IL319878B1 - Printable polyolefin film and methods for manufacturing thereof - Google Patents

Description

PRINTABLE POLYOLEFIN FILM AND METHODS FOR MANUFACTURING THEREOF FIELD OF THE INVENTION id="p-1"

[001] The invention relates generally to the field of printable extruded polyethylene films devoid of printable prime coatings.

BACKGROUND id="p-2"

[002] At present, priming is an essential part of the production of self-adhesive materials and films for flexible packaging. Generally, the process of producing films for these applications includes the following steps: first, the film is made by flat-slot die or blow extrusion. In the case of flat-slot die extrusion, the film is oriented in both the machine and transverse directions. After that, it is slit into narrow rolls and sent for further processing. In blow extrusion, the film is blown through an extruder, creating a bubble that is inflated with hot air, resulting in biaxial orientation. id="p-3"

[003] After extrusion, the next step in production is priming, also called Topcoat. During this step, a coating composition usually in a form of water-based polymeric emulsions is applied to the film surface. The coating composition provides the surface of the extruded film with a sufficient adhesion to the printing ink, thus inducing printability of otherwise non-printable polyolefin film. id="p-4"

[004] However, the major drawback of the current printable film manufacturing process is the necessity of a separate coating step, which requires specific equipment and significantly increases energy consumption and technological waste. To this end, the priming step reduces overall productivity by adding production complexity and by significantly increasing the overall production costs. id="p-5"

[005] Accordingly, there is a need for an alternative cost effective technology for simplifying the manufacturing of printable films.

SUMMARY id="p-6"

[006] The following embodiments and aspects thereof are described and illustrated in conjunction with systems, tools and methods which are meant to be exemplary and illustrative, not limiting in scope. id="p-7"

[007] In one aspect of the invention, there is provided a film comprising an inner layer in contact with at least one outer layer, wherein the inner layer comprises a first outer portion and a second outer portion; at least one of the first outer portion and the second outer portion faces the at least one outer layer; the inner layer is a single layer film or a multi-layer film and comprises a polyolefin; the at least one outer layer comprises ABS; and wherein a polymeric material of the at least one outer layer and a polymeric material of the inner layer are oriented. id="p-8"

[008] In one embodiment, the inner layer and the at least one outer layer consist of extrudable polymeric material. id="p-9"

[009] In one embodiment, at least one outer layer is a single layer comprising at least 15%w/w of ABS. id="p-10"

[0010] In one embodiment, at least one outer layer further comprises (i) a polyolefin compatible with ABS; or (ii) a polyolefin and a compatibilizer. id="p-11"

[0011] In one embodiment, ABS content of said single layer is between 50 and 90% by weight. id="p-12"

[0012] In one embodiment, single layer is between 0.5 and 30 um thick; and wherein ABS content of said single layer is between 70 and 90% by weight. id="p-13"

[0013] In one embodiment, the at least one outer layer comprises a first layer comprising a polyolefin compatible with ABS; and a second layer comprising ABS; wherein the first layer and the second layer are consecutive layers; and wherein the first layer is in contact with the first outer portion and/or with the second outer portion of the inner layer. id="p-14"

[0014] In one embodiment, said first layer is between 0.5 and 30 µm thick; and wherein said second layer is between 1 and 150 µm thick. id="p-15"

[0015] In one embodiment, ABS weight content of said second layer is between 80 and 100% by weight. id="p-16"

[0016] In one embodiment, the polyolefin compatible with ABS is or comprises maleic anhydride grafted polyethylene. id="p-17"

[0017] In one embodiment, the polyolefin is selected from PE and PP, including any co-polymer and blend thereof. id="p-18"

[0018] In one embodiment, the inner layer and the at least one outer layer further comprises between 0.1 and 10% w/w of an additive (e.g. UV- scavenger, colorant, antioxidant, etc.). id="p-19"

[0019] In one embodiment, the at least one outer layer is stably bound to the inner layer and wherein the film is characterized by peel strength above 10 N/cm, as determined by ASTM D3330 peel test. id="p-20"

