage
The shrinkage percentage is measured by soaking a sample for a couple of seconds in hot water and measuring the shrinkage percentage, both in the longitudinal and transverse direction. The highest is the shrinkage percentage, the lowest is the rendering of the material in terms of presentation of packaging.
In practice, the maximum percentage of shrinkage obtainable is that measured at the temperature at which the material meets the minimum HPVB requirements expressed in mm of water pressure (see point A). To predict the shrinkage behavior, it is therefore useful to plot the% shrinkage and the HPVB as a function of temperature in the same diagram.
C. Cold seal resistance
Cold seal resistance represents the quality of the seal at room temperature and predicts the performance of the seal when it is loaded with a product, manually or through automatic loaders, which operate with a pusher, which pushes the product into the bag. The cold seal resistance was measured with a modified pusher from a commercial magazine, equipped with a system to record the pressure required to open the bottom seal. The pusher head operates over a 6 cm length of seal and the cold seal resistance is expressed in kg / 6 cm. The maximum recordable pressure with these systems is 40 kg / 6 cm.
The results presented are the average of 10 measurements.
The following raw materials were used in the examples:
(See Table on the following page)
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Raw materials
<td>Abbreviation</td><td>Composition</td><td>Punt. Fusion</td><td>Dens. (g / cm<sup>3</sup>)</td>
<td>E / 15% B</td><td>ethylene-butene copolymer, 15% butene</td><td> 118<sup>or</sup> C</td><td> 0.906</td>
<td>E / 8% B</td><td>alkylene-butene copolymer, 8% butene</td><td> 121,5<sup>or</sup> C</td><td> 0.918</td>
<td>E / 6% VA</td><td>6% VA ethylene-vinyl acetate copolymer</td><td> 105<sup>or</sup> C</td><td> 0.926</td>
<td>E / 9% VA</td><td>9% ethylene-vinyl acetate VA copolymer</td><td> 96<sup>or</sup> C</td><td> 0.929</td>
<td>E / 14% VA</td><td>ethylene-vinyl acetate copolymer 14% VA</td><td> 90<sup>or</sup> C</td><td> 0.932</td>
<td>E / 18% VA</td><td>18% VA ethylene-vinyl acetate copolymer</td><td> 91<sup>or</sup>C</td><td> 0.940</td>
<td>Ionomero (Na)</td><td>ionomeric resin (Na salt)</td><td>90-92 ° C</td><td> 0.940</td>
<td>E / 19% O</td><td>ethylene-octene copolymer, 19% octene</td><td> 124<sup>or</sup> C</td><td> 0.911</td>
<td>E / 13% O</td><td>ethylene-octene copolymer, 13% octene</td><td> 124<sup>or</sup> C</td><td> 0.915</td>
<td>E / 10.5% O</td><td>ethylene-octene copolymer, 10.5% octene</td><td> 123<sup>or</sup> C</td><td> 0.920</td>
<td>Modified acid, EVA</td><td>acid modified ethylene-vinyl acetate</td><td> (55<sup>or</sup>)</td><td> 0.948</td>
<td>PA</td><td>Polyamide (nylon 6.12 copolymer)</td><td>140-147 ° C</td><td> 1.06</td>
<td>EMA (20% MA)</td><td>ethylene methacrylate copolymer, 20% MA</td><td>85-90 ° C</td><td> 0.942</td>
<td>EBA (7% BA)</td><td>ethylene butylacrylate copolymer, 7% BA</td><td>98-108 ° C</td><td> 0.923</td>
<td>P / 4.5% E</td><td>propylene-ethylene copolymer, 4.5% E</td><td> 135<sup>or</sup> C</td><td> 0.900</td>
Comparative Examples 1 to 4 and Examples 1 to 3
In the form that follows, multilayer packaging films of the composition which are summarized in Table I below were prepared. The first two layers A and B were coextruded through a conventional tubular stripper to form a tube. After leaving the matrix, the substrate was cooled or flattened. It was then sent through an irradiation cupola where it was irradiated by high-energy electrons up to a dose of about 4.5 MR. Depending on the desired characteristics, this dose may vary from 2 to 20 MR. After leaving the irradiation cupola, the substrate was again inflated and sent through a first coating matrix by tubular extrusion where it receives a vinylidene chloride copolymer coating. Then the film still swollen and now triple wall passes through a second coating matrix by tubular extrusion where it receives a layer of ethylene-vinyl acetate copolymer. After coating by tubular extrusion where it receives a layer of ethylene-vinyl acetate copolymer. After the final coating, the film is cooled, crushed and rolled. This tape is subsequently unwound, fed through a hot water bath, maintained at a temperature of about 80 to 98<sup>or</sup>C, and when it leaves the water it swells and blows to form thin tubing with a total wall thickness of about 59 microns. This "trapped bubble" technique is well known in the art. Then the film is cooled rapidly to fix the orientation and then rolled up for further processing.
