BR112018070110B1 - PACKAGING ARTICLE COMPRISING A HEAT-SHRINK FILM TUBE IN FLAT CONFIGURATION, ASSEMBLY COMPRISING A SET OF PACKAGING ARTICLES IMBRICATE IN TWO CORDS OF RIBBON AND PROCESS FOR PACKAGING A MULTITUDE OF INDIVIDUAL MEAT PRODUCTS - Google Patents

Abstract

A heat shrinkable packaging article comprises a heat shrinkable film tube having an inner heat seal layer sealed to itself, with the heat seal layer having a thickness of at least 0.1 mil (0.00254 mm) and made from of a polymeric composition having a density of 0.92 g/cm3, the sealing layer comprising = 2000 ppm of anti-blocking particles with an average particle size = 3 μ, fast bloom release agent, slow bloom release agent and a outer layer. The packaging item can be dust free and passes the Standard Opening Test. Also described is a dust-free packaging article having a low peak or instantaneous coefficient of friction, an assembly comprising an imbricated array of packaging articles adhered to tapes, and a rotary chamber packaging process using the packaging articles. The packaging article may be dust-free.

Description

BACKGROUND

[001] For decades, it has been known to use loose powder, for example, loose cornstarch powder, on the inner and outer surfaces of a seamless heat-shrinkable tubular film which is converted into heat-shrinkable bags for packaging meat. In the manufacturing process, the powder is applied to the interior of an annular, seamless, thick film "tape" immediately after it is extruded from an annular die, i.e., before the tape undergoes solid-state orientation to form the heat-shrinkable tubular film. The presence of powder on the inner surface of the tube facilitates the manufacture of the heat shrinkable film and subsequent processing of the film, including (a) printing, (b) converting into packaging articles, (c) processing the resulting packaging articles on packaging machines , including opening and inserting the product into the packaging article.

[002] The powder is applied to the outside of the heat-shrinkable tubular film during conversion of the heat-shrinkable tubular film tape into individualized packaging articles, for example, bags, for example, by means of sealing and cutting. The presence of the powder on the outside of the heat shrink tube facilitates subsequent handling of the individualized packaging articles during the process of filling the packaging article with a meat product. More particularly, the presence of powder on the outer surface of the individualized packaging articles decreases the film-to-film friction coefficient, i.e. acts as a slip agent, i.e. lubricant, allowing the individualized packaging articles to readily slide and readily release from each other and machine surfaces.

[003] For example, when packaging meat products using a stack of bags in a box, the presence of dust on the outer surface of each of the individualized bags allows the top bag to be readily removed from the stack of bags for filling with product. With no dust on the outside of the bags, the top bag can adhere to the next bag (i.e., the bag immediately below the top bag) to a degree that the next bag moves out of the stack when the top bag is being removed. from the stack of bags and to a loading station. That is, the next bag can move partially or completely from the stack of bags as the top bag is moved to the loading station. This undesirable movement of the next bag can range from a slight movement of the stack of bags to moving to the product loading station with the top bag. Without the powder on the outside of the bags, moving the top bag to the loading station would likely move the next bag at least out of alignment with the remaining bags in the stack and part of the distance to the product loading station. Whether performed manually or through automation, removal of the top bag from the stack of bags, without substantially changing the position of the next bag, is aided by the powder on the outer surface of the top bag and the outer surface of the next bag.

[004] Furthermore, in "taped shingled" bags, after a product is placed inside the downstream bag (i.e., a "first bag") that is adhered to the tape(s), the presence of dust on the outer surface of all bags adhered to the tape(s) allows the first bag containing the product to be removed from the tape(s) with little or no alteration of the next upstream bag (i.e. the "second bag") on the tape(s), making it easier to load the next product into the second bag. This loading facilitation occurs both for manual and automatic product loading. The resulting first loaded bag can then be removed from the tape(s) and further processed manually or automatically, including transport to a vacuum chamber where the atmosphere is evacuated from the bag while the product remains in it, with the bag being closed with a heat seal and the excess bag material being cut off and discarded or recycled. Machinery and processes for vacuum packaging meat and other products placed in heat shrink bags are described in US Patents Nos. 4,958,391 (Kujubu); 4,580,393 (Furukawa) and 4,640,081 (Kawaguchi et al.), each of which is incorporated herein in full.

[005] After the first bag of the tape(s) is loaded with the product and removed from the tape(s) and forwarded to other packaging operations, the second bag is subsequently positioned for loading the product, it is subsequently opened and is further loaded with product, the resulting second loaded bag being released from the tape(s) and moved downstream for further packaging operations as with the first bag. Powder facilitates these packing operations.

[006] The powder on the inner surface of the tube helps in the manufacture of heat-shrinkable tubular film. If powder is used to make a tube in a process as illustrated schematically in Figure 1, the powder is supplied into the annular extrudate via a passage through the center of the annular die. The powder is applied to the inside of the tube immediately after extrusion of the annular extrudate from the annular die. The annular extrudate emerging from the annular die is referred to here as a "ribbon". The annular tape is thick and not yet solid state oriented and therefore not yet heat shrinkable. The powder contacts the inner surface of the annular ribbon shortly after exiting the die. The annular strip is cooled by the coolant. Once cooled, the annular ribbon is folded into its flat (flat) configuration. The annular tape in the flat configuration can thus undergo optional further processing while in the tape form, e.g. irradiation, extrusion coating, etc. However, in the production of heat shrinkable film, the annular ribbon in the flat configuration is then reheated to its softening temperature (e.g. passing through a hot water bath at 85-90°C), with the resulting annular ribbon softened after passing through a first pair of nip rollers rotating at a surface speed of X meters per minute, after which the annular film is stretched both transversely by passing around an enclosed air bubble, and longitudinally by a second set of pinch rollers that rotate at a higher surface speed, e.g. X + Y meters per minute. Entrained air is present in an amount that forces the softened annular strand to open and expand transversely enough to cause a desired level of transverse orientation in the solid state. The relative surface speeds of the nip rollers, combined with increasing the length of the machine direction travel from the expansion around the enclosed air bubble, produce a desired level of guidance in the machine direction in the solid state. Opening of the softened tape is facilitated by the presence of the powder within the softened tube, as without the powder the tape can "stick", i.e., present substantial resistance to opening to allow the air plug to expand the tape in the transverse direction. . If the tape gets stuck, the solid state orientation process will fail. Thus, the first reason for providing powder within the ribbon is to allow opening of the softened ribbon at the beginning of the solid state orientation process.

[007] After solid-state orientation, the resulting seamless annular heat-shrinkable film is folded flat and wound into a roll. This annular heat-shrinkable tubular film in the flat configuration can then be unrolled and converted, by means of cutting and sealing, into a plurality of bags or envelopes, i.e. into a plurality of packaging articles. During the conversion of heat shrinkable tubular film into packaging articles (bags and wrappers), powder is added to the outer surface of the tube as described above. However, the powder added to the interior of the annular extrudate provides enough powder to ensure that the softened tube readily splits open at the start of the solid state orientation process, as well as enough powder to ensure that when unrolling the flat seamless heat shrink tube , followed by cutting and sealing operations to convert the tubular film into heat-shrinkable packaging articles, the resulting packaging articles readily open for subsequent operations to insert the product therein. It should be noted that the solid state orientation of the softened tape to form the heat shrinkable tubular film increases the surface area of the inner surface of the tube by the amount of the total film orientation. For example, a tape subjected to a solid state transverse orientation of 3X in combination with a solid state orientation in the machine direction of 3X results in an internal surface area of the tube that is nine times the internal surface area of the tape. The amount of powder fed into the ribbon immediately after extrusion must be adequate to do more than just allow the softened annular ribbon to open. That is, the amount of powder added must be adequate to avoid blocking the inner surface of the heat shrinkable tubular film itself, so that the tube can be opened for insertion of the product after the tube is converted into a packaging product.

[008] Although cornstarch powder and/or powder made from any other suitable material provides the above-described sliding and anti-blocking properties necessary for the manufacture and use of heat-shrink bags, during application of the powder to the outside of the tube, the powder escapes to the factory because the powder loses its adherence to the outer surface of the tube, as well as escaping from the inside of the tube during conversion into packaging articles. Dust that escapes into the factory passes into whatever environment the tube or packaging article is in. The result is dust in the air and on the surfaces of air filters, equipment, building surfaces, etc. Furthermore, since cornstarch powder is nutritional, microbes can be sustained and multiply when supplied with the powder as a food source. Dust also detracts from the aesthetic appearance of the packaging article before a meat product is placed within the packaging article and the powder is washed off the exterior of the packaging article. Thus, it would be desirable to provide tubes and packaging articles with the desired slip and anti-blocking properties without the use of powder.

[009] Heat-shrinkable tubular films that are dust-free but have desirable slip and anti-blocking properties are known in the prior art. These prior art heat-shrinkable tubular films have been used as packaging films, but have not been converted into heat-shrinkable bags and wraps (which comprise or are made of seamless tubes) for packaging meat products. In contrast to heat-shrink bags and wrappers used for packaging meat and other products, these state-of-the-art heat-shrink films are manufactured as seamless tubes in order to impart the heat-shrink character, but the heat-shrink tubes are cut in the direction of the machine to open the tube to result in a flat film product which is rolled up as a flat film and then unrolled and used as a flat film in various packaging applications. Furthermore, these flat films have a total film thickness (before shrinkage) of less than 1.6 mm. These prior art flat films have been used for packaging food and non-food articles and typically exhibit free shrinkage at 85°C of 5 to 15% in the longitudinal direction (i.e., machine direction) and 5 to 20% in the transverse direction.

[0010] Furthermore, since these state-of-the-art powder-free heat-shrink flat films are not converted into packaging articles in the form of tubes in which the tube is placed in the flat configuration with the flat tube having to be opened so to be filled with the product, these heat-shrink flat films are not subject to the same release requirements as are present in the manufacture and use of the heat-shrink bags described above. Instead, the only release requirements are on unwinding flat film from a roll, which is different and much less sensitive to blockage than the release requirements on opening a packaging article made from a tube in the configuration flat, particularly a tube in the flat configuration which has been on a roll and/or which has been passed through pinch rollers in a flat lay during film processing.

SUMMARY OF THE INVENTION

[0011] Heat shrinkable packaging articles used for packaging meat have relatively thick heat seal layers comprising a relatively low density polymeric composition. It has been found that the combination of slip and anti-blocking components used in prior art powder-free heat shrinkable films are inadequate to impart the anti-blocking characteristics necessary to impart openability to heat shrinkable meat packaging articles, i.e. of heat shrinkable packaging comprising a multilayer heat shrinkable tubular film in a flat configuration, the tubular film having an inner heat seal layer sealed to itself. This finding confirms why commercially available heat shrink bags for meat packaging have dust on both the inner and outer surfaces. The combination of slip and anti-blocking components used in prior art powder-free heat-shrink films need not meet the openability performance of packaging articles comprising a tube having multiple layers of heat-shrink film in a flat configuration in which a first side one plane is in contact with a second plane side, since prior art powder-free heat-shrink films have not been used to make such packaging articles. Attempts to use prior art powder-free heat shrinkable films to make packaging articles comprising multilayer heat shrinkable tubular film in the flat configuration have resulted in failure as the packaging article has become trapped (i.e., not opened) under standard opening capability conditions.

[0012] In addition, the elimination of the use of corn starch powder, tapioca powder, etc. (i) reduces microbial growth by eliminating a food source, (ii) provides a cleaner production area and better working environment, (iii) reduces contamination of equipment and sensors, (iv) reduces the need for air, (v) reduces equipment wear, (vi) extends the life of heat sealing equipment, (vii) reduces or eliminates air in rolls, (viii) reduces or eliminates film creases and feathered edges, ( ix) improves the loading and handling consistency of heat-shrinkable tubular films and packaging articles made therefrom.