[0020] In one embodiment, the at least one outer layer is devoid of a printable coating and further devoid of heat-sensitive particles. id="p-21"

[0021] In one embodiment, the at least one outer layer is printable. id="p-22"

[0022] In one embodiment, the at least one outer layer is characterized by at least one of: (i) a score between 1B and 5B, as determined by ASTM D3359– 09 tape test and (ii) a surface tension of at least 38 dynes/cm. id="p-23"

[0023] In one embodiment, a weight portion of the inner layer relative to a total weight of the film is at least 50%. id="p-24"

[0024] In one embodiment, the film of the invention is an oriented co-extruded film. id="p-25"

[0025] In one embodiment, the inner layer and the outer layer are manufactured by extrusion.

BRIEF DESCRIPTION OF THE DRAWINGS id="p-26"

[0026] The subject matter regarded as the invention is particularly pointed out and distinctly claimed in the concluding portion of the specification. The invention, however, both as to organization and method of operation, together with objects, features, and advantages thereof, may best be understood by reference to the following detailed description when read with the accompanying drawings in which: id="p-27"

[0027] Figs. 1A-B are non-limiting illustrations of cross sections of films according to an embodiment of the invention. id="p-28"

[0028] In addition to the exemplary aspects and embodiments described above, further aspects and embodiments will become apparent by reference to the figures and by study of the following detailed description.

DETAILED DESCRIPTION id="p-29"

[0029] The present invention in some embodiments thereof is directed to simplify the current manufacturing process by providing a one-step process for manufacturing of printable films which doesn’t include the priming step. Accordingly, films manufactured according to the invention allow for various print types immediately after extrusion and orientation, which provides significant advantage over existing technologies. The inventors successfully manufactured a printable polyethylene (PE) film by adding an additional (outer) layer containing a printable polymer (e.g. ABS, Acrylonitrile butadiene styrene) characterized by surface tension of between about 38 and 42 dyne/cm. id="p-30"

[0030] The inventors manufactured a printable PE-based film (containing an outer ABS layer) solely by thermoplastic polymer processing without priming. id="p-31"

[0031] According to one aspect there is provided a film comprising an inner layer in contact with at least one outer layer, wherein the inner layer comprises a first outer portion and a second outer portion; at least one of the first outer portion and the second outer portion faces the at least one outer layer; the inner layer is a single layer film or a multi-layer film and comprises a polyolefin; wherein the at least one outer layer comprises ABS. In some embodiments, the at least one outer layer is printable. id="p-32"

[0032] In some embodiments, the film of the invention is in a form of a packaging article or packaging film. In some embodiments, the film of the invention is in a form of a labeling article. In some embodiments, the packaging/labeling article further comprises an adhesive layer in contact with the inner layer and optionally a release liner (or protective non-adhesive backing layer) in contact with the adhesive layer. In some embodiments, the labeling article is a pressure-sensitive adhesive (PSA) label. id="p-33"

[0033] Reference is now made to Fig. 1A which is an illustration of an exemplary film of the invention 100. In some embodiments, film 100 includes the inner layer 10 in contact with the outer layer 20. The inner layer 10 may have a first outer portion 30 and a second outer portion 40. Film 100 may be such that one of the first outer portion 30 and the second outer portion 40 faces and is in contact with the outer layer 20. id="p-34"

[0034] In some embodiments, the inner layer 10 may include a polyolefin (e.g. PE such as HDPE, LDPE, LLDPE, HDPE or MDPE, and/or polypropylene PP). In some embodiments, the inner layer 10 may be a single layer or include a plurality of layers. id="p-35"