Polyvinylidene chloride and ethylene vinyl acetate copolymer can alternatively be coated on the substrate using a two-layer coextrusion matrix.
The test results are summarized in Table II below.
(See Table in the following page)
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TABLE I
<td></td><td colspan="2">TO</td><td colspan="2">B</td><td colspan="2">D</td><td colspan="2">F</td>
<td>Example No.</td><td>layer of</td><td>μπ</td><td>layer of</td><td>© m</td><td>layer of</td><td>© m</td><td>cap</td><td>© m</td>
<td></td><td>sealed</td><td></td><td>core</td><td></td><td>barrier</td><td></td><td>external</td><td></td>
<td>Comp. 1</td><td>E / 9% VA</td><td> 37</td><td></td><td></td><td>PVDC</td><td> 8</td><td>E / 9% VA</td><td> 14</td>
<td>Comp. 2</td><td></td><td></td><td>E / 9% VA</td><td> 22</td><td>PVDC</td><td> 8</td><td>E / 9% VA</td><td> 14</td>
<td>Comp.3</td><td>E / 8% B</td><td> 15</td><td>E / 9% VA</td><td> 22</td><td>PVDC</td><td> 8</td><td>E / 9% VA</td><td> 14</td>
<td>Comp. 4</td><td>E / 10.5% O</td><td> 15</td><td>E / 9% VA</td><td> 22</td><td>PVDC</td><td> 8</td><td>E / 9% VA</td><td> 14</td>
<td> 1</td><td>E / 15% B</td><td> 15</td><td>E / 9% VA</td><td> 22</td><td>PVDC</td><td> 8</td><td>E / 9% VA</td><td> 14</td>
<td> 2</td><td>E / 13% O</td><td> 15</td><td>E / 9% VA</td><td> 22</td><td>PVDC</td><td> 8</td><td>E / 9% VA</td><td> 14</td>
<td> 3</td><td>E / 19% O</td><td> 15</td><td>E / 9% VA</td><td> 22</td><td>PVDC</td><td> 8</td><td>E / 9% VA</td><td> 14</td>
TABLE II
<td>Example</td><td colspan="2">Comparison 1</td><td colspan="2">Comparison 2</td><td colspan="2">Comparison 3</td><td colspan="2">Comparison 4</td>
<td>Temperatures</td><td>HPV mm H2O</td><td>Shrinkage% L + T two</td><td>HPV mm H2O</td><td>Shrinkage% L + T two</td><td>HPV mm H2O</td><td>Shrinkage% L + T two</td><td>HPV mm H2O</td><td>Shrinkage% L + T two</td>
<td> 60<sup>or</sup></td><td></td><td></td><td></td><td> 4</td><td></td><td> 2</td><td></td><td> 2</td>
<td> 70<sup>or</sup></td><td></td><td></td><td></td><td> 11</td><td></td><td> 6</td><td></td><td> 7</td>
<td> 80<sup>or</sup></td><td> 663</td><td> 21</td><td> 856</td><td> 25</td><td> 855</td><td> 12</td><td> 930</td><td> 14</td>
<td> 85<sup>or</sup></td><td> 652</td><td> 30</td><td> 782</td><td></td><td> 795</td><td></td><td> 841</td><td></td>
<td> 90<sup>or</sup></td><td> 520</td><td> 41</td><td> 608</td><td> 45</td><td> 644</td><td> 24</td><td> 695</td><td> 28</td>
<td> 95<sup>or</sup></td><td> 318</td><td> 57</td><td> 438</td><td></td><td> 540</td><td></td><td> 562</td><td></td>
<td> 100<sup>or</sup></td><td></td><td></td><td> 268</td><td> 63</td><td> 420</td><td> 42</td><td> 432</td><td> 49</td>
<td>Resistance</td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td>
<td>of the seal</td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td>
<td>to the cold</td><td colspan="2"> 24,5</td><td colspan="2"> 15,8</td><td colspan="2"> 16,1</td><td colspan="2"> 17,3</td>
<td>(kg / 6 cm)</td><td colspan="2">(10% without</td><td></td><td></td><td></td><td></td><td></td><td></td>