[0013] A first aspect of the invention is directed to a packaging article comprising a tubular heat shrinkable film in flat configuration. The heat shrinkable tubular film has a flat first side in contact with a flat second side. The tubular heat shrinkable film comprises a multilayer heat shrinkable film comprising (A) an inner heat seal layer comprising a seal layer polymeric composition and (B) an outer layer comprising an outer layer polymeric composition. The inner heat seal layer is heat sealed to itself. A first portion of the inner heat seal layer is on the first flat side of the packaging article and a second portion of the inner heat seal layer is on the second flat side of the packaging article, with the first portion of the heat seal layer in contact with the second portion of the heat seal layer. The heat seal layer comprises a polymeric seal layer composition comprising a polyolefin having an average density of less than 0.92 g/cm 3 . The inner heat seal layer has a thickness of at least 0.1 mm. The inner heat seal layer further comprises: (a) (i) antiblock particles in an amount from at least 2000 ppm, based on the total weight of the layer, the antiblock particles having an average particle size from at least 3 microns; (a) (ii) a fast blooming mold release agent in the inner sealing layer in an amount from at least 1200 ppm, based on the total weight of the layer, comprising at least one element selected from the group consisting in erucamide, oleamide, lauramide, lauric diethanolamide, monoglyceride, diglyceride, glycerol monooleate, glycerol monostearate and (a) (iii) a slow bloom release agent in the inner sealing layer in an amount from at least 1200 ppm, based on the total weight of the layer, the slow blooming agent comprising at least one member selected from the group consisting of stearamide, bis-stearamide, ethylene bis-stearamide, stearyl stearamide, stearyl erucamide, erucyl erucamide, behenamide , ethylene bis-oleamide, oleyl palmitamide, stearate ester, sorbitan stearate, monostearate, distearate, tristearate, sorbitan monolaurate, pentaerythritol stearate ester, polyglycerol stearate, zinc stearate, calcium stearate, magnesium stearate, stearate sodium, potassium stearate. The packaging article has an open end. The anti-blocking particles, the fast blooming mold release agent and the slow blooming mold release agent are present in the inner heat sealing layer of the multilayer heat shrinkable film in an amount so that the packaging article will open in a Standard opening in which a strip of multilayer heat shrinkable tubular film was stored in a flat configuration while wrapped around a core having a diameter of 8.9 cm for 7 days, with the multilayered heat shrinkable tubular film tape being wound onto the core to a roll diameter of 50 cm, with the film being wound onto a tension of 179 gm/cm wide flat tube, at the end of which a portion of the tube 2.54 cm from the core is converted in a packaging article while the tube remains in the flat configuration. The resulting packaging article is provided with an open top portion having an open top edge transverse to a length of tube, with a lower flat outer surface of the packaging article being in flat contact with an upper horizontal surface of a support platform having a linear leading edge wider than a width of the packaging article and a length greater than the packaging article. The lower flat outer surface of the packaging article is in adherent contact with the upper horizontal surface of the support platform by a pair of tapes each having a width of 6 mm and an adhesion to steel of at least 90 g/6 mm measured in accordance with AFERA Standard 4001-ED.9/79, with each strip running 3.81 cm (1.5 inches) from the linear leading edge of the packaging article in a perpendicular direction to the open top edge of the article . The strips are located on the top horizontal surface of the support platform such that each strip has a center line positioned at a position that corresponds to 33.3% of a distance across the flat width of the tube. The open top edge of the packaging article is parallel to and directly above the leading edge of the support platform. The packaging article that opens when simultaneously subjected to: (i) a 0.5 second burst of air supplied from a Laval air nozzle that has an air consumption of 28.9 Nm3/h (= 17 scfm), the air nozzle positioned along a 15 degree inclined centerline of the support platform, the air nozzle having a tip positioned 7.62 cm (3 inches) from the edge of the packaging article, the air nozzle being facing the open top edge of the packaging article and (ii) a second air flow from an air knife positioned parallel to and coincident with the support platform, the air knife having a discharge line 13.97 cm (5.5 inches) from the edge of the packaging article, the air knife having an air consumption of 76.5 Nh3/h (=45 scfm).

[0014] A second aspect is directed to a packaging article comprising: (A) a heat shrinkable tubular film having an inner heat seal layer containing a polymeric seal layer composition, antiblocking particles, a bloom release agent fast and a slow bloom release agent; (B) an outer layer comprising a polymeric outer layer composition as in the first aspect, wherein the outer layer has an outer surface having a maximum peak coefficient of friction less than 0.8 as measured in accordance with the standard ASTM D 1894, and the inner layer also has a maximum peak coefficient of friction less than 0.8, measured in accordance with ASTM D 1894.

[0015] A third aspect is directed to a packaging article comprising: (A) a heat shrinkable tubular film having an inner heat seal layer containing a polymeric seal layer composition, antiblocking particles, a bloom release agent fast and a slow bloom release agent; (B) an outer layer comprising a polymeric outer layer composition as in the first aspect, wherein the outer layer comprises a polymeric outer layer composition and wherein the outer layer has an outer surface having an instantaneous coefficient of friction less than than 0.6, measured in accordance with ASTM D 1894, and the inner layer also has an instantaneous coefficient of friction less than 0.6, measured in ASTM D 1894.

[0016] A fourth aspect is directed to a set comprising a set of packaging articles imbricated in two strands of tape. Each of the tape strands has a sticky surface and an opposite non-sticky surface. Each of the packaging articles complies with the above first or second or third aspects. Each of the packaging articles has two overlapping sides of substantially identical dimensions. Each of the packaging articles has one side attached to the adherent surface of both said tapes. The open end of each of the packaging articles is in the same direction relative to the tapes as all other packaging articles in the set. Each successive article of packaging adhered to the tapes is offset from the other packaging articles in the set and overlaps the opening of an underlying packaging article. The strands are spaced apart and parallel to each other.

[0017] A fifth aspect is directed to a packaging process for a plurality of individual meat products. The method comprises (A) placing each of the plurality of individual meat products into each of a corresponding plurality of individual packaging articles having an open top, each of the corresponding individual packaging articles being free of dust and being in accordance with the first aspect, the second aspect or the third aspect as set forth above, 1, to produce a plurality of partially packaged products, including a first partially packaged product and a second partially packaged product, (B) moving a first plate to a loading zone, the first plate being in a state of continuous movement; (C) placing the first partially packaged product onto a first plate as the first plate moves through the loading zone; (D)(d)(i) moving the first plate out of the loading zone while the first partially packaged product remains on the first plate; and (D)(d)(ii) bringing a first vacuum chamber lid down and in contact with the first plate to form a first vacuum chamber that has the first product partially packaged therein while the first plate remains in motion continuous; (D)(d)(iii) evacuating the atmosphere within the first vacuum chamber, including evacuating the atmosphere within the first partially packaged product as the first vacuum chamber continues to travel; (D)(iv) hermetically sealing the individual packaging article of the first partially packaged product while the atmosphere continues to be evacuated from the first vacuum chamber to produce a first vacuum packaged product as the first vacuum chamber continues to move ; (D)(d)(v) allowing atmosphere to re-enter the first vacuum chamber as the first plate having the first vacuum packed product continues to move; (D) (d) (vi) separating the first vacuum chamber lid from the first plate as the first plate continues to move and (D) (d) (vii) removing the first vacuum packed product from the first plate as the first plate continues to move; (E) placing the second partially packaged product onto a second plate after the first plate has exited the loading zone and the second plate has passed into the loading zone; and (F)(f)(i) moving the second plate out of the loading zone while the second partially packaged product remains on the second plate; (F)(f)(ii) bring a second vacuum chamber lid down and in contact with the second plate to form a second vacuum chamber that has the second product partially packed in it while the second plate remains in continuous motion ; (F)(f)(iii) evacuating the atmosphere within the second vacuum chamber, including evacuating the atmosphere within the second partially packaged product while the second vacuum chamber continues to travel; (F)(iv) hermetically sealing the individual packaging article of the second partially packaged product while the atmosphere remains evacuated from the second vacuum chamber to produce a second vacuum packaged product as the second vacuum chamber continues to move; (F)(f)(v) allowing atmosphere to re-enter the second vacuum chamber as the second plate having the second vacuum packed product continues to move; (F)(f)(vi) separating the second vacuum chamber lid from the second plate as the second plate continues to move and (F)(f)(vii) removing the second vacuum packed product from the second plate as the second plate continues to move.

BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 is a schematic of a cross-sectional view of a multi-layer heat shrinkable film.

[0019] Figure 2 is a schematic of a process for producing a multilayer heat-shrinkable tubular film useful in manufacturing the packaging article, such as the film in Figure 1.

[0020] Figure 3 is a schematic of an end-seal heat shrink bag made from the tubular film of Figure 1.

[0021] Figure 4 is a cross-sectional view of the bag of Figure 3, taken through section 4-4 thereof.

[0022] Figure 5 is a schematic of a heat-shrink side sealing bag also made from the tubular film of Figure 1.

[0023] Figure 6 is a cross-sectional view of the side seal bag of Figure 5, taken through section 6-6 thereof.

[0024] Figure 7 is a schematic of a heat-shrinkable bag that can also be made from the tubular film of Figure 1.

[0025] Figure 8 is a cross-sectional view of the heat-shrink bag of Figure 7, taken through section 8-8 thereof.

[0026] Figure 9 is a longitudinal sectional view of the heat-shrink bag of Figure 7, taken through section 9-9 thereof.

[0027] Figure 10 is a schematic of an end-seal heat-shrink hollow bag.

[0028] Figure 11 is a sectional view of the hollow bag of Figure 10, taken through section 11-11 thereof.

[0029] Figure 12 is a schematic of a side-sealing heat-shrinkable hollow bag.

[0030] Figure 13 is a cross-sectional view of the side-seal hollow bag of Figure 12, taken through section 1313 thereof.

[0031] Figure 14 illustrates a perspective view of a schematic of a "standard bag openability test device".

[0032] Figure 15 illustrates a schematic top view of the standard bag opening capacity test device of Figure 14.

[0033] Figure 16 illustrates a schematic side view of the standard bag opening capacity test device of Figure 14.

[0034] Figure 17 illustrates a schematic top view of the standard bag opening capacity test device of Figure 14.

[0035] Figure 18 illustrates a schematic perspective view of the standard bag openability test device with a terminal sealing bag in flat configuration on it, i.e. ready for the openability test to be carried out conducted.

[0036] Figure 19 illustrates a schematic top view of the standard bag openability test device with a terminal sealing bag in flat configuration on it, i.e., ready for the openability test to be conducted .

[0037] Figure 20 illustrates a schematic side view of the standard bag openability test device with a terminal sealing bag in flat configuration on top of it, i.e., ready for the openability test to be conducted .

[0038] Figure 21 illustrates a schematic end view of the standard bag openability test device with a terminal sealing bag in flat configuration on it, i.e., ready for the openability test to be conducted .

[0039] Figure 22 illustrates a perspective view of the openability tester and the bag of Figure 18 two seconds after the openability test is started, with the bag passing the openability test.

[0040] Figure 23 illustrates a top view of the openability test device and the bag of Figure 22.

[0041] Figure 24 illustrates a side view of the openability test device and the bag of Figure 22.

[0042] Figure 25 illustrates an end view of the openability tester and the bag of Figure 19.

[0043] Figure 26 illustrates a perspective view of the openability tester and the bag of Figure 18 two seconds after the openability test is started, with the bag failing the openability test.

[0044] Figure 27 illustrates a top view of the openability test device and the bag of Figure 26.

[0045] Figure 28 illustrates a side view of the openability test device and the bag of Figure 26.

[0046] Figure 29 illustrates an end view of the openability tester and the bag of Figure 26.

[0047] Figure 30 is a perspective view of an air nozzle to be used in the packaging article openability device.

[0048] Figure 31 is a perspective view of an air knife to be used in the packaging article openability device.

DETAILED DESCRIPTION

[0049] As used herein, the term "film" is used in a generic sense to include a plastic web, regardless of whether it is film or sheet.

[0050] As used herein, the term "packaging" refers to a product packaged in a packaging material, such as film.

[0051] As used herein, the term "packaging article" refers to an article of manufacture that is suitable for use in packaging a product to be placed within the packaging article. Bags and wrappers are examples of packaging articles that can be used for packaging meat products. The bag may be an end seal bag, a side seal bag, an L seal bag or a bag. The wrapper can be a seamless wrapper or a seam-back wrapper. Back seam wraps include a tuck seal wrap, a fin seal wrap, and a butt-seal wrap with back seam tape.

[0052] As used herein, the phrases "seal layer", "seal layer", "heat seal layer" and "seal layer" refer to an outer film layer or layers, involved in sealing the film to itself same, another film layer of the same or another film and/or another non-film article. It should also be recognized that, in general, up to 3mm of distance from a film may be involved in sealing the film to itself or another layer. In relation to packages that have only fin-type seals, as opposed to fold-type seals, the phrase "seal layer" generally refers to the inner film layer of a package, as well as backing layers within 3mm of the inner surface of the sealing layer, the inner layer often also serving as a food contact layer in food packaging.

[0053] As used herein, the term "seal" refers to any sealing of a first region of a film surface to a second region of a film surface, wherein the seal is formed by heating the regions to at least their respective sealing start temperatures. Heating can be accomplished in any one or more of a variety of ways, such as using a hot wire, hot knife, heated bar, hot air, infrared radiation, ultrasonic sealing, etc. More preferably, the seal is formed by a hot wire and/or hot knife. As known to those skilled in the art, a static seal is another useful seal in forming a package from the film of the present invention.

[0054] As used herein, the phrase "a layer comprising a polymeric composition that has a density of less than X g/cm3 " means that, taken together, all of the polymer(s) in the layer , but not including the non-polymeric components in the layer, the average density of the polymer(s) in the layer is calculated on a weight percent basis, with the resulting average value being less than 0.92 g/cm3 . The same analysis applies for a density range. If different polymers are mixed to make the polymeric composition from which the heat seal layer is made, the density of the polymeric composition is the density of the polymer mixture in the proportions in which they are mixed. Solid materials, such as antiblocking compounds, are not included in determining the density of the first polymeric composition. For example, the density of the inner layer polymeric composition is the weighted average of the densities of each of the polymers present in the inner layer.

[0055] As used herein, the phrase "...the film layer comprising..." refers to the film layer that has the cited components along the cross section of the layer as well as on both outer major surfaces of the layer.

[0056] As used herein, the term "tube" refers to a seamless tubular film or a backseam tube in the form of a ply-sealed tube, a fin-sealed tube, or a sealed tube having a seam tape later. As used herein, in relation to tubular films and packaging articles made therefrom, the phrase "in the flat configuration" refers to a tube or packaging article comprising a tube in a flat state with a flat first side and a flat flat second side that are connected to each other along side edges, which may be creased edges or sealed edges.

[0057] As used herein, the term "oriented", when used in relation to heat-shrinkable films and tubes, refers to a material containing a polymer that has been stretched while in the solid state, but at an elevated temperature (the orientation temperature ), followed by being "hardened" in the drawn configuration by cooling the material while substantially retaining the drawn dimensions. Upon subsequent heating of the uncontained, unannealed, oriented polymer-containing material to its softening point (i.e., the temperature at which solid-state orientation was performed), thermal shrinkage is produced. More particularly, the term "oriented", as used herein, refers to oriented films, where solid state orientation can be produced in one or more of a variety of ways, including the contained bubble method and the bubble method. stretch frame (tent frame).