[0035] In some embodiments, the inner layer 10 may be any one of: (i) Polypropylene Film, such as Polypropylene film made by flat extrusion method with biaxial orientation, including: Three-layer film, Five-layer film, Seven-layer film, or Film with other numbers of co-extrusion layers; Polypropylene film made by cast extrusion method, including: Three-layer film, Five-layer film, Seven-layer film, or film with other numbers of co-extrusion layers. (ii) Polyethylene Film, such as Polyethylene film made by the blow extrusion method, including: Three-layer film, Five-layer film, Seven-layer film, or Film with other numbers of co-extrusion layers; Polyethylene film made by the cast extrusion method, including: Three-layer film, Five-layer film, Seven-layer film, or Films with other numbers of co-extrusion layers. (iii) Polyethylene and/or Polypropylene Film Made by Other Extrusion Methods Containing Other Numbers of Layers From One to Eleven. id="p-36"

[0036] In some embodiments, the outer layer 20 is printable, e.g. the outer surface 20A is suitable for printing, for example as determined by ASTM D3359– 09 tape test. In some embodiments, the outer surface 20A has a surface tension of at least 38, at least 39, at least or between 38 and 40, or greater than 40dynes/cm (e.g. as determined by dyne testing such as according to ASTM D2578). The term "printable" encompasses both surface wettability by ink (as determined for example by dyne testing) and sufficient adhesion strength of the printed ink to the surface (as determined for example by tape test). The printable surface of the film disclosed herein is suitable for printing using any printing techniques, such as Offset printing (Oil-based inks, UV inks, water-based inks, soy-based inks); Flexographic printing (Water-based inks, solvent-based inks, UV inks); Gravure printing (Solvent-based inks, water-based inks); Letterpress printing (Oil-based inks, UV inks, water-based inks); Screen printing (Plastisol inks, water-based inks, UV inks, solvent inks); Pad printing (Solvent-based inks, UV inks, epoxy inks); Inkjet printing (Water-soluble inks, pigment inks, UV inks, solvent-based inks, eco-solvent inks, latex inks); Laser printing (Powdered toner pigments); Electrostatic printing (Dry toner, liquid toner); Thermal transfer printing (Wax, resin, wax-resin ribbons); UV printing (UV-cured inks); Rotary printing (Water-based inks, solvent-based inks, oil-based inks); Intaglio printing for banknotes and documents (Oil-based inks, metallic inks, security inks); Lenticular printing (UV inks, solvent-based inks); Electrostatic printing (Dry toner, liquid toner); Nanographic printing (Water-based nanopigment inks) or a combination thereof. id="p-37"

[0037] In some embodiments, the outer surface 20A is non-coated. In some embodiments, the outer surface 20A is devoid of priming. In some embodiments, the outer surface 20A is devoid of a printable coating. In some embodiments, the outer layer 20 is homogenous, i.e. the chemical composition of the outer surface 20A is the same as the chemical composition of the entire outer layer 20. id="p-38"

[0038] In some embodiments, the outer layer 20 is a single layer or includes a plurality of layers (e.g. 2, 3, 4 or more layers). id="p-39"

[0039] Reference is now made to Fig. 1B, which is an illustration of an exemplary film of the invention 100. In some embodiments, film 100 includes the inner layer 10 in contact with the outer layer 20 comprising a plurality of layers. In some embodiments, the outer layer 20 comprises a first layer 21 comprising a polymer compatible with ABS (e.g. polyolefin) and a second layer 22 comprising ABS. In some embodiments, the first layer 21 is a tie layer bonding the second layer 22 and the inner layer 10 together. In some embodiments, the first layer 21 and the second layer 22 are consecutive layers. In some embodiments, the first layer 21 is in contact with the first outer portion 30 and/or with the second outer portion of the inner layer. id="p-40"

[0040] In some embodiments, the inner layer and the at least one outer layer consist of extrudable polymeric material. In some embodiments, the inner layer and the at least one outer layer consist essentially of extrudable polymeric material. In some embodiments, at least 90%, at least 95%, or at least 99% by dry weight of the inner layer and the at least one outer layer consist of extrudable polymeric material. In some embodiments, at least 90%, at least 95%, or at least 99% from the total polymer content of the inner layer and the at least one outer layer consist of extrudable polymeric material. In some embodiments, at least 90%, at least 95%, or at least 99% of the total polymer content of the film consist of extrudable polymeric material, including any range between. id="p-41"