<td></td><td colspan="2">breakages</td><td></td><td></td><td></td><td></td><td></td><td></td>
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TABLE II (continued)
<td>Example</td><td colspan="2">Example 1</td><td colspan="2">Example 2</td><td colspan="2">Example 3</td>
<td>Temperatures</td><td>HPV mm H2O</td><td>Shrinkage % L + T two</td><td>HPV mm H2O</td><td>Shrinkage % L + T two</td><td>HPV mm H2</td><td>Shrinkage % L + T two</td>
<td> 60°</td><td></td><td> 3</td><td></td><td> 2</td><td></td><td> 4</td>
<td> 70°</td><td></td><td> 10</td><td></td><td> 7</td><td></td><td> 9</td>
<td> 80°</td><td> 1040</td><td> 27</td><td> 1051</td><td> 16</td><td> 1074</td><td> 25</td>
<td> 85°</td><td> 940</td><td></td><td> 928</td><td></td><td> 990</td><td></td>
<td> 90°</td><td> 783</td><td> 48</td><td> 745</td><td> 33</td><td> 802</td><td> 49</td>
<td> 95°</td><td> 647</td><td></td><td> 558</td><td></td><td> 621</td><td></td>
<td> 100°</td><td> 398</td><td> 64</td><td> 429</td><td> 53</td><td> 636</td><td> 67</td>
<td>Resistance</td><td></td><td></td><td></td><td></td><td></td><td></td>
<td>of the seal</td><td></td><td></td><td></td><td></td><td></td><td></td>
<td>to the cold</td><td></td><td> 22,5</td><td></td><td> 19,4</td><td></td><td> 23,5</td>
<td>(kg / 6 cm)</td><td></td><td></td><td></td><td></td><td></td><td></td>
When comparing the results, it should be taken into account that the shrinkage temperature must not exceed a value where the heat burst pressure falls below 650 mm / H<sub>2</sub>O. For some food products the maximum shrinkage temperature may be more limited but a higher heat burst will offer additional safety. It is evident from the data in Table II that comparison 1 offers good cold seal resistance but hot seal resistance and shrinkage percentage cease to be desired. In addition, this material results in poor resistance to the seal with contamination such as fat or blood. Comparison 2 shows improved shrinkage characteristics but the strength of the seal seal is considerably lower and this material cannot be reliably sealed by blood contamination.
Examples 1, 2 and 3 show that excellent shrinkage characteristics and very good seal resistance are obtained both at room temperature and at elevated temperatures. It has been further found that seal resistance is not significantly affected by contamination such as fat or blood. Comparisons 3 and 4 show that there is a significant decrease in both seal strength and percentage shrinkage when the comonomer content in alpha-olefin ethylene copolymer drops below a certain level, that is, the comonomer minimum content is a characteristic essential if the combination of desired properties is obtained.
Comparative Examples 5 and 6, Examples 4 to 10
Multilayer packaging films of the composition that are summarized in Table III below are produced by conventional techniques, that is, by coextrusion of a tubular film of layers A to F and subsequent stretching and orientation, for example in a blown bubble, so as to obtain a heat shrinkable film. In this case no irradiation was used. The test results obtained are shown in Table IV below.