[0058] As used herein, the phrase "orientation ratio" refers to the product of multiplying the point to which the plastic film material is expanded in various directions, usually two mutually perpendicular directions. Expansion in the machine direction is referred to herein as "stretching", while expansion in the transverse direction is referred to herein as "elongation". For tubular films extruded through an annular die to form an unoriented tube called a "tape", elongation is achieved by heating the tape to its softening temperature, passing the tape through an enclosed air bubble to thereby "blowing" the ribbon to produce transverse orientation in heat-shrink film production. For such films, stretching is achieved by passing the film through two sets of driven nip rollers, with the downstream set having a higher surface speed than the upstream set, with the resulting stretch ratio being the speed surface speed of the downstream set of pinch rollers divided by the surface speed of the upstream set of pinch rollers. The degree of orientation is also referred to as the orientation ratio or sometimes as the "racking ratio", which is the orientation in the machine direction (MD) multiplied by the orientation in the cross direction. (in English, TD).

[0059] As used herein, the term "polymer" refers to the product of a polymerization reaction and is inclusive of homopolymers, copolymers, terpolymers, etc. In general, the layers of a film may consist essentially of a single polymer or may have additional polymers along with, i.e., blended with, them.

[0060] As used herein, the term "copolymer" refers to polymers formed by the polymerization reaction of at least two different monomers. For example, the term "copolymer" includes the copolymerization reaction product of ethylene and an alpha-olefin, such as 1-hexene. However, the term "copolymer" also includes, for example, the copolymerization of a mixture of ethylene, propylene, 1-hexene and 1-octene.

[0061] As used herein, a copolymer identified in terms of a plurality of monomers, for example, "propylene/ethylene copolymer", refers to a copolymer in which any monomer can copolymerize at a weight or mole percentage greater than the another monomer or monomers. However, the first listed monomer preferably polymerizes at a greater weight percentage than that of the second listed monomer and, for copolymers that are terpolymers, quadripolymers, etc., preferably the first monomer copolymerizes at a greater weight percentage. than the second monomer, and preferably the second monomer copolymerizes at a greater weight percent than the third monomer, etc.

[0062] As used herein, copolymers are identified, that is, named, in terms of the monomers from which the copolymers are produced. For example, the phrase "propylene/ethylene copolymer" refers to a copolymer produced by the copolymerization of propylene and ethylene, with or without additional comonomer(s).

[0063] As used herein, terminology that uses a "/" in relation to the chemical identity of a copolymer (eg, "an ethylene/alpha-olefin copolymer"), identifies the comonomers that are copolymerized to produce the copolymer. As used herein, "ethylene alpha-olefin copolymer" is equivalent to "ethylene/alpha-olefin copolymer".

[0064] As used herein, the phrase "heterogeneous polymer" refers to polymerization reaction products of relatively wide variation in molecular weight and relatively wide variation in composition distribution, i.e., typical polymers prepared, for example, using conventional Ziegler-Natta catalysts. Heterogeneous polymers are useful in various layers of the film used in the present invention. Although there are some exceptions, such as homogeneous linear ethylene/alpha-olefin copolymers (such as TAFMER®) produced by the Mitsui Petrochemical Corporation using Ziegler-Natta catalysts, heterogeneous polymers typically contain a relatively wide range of chain lengths and percentages of comonomers.

[0065] As used herein, the phrase "homogeneous polymer" refers to polymerization reaction products of relatively narrow molecular weight distribution and relatively narrow composition distribution. Homogeneous polymers are useful in multiple layers of the multilayer film used in the present invention. Homogeneous polymers are structurally different from heterogeneous polymers in that homogeneous polymers exhibit a relatively uniform sequence of comonomers within a chain, a mirroring of sequence distribution across all chains, and a similarity in length of all chains, i.e. , a narrower molecular weight distribution. Furthermore, homogeneous polymers are typically prepared using metallocene or other single-site type catalysis rather than using Ziegler-Natta catalysts.

[0066] More particularly, homogeneous ethylene/alpha-olefin copolymers can be characterized by one or more methods known to those skilled in the art, such as Molecular Weight Distribution (Mw/Mn), Composition Distribution Range Index (in English, CDBI) and narrow melting point range and single melting point behavior. Molecular weight distribution (Mw/Mn), also known as polydispersity, can be determined using gel permeation chromatography. Homogeneous ethylene/alpha-olefin copolymers useful in the present invention generally have a (Mw/Mn) of less than 2.7; preferably from about 1.9 to 2.5; more preferably from about 1.9 to 2.3. The Compositional Breadth of Distribution Index (CDBI) of such homogeneous ethylene/alpha-olefin copolymers will usually be greater than about 70 percent. CDBI is defined as the percentage by weight of copolymer molecules with a comonomer content within 50 percent (i.e., plus or minus 50%) of the total molar median comonomer content. Linear polyethylene CDBI, which does not contain a comonomer, is defined as being 100%. The Compositional Distribution Range Index (CDBI) is determined using the Temperature Elevation Elution Fractionation (TREF) technique. CDBI determination clearly distinguishes the homogeneous copolymers used in the present invention (narrow composition distribution, as judged by CDBI values generally above 70%) from heterogeneous polymers, such as VLDPE's, which are commercially available with a broad composition distribution, as judged by CDBI values generally below 55%. The CDBI of a copolymer is readily calculated from data obtained by methods known in the art such as, for example, TREF, as described, for example, in Wild et al., J. Poly. Sci. Poli. Phys. Ed. Vol. 20, page 441 (1982). Preferably, the homogeneous ethylene/alpha-olefin copolymers have a CDBI of greater than about 70%, i.e., a CDBI of about 70% to 99%. These homogeneous polymers exhibit a relatively narrow melting point range compared to "heterogeneous copolymers", ie polymers with a CDBI of less than 55%. Preferably, homogeneous ethylene/alpha-olefin copolymers exhibit an essentially unique melting point characteristic, with a melting peak (Tm), as determined using Differential Scanning Colorimetry (DSC), of about 60 °C to 105 °C. Preferably, the homogeneous copolymer has a DSC peak Tm of about 80°C to 100°C. As used herein, the phrase "essentially single melting point" means that at least about 80% by weight of the material corresponds to a single peak Tm at a temperature within the range of about 60°C to 105°C and essentially no substantial fraction of the material has a melting peak greater than about 115°C as determined by DSC analysis. DSC measurements are made on a Perkin Elmer System 7 Thermal Analysis system. Melt information reported is second melt data, ie the sample is heated at a programmed rate of 10 °C/min to a temperature below its critical range. The sample is then reheated (2nd melt) at a programmed rate of 10 °C/min. The presence of higher melting peaks is detrimental to film properties such as turbidity and compromises the chances of a significant reduction in the initial sealing temperature of the final film.

[0067] A homogeneous ethylene/alpha-olefin copolymer can generally be prepared by copolymerizing ethylene and any one or more alpha-olefins. Preferably, the alpha-olefin is a C3-C20 alpha-mono-olefin, more preferably a C4-C12 alpha-mono-olefin, even more preferably a C4-C8alpha-mono-olefin. Even more preferably, the alpha-olefin comprises at least one element selected from the group consisting of butene-1, hexene-1 and octene-1, i.e. 1-butene, 1-hexene and 1-octene, respectively. More preferably, the alpha-olefin comprises octene-1 and/or a mixture of hexene-1 and butene-1.

[0068] Processes for the preparation and use of homogeneous polymers are described in United States Patent No. 5,206,075, United States Patent No. 5,241,031 and PCT International Application WO 93/03093, each of which is incorporated herein by full reference. Additional details concerning the production and use of homogeneous ethylene/alpha-olefin copolymers are described in PCT International Publication No. WO 90/03414 and PCT International Publication No. WO 93/03093, both assigned to Exxon Chemical Patents, Inc. as Claimant and both of which are hereby incorporated by reference in their respective entireties.

[0069] Yet another genus of homogeneous ethylene/alpha-olefin copolymers is described in US Patent No. 5,272,236, to LAI et al. and US Patent No. 5,278,272 to LAI et al., both of which are incorporated herein by reference in full.

[0070] As used herein, the term "polyolefin" refers to any polymerized olefin, which may be linear, branched, cyclic, aliphatic, aromatic, substituted or unsubstituted. More specifically, included in the term polyolefin are olefin homopolymers, olefin copolymers, copolymers of an olefin and a non-olefin comonomer copolymerizable with the olefin, such as vinylic monomers, their modified polymers and so on. Specific examples include polyethylene homopolymer, polypropylene homopolymer, polybutene, ethylene/alpha-olefin copolymer, propylene/alpha-olefin copolymer, butene/alpha-olefin copolymer, ethylene/vinyl acetate copolymer, ethylene/acrylate copolymer ethyl acrylate copolymer, ethylene/butyl acrylate copolymer, ethylene/methyl acrylate copolymer, ethylene/acrylic acid copolymer, ethylene/methacrylic acid copolymer, modified polyolefin resin, ionomer resin, polymethylpentene, etc. The modified polyolefin resin is inclusive of a modified polymer prepared by copolymerizing the olefin homopolymer or copolymer thereof with an unsaturated carboxylic acid, e.g., maleic acid, fumaric acid or the like, or a derivative thereof, such as the anhydride. , ester or metal salt or the like. It can also be obtained by incorporating, in the olefin homopolymer or copolymer, an unsaturated carboxylic acid, for example, maleic acid, fumaric acid or the like or a derivative thereof, such as the anhydride, ester or metal salt or the like.

[0071] As used herein, terms identifying polymers, such as "polyamide", "polyester", "polyurethane", etc. include not only polymers comprising repeating units derived from monomers known to polymerize to form a polymer of the named type, but are also inclusive of comonomers, derivatives, etc. which can copolymerize with monomers known to polymerize to produce the named polymer. For example, the term "polyamide" encompasses both polymers comprising repeating units derived from monomers, such as caprolactam, which polymerize to form a polyamide, and copolymers derived from the copolymerization of caprolactam with a comonomer which, when polymerized alone, does not result in the formation of a polyamide. Furthermore, terms identifying polymers are also inclusive of mixtures, blends, etc. of these polymers with other polymers of a different type. More preferably, however, the polyolefin is a polymerization product of one or more unsubstituted olefins, the polyamide is the polymerization product of one or more unsubstituted amides, and the like.

[0072] As used herein, the phrases "ethylene alpha-olefin" and "ethylene/alpha-olefin copolymer" refer to heterogeneous materials, such as linear low-density polyethylene (LLDPE) and high-density polyethylene low and ultra-low (in English, VLDPE and ULDPE); and homogeneous polymers, such as EXACT® metallocene-catalyzed linear homogeneous ethylene/alpha-olefin copolymer resins obtainable from Exxon Chemical Company of Baytown, Texas, and TAFMER® linear homogeneous ethylene/alpha-olefin copolymer resins obtainable from Mitsui Petrochemical Corporation. All of these materials include, in general, copolymers of ethylene with one or more comonomers selected from C4 to C10 alpha-olefin, such as butene-1 (i.e., 1-butene), hexene-1, octene-1, etc. , wherein the molecules of the copolymers comprise long chains with relatively few side-chain branches or cross-linked structures. This molecular structure should be contrasted with conventional low or medium density polyethylenes, which are more highly branched than their respective counterparts. The heterogeneous ethylene/alpha-olefin copolymer commonly known as LLDPE generally has a density in the range of about 0.91 grams per cubic centimeter to about 0.94 grams per cubic centimeter. Other ethylene/alpha-olefin copolymers, such as the long-chain branched homogeneous ethylene/alpha-olefin copolymers available from The Dow Chemical Company, known as AFFINITY® resins, are also included as another type of ethylene/alpha-olefin copolymer. homogeneous alpha-olefin useful in the present invention.

[0073] In general, the ethylene/alpha-olefin copolymer comprises a copolymer resulting from the copolymerization of about 80 to 99 weight percent ethylene and from 1 to 20 weight percent alpha-olefin. Preferably, the ethylene/alpha-olefin copolymer comprises a copolymer resulting from the copolymerization of about 85 to 95 weight percent ethylene and from 5 to 15 weight percent alpha-olefin.

[0074] As used herein, the phrases "inner layer" and "inner layer" refer to any layer, of a multilayer film, which has both of its major surfaces directly adhered to another layer of film.

[0075] As used herein, the phrase "outer layer" refers to any layer of film that has less than two of its major surfaces directly adhered to another layer of film. The phrase includes both single-layer and multi-layer films. In multilayer film, there are two outer layers, each of which has a major surface adhered to only one other layer of the multilayer film. In single layer films, there is only one layer which, of course, is an outer layer in which neither of its two main surfaces is adhered to the other layer of the film.

[0076] As used herein, the phrase "inner layer" refers to the outer layer of a multilayer film that packs a product, which is closest to the product relative to the other layers of the multilayer film. "Inner layer" is also used in reference to the innermost layer (which is also an outer layer) of a plurality of concentrically arranged layers extruded through one or more annular dies. The inner layer is also often referred to as the "seal layer" or "heat seal layer".

[0077] As used herein, the phrase "outer layer" refers to the outer layer of a multilayer film that packs a product, which is furthest from the product relative to the other layers of the multilayer film. "Outer layer" is also used in reference to the outermost layer of a plurality of concentrically arranged layers extruded through one or more annular dies.