[0041] The term "extrudable" refers to a polymeric material which is shapeable under conditions suitable for hot melt polymeric processing, i.e. the polymeric material is characterized by mechanical and/or rheological properties as well as chemical stability in a molten state sufficient for shaping or processing thereof by means of thermoplastic polymer processing (e.g. a process selected from injection molding, extrusion, injection, hot blown film, and molding or any combination thereof). For example, extrudable polymeric material is flowable (without undergoing chemical decomposition) at a temperature between 100 and 300ºC, including any range between. id="p-42"

[0042] In some embodiments, the film is an oriented film. In some embodiments, the at least one outer layer and the inner layer are oriented (e.g. machine direction oriented, biaxially oriented, transverse direction oriented). In some embodiments, the orientation of the at least one outer layer and of the inner layer is the same or substantially the same. id="p-43"

[0043] Film orientation can be determined spectroscopically, for example using FTIR (e.g. based on polarized transmission measurement, tilted film measurement, Attenuated total reflectance measurement, etc.) or by RAMAN. Furthermore, orientation can be determined based on mechanical properties measurement of the film along different film dimensions. id="p-44"

[0044] In some embodiments, the film is characterized by weight loss of at most 5%, at most 3%, at most 1%, at most 0.5% at a temperature ranging between 100 and 280C, or between 150 and 300C or between 150 and 280C including any range between, as determined by thermogravimetric analysis (TGA). id="p-45"

[0045] In some embodiments, the at least one outer layer comprises at least 15%, at least 20%, at least 30%, at least 35%, at least 40%, at least 50% or between 15 and 90%, between and 100%, between 30 and 90%, between 40 and 90%, between 50 and 90%, between and 70%, between 60 and 90%, between 65 and 90%, between 70 and 90%, between and 85%, between 70 and 80%, between 80 and 90%, between 90 and 95%, between 95 and 99%, between 95 and 100% w/w of ABS, including any range between. id="p-46"

[0046] In some embodiments, the at least one outer layer further comprises (i) a polyolefin compatible with ABS; or (ii) a polyolefin and a compatibilizer (i.e. a polymeric compatibilizer such as anhydride modified polyethylene, or cyano-modified polyethylene, or a particulate compatibilizer, such as Janus particle). In some embodiments, a concentration of the compatibilizer within the at least one outer layer is between 0.5 and 20%w/w, or any value or range in between. id="p-47"

[0047] In some embodiments, the at least one outer layer is characterized by a thickness of between 0.5 and 200um, between 0.5 and 5 um, between 5 and 10 um, between 1 and um, between 10 and 20 um, between 10 and 150 um, between 20 and 30 um, between and 50 um, between 50 and 100 um, between 100 and 150 um, including any rage or value therebetween. id="p-48"

[0048] In some embodiments, the at least one outer layer comprises one or more first layer(s) comprising a polyolefin compatible with ABS and one or more second layer(s) comprising ABS (see for example Fig. 1B). id="p-49"

[0049] In some embodiments, the one or more first layer(s) is a single layer characterized by a thickness of between 0.5 and 30um, between 1 and 10 um, between 10 and 20 um, between 10 and 30 um, between 20 and 30 um, including any rage or value therebetween. id="p-50"

[0050] In some embodiments, the one or more second layer(s) is characterized by a thickness of between 0.5 and 200um, between 1 and 10 um, between 10 and 20 um, between and 150 um, between 20 and 30 um, between 30 and 50 um, between 50 and 100 um, between 100 and 150 um, including any rage or value therebetween. In some embodiments, the one or more second layer(s) is a single layer characterized by a thickness of between 0.and 200um, between 1 and 10 um, between 10 and 20 um, between 10 and 150 um, between and 30 um, between 30 and 50 um, between 50 and 100 um, between 100 and 150 um, including any rage or value therebetween. id="p-51"