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TABLE III
<td></td><td colspan="2">TO</td><td colspan="2">B</td><td>C</td>
<td>Example No.</td><td>layer of</td><td>μm</td><td>layer of</td><td>μm</td><td>promoter of;, th</td>
<td></td><td>sealed</td><td></td><td>core</td><td></td><td>adhesion</td>
<td>Comp. 5</td><td>Ionomero (Na)</td><td> 25</td><td>E / 18% VA</td><td> 9+</td><td>acid modified</td>
<td></td><td></td><td></td><td>E / 14% VA</td><td> 43</td><td>EVA 6</td>
<td>Comp. 6</td><td>E / 8% B</td><td> 25</td><td>E / 18% VA</td><td> 9+</td><td>acid modified</td>
<td></td><td></td><td></td><td>E / 14% VA</td><td> 49</td><td>EVA 6</td>
<td> 4</td><td>E / 15% B</td><td> 25</td><td>E / 18% VA</td><td> 9+</td><td>acid modified</td>
<td></td><td></td><td></td><td>E / 14% VA</td><td> 43</td><td>EVA 6</td>
<td> 5</td><td>E / 13% O</td><td> 25</td><td>E / 18% VA</td><td> 9+</td><td>acid modified</td>
<td></td><td></td><td></td><td>E / 14% VA</td><td> 43</td><td>EVA 6</td>
<td> 6</td><td>E / 19% O</td><td> 25</td><td>E / 18% VA</td><td> 9+</td><td>acid modified</td>
<td></td><td></td><td></td><td>E / 14% VA</td><td> 43</td><td>EVA 6</td>
<td> 7</td><td>75% E / 13% O</td><td></td><td>E / 18% VA</td><td> 9+</td><td>acid modified</td>
<td></td><td>25% + EBA</td><td> 25</td><td>E / 14% VA</td><td> 43</td><td>EVA 6</td>
<td> 8</td><td>90% E / 13% O</td><td></td><td>E / 18% VA</td><td> 9+</td><td>acid modified</td>
<td></td><td>10% acid modified EVE</td><td> 25</td><td>E / 14% VA</td><td> 43</td><td>EVA 6</td>
<td> 9</td><td>50% E / 13% C</td><td></td><td>E / 18% VA</td><td> 9+</td><td>acid modified</td>
<td></td><td>50% + E / 0% VA</td><td> 25</td><td>E / 14% VA</td><td> 43</td><td>EVA 6</td>
<td> 10</td><td>50% E / 15% B</td><td> 25</td><td>E / 18% VA</td><td> 9+</td><td>acid modified</td>
<td></td><td>50% + P / 4.5% E</td><td></td><td>E / 14% VA</td><td> 43</td><td>EVA 6</td>
TABLE III (Continued)
<td></td><td colspan="2">D</td><td>AND</td><td colspan="2">F</td>
<td>Example No.</td><td>layer of</td><td>μm</td><td>promoter of;, th</td><td>cap</td><td>μm</td>
<td></td><td>barrier</td><td></td><td>accession</td><td>external</td><td></td>
<td>Comp. 5</td><td></td><td></td><td>acid modified</td><td></td><td></td>
<td></td><td>PVDC</td><td> 8</td><td>EVA 6</td><td>PA</td><td> 23</td>
<td>Comp. 6</td><td></td><td></td><td>acid modified</td><td></td><td></td>
<td></td><td>PVDC</td><td> 8</td><td>EVA 6</td><td>PA</td><td> 23</td>
<td> 4</td><td></td><td></td><td>acid modified</td><td></td><td></td>
<td></td><td>PVDC</td><td> 8</td><td>EVA 6</td><td>PA</td><td> 23</td>
<td> 5</td><td></td><td></td><td>Acid modified</td><td></td><td></td>
<td></td><td>PVDC</td><td> 8</td><td>EVA 6</td><td>PA</td><td> 23</td>
<td> 6</td><td></td><td></td><td>acid modified</td><td></td><td></td>
<td></td><td>PVDC</td><td> 8</td><td>EVA 6</td><td>PA</td><td> 23</td>
<td> 7</td><td></td><td></td><td>acid modified</td><td></td><td></td>
<td></td><td>PVDC</td><td> 8</td><td>EVA 6</td><td>PA</td><td> 23</td>
<td> 8</td><td></td><td></td><td>acid modified</td><td></td><td></td>
<td></td><td>PVDC</td><td> 8</td><td>EVA 6</td><td>PA</td><td> 23</td>
<td> 9</td><td></td><td></td><td>acid modified</td><td></td><td></td>
<td></td><td>PVDC</td><td> 8</td><td>EVA 6</td><td>PA</td><td> 23</td>
<td> 10</td><td></td><td></td><td>acid modified</td><td></td><td></td>
<td></td><td>PVDC</td><td> 8</td><td>EVA 6</td><td>PA</td><td> 23</td>
003 111
TABLE IV
<td>Example</td><td colspan="2">Comparison 5</td><td colspan="2">Comparison 6</td><td colspan="2">Example 4</td><td colspan="2">Example 5</td><td colspan="2">Example 6</td>
<td></td><td colspan="2">HPV shrinked</td><td colspan="2">HPV shrinked</td><td colspan="2">HPV shrinked</td><td colspan="2">VHPB shrunk</td><td colspan="2">HPV shrinked</td>
<td></td><td colspan="2">I lie %</td><td colspan="2">I lie %</td><td colspan="2">I lie %</td><td colspan="2">I lie %</td><td colspan="2">I lie %</td>