[0078] As used herein, the phrase "machine direction", herein abbreviated "MD", refers to a direction "along the length" of the film, i.e., in the direction of the film as the film is formed during extrusion and/or coating.

[0079] As used herein, the phrase "transverse direction", herein abbreviated "TD", refers to a direction through the film perpendicular to the machine direction.

[0080] As used herein, the phrase "free shrinkage" refers to the percent dimensional change in a 10 cm x 10 cm sample of film when shrunk at 85 °C (= 185 °F), with the quantitative determination being performed from according to ASTM D 2732, as presented in the 1990 Annual Book of ASTM Standards, vol. 08.02, pages 368-371, which is hereby incorporated in full by reference thereto. Free shrinkage measurements can be reported for the machine direction ("MD", which is the direction in which the film is extruded) or the transverse direction ("TD", which is perpendicular to the machine direction and directly through the direction in which the film is extruded) or as "total free shrinkage", which is MD + TD, i.e. summed together.

[0081] The heat shrinkable packaging article is made from a heat shrinkable tube. The heat shrink tube can be a seamless tube or a tube with a back seam. A seam-back tube is a tube in which the film has a lengthwise seal to itself or a tape. If backseamed, the tube can be formed with a fin seal or a ply seal or the tubular film can be sealed to a backseam tape.

[0082] The heat shrink tube can be used to make a heat shrink packaging article such as a heat shrink bag or a heat shrink wrap. Bag types include end seal, side seal, bag (ie U-seal) and L-seal (made by folding a flat film and providing a bottom seal and a side seal. The bag may have one or more patches adhered to the Enclosures may be seamless or backseamed, the latter of which includes fin sealing, fold sealing, and sealing with a backseam tape.

[0083] The packaging article can be used for packaging a wide variety of products, and is especially useful for packaging meat products. Typical meat products include beef, pork, poultry, fish, lamb, etc. and include fresh meat products and processed meat products such as sausage.

[0084] It has been found that if the outer layer of the film from which the bag is made contains only siloxane and/or anti-blocking particles and does not contain amides or fatty acid waxes, the adhesion of the patch film is much stronger than if a migratory slip or mold release agent, such as erucamide, were added to the outer layer of the bag.

[0085] The film used to make the packaging article is a multilayer heat shrinkable film. Heat shrinkable film can have a total thickness, before shrinkage, from 1.7 mm to 20 mm or from 1.8 to 10 mm or from 1.9 to 5 mm or from 2 to 4 mm or from 2 to 3 mm or from 2 to 2.5 mm.

[0086] The film may have a total free shrinkage at 85°C of at least 50% (measured in accordance with ASTM D 2732). The film can have a total free shrinkage at 85°C from 50% to 120% or from 55% to 115% or from 60% to 110% or from 65% to 105% or from 70 % to 100% or from 75% to 100% or from 80% to 100% or from 85% to 100%.

[0087] In one embodiment, the tubular film is made from a film with the following layer arrangement: (interior) sealing / 1st volume / 1st binding / O2 barrier / 2nd binding / 2nd volume / tamperproof layer (outside). In another embodiment, the tubular film is made from a multilayer film of the following layer arrangement: (inside) sealing/1st volume/2nd volume/1st binding/O2 barrier/2nd binding/2nd volume/tamper layer (outside).

[0088] The film from which the heat-shrinkable multilayer tubular film is made may be partially or wholly irradiated to induce crosslinking. In the irradiation process, the film is subjected to a treatment of energetic radiation, such as corona discharge, plasma, flame, ultraviolet, X-rays, gamma rays, beta and treatment with high energy electrons, which leads to the interconnection between molecules of the material. irradiated. Irradiation of polymeric films is described in US Patent No. 4,064,296 to BORNSTEIN et al., which is incorporated herein in full by reference. BORNSTEIN et al. describe the use of ionizing radiation for crosslinking the polymer present in the film. The extrusion coating process illustrated in Figure 2 (described below) allows several layers to be extruded and crosslinked before an irradiation sensitive polyvinylidene chloride O2 barrier layer and other layers are extruded over the irradiated crosslinked substrate portion of the tubular film with multiple layers, resulting in a stronger tubular film, whereas a complete coextrusion of all the layers together, followed by irradiation, could result in the degradation of the PVDC layer, causing a decrease in its oxygen barrier properties.

[0089] To produce crosslinking, a suitable dose of high-energy electron radiation, preferably using an electron accelerator, is applied, with the dose level being determined by means of standard dosimetry methods. Other accelerators, such as a Van de Graaf generator or a resonant transformer, can be used. Radiation is not limited to electrons from an accelerator, as any ionizing radiation can be used. Ionizing radiation can be used to crosslink the polymers in the film. Preferably, the film is irradiated at a level of 2-15 MR, more preferably 2-10 MR. As can be seen from the descriptions of preferred films for use in the present invention, the most preferred amount of radiation depends on film composition, thickness, etc. and its end use.

[0090] The outer film layer is the outer layer of the heat shrinkable tubular film used to make the heat shrinkable packaging article. The outer layer contains a polymeric outer layer composition. The outer layer polymeric composition may comprise at least one element selected from the group consisting of polyolefin, ethylene/alpha-olefin copolymer, ethylene/unsaturated ester copolymer, ionomer resin, propylene/ethylene copolymer, polystyrene, polyamide , polyester and polycarbonate.

[0091] The outer layer polymeric composition may have a density of less than 0.92 g/c3 or less than 0.915 g/c3 or less than 0.912 g/c3 or less than 0.910 g/c3 or less than 0.909 g/c3 or less than 0.908 g/c3 or less than 0.907 g/c3 or from 0.900 to 0.915 g/c3 or from 0.900 to 0.912 g/c3 or from 0.900 to 0.910 g/c3 or from 0.902 to 0.909 g/c3 or from 0.904 to 0.908 g/c3 or from 0.905 to 0.907 g/c3.

[0092] It is desirable to provide a dust-free outer layer that does not stick and that the outer surface of the packaging article has a low coefficient of friction. This can be achieved by mixing one or more fast blooming or slow blooming mold release agents (the same as for the heat seal layer described below), polysiloxane and antiblocking particles into the outer layer.

[0093] The outer layer may comprise a glidant. The glidant may comprise at least one member selected from the group consisting of polysiloxane (including high molecular weight polysiloxane and/or ultra-high molecular weight polysiloxane), erucamide, oleamide, stearamide, behenamide, oxidized polyethylene wax , glycerol monostearate, metallic stearate (eg calcium stearate, ethylene bis-stearamide), fatty acid amide, oxidized polyethylene, fatty acid ester and fatty acid alcohol and wax. The slip agent(s) may be present in the outer layer at a total from 1,000 to 15,000 ppm, based on the total weight of the outer layer, from 1,500 to 12,000 ppm, from 2,000 to 10,000 ppm, from 2,000 to 8,000 ppm, from 2,000 to 6,000 ppm, from 2,500 to 5,000 ppm.

[0094] The use of polysiloxane and/or antiblocking particles in the outer layer is preferable to the use of release agents in the outer layer, as release agents can interfere with the printing of the outer layer.

[0095] It has been found that polysiloxane individually or a combination of antiblocking particles and polysiloxane can impart the outer layer with the desired slip and antiblocking properties without adversely affecting the printability and at the same time imparting relatively low haze . The polysiloxane alone, i.e., without antiblocking particles and without release or slip aids, may suffice and impart even lower haze, giving the packaging article the desired slip and antiblocking properties. Individual polysiloxane in the outer layer may be suitable for closed bags. For stacked bags, a combination of antiblocking particles and polysiloxane can give the packaging articles the desired slip and antiblocking properties, and this combination improves the performance of the outer layers of the packaging article and provides an easily printable outer surface for the packaging article. The presence of polysiloxane individually or the combination of antiblock particles and polysiloxane can give the packaging article good machinability.

[0096] In one embodiment, the polysiloxane is the sole slip agent in the outer layer. The polysiloxane can be present in the outer layer in an amount from 2500 to 5000 ppm or from 3000 to 4000 ppm.

[0097] The outer layer may comprise anti-blocking particles that may have an average particle size from at least 3 microns (measured in accordance with ASTM D4664) or from 3 μ to 25 μ or from 3 μ to 15 μ or from 3 μ to 12 μ or from 3 μ to 9 μ or from 3.5 μ to 6 μ. The antiblocking particles can be present in the inner layer in an amount from 1500 to 20,000 ppm or from 2000 to 15,000 ppm or from 2500 to 12,000 ppm or from 4000 to 10,000 ppm or from 6000 to 9000 ppm.

[0098] The outer layer may further comprise a print intensifier comprising a polar polymer. Preferably, the polar polymer comprises at least one member selected from the group consisting of ethylene/maleic anhydride/ester terpolymer, ethylene/glycidyl methacrylate/ester terpolymer, and ethylene/acrylic acid copolymer. Preferably, the print enhancer is present on the outer layer of the film in an amount from about 1 to 25 percent, based on the weight of the outer layer of the film; more preferably from about 2 to 20 percent; even more preferably from about 5 to 15 percent; more preferably from about 5 to 10 percent.

[0099] The outer layer may have a thickness of at least 0.05 mm or from 0.05 to 1.5 mm or from 0.08 to 1 mm or from 0.09 to 0.8 mm or from 0.1 to 0.6 mm or from 0.13 to 0.4 mm or from 0.15 to 0.2 mm.

[00100] The heat seal layer is the inner layer of the heat shrinkable tubular film. The heat seal layer may contain a heat seal polymeric composition comprising at least one member selected from the group consisting of polyolefin, ethylene/alpha-olefin copolymer, ethylene/unsaturated ester copolymer, ionomer resin, propylene/ethylene, polystyrene, polyamide, polyester and polycarbonate.

[00101] The heat seal layer contains a polymeric seal layer composition that has a density of less than 0.92 g/c3 or less than 0.915 g/c3 or less than 0.912 g/c3 or less than 0.910 g/c3 or less than 0.909 g/c3 or less than 0.908 g/c3 or less than 0.907 g/c3 or less than 0.906 g/c3 or less than 0.905 g/c3 or less than 0.904 g/c3 or less than 0.903 g/c3 or from 0.900 to 0.915 g/c3 or from 0.900 to 0.912 g/c3 or from 0.900 to 0.910 g/c3 or from 0.901 to 0.909 g/c3 or from 0.902 to 0.908 g/c3 or from from 0.903 to 0.907 g/c3.

[00102] The inner sealing layer also comprises antiblocking particles, a fast blooming mold release agent and a slow blooming mold release agent, each of which is as described in various parts herein. Each of these components is mixed and extruded with the polymeric components present in the film. The antiblocking particles can be of any of the various compositions described herein. Anti-blocking particles are present in the inner sealing layer in a minimum amount of 2000 ppm based on the total weight of the sealing layer, or from 1500 to 20,000 ppm or from 2000 to 15,000 ppm or from 2500 to 12,000 ppm or from 4,000 to 10,000 ppm or from 6,000 to 9,000 ppm.

[00103] Antiblocking particles have a relatively large average particle size (ie, average) as determined by ASTM D4664. Anti-blocking particles can have an average particle size from at least 3 μ or from 3 μ to 20 μ or from 3 μ to 15 μ or from 3 μ to 12 μ or from 3 μ to 9 μ or from 3.5 μ to 6 μ.

[00104] The fast bloom mold release agent comprises at least one element selected from the group consisting of erucamide, oleamide, lauramide, lauric diethanolamide, monoglyceride, diglyceride, glycerol monooleate and glycerol monostearate. The fast bloom release agent can be present in the inner seal layer in a minimum amount of 1200 ppm based on the total layer weight, or from 2000 to 20,000 ppm or from 2500 to 15,000 ppm or from from 3,000 to 12,000 ppm or from 4,000 to 10,000 ppm or from 5,000 to 9,000 ppm.

[00105] Alternatively, the fast bloom release agent may have a single fatty acid chain which is unsaturated or less than about C16 in length or both. Alternatively, the slow bloom release agent can have a single saturated fatty acid chain that is more than C16 in length, or multiple fatty acid chains that are saturated or unsaturated, with a total carbon chain length of at least C20.

[00106] The slow-blooming mold release agent comprises at least one element selected from the group consisting of stearamide, bis-stearamide, ethylene bis-stearamide, stearyl stearamide, stearyl erucamide, erucyl erucamide, behenamide, ethylene bis-oleamide, oleyl palmitamide, stearate, sorbitan stearate, monostearate, distearate, tristearate, sorbitan monolaurate, pentaerythritol stearate ester, polyglycerol stearate, zinc stearate, calcium stearate, magnesium stearate, sodium stearate, potassium stearate. The slow bloom release agent may be present in the inner layer in an amount from at least 1200 ppm, based on the total weight of the layer, or from 2,000 to 20,000 ppm, or from 2,500 to 15,000 ppm, or from from 3,000 to 12,000 ppm or from 4,000 to 10,000 ppm or from 5,000 to 9,000 ppm.

[00107] The heat seal layer may have a thickness of at least 0.1 mm or from 0.15 to 5 mm or from 0.18 to 4 mm or from 0.2 to 2 mm or from 0.1 to 1.5 mm or from 0.2 to 1.1 mm or from 0.25 to 1 mm or from 0.3 to 0.8 mm or from 0. .35 to 0.7 mm or from 0.35 to 0.6 mm or from 0.4 to 0.6 mm or from 0.4 to 0.6 mm or about 0.47 mm .