[0051] In some embodiments, the ABS content by weight of the one or more second layer(s) is between 15 and 100%, between 20 and 100%, between 30 and 100%, between and 100%, between 50 and 100%, between 80 and 100%, including any range between. In some embodiments, the one or more second layer(s) comprise ABS as the sole polymer. id="p-52"

[0052] In some embodiments, one or more first layer(s) comprise polyolefin compatible with ABS at a w/w concentration between 15 and 100%, between 20 and 100%, between and 100%, between 40 and 100%, between 50 and 100%, between 80 and 100% including any range between. In some embodiments, the one or more second layer(s) comprise polyolefin compatible with ABS as the sole polymer. id="p-53"

[0053] In some embodiments, a weight portion of the inner layer relative to a total weight of the film is at least 50%, at least 60%, at least 70%, at least 80%, at least 90%, including any range between. id="p-54"

[0054] In some embodiments, the inner layer comprises a plurality of layers. In some embodiments, the inner layer comprises two or more layers. In some embodiments, the inner layer comprises three or more layers. In some embodiments, the inner layer comprises four, five, six, seven, eight, nine, ten or more layers. In some embodiments, each of the layers within the inner layer is in contact with or bound to at least one additional layer. id="p-55"

[0055] In some embodiments, the film of the invention (and/or inner layer) comprises a plurality of coextruded layers. id="p-56"

[0056] The term "layer", refers to a substantially homogeneous substance of substantially uniform-thickness (optionally, the layer is visible microscopically, e.g. by SEM, TEM etc.). In some embodiments, the term "layer", refers to a polymeric layer. id="p-57"

[0057] In some embodiments, the polymeric content (i.e. the content of one or more thermoplastic polymer) of the inner layer and of the outer layer is at least 80%, at least 90%, at least 95%, at least 97%, at least 99%w/w, including any range between. In some embodiments, the polymeric content of the film is at least 80%, at least 90%, at least 95%, at least 97%, at least 99%w/w, including any range between. id="p-58"

[0058] In some embodiments, the film is devoid of a thermoset polymer. In some embodiments, the polyolefin of the inner layer is a homopolymer. In some embodiments, the inner layer is substantially devoid of a PE-, or PP-co-polymer. id="p-59"

[0059] In some embodiments, each of the inner layer and the outer layer disclosed herein, independently comprises an additive. In some embodiments, a w/w concentration of the additive within each of the layers disclosed herein is between 0.01 and 20%, including any range between. id="p-60"

[0060] In some embodiments, the film comprises a mixture or a plurality of additives. Non-limiting examples of additives according to the present invention include a photoinitiator, a stabilizer (e.g. pH stabilizer, light stabilizer, UV-stabilizer), a dye or pigment, a filler, a tackifier, an antioxidant (such as a radical scavenger, an antiozonant), dehydrating agent, a plastomer, an elastomer, a heat stabilizer, a flame retardant and a biocide or any combination thereof. id="p-61"

[0061] Non-limiting examples of dehydrating agents according to the present invention include commonly used and known in the art salts of weak organic acids (metal stearates) or inorganic bases (hydrotalcite). id="p-62"

[0062] In some embodiments, UV-stabilizers include screeners, absorbers, quenchers, free radical scavengers, and peroxide decomposers. Non-limiting examples of UV-absorber include benzophenones, benzotriazoles, aryl esters, oxanilides, acrylic esters and formamidine. id="p-63"

[0063] Non-limiting examples of antioxidants according to the present invention include phenols, aromatic amines, phosphates, phosphites, and BHT. id="p-64"

[0064] Non-limiting examples of dehydrating agents according to the present invention include silane compounds such as vinyltrimethoxysilane, dimethyldimethoxysilane, tetraethoxysilane, methyltrimethoxysilane, methyltriethoxysilane, tetramethoxysilane, tetraethoxysilane, phenyltrimethylsilane, and diphenyldimethoxysilane; hydrolyzable ester compounds such as methyl orthoformate, ethyl orthoformate, methyl orthoacetate, and ethyl orthoacetate, and the like. These compounds may be used alone or in combinations of two or more thereof. id="p-65"