<td>Temperatures</td><td>mm</td><td>L + T two</td><td>mm</td><td>L + T two</td><td>mm</td><td>L + T two</td><td>mm</td><td>L + T two</td><td>mm</td><td>L + T two</td>
<td></td><td>H2</td><td></td><td>H2 O</td><td></td><td>H2O</td><td></td><td>H2 O</td><td></td><td>H2O</td><td></td>
<td> 60<sup>or</sup> C</td><td></td><td> 15</td><td></td><td> 4,5</td><td></td><td> 13,5</td><td></td><td> 5</td><td></td><td> 9</td>
<td> 70<sup>or</sup> C</td><td></td><td> 25</td><td></td><td> 9,5</td><td></td><td> 21,5</td><td></td><td> 11</td><td></td><td> 19,5</td>
<td> 80<sup>or</sup> C</td><td> 993</td><td> 37</td><td> 951</td><td> 15,6</td><td> 1084</td><td> 33,5</td><td> 1043</td><td> 19</td><td> 1007</td><td> 33</td>
<td> 85<sup>or</sup> C</td><td> 877</td><td></td><td></td><td></td><td></td><td></td><td> 534</td><td></td><td> 431</td><td></td>
<td> 100<sup>or</sup> C</td><td> 319</td><td> 46</td><td> 599</td><td> 42,0</td><td> 546</td><td> 55,0</td><td> 436</td><td> 51</td><td> 338</td><td> 51</td>
<td>Resistance</td><td></td><td> 17,6</td><td colspan="2"> 25,6</td><td colspan="2"> 32,7</td><td colspan="2"> 29,6</td><td></td><td> 28</td>
<td>of the seal</td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td>
<td>cold</td><td></td><td></td><td></td><td></td><td colspan="2">(70% without</td><td></td><td></td><td></td><td></td>
<td>(kg / 6 cm)</td><td></td><td></td><td></td><td></td><td colspan="2">breaks)</td><td></td><td></td><td></td><td></td>
TABLE IV (Continued)
<td>Example</td><td colspan="2">Example 7</td><td colspan="2">Example 8</td><td colspan="2">Example 9</td><td colspan="2">Example 10</td>
<td></td><td colspan="2">HPV shrinked</td><td colspan="2">HPV shrinked</td><td colspan="2">HPV shrinked</td><td colspan="2">VHPB shrunk</td>
<td></td><td colspan="2">I lie %</td><td colspan="2">I lie %</td><td colspan="2">I lie %</td><td colspan="2">I lie %</td>
<td>Temperatures</td><td>mm</td><td>L + T two</td><td>mm</td><td>L + T two</td><td>mm</td><td>L + T two</td><td>mm</td><td>L + T two</td>
<td></td><td>H2</td><td></td><td>H2O</td><td></td><td>H2O</td><td></td><td>H2O</td><td></td>
<td> 60<sup>or</sup> C</td><td></td><td> 5</td><td></td><td> 6</td><td></td><td> 10</td><td></td><td> 4</td>
<td> 70<sup>or</sup> C</td><td></td><td> 12</td><td></td><td> 13</td><td></td><td> 16</td><td></td><td> 10</td>
<td> 80<sup>or</sup> C</td><td> 1020</td><td> 18</td><td> 980</td><td> 20</td><td> 940</td><td> 20</td><td> 1150</td><td> 18</td>
<td> 85<sup>or</sup> C</td><td> 850</td><td></td><td> 780</td><td></td><td> 720</td><td></td><td> 810</td><td></td>
<td> 90<sup>or</sup> C</td><td> 700</td><td> 35</td><td> 670</td><td> 35</td><td> 610</td><td> 34</td><td> 700</td><td> 34</td>
<td> 95<sup>or</sup> C</td><td> 525</td><td></td><td> 510</td><td></td><td> 470</td><td></td><td> 560</td><td></td>
<td> 100<sup>or</sup> C</td><td> 410</td><td> 52</td><td> 430</td><td> 48</td><td> 320</td><td> 52</td><td> 490</td><td> 44</td>
<td>Resistance</td><td colspan="2"> 32,0</td><td></td><td> 34</td><td></td><td> 32</td><td></td><td> 25</td>
<td>of the seal</td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td>
<td>by cold (kg / 6 cm)</td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td>
003 111
The results are essentially similar to those obtained with the irradiated material. Only the films of the present invention combine excellent shrinkage characteristics with relevant seal resistance by heat and cold. In addition, it can be sealed without damaging the resistance of the seal through contamination such as grease or blood that are always found in the packaging of meat products. In addition, the non-irradiated structures show the same effect, that is, a strong dependence on shrinkage and seal characteristics on the comonomer content of the ethylene / alpha-olefin copolymer.