[00108] The multi-layer heat-shrinkable film may contain one or more intermediate layers between the inner film layer of the tube and the outer film layer of the tube. The intermediate layers may comprise one or more (i) O2 barrier layer, (ii) tie layers to adhere the barrier layer to the inner and/or outer film layers, and (iii) bulking layers to add strength to the film. . The O2 barrier layer may be made from at least one element selected from the group consisting of polyvinylidene chloride, ethylene/vinyl alcohol copolymer, polyamide and polyester. The design and arrangement of the O 2 barrier layer can be designed to achieve any low level of oxygen transmission through the film as known to those skilled in the art.

[00109] The one or more tie layers may include at least one element selected from the group consisting of ethylene/carboxylic acid copolymer, ethylene/ester copolymer and anhydride-modified ethylene/alpha-olefin copolymer. In general, tie layers are relatively thin, as their purpose is simply to provide a chemically compatible composition between two layers which would otherwise not bond together to a desired degree.

[00110] The one or more bulk layers may comprise at least one element selected from the group consisting of polyolefin, ethylene/alpha-olefin copolymer, ethylene/unsaturated ester copolymer, ionomer resin, propylene/ethylene copolymer , polystyrene, polyamide, polyester and polycarbonate. Bulk layers are generally relatively thick and/or made from relatively strong polymers, as the purpose of bulk layers is to add strength, shrinkage (including free shrinkage and shrinkage strength), puncture resistance, etc. , to the movie.

[00111] Anti-blocking particles are hard particles that are supplied to the inner layer and optionally to the outer layer. Although many of the particles may be fully embedded in the thickness of the layer and therefore do not affect either the inner surface or the outer surface, at least some of the particles do protrude from the surface of the layer and cause the surface to be somewhat rough, with the raised regions reducing the degree to which adjacent film surfaces adhere to one another and allowing the film surfaces to slide easily over one another.

[00112] It has been found that for heat shrinkable packaging articles with relatively thick sealing layers made from a relatively low density polymeric composition, relatively large antiblocking particles (e.g. 3 microns and above) with relatively high loading (at least least 2000 ppm in layer weight) are required for the pipe to be opened by a Standard Openability Test as described below. Anti-blocking particles can have an average particle size from at least 3 microns (measured in accordance with ASTM D4664 or from 3 μ to 25 μ or from 3 μ to 15 μ or from 3 μ to 12 μ or from 3 μ to 9 μ or from 3.5 μ to 6 μ olAB layer size: 3-25 microns; 3-20 microns; 3.2-15 microns; 3.5 -10 microns; 4-7 microns; 4-6 microns; 4.5-5.5 microns. Anti-blocking particles can be present in the inner layer in an amount from 1500 to 20,000 ppm or from 2000 to 15,000 ppm or from 2500 to 12,000 ppm or from 4000 to 10,000 ppm or from 6000 to 9000 ppm.

[00113] Anti-blocking particles can be made of natural silica, synthetic silica, silicate, diatomaceous earth, fumed synthetic silica, precipitated synthetic silica, gelled synthetic silica, calcium sodium silicate, and sodium calcium aluminum silicate, talc, kaolin , clay, mica, silicate, aluminum silicate, silicon dioxide, magnesium silicate, calcium silicate, calcium carbonate and magnesium oxide. Antiblocking particles with a refractive index of 1.4-1.6 or 1.45-1.55 are preferred, as having a refractive index in this range results in a heat shrinkable film of less turbidity than if antiblocking particles with a refractive index outside this range were used.

[00114] If the tube is to be printed, the powder is applied after the ink has dried, but before winding. If the tube is not printed, the tube is unrolled just before converting into bags, with powder being applied after unrolling but before converting. Conversion of powdered tube (printed or unprinted) is accomplished by sealing and cutting the tube to form either end seal bags or side seal bags. Sealing can be accomplished using an impulse type heat sealer. Tube cutting to form distinct bags is performed after sealing using conventional film cutting methodologies.

[00115] For many uses, consumers and others place greater value on an article of packaging that exhibits a low level of turbidity. Haze is determined by the level of clarity across the entire film thickness. Turbidity measurements, as reported here, are determined using ASTM D1003-13. The heat shrinkable film can have a haze level of less than 15% or less than 12% or less than 10% or from 5% to 10%.

[00116] It has been found that the level of turbidity exhibited by heat shrinkable film is somewhat proportional to the amount and type of antiblocking particles used in the inner layer and outer layer of the tubular film. In general, the higher the level of particles, the higher the level of turbidity. The use of particulate materials with a refractive index from 1.4 to 1.6 or from 1.45 to 1.55 helps to minimize the haze effect of the anti-blocking particles. It has been found that the use of relatively large particles (average particle size from 3 μ to 10 μ) in relatively controlled amounts (for example, up to about 9,000 ppm, based on the weight of the layer) allows to obtain a heat shrinkable film which exhibits relatively high brightness while having desirable sliding and anti-jamming characteristics and opening ability.

[00117] For many uses, consumers and others place greater value on an article of packaging that exhibits a high level of gloss. Gloss is largely determined by the character of the outer surface of the packaging article. Gloss measurements, as reported here, are specular gloss measurements obtained using ASTM D 2457.

[00118] Supplying the outer layer with release agents, anti-blocking particles, and slip agents can decrease the gloss level displayed by the packaging article. It has been found that the outer surface of the heat shrinkable packaging article can exhibit a relatively high gloss while having the desired anti-blocking and slip properties by providing the outer layer with polysiloxane alone or the combination of polysiloxane and anti-blocking particles. In this way, the specular gloss can be at least 70% (measured in accordance with ASTM D 2457) or at least 75% or at least 78% or at least 80% or from 80% to 85%.

[00119] It is desirable that the outer layer of the packaging article has a low coefficient of friction, so that it readily slides in relation to other packaging articles with which it is in contact, without altering any other packaging article that it may contact . This is particularly important when using bags overlapped on strips or bags stacked in a box or other dispenser.

[00120] It is also desirable that the inner layer of the packaging article has a low coefficient of friction with respect to itself, since it is in contact with itself when the packaging article tube is in its flat configuration. This allows air to move freely between the inner surfaces of the tube to prevent air from being trapped or crushed while passing the tube through the nip rollers, as required during printing of packaging articles, as well as during converting. of heat-shrinkable tubular films into heat-shrinkable packaging articles such as bags.

[00121] The coefficient of friction (in English, COF) can be determined in accordance with the ASTM D 1894 standard, incorporated herein by reference in full. The inner and/or outer surfaces of the packaging article may have a peak coefficient of friction value less than 0.8 or less than 0.7 or less than 0.6 or less than 0.5 or 0.1 to 0.8 or from 0.1 to 0.7 or from 0.1 to 0.6 or from 0.1 to 0.5. The inner and/or outer surfaces of the packaging article may have an instantaneous coefficient of friction value less than 0.6 or less than 0.5 or less than 0.4 or less than 0.3 or from from 0.1 to 0.6 or from 0.1 to 0.5 or from 0.1 to 0.4 or from 0.1 to 0.3.

[00122] While it is desirable to completely eliminate dust from the packaging article, the powder can be supplied to the inside of the tube that is used to make the packaging article, while the outside remains dust-free or the powder can be supplied to the outside of the packaging article. packing item, while the inside is dust-free. If powder is used inside or outside, the powder may comprise at least one element selected from the group consisting of corn starch, tapioca starch, potato starch, talc and silica.

[00123] Figure 1 illustrates a cross-sectional view of a heat-shrink film with multiple layers 20. In the examples below, films 1-11 have cross sections that correspond to the number of layers and arrangement illustrated in Figure 1. The heat-shrink film 20 has seven layers, wherein the first layer 21 is an outer film layer that functions as an inner product contact layer and a heat seal layer. The second layer 22 functions as a first bulking layer. The third layer 23 functions as a first tie layer. The fourth layer 24 functions as an oxygen barrier layer. The fifth layer 25 functions as a second tie layer. The sixth layer 26 functions as a second volume layer. The seventh layer 27 functions as a tamper-evident layer.

[00124] Heat-shrinkable tubular films can be produced according to a process schematically illustrated in Figure 2. In the process illustrated in Figure 2, solid polymer granules (not shown) are fed to a plurality of extruders 28 (for simplicity, only one extruder is illustrated). Inside the extruders 28, the polymer granules are routed, melted and degassed, after which the resulting bubble-free melt is routed to the die head 30 and extruded through an annular die, resulting in the tube 32 which may have, for example about 15 mm thick and which includes the sealing layer, the first bulking layer and the first binding layer. Through passing into the die head 30, a continuous stream of corn starch powder (corn starch C-3170) obtained from the Flint Group; see AB10 in Table 1, below) is injected into the interior of tube 32 at such a rate that the amount of cornstarch powder deposited on the inner surface of tube 32 is adequate to prevent the tube from sticking to itself as that the tube is bent in the flat configuration, as well as after the biaxial orientation in the closed bubble process, as described below. The amount of powder placed inside the tube can be, for example, about 95 mm per 254 cm (100 inches) square of the inner surface of the unoriented tube 32. Other types of powder that can be used include tapioca powder and of potato starch, talc and silica.

[00125] After cooling or quenching by water from the cooling ring 34, the tube 32 is bent by clamping rollers 36 and is then fed through the irradiation dome 38 surrounded by the shield 40, where the tube 32 is irradiated with high-energy electrons energy (i.e., ionizing radiation) from iron-core transformer accelerator 42. Tube 32 is guided through irradiation dome 38 over rollers 44. Preferably, tube 32 is irradiated at a level of about 3 to 8 MR.

[00126] After irradiation, the irradiated tube 46 is driven through the pinch rollers 48, after which the irradiated tube 46 is slightly inflated, resulting in the closed bubble 50. However, in the closed bubble 50, the tube is not significantly stretched longitudinally, since the surface speed of the pinch rollers 52 is approximately the same speed as the pinch rollers 48. Furthermore, the radiated tube 46 is inflated just enough to provide a substantially circular tube without significant transverse orientation, i.e. , without stretching.

[00127] The slightly inflated irradiated tube 50 is passed through the vacuum chamber 54 and then routed through the coating die 56. The second tubular film 58 is melt-extruded from the coating die 56 and coated onto lightly inflated irradiated tube 50 to form two layers of tubular film 60. The second tubular film 58 preferably comprises an O2 barrier layer which does not pass through ionizing radiation. Additional details of the coating step described above are generally as set forth in US Patent No. 4,278,738 to BRAX et al., which is incorporated herein by reference in full.

[00128] After irradiation and coating, the tubular film 60 is wound on the winding roller 62. Then, the winding roller 62 is removed and installed as the unwinding roller 64, in a second stage in the production process of the desired heat-shrinkable tubular film. The tubular film 60 from the unwinding roller 64 is unrolled and passed over the guide roller 66, after which the two-layer tubular film 60 passes into the hot water bath tank 68 containing hot water 70. The tubular film coated now irradiated 60 is submerged in hot water 70 (having a temperature of about 85°C (185°F)) for a holding time of at least about 30 seconds, i.e., for a period of time so as to bring the film to the desired temperature for biaxial orientation. Subsequently, the irradiated tubular film 60 is guided through the pinch rollers 72 and the bubble 74 is blown, thereby transversely stretching the tubular film 60. Furthermore, while it is blown, i.e., transversely stretched, the pinch rollers 76 stretch the tubular film 60 in the longitudinal direction, since the nip rollers 76 have a surface velocity greater than the surface velocity of the nip rollers 72.

[00129] As a result of transverse stretching and longitudinal stretching, irradiated and coated biaxially oriented blown tubular film 78 is produced, this blown tube having preferably been stretched in a ratio of about 1:1.5 - 1: 6 and stretched in a ratio of about 1:1.5 - 1:6. More preferably, elongation and stretching are each performed in a ratio of about 1:2 - 1:4. The result is a biaxial orientation of about 1:2.25 - 1:36, more preferably 1:4 - 1:16. While the bubble 74 is held between the pinch rollers 72 and 76, the inflated tube 78 is bent by the rollers 80 and then transported through the pinch rollers 76 and through the guide roller 82 and then wound on the winder roller 84. The center roller 86 ensures good winding.

[00130] The resulting biaxially oriented heat-shrinkable tubular film is then unrolled and converted into heat-shrinkable bags by means of sealing and cutting through the tube. Optionally, the bags can have a print applied to the outer surface. During printing, ink is applied to the tube before the tube is converted into bags. In addition to preventing the interior of the oriented tubular film from sticking to itself, the cornstarch powder present within the tubular film also allows the tube to slide against itself and allows the air within the tubular film to move within the tube. , so that tube creasing is reduced or eliminated as the tube passes through nip rollers used in processing, including printing.

[00131] In addition, during the conversion of the oriented tubular film into bags, the same cornstarch powder was applied to the outside of the tube. Cornstarch powder was applied to the outer surface of the tube at a level of about 95 milligrams per 254 cm (100 square inches). Cornstarch powder can be applied using a metering roller or gravity feed. Cornstarch powder can be applied to just one side of the tube while the tube is in a flat configuration. Thereafter, when the powdered heat shrinkable tubular film is rolled up to form a tube roll, the powder applied to one flat side is transferred to the other flat side while the first flat side comes into contact with the flat side on the tubular film roll. heat shrink wrapped, dusted.