[0065] Non-limiting examples of fillers according to the present invention include talc, calcium carbonate, clay, silica, mica, wollastonite, feldspar, aluminum silicate, alumina, hydrated alumina, glass microspheres, ceramic microspheres, thermoplastic microspheres, barite and wood flour. id="p-66"

[0066] In some embodiments, the film of the invention is stable (e.g. chemically stable and/or physically stable) at a temperature of up to 190ºC, up to 200ºC, up to 220ºC, up to 250ºC, up to 280ºC, up to 290ºC, up to 300ºC, up to 350ºC, including any range between. The film of the invention is stable referred to as stable, if the film substantially retains its functional properties. Additionally, the film is referred to as stable, if the film substantially retains its intactness, i.e. is devoid of disintegration (such as separation of layers). id="p-67"

[0067] In some embodiments, the film is a stable film and is characterized by (i) peel strength above 10 N/cm, above 15 N/cm, above 20 N/cm, above 30 N/cm, above 40 N/cm, including any range between, as determined by ASTM D3330 peel test and/or (ii) layer to layer adhesion (e.g. between the outer and inner layer) above 3 N/cm, above 4 N/cm, above N/cm, above 6 N/cm, above 7 N/cm, above 8 N/cm, above 10 N/cm, above 15 N/cm, above N/cm, including any range between, as determined by ASTM D1000 adhesion test. id="p-68"

[0068] In some embodiments, the film of the invention is characterized by tensile strength between 150 and 250, between 200 and 300, between 200 and 500, between 200 and 1000, or at least 200, at least 250, at least 300, at least 400 MPa, including any range between, as determined according to ASTM D-882 or according to ASTM F904. id="p-69"

[0069] In some embodiments, the film of the invention (both inner and outer layers) undergoes shrinkage (e.g. shrinkage of at least 10%) upon heating thereof to temperature of at least 100ºC, at least 150ºC, at least 170ºC, at least 190ºC, at least 200ºC, at least 220ºC, at least 250ºC, at least 280ºC, including any range between. id="p-70"

[0070] In some embodiments, the film of the invention is manufactured by one or more methods of (hot melt) thermoplastic polymer processing. In some embodiments, the film of the invention is manufactured by co-extrusion. id="p-71"

[0071] Exemplary films according to some embodiment of the invention can be manufactured as follows. The entire manufacturing process according to the invention is devoid of priming or Topcoat application. id="p-72"

[0072] Polypropylene films : 1. Blown Film Extrusion Production Process: id="p-73"

[0073] Raw material feeding. Polypropylene granules are loaded into the extruder hopper, where they pass through the heating system and melt into a homogeneous state. The melting temperature is usually between 200–250°C. id="p-74"

[0074] Melt formation. The melted polymer is forced under pressure through a ring die, forming a thin tube. id="p-75"

[0075] Blowing the film. Compressed air is injected into the tube, inflating it to the required diameter. At this stage, the thickness and mechanical properties of the film are controlled. id="p-76"

[0076] Cooling. Air streams cool the film, fixing its size and preventing deformation. The faster the cooling, the higher the film's transparency. id="p-77"

[0077] Flat formation. The inflated tube is captured by drawing rolls, which flatten it into a film. id="p-78"

[0078] Winding. The finished film passes through a system of rollers that regulate its tension and thickness, after which it is wound into rolls. id="p-79"

[0079] Additional processing. Depending on the application, the film may undergo corona treatment and/or printing, lamination, etc. 2. Cast Film Extrusion Production Process: id="p-80"

[0080] Polymer melting. Polypropylene granules are loaded into the extruder and melted at a temperature of 220–260°C, forming a homogeneous, viscous mass. id="p-81"

[0081] Extrusion through a slot die. The melted polymer is forced under pressure through a special slot die, forming a wide, thin strip of melt. The film width is controlled by adjusting the die. id="p-82"