003 111
Contents5
35 members in 15 offices
Priority claims10
| Document | Office | Kind | Date |
|---|---|---|---|
| 19850022305 | Italy | – | |
| 2230585 | Italy | A | |
| 2230585 | Italy | A | |
| 19860020457 | Italy | – | |
| 2045786 | Italy | A | |
| 2045786 | Italy | A | |
| 2045786 | – | – | – |
| 2230585 | – | – | – |
| IT19850022305 | – | – | – |
| IT19860020457 | – | – | – |
Members35
| Document | Office | Kind | |
|---|---|---|---|
| IT8522305D0 | Italy | D0 | |
| IT8620457D0 | Italy | D0 | |
| DK463186D0 | Denmark | D0 | |
| FI863919A0 | Finland | A0 | |
| DK463186A | Denmark | A | |
| FI863919A | Finland | A | |
| FI863919L | Finland | L | |
| AU6310286A | Australia | A | |
| EP0217252A2 | European Patent Office (EPO) | A2 | |
| JPS6280043A | Japan | A | |
| ZA867086B | South Africa | B | |
| BR8604693A | Brazil | A | |
| IT1190394B | Italy | B | |
| IT8522305A0 | Italy | A0 | |
| EP0217252A3 | European Patent Office (EPO) | A3 | |
| ES2003111A6This record | Spain | A6 | |
| US4801486A | United States of America | A | |
| AU582902B2 | Australia | B2 | |
| IT1207999B | Italy | B | |
| IT8620457A0 | Italy | A0 | |
| DE217252T1 | Germany | T1 | |
| NZ217626A | New Zealand | A | |
| EP0217252B1 | European Patent Office (EPO) | B1 | |
| AT69427T | Austria | T | |
| ATE69427T1 | Austria | T1 | |
| JPH0378065B2 | Japan | B2 | |
| DE3682473D1 | Germany | D1 | |
| CA1303473C | Canada | C | |
| FI88375B | Finland | B | |
| FI88375C | Finland | C | |
| MX168438B | Mexico | B | |
| JPH0639978A | Japan | A | |
| DK170038B1 | Denmark | B1 | |
| JPH0773904B2 | Japan | B2 | |
| USRE35285E | United States of America | E |
1 legal event, as the office reported them to INPADOC
Events
| Event | Code | |
|---|---|---|
| Expiration date (snapshot 920101)2006-09-29SA6 | SA6 |
Numbers
- Publication
- 2003111
- Publication, DOCDB
- 2003111
- Publication, EPODOC
- ES2003111
- Application
- 8602261
- Application, DOCDB
- 8602261
- Application, EPODOC
- ES19860002261
Titles2
- Spanish
- UN METODO PARA MEJORAR LAS PROPIEDADES DE SELLADO EN FRIO EN RECEPTACULOS OBTENIDOS DE PELICULA
- English
- A METHOD FOR IMPROVING COLD SEALING PROPERTIES IN RECEPTACLES OBTAINED FROM THERMOPLASTIC PACKING FILM OF MULTIPLE LAYERS.
Classification
- CPC, 28
- B32B27/08
- B32B27/32
- C09J123/0815
- Y10T428/2826
- Y10T428/1328
- Y10T428/1341
- Y10T428/3192
- Y10T428/3175
- Y10T428/31757
- Y10T428/31913
- Y10T428/31928
- B32B27/34
- B32B2331/04
- B32B2307/736
- B32B2327/06
- B32B2038/0076
- B32B2377/00
- B32B27/306
- B32B27/304
- B32B2439/70
- B32B2323/04
- B32B7/12
- B32B2553/00
- B32B27/308
- B32B2305/72
- B32B2307/31
- B32B27/16
- B32B2307/7244
- IPC, 7
- B32B7 02
- B32B27 08
- B32B27 28
- B32B27 30
- B32B27 32
- B65D65 40
- C09J123 08