[00132] Figure 3 is a schematic of an end-seal heat shrink bag 160 in flat configuration. End seal bag 160 is made from heat shrinkable film seamless tube 162. Figure 4 is a cross-sectional view of bag 160 taken through section 4-4 of Figure 3. Looking at Figures 3 and 4 together, bag 160 comprises a bag film 162, a top edge 164 defining an open top, a first side bag edge 166, a second side bag edge 168, a bottom edge 170, and an end seal 172.

[00133] Figures 5 and 6 together illustrate the heat-shrink side sealing bag 180 in the flat configuration. Figure 6 is a cross-sectional view of the bag 180 taken through section 6-6 of Figure 5. The side seal bag 180 is also made from the heat shrinkable tubular film as seen in the end seal bag of Figures 3 and 4, however , in producing the side seal bag 180, the seamless tube was cut in the machine direction to form the top portion of the bag 184 and heat sealed through the tube to make the side seals 192 and 194, with the orientation in the direction of the film machine 182 running transversely through side seal bag 180. Looking at Figures 5 and 6 together, side seal bag 180 is made from a bag film 182 that is heat sealed to itself. The side seal bag 180 has top edge 184 defining an open top, a folded bottom edge 190, a first side seal 192, and a second side seal 194.

[00134] Figure 7 illustrates a tote bag 66 made from sealing two separate flat film parts together. Tote bag 66 has open top 68, bottom heat seal 70 and bottom edge 72, first side seal 74 and first side edge 76, second side seal 78 and second side edge 80. Together, the first and second side seals 74 and 76 join with the bottom seal 70 to form a "U" seal that joins the two flat film parts together to form the bag-like bag 66.

[00135] Figures 7, 8 and 9 illustrate a tote bag 266 made by sealing two separate pieces of flat film together. In Figures 7, 8 and 9, the bag 266 has an open top 268, bottom heat seal 270 and bottom edge 272, first side seal 274 and first side edge 276, second side seal 278 and second edge side seal 280. Together, the first and second side seals 274 and 276 join the bottom seal 270 to form a "U" seal that joins the two flat film parts together to form the tote bag 266.

[00136] Figures 10 and 11 illustrate the end sealing hollow bag 206 in the flat configuration. End sealing hollow bag 206 is a seamless tubular film 212 to which patches 214 and 216 are adhered. Bag 206 has end seal 210 and open top 208. Each patch is confined to one flat side of bag 206 by end sealing 210 the inner layer of tubular film 212 to itself. End seal 210 is not made through either patch 214 or 216. Furthermore, patches 214 and 216 do not fully extend to either of the flat, folded side edges of end seal bag 206.

[00137] Figures 12 and 13 illustrate the side seal hollow bag 218 in a flat configuration. The side-seal hollow bag 218 is made from a folded bag film 220 to which the first patch 230 and the second patch 232 are adhered. The bag film 220 has a seamless (i.e., folded) bottom edge 224, a open top portion 222, the first side seal 226 and the second side seal 228, with each of the side seals 226 and 228 being from the inner layer of the tube itself. Each of the patches 230 and 232 is confined to a flat side of the bag 220, with the patches not extending to either the side seals 226 or 228 or the open top portion 222 or the folded bottom portion 224.

[00138] Additional hollow bags are described in the following United States patent documents, each of which is hereby incorporated in full by reference thereto: (A) US 6,287,613; US 6,383,537; US 5,540,646; US 5,545,419; US 6,270,819; US 6,790,468; US 6,663,905; US 6,296,886; US 7,338,691; US 5,534,276; US 6,228,446; and US 7,048,125.

[00139] The "green strength" (i.e., the strength of the adhesive bond between the patch film and the tube within 15 minutes after the patch and tube films contact each other with adhesive between them) is found to be significantly increased by the presence of anti-blocking particles in the outer layer of the tubular film. For example, the outer layer of the heat shrinkable tubular film may comprise antiblocking particles having an average particle size of 3000 microns to 10,000 microns, the antiblocking particles being present in the outer layer in an amount from 3000 to 10,000 ppm. The result can be that the patch film is adhered to the outer surface of the tubular film with a green adhesion force of at least 0.1126 N/m (1 pound/inch) of patch width measured within 15 minutes of application of the patch. patch film to tubular film versus 0.0677 N/m (0.6 pounds/inch) patch width without the antiblock particles present.

BAG OPENING CAPACITY TEST: DEVICE AND CONFIGURATION

[00140] Figure 14 illustrates a perspective view of a schematic of a Standard Bag Open Capability Tester 300 having a horizontal bag platform 302 having the upper surface 304 for supporting a bag 310 in flat configuration ( see Figures 18-21). Bag platform 302 is designed to be long enough and wide enough to provide full widthwise and lengthwise support for the longest bag being tested for openability in tester 300.

[00141] Adhered to the top surface 304 of the bag platform 302, extending behind the front edge 306 of the bag platform 302 in a direction perpendicular to the front edge 306 of the bag platform 302, is a pair of bag retention tapes 308, each extending 3.81 cm (1.5 inches) below the length of bag platform 302. See Figure 15.

[00142] Each of the tapes 308 is attached with the "sticky" side to the upper surface of the bag platform 302 by applying glue or double-sided tape under the back of each tape 308, that is, to keep the tapes 308 face down on top surface 304 of bag platform 302. Each of the bag retention tapes 306 is 6 mm wide, with the "adhesive side" of the tapes having an adhesion to steel of at least 90 g/6 mm measured according to the AFERA 4001 - ED.10/87 standard. One such tape is BN 39 bag tape, obtained from Boston tapes S.p.A. of Sessa Aurunca, Italy.

[00143] The spacing between the two pieces of tape 308 is dependent on the flat width of the bag being tested. More particularly, the centerings running down the center of each of the two pieces of tape 308 are spaced a distance of one-third of a full flat width of the packaging article being tested. This arrangement is easily evident in Figure 19, where the ribbons 306 are spaced one third of the flat width of the bag 310.

[00144] Outside the front edge 306 of the bag platform 302 is the mounting bracket 312 which was mounted on the air nozzle 314 and on the air knife 316. The air nozzle 314 has a tip positioned along the center line of the bag, the center line being inclined at 15° from the horizontal. The air nozzle 314 has a tip positioned 7.62 cm (3 inches) from the edge 318 of the bag 310. The air knife 316 has an upper surface (i.e., facing the bag 310) that coincides with the bag 302 and a parallel air discharge line 13.97 cm (5.5 inches) from front edge 306 and bag edge 318.

[00145] Not illustrated in Figures 14-21 are solenoid control valves and air ducts to supply 20.8 scfm of dry and clean compressed air at 0.689 MPa (100 psi) to the air nozzle 314 and even to supply clean compressed air and dried to air nozzle 314 and air knife 316. Also not illustrated in Figures 14-21 is the compressor for generating the compressed air.

PERFORMING THE BAG OPENING CAPACITY TEST

[00146] The Bag Opening Capability Test is performed first by storing a heat shrinkable tubular film in the flat configuration wrapped around an 8 cm diameter core for 7 days, with the multilayer heat shrinkable tubular film yarn being wound the core until it has reached a total diameter (core plus wound film) of 48 cm, with the tubular film being wound onto the core until a total diameter (core plus wound film) of 48.26 cm (19 inches) is reached, with the tubular film being wound at a tension of 179 g/cm tube width, at the end of which the wound tube is allowed to stand under ambient conditions for a full 7 days, with the tubular film being unwound until the coils are at 2, 54 cm (1 inch) from the core. At this point, a portion of the tubular film is removed and converted into end seal bags and tested according to the Bag Open Capability Test procedure as shown immediately below.

[00147] The packaging article, in the flat configuration, is then placed on the top surface 304 of the bag platform 302, with the bag edge 318 being directly over the front edge 306 of the bag platform 302. The packaging article 310 has a flat width of at least 3.5 inches (8.89 cm) and a flat length of at least 4 inches (10.16 cm).

[00148] The packaging article 310 is initially in its flat configuration, with the flat bottom side being held against the upper surface 304 of the bag platform 302 by the pair of bag retention tapes 308, each of which extends 3, 81 cm (1.5 inches) along the length of the packaging item. Each pair of tapes has a width of 6 mm and an adhesion to steel of at least 90 g/6 mm, measured according to AFERA 4001-ED.9/79. Each of the ribbons runs for a length of 3.81 cm (1.5 inches) from the linear leading edge of the packaging article in a direction perpendicular to the open top edge of the packaging article and each ribbon has a center placed on a position corresponding to 33.3% of a distance across the flat width of the packaging article, with the edge of the packaging article parallel and directly above the front edge 306 of the support member 302. At this point, there is no airflow through the air nozzle 314 or air knife 316 and the packaging article 310 in the tester 300 appears as illustrated in Figures 18, 19, 20 and 21.

[00149] Once the packaging article is positioned on the upper surface 304 of the platform 302 and held in place by tapes 308, a first solenoid is activated to supply compressed air to the air nozzle 314 and, simultaneously, a second solenoid is activated to supply compressed air to air knife 316. Compressed air is supplied to the air nozzle for 500 milliseconds, at which time the first solenoid is closed, thereby disabling more air to the air nozzle. Compressed air supplied to the air knife continues for a full 2 seconds, after which the second solenoid is closed, thereby turning off more air to the air knife.

[00150] At the end of the two seconds of air flow through the air knife 316, the packaging article is considered "open" if it inflates with air, that is, the article appears as illustrated in Figures 22, 23, 24 and 25. As is evident from Figures 22-25, if the article inflates, the flat sides are separated by the air flow passing through the air knife 316.

[00151] On the other hand, if at the end of the two seconds of air flow through air knife 316 the packaging article 310 is considered "not opened", the article does not inflate with air, that is, the article appears as illustrated in the Figures 26, 27, 28, and 29. This appearance results if the inner layer of the tube adheres to itself (ie, "gets stuck") to a degree to which the airflow from the air nozzle followed by the air knife is unsuitable for opening the packaging item.

[00152] Figure 30 is a perspective view of the air nozzle 400 to be used with the test device 300. The air nozzle 400 is commercially available as a SILVENT stainless steel Laval nozzle 1011. The air nozzle 400 has a 1/8" male thread, has a center hole 402 that creates a concentrated supersonic air jet and a center wraparound hole 402 that has six diverging grooves 404 to generate a laminar airflow. Also, the center wraparound hole is comprised of six fins 406 which serve to prevent the terminal static pressure from going above 210 kPa The SILVENT 1011 Laval air nozzle can be obtained from Silvent AB at Vevgatan 15, SE-504 64 Boras, Sweden.

[00153] Figure 31 is a perspective view of air knife 420 to be used with test device 300. Air knife 420 is commercially available as Aluminum Strip Airmover SE150 from Brauer Clamps USA Inc. of Warren, Michigan. The 420 Air Knife uses the energy of a small volume of compressed air, supplied by a standard compressor, to amplify the surrounding air for a high-velocity, high-volume, low-pressure output airflow using the coanda effect.

[00154] Figure 32 is a schematic of the tape bag assembly 450 comprising bags 452, 454, 456 held together by overlapping bags (shingled bags, in overlapping relationship) held in place with respect to each other others by their adherence to the sticky side of parallel strips 458 and 460. Such lap bag assemblies 450 are supplied in long strips containing hundreds or even thousands of bags, supplied to bag loading devices. Wrapped bags held by straps, such as the two parallel straps illustrated in Figure 32, and the use of assemblies comprising these strapped sacks and their use in product loading devices are described in USPN 3,587,843, USPN 3,698. 547, USPN 4,032,038 and USPN 4,076,122, each of which is hereby incorporated in full by reference thereto.

[00155] Figure 33 is a schematic illustration of a top view of the rotary chamber vacuum machine 470 that has been used for decades for packaging a wide variety of packaged meat products (not illustrated). A heat shrink bag with a product (not shown) is placed on plate 472 which is in the product loading zone. Thereafter, chamber lid 474 pivots over and falls onto platen 472 as vacuum chamber carousel assembly 476 rotates counterclockwise to position A, then B, then C, then D, then E, movement during which the atmosphere from plate 472 and chamber 474 is evacuated from within the chamber and into the bag, the bag is hermetically sealed and the excess bag length is cut off and sucked into a waste area. Then, in position F, the vacuum is released and air fills the chamber and the chamber 474 lifts the platen 472, allowing the vacuum packed product to be directed off the platen 474 and onto the conveyor 478 for further processing, such as passage through a hot air tunnel (not shown) to retract the bag film tightly around the meat product. The counterclockwise rotational movement of the vacuum chamber carousel assembly 476 is continuous throughout the process, as is the associated counterclockwise rotation of the plate carousel assembly 480.

EXAMPLES

[00156] Various films were produced in the form of multilayer heat-shrinkable tubular films using the process illustrated in Figure 2, described above. While these tubes can be converted into a variety of heat-shrinkable packaging articles, such as end-seal bags, side-seal bags, and overwraps, the tubes have been converted into packaging articles (i.e., end-seal bags, as illustrated in Figures 3 and 4) which were later tested for opening ability. The structures of these films, including layer arrangement, layer composition and layer thicknesses, are provided in various tables below. The resins and other components used in these films are given in Table 1, immediately below.TABLE 1

[00157] Table 2 below provides the structure and composition of Film No. 1, including the identities of the polymers used in the various layers, the arrangement of the layers, and the thickness of the layers. Film No. 1 was a prior art film produced according to the process illustrated in Figure 2, described above. The solid-state orientation of the tape was performed at about 3.6:1 in the machine direction and 3.6:1 in the cross direction, for a total orientation ratio of about 13:1. The process included the addition of cornstarch powder to the inside of the ribbon immediately after extrusion, as well as the addition of cornstarch powder to the outside of the heat shrinkable film, as described above in Figure 2.TABLE 2

[00158] Several additive compositions (in English, ACs) have also been prepared for use in the sealing layer and/or in the outer tamper layer, in order to eliminate the need to use powder, while maintaining the properties of sliding and anti-blocking of the film with powder over it, as follows. TABLE 3 Additive Compositions for Dust-Free Tubular Films

[00159] Heat-shrinkable tubular films No. 2 to No. 11 were also prepared by the process illustrated in Figure 2, except that (i) no powder of any kind was added to the inside of the tape immediately after extrusion and (ii) no powder of any kind has been added to the outside of the resulting heat-shrinkable tubular film, even before or during conversion into heat-shrinkable packaging articles. Tubular Films #2 through #11 were prepared by performing solid state orientation of the tape at 3.6X in the machine direction and 3.6X in the cross direction for a total orientation ratio of approximately 13:1. No. 2 Heat Shrink Tube Film to No. 11 Tube Film were powder-free heat shrink films that were supplied with additives to the inner layer and/or outer layer in an effort to impart the tube and resulting bags with anti-blocking character (e.g., ability to opening) and slippage desired, i.e., in an effort to give the resulting heat-shrinkable films and the resulting packaging articles a slippage and anti-blocking character comparable to bags with powder on their inner surface and with powder on their outer surface .TABLE 4

[00160] Tubular Film No. 2 opened before orientation in the solid state, but did not open after orientation in the solid state, since the inner layer of the oriented tubular film was stuck to itself.TABLE 5

[00161] Tubular Film No. 3 opened readily before solid-state orientation, but did not open after solid-state orientation, as the inner layer of the oriented tubular film stuck to itself. Thus, the layer thickness reported is that of the unoriented pipe layers.TABLE 6

[00162] Tubular Film No. 4 opened before solid state orientation and after solid state orientation. Since the tube can be opened after orienting (ie, because the inner surface has not adhered to itself tightly enough to get stuck), the reported layer thickness is of the layers of heat shrink film taken from the oriented tubular film.Table 7

[00163] Tubular Film No. 5 was stuck to such an extent that it did not open even before solid state orientation. Since the tape tube cannot be opened even before solid-state orientation (i.e., because the inner layer of the unoriented tape has stuck to itself), the layer thickness numbers given in Table 7 above are with based on rates of materials pumped through the annular die. Table 8

[00164] As with Film Tube No. 4, Film Tube No. 6 opened before solid state orientation and after solid state orientation. Since the tube can be opened after orientation, the reported layer thickness is of the layers of heat shrinkable film taken from the oriented tubular film.

Opening Results: Tubular Films No. 1 to No. 6

[00165] The data obtained from the production of Film No. 1 to Film No. 6 resulted in the discovery that the size and amount of anti-blocking particles provided in the inner layer, as well as the presence and amount of both bloom release agents both slow and fast on the inner layer, resulted in (i) the ability to open the tape prior to solid state orientation so that the shrink film production process could run to completion and (ii) a heat shrink tube that could be rolled into a roll in a flat configuration and then unrolled and converted into packaging articles that can be opened by an Openability Test. Considering the above results for Tube Films #1 to #6, only Tube Film #4 and Tube Film #6 were prepared in a manner that produced both (i) the ability to open the tape prior to orientation in the solid state as (ii) a heat shrinkable tubular film which can then be converted into openable packaging articles.

[00166] Since all process factors remained substantially constant, except the composition of the additives in the internal heat seal layer of the tube, it is believed that the differences in composition between the various heat seal layers were responsible for the differences in the data of opening capacity between Tube Films Nos 4 and 6 versus Tube Films Nos 2, 3 and 5.

[00167] More particularly, the type and amount of antiblocking particles and release agents were sufficient for Tubular Film No. 2 to open before solid state orientation, but not after solid state orientation. The fact that Tubular Film No. 3 opened before solid-state orientation but not after solid-state orientation confirmed that, relative to Tubular Film No. 2, it nearly tripled the % by weight and size (μ) of antiblocking particles ( Tube Film No. 3 vs. No. 2) in combination with half of the fast bloom release agent, but nearly doubling the slow bloom release agent (Tube Film No. 3 vs. No. 2) did not give the tube a combination of type and amount of anti-blocking particles and release agents to produce a different opening result. In Tubular Film No. 5, raising the amount of anti-blocking particles even more, but eliminating the fast blooming release agent, proved to impede even the opening ability of the tubular tape, establishing the importance of the fast blooming release agent in the layer inside of the tube.

[00168] In contrast, Tubular Film No. 4 opened at all stages (ie, before orientation as well as after orientation and winding). Tubular Film No. 4 received relatively high levels of both fast and slow bloom release agents (9000 ppm and 7000 ppm, respectively), but with 2500 ppm of antiblocking particles that are 3.5 µm in size. This combination of 3.5 µm particle size at 2500 ppm along with 9000 and 7000 ppm release agents gave better openability over the somewhat different combination of additives present in Tube Films Nos. 2 and 3.

[00169] Regarding the opening ability at all stages obtained with Tube Film No. 4, the complete lack of opening ability for Tube Film No. 5 revealed that the elimination of the slow bloom release agent, in combination by decreasing the fast bloom release agent to 1000 ppm while simultaneously increasing the anti-block particle content to 9600 ppm (compared to 2500 ppm for Tube Film No. 4) and increasing the particle size from 3.5 µm (Tubular Film No. 4) to 5 µm (Tubular Film No. 5), demonstrated the need for a substantial amount of the fast bloom release agent. A comparison of the two-stage openability of Film #4 versus the one-stage openability of Tube Films #2 and #3 further confirms the need for a substantial amount of fast bloom release agent.

[00170] Film No. 4 opening ability data demonstrates that relatively high levels of slow and fast bloom release agents in combination with a moderate amount of relatively large anti-blocking particulates (3.5 μ) produced an opening ability at both stages in the production of a heat-shrinkable tubular film. Relative to Tubular Film No. 4, Tubular Film No. 6 received even higher levels of fast and slow bloom release agents and approximately the same wt% of 3.5 µm antiblocking particles plus about one % in Equal weight of 15 μm particles with the opening ability of Tube Film No. 6 confirming that the presence of even more release agents and anti-blocking particles also generates the two-stage opening ability as previously found for Tube Film No. No. 4. However, the turbidity level for Tube Film #6 was significantly higher than the turbidity level measured for Tube Film #4. See Table 14 below.

[00171] Additional work to develop a tube with two-stage opening capability was carried out when producing Tube Films Nos. 7 to 11, as shown below. Tube Film Nos. 7 to 11 each varied only in the types of additives and/or amounts supplied to the inner heat seal layer of the film. Tables 9-13, below, give the layer arrangement, layer composition and layer thickness for each of Tubular Films Nos. 7 through 11. TABLE 9 TABLE 10 TABLE 11 TABLE 12 TABLE 13

[00172] The amounts of fast blooming mold release agent and slow blooming mold release agent were relatively flat for the heat seal layers of each Tubular Film No. 7 to No. 11. More particularly, the amount of release agent The fast blooming release agent in the inner layer ranged from 8,100 ppm to 9,000 ppm, while the slow blooming release agent ranged from 5,600 ppm to 7,000 ppm. In contrast, the amount of antiblocking particles ranged from high at 17,500 ppm to low at 4,375 ppm. Haze data for Tube Films #7 through #11 revealed that a lower amount of antiblocking particles produced a film that exhibited a lower incidence of haze. Low turbidity is desirable as the film appears more transparent the lower the turbidity. See Table 14 below.

[00173] Table 14 also includes results for Additional Tube Films Nos. 12 to 17. In this set of examples, the same base film used for Tube Films Nos. 2 to 11 again received different amounts of release agents and antiblocking particles. Although Tube Films Nos. 12 to 17 each exhibit a two-stage opening ability, Tube Films Nos. 16 and 17 exhibit "moderate resistance" to opening, while Tube Films Nos. 12 to 15 exhibited "substantial resistance". the opening. For Tubular Films Nos. 2 to 17, the openability characterization was a subjective description based on a manual manipulation and blowing on the heat-shrink film coiled tube. It was not performed in accordance with the Opening Capability Test described below. TABLE 14: RESULTS FOR THE INNER LAYER

[00174] * Opened: tube opened initially, but with slight resistance to opening, i.e., not as readily as samples marked as simply "opened"

[00175] ** Opened: the tube initially opened, but with substantial resistance to opening

[00176] Additional tubular films were prepared in an effort to discover what additive(s) were needed in the outer layer of the tube to impart performance characteristics at least substantially equivalent to the use of powder on the outside of the film tubular. Powder on the outside of the tubular film increases the release properties of the film (i.e., so that the film does not stick during unrolling and when handling stacked bags and glued bags) and decreases the coefficient of friction of the outer surface of the film, so that the tubular film and packaging articles made therefrom slide freely relative to equipment surfaces, etc., during further processing of the film, including during converting the tube into packaging articles and subsequent processing of the packaging items.

[00177] Table 15, below, provides composition and performance data for Tubular Films Nos. 19-31, each of which had an outer layer that was extruded with one or more anti-block or slip additives. While no powder was added to the outer surface of any of Tube Films Nos. 19-31, powder was added to the interior of Tube Films Nos. 19-31 during manufacture.

[00178] Among Tubular Films Nos 19-31, turbidity ranged from a minimum of about 5% to a maximum of about 15%, with most films exhibiting from 6% to 11% turbidity. Brightness ranged from low at about 45% to high at about 78%. Table 15

[00179] Tubular Films Nos. 33 to 41 were prepared entirely free of dust inside the tube or on the outside of the tube. In each of these tubular films, a release agent and/or antiblocking particles were mixed into each of the inner tube layer and the outer tube layer. The multilayer structures of Tubular Film Nos. 33-41 are given in Table 16 to Table 24, below. Tables 16 to 24 include the composition and thickness of each layer.TABLE 16 TABLE 17 TABLE 18 TABLE 19 TABLE 20 TABLE 21 TABLE 22 TABLE 23 TABLE 24

[00180] In Tubular Films Nos. 33-41, each of the inner layers contained 20% by weight of AC # 5, which provided the inner layer with 7000 ppm of fast bloom release agent (erucamide), 7000 ppm of slow bloom release agent (bis-stearamide) and 6000 ppm of 5 µm silica anti-blocking particles. This blend was selected as imparting two-stage opening capability without increasing turbidity to an undesirable level.

[00181] Tubular Film No. 35 and Tubular Film No. 36 exhibited adhesion on converting and less adhesion on loading. Tube Film No. 37 and Tube Film No. 38 provided no stick/free hanging bags on converting and no iridescence when hand loading. However, Tube Films Nos. 37 and 38 exhibited greater haze and lower brightness than Tube Films Nos. 35 and 36.

[00182] Table 25, below, provides a summary of the composition and various results obtained for Tubular Films Nos. 33-41. The turbidity values were affected by the inner layer and the outer layer. The gloss and coefficient of friction values were determined by the characteristics of the outer layer only. Low haze and high gloss are a desirable combination of properties. The results in Table 25 show the effects on haze and gloss and the coefficient of friction as a function of the combination of slip and antiblocking agents present in the outer and inner layers of Film Nos. 33-41, as well as for Films A through H. .

[00183] Additional Tubular Films Nos. 42 to 49 were prepared in the same way as Tubular Films Nos. 33-41, except that (i) powder was supplied to the inside of the tube during manufacture and (ii) the composition of the outer layer of the tube was changed. The composition of the outer tube layer for Tubular Films Nos. 42-49 and the gloss, haze and other performance characteristics are also given in Table 25. TABLE 25

[00184] Tubular Films Nos. 50-55 were also prepared to further evaluate the effects of various combinations of slip agents and antiblocking particles for use on the outer layer in order to obtain the desired haze, gloss, and slip characteristics. Tubular Films Nos. 50-55 were 7-ply films of the same type as Tubular Films Nos. 2 through 32 and were prepared with powder added to the inside of the tube during manufacture. The results, including the composition of the additives in the outer layer, haze, gloss, clarity and coefficient of friction, are given in Table 26, below. TABLE 26

[00185] Tubular Films Nos. 56 to 59 were prepared entirely free of dust inside the tube or on the outside of the tube. In each of these tubular films, a release agent and/or antiblocking particles were mixed into each of the inner tube layer and the outer tube layer.

[00186] The multilayer structures of Tubular Film Nos. 56-59 are given in Table 27 to Table 30, below. Tables 27-30 include the composition and thickness of each layer. Tubular Films Nos. 56 to 59 each had inner layers containing 7000 ppm of erucamide, 7000 ppm of bis-stearamide and 6000 ppm of 5 micron silica antiblocking particles. Tube Films Nos. 56 and 59 had outer layers with a polymer density of about 0.907 g/cm3, while Tube Films Nos. 57 and 58 had outer layers with a polymer density of about 0.914 g/cm3. TABLE 28 TABLE 29 TABLE 30

[00187] Table 31 provides the results for gloss and haze depending on the type and amount of slip agent and the type and amount of antiblocking particles. TABLE 31

[00188] Tubular Films Nos. 56 to 59 each had inner layers containing 7000 ppm of erucamide, 7000 ppm of bistearamide and 6000 ppm of 5 micron silica antiblocking particles. Tube Films Nos. 56 and 59 had outer layers having a polymer density of about 0.907 g/cm3, while Tube Films Nos. 57 and 58 had outer layers having a polymer density of about 0.914 g/cm3.

[00189] While the present invention has been described with respect to preferred embodiments, it should be understood that modifications and variations may be used without departing from the principles and scope of the invention, as those skilled in the art will readily understand. Therefore, such modifications may be practiced within the scope of the following claims.

Claims (15)

1. Packaging article comprising a heat shrinkable film tube in flat configuration, the heat shrinkable film tube having a first flat side in contact with a second flat side, the heat shrinkable film tube comprising a multilayer heat shrinkable film characterized in that comprising: (A) a self-sealed inner heat seal layer, with a first portion of the inner heat seal layer being on the first flat side of the packaging article and a second portion of the inner heat seal layer being on the second flat side of the packaging article, with the first portion of the heat seal layer being in contact with the second portion of the heat seal layer, with the heat seal layer comprising a polymeric composition of the seal layer comprising polyolefin having a average density of less than 0.92 g/cm3, the inner heat seal layer having a thickness of at least 2.54 µm (0.1 mm), the inner heat seal layer further comprising: (a) (i) antiblocking particles in an amount from at least 2000 ppm, based on the total weight of the layer, the antiblocking particles having an average particle size from at least 3 microns; (a) (ii) a fast blooming mold release agent in the inner seal layer in an amount from at least 1200 ppm, based on the total weight of the layer, the fast blooming mold release agent comprising at least one selected element from the group consisting of erucamide, oleamide, lauramide, lauric diethanolamide, monoglyceride, diglyceride, glycerol monooleate, glycerol monostearate; and (a) (iii) a slow blooming mold release agent in the inner sealing layer in an amount from at least 1200 ppm, based on the total weight of the layer, the slow blooming mold release agent comprising at least one element selected from the group consisting of stearamide, bis-stearamide, ethylene bis-stearamide, stearyl stearamide, stearyl erucamide, erucyl erucamide, beanamide, ethylene bis-oleamide, oleyl palmitamide, stearate ester, sorbitan stearate, monostearate, distearate, tristearate, sorbitan monolaurate, pentaerythritol stearate ester, polyglycerol stearate, zinc stearate, calcium stearate, magnesium stearate, sodium stearate, potassium stearate; and (B) an outer layer comprising a polymeric outer layer composition comprising at least one member selected from the group consisting of polyolefin, ethylene/alpha-olefin copolymer, ethylene/unsaturated ester copolymer, ionomer resin, propylene copolymer /ethylene, polystyrene, polyamide, polyester and polycarbonate; wherein the inner layer has an inner surface and the outer layer has an outer surface, wherein at least one of the inner surface of the inner layer and the outer surface of the outer layer is free of dust thereon, and wherein the article The packaging article has an open end and the anti-blocking particles, the fast blooming mold release agent and the slow blooming mold release agent are present in the inner heat seal layer of the multilayer heat shrink film in such an amount that the packaging article opens in a Standard Opening Test in which a strand of multi-ply heat-shrinkable film tube was stored in a flat configuration while wrapped around a core having a diameter of 8.9 cm for 7 days, with the multilayer heat-shrink film being wound onto the core to a roll diameter of 50 cm, with the film being wound at a tension of 179 gm/cm flat tube width, at the end of which a portion of the tube 2.54 cm from the core is converted into a packaging article while the tube remains in the flat configuration, with the resulting packaging article being provided with an open top having an open top edge transverse to a length of the tube, with an outer bottom surface plane of the packaging article being in plane contact with an upper horizontal surface of a support platform that has a linear leading edge that is wider than the width of the packaging article and a length greater than the packaging article, with the lower flat outer surface of the packaging article being in adherent contact with the upper horizontal surface of the support platform by a pair of tapes, each having a width of 6mm and an adhesion to steel of at least 90g/6mm, measured in accordance with AFERA Standard 4001-ED.9/79, with each strip running 3.8 cm (1.5 inches) from the linear leading edge of the packaging article in a perpendicular direction to the open top edge of the article and each tape having a center line placed at a position corresponding to 33.3% of a distance across the flat width of the tube, with the open top edge of the packaging article parallel to and directly above the leading edge of the support platform , the packaging article opening when simultaneously subjected to: (i) a 0.5 second burst of air supplied by a Laval air nozzle that has an air consumption of 28.9 Nm3/h (15 scfm), the air nozzle being positioned along a 15 degree inclined center line from the support platform; the air nozzle having a tip positioned 7.6 cm (3 inches) from the edge of the packaging article, with the air nozzle pointing toward the upper open edge of the packaging article, the anti-blocking particles made of natural silica, silica synthetic silicate, diatomaceous earth, synthetic fumed silica, synthetic precipitated silica, synthetic gelled silica, calcium sodium silicate, and sodium calcium aluminum silicate, talc, kaolin, clay, mica, silicate, aluminum silicate, silicon dioxide , magnesium silicate, calcium silicate, calcium carbonate, magnesium oxide or mixtures thereof, and (ii) a 2 second air flow from an air knife positioned parallel to and coincident with the support platform, the air having a discharge line 14.0 cm (5.5 inches) from the edge of the packaging article, the air knife having an air consumption of 76.5 Nm 3 /h (= 45 scfm). 2. Packaging article, according to claim 1, characterized in that the heat sealing layer has a thickness from 5.08 to 27.94 μm (0.2 mil to 1.1 mil) and the The polymeric composition of the sealing layer has a density of less than 0.915 g/cm3, the antiblocking particles are present in an amount from 1,500 to 20,000 ppm and have an average particle size from 3 to 25 microns, the fast blooming mold release is present in an amount from 2000 to 20,000 ppm and slow blooming mold release is present in an amount from 2000 to 20,000 ppm. 3. Packaging article according to claim 1 or 2, characterized in that the outer layer is free of dust on it and the inner layer is free of dust on it. 4. Packaging article according to claim 1 or 2, characterized in that the outer layer has a dust-free outer surface and the inner layer has a dust-free inner surface and the outer layer comprises at least one agent slip selected from the group consisting of polysiloxane, release agent and wax. 5. Packaging article according to claim 4, characterized in that the at least one glidant is present in a total amount from about 1,000 to 15,000 ppm, based on the weight of the outer layer. 6. Packaging article according to claim 1 or 2, characterized in that the outer layer has a thickness of at least 1.27 μm (0.05 mil) and the outer layer comprises at least one slip agent selected from the group consisting of polysiloxane, release agent and wax and at least one slip agent is present in a total amount of 1000 to 15000 ppm based on the weight of the outer layer. 7. Packaging article according to claim 1 or 2, characterized in that the heat-shrinkable film has a free shrinkage L+T at 85°C of at least 50%, measured in accordance with ASTM D 2732. 8. Packaging article according to claim 1 or 2, characterized in that the inner layer has an inner surface that exhibits a peak friction coefficient of less than 0.8, measured in accordance with ASTM D 1894, and the outer layer has an outer surface that exhibits a peak coefficient of friction less than 0.8, measured in accordance with ASTM D 1894. 9. Packaging article, according to claim 1 or 2, characterized in that the heat-shrink film with multiple layers exhibits a specular brightness of at least 70%, measured in accordance with ASTM D 2457 and/or in which multilayer heat shrinkable film exhibits haze of less than 15% measured in accordance with ASTM D1003-13. 10. Packaging article according to claim 1 or 2, characterized in that the heat shrinkable film tube has a heat shrinkable adhesive film adhered to its outer surface and the outer layer of the heat shrinkable film tube comprises anti-blocking particles with a size particle average from 3000 microns to 10,000 microns, the anti-blocking particles being present in the outer layer in an amount from 3000 to 10,000 ppm, the adhesive film being adhered to the outer surface of the film tube with a "green bond" resistance of at least 0.18 kg/cm (1 pound/inch) of adhesive width measured within 15 minutes of applying the adhesive film to the film tube. 11. Packaging article according to claim 1 or 2, characterized in that the anti-blocking particles comprise particles having a refractive index from 1.4 to 1.6. 12. Packaging article according to claim 1 or 2, characterized in that the packaging article is selected from the group consisting of a terminal sealing bag, a side sealing bag, a bag and a wrapper selected from the group consisting of a fold-seal wrapper, a fin-seal wrapper, and a butt-seal backseam wrapper with backseam tape. 13. Packaging article comprising a heat shrinkable film tube in flat configuration, the heat shrinkable film tube having a first flat side in contact with a second flat side, the heat shrinkable film tube comprising a multilayer heat shrinkable film characterized in that comprising: (A) a self-sealed inner heat seal layer, with a first portion of the inner heat seal layer being on the first flat side of the packaging article and a second portion of the inner heat seal layer being on the second flat side of the packaging article, with the first portion of the heat seal layer being in contact with the second portion of the heat seal layer, with the heat seal layer comprising a polymeric composition of the seal layer comprising polyolefin having a average density of less than 0.92 g/cm3, the inner heat seal layer having a thickness of at least 2.54 µm (0.1 mm), the inner heat seal layer further comprising: (a) (i) antiblocking particles in an amount from at least 2000 ppm, based on the total weight of the layer, the antiblocking particles having an average particle size from at least 3 microns; (a) (ii) a fast blooming mold release agent in the inner seal layer in an amount from at least 1200 ppm, based on the total weight of the layer, the fast blooming mold release agent comprising at least one selected element from the group consisting of erucamide, oleamide, lauramide, lauric diethanolamide, monoglyceride, diglyceride, glycerol monooleate, glycerol monostearate; and (a) (iii) a slow blooming mold release agent in the inner sealing layer in an amount from at least 1200 ppm, based on the total weight of the layer, the slow blooming mold release agent comprising at least one element selected from the group consisting of stearamide, bis-stearamide, ethylene bis-stearamide, stearyl stearamide, stearyl erucamide, erucyl erucamide, beanamide, ethylene bis-oleamide, oleyl palmitamide, stearate ester, sorbitan stearate, monostearate, distearate, tristearate, sorbitan monolaurate, pentaerythritol stearate ester, polyglycerol stearate, zinc stearate, calcium stearate, magnesium stearate, sodium stearate, potassium stearate; and (B) an outer layer comprising an outer layer polymeric composition; wherein the inner layer has an inner surface and the outer layer has an outer surface, wherein at least one of the inner surface of the inner layer and the outer surface of the outer layer is free of dust thereon, and wherein the inner layer outer layer has an outer surface that has a peak coefficient of friction less than 0.8, measured in accordance with ASTM D 1894, and the inner layer also has a peak coefficient of friction less than 0.8, measured according to ASTM D 1894 standard. 14. Assembly characterized in that it comprises a set of packaging articles imbricated in two strands of tape, each of said strands of tape having an adherent surface and an opposing surface free of adhesion and each of the packaging articles being as defined in any one of claims 1, 2 or 13, with each of said packaging articles having two superimposed sides of substantially identical dimensions, each of said packaging articles having one side attached to said adherent surface of both said tapes, with the open end of each of the packaging articles being in the same direction with respect to the tapes of all other packaging articles in the set and each successive packaging article adhered to the tapes being offset from the other packaging articles in the set and overlapping the opening of one base packaging article, with the strips being spaced apart and parallel to each other. 15. A process for packaging a plurality of individual meat products comprising: (A) placing each of the plurality of individual meat products in each of a plurality of corresponding individual packaging articles having a top part opened, each of the corresponding individual packaging articles being dust-free and being as defined in any one of claims 1, 2 or 13, to produce a plurality of partially packaged products, including a first partially packaged product and a second partially packaged product ; (B) moving a first tray to a loading zone, the first tray being in a state of continuous movement; (C) placing the first partially packaged product onto a first tray as the first tray moves through the loading zone; (D) (d) (i) move the first tray out of the loading zone while the first partially wrapped product remains on the first tray; and (d) (ii) maintaining a first vacuum chamber cover over and in contact with the first tray to form a first vacuum chamber that has the first product partially packaged therein while the first tray remains in continuous motion, (d) (iii) evacuating the atmosphere within the first vacuum chamber, including evacuating the atmosphere within the first partially packaged product as the first vacuum chamber continues to travel; (d) (iv) tightly sealing the individual packaging article of the first partially packed product while the atmosphere remains evacuated from the first vacuum chamber to produce a first vacuum packed product as the first vacuum chamber continues to move ; (d) (v) allowing atmosphere to re-enter the first vacuum chamber as the first tray having the first vacuum packed product continues to move; (d) (vi) separating the first vacuum chamber lid from the first tray as the first tray continues to move, (d) (vii) removing the first vacuum packed product from the first tray as the first tray continues to move; (E) placing the second partially wrapped product on a second tray after the first tray has left the loading zone and the second tray has passed into the loading zone; (F) (f) (i) move the second tray out of the loading zone while the second partially wrapped product remains on the second tray; and (f) (ii) maintaining a second vacuum chamber cover over and in contact with the second tray to form a second vacuum chamber that has the second product partially packaged therein while the second tray remains in continuous motion; (f) (iii) evacuating the atmosphere within the second vacuum chamber, including evacuating the atmosphere within the second partially packaged product as the second vacuum chamber continues to travel; (f) (iv) tightly sealing the individual packaging article of the second partially packed product while the atmosphere remains evacuated from the second vacuum chamber to produce a second vacuum packed product as the second vacuum chamber continues to move ; (f) (v) allowing atmosphere to re-enter the second vacuum chamber as the second tray holding the second vacuum packed product continues to move; (f) (vi) separating the second vacuum chamber lid from the second tray as the second tray continues to move, (f) (vii) removing the second vacuum packed product from the second tray as the second tray continues to move.