[0082] Cooling on calender rolls. After leaving the die, the film is immediately placed on a cooling roll, which sharply reduces its temperature. Cooling is important for forming a smooth surface. id="p-83"

[0083] Thickness alignment. The film passes through a system of additional rolls that adjust its tension and thickness. This ensures the even distribution of material across the entire width. id="p-84"

[0084] Cutting and winding. Depending on the intended use, the film may be cut into individual strips or wound into rolls. id="p-85"

[0085] Final processing. The film may undergo corona treatment and/or printing, lamination, or the application of protective coatings to enhance its performance characteristics. 3. Biaxially Oriented Polypropylene Film (BOPP) Production Process: id="p-86"

[0086] Extrusion. Polypropylene pellets are melted in the extruder and pressed through a slot die, forming a thick polymer sheet. id="p-87"

[0087] Longitudinal orientation. The sheet passes through a system of heated rollers where it is stretched in the longitudinal direction (along the line of movement). This imparts additional strength and improves the film's transparency. id="p-88"

[0088] Transverse orientation. The film then enters an oven, where it is stretched in the transverse direction. Special guides are used to evenly expand the material, improving its mechanical and optical properties. id="p-89"

[0089] Thermal stabilization. After stretching, the film undergoes thermal treatment to stabilize its properties. This is crucial to prevent deformation during subsequent processing. id="p-90"

[0090] Cutting and winding. The finished film is cut into rolls of a specified width and packaged for further use. id="p-91"

[0091] Additional processing. Depending on its intended use, the film may be printed, metallized, laminated, or coated with protective or decorative layers. id="p-92"

[0092] Polyethylene films: 1. Blown Film Extrusion Production Process: id="p-93"

[0093] Raw material feeding. Polyethylene granules (usually LDPE, LLDPE, or HDPE) are loaded into the extruder hopper, where they pass through a heating system and melt. The melting temperature varies between 150–250°C depending on the type of polyethylene. id="p-94"

[0094] Melt formation. The melted polymer is forced under pressure through the extruder’s ring die, forming a thin tubular film. id="p-95"

[0095] Blowing the film. Compressed air is pumped into the tube, inflating it to the required diameter. By adjusting air pressure and the drawing speed, the thickness and mechanical properties of the film can be controlled. id="p-96"

[0096] Cooling. Streams of cooled air stabilize the film, preventing deformation. The faster the cooling, the better the film’s transparency. id="p-97"

[0097] Flat formation. The inflated tube is captured by drawing rolls, which flatten it into a film. id="p-98"

[0098] Winding. The finished film passes through a system of rollers that regulate its tension, after which it is wound into rolls. id="p-99"

[0099] Final processing. Depending on the application, the film may undergo corona treatment and/or printing, lamination, metallization. 2. Cast Film Extrusion Production Process: id="p-100"

[00100] Polymer melting. Polyethylene granules are loaded into the extruder and melted at temperatures between 180–270°C, forming a homogeneous viscous mass. id="p-101"

[00101] Extrusion through a slot die. The molten polyethylene is forced under high pressure through the slot die, forming a wide, thin film. id="p-102"

[00102] Cooling on calender rolls. The film immediately passes onto a cooling roll, where it rapidly cools and hardens, which contributes to obtaining a smooth surface and high transparency. id="p-103"

[00103] Thickness alignment. Additional rollers adjust the film’s tension, ensuring the material is evenly distributed across the full width. id="p-104"

[00104] Cutting and winding. The film is cut into strips or wound into rolls depending on the intended use. id="p-105"

[00105] Final processing. The film may undergo corona treatment, and/or printing. 3. Biaxially Oriented Polyethylene Film (BOPE) Production Process: id="p-106"

[00106] Extrusion. Polyethylene pellets are melted in the extruder and pressed through a slot die to form a thick polymer sheet. id="p-107"

[00107] Longitudinal orientation. The sheet passes through a system of heated rollers where it is stretched longitudinally, improving its strength and transparency. id="p-108"

[00108] Transverse orientation. The film is then sent through an oven, where it is stretched in the transverse direction. This makes the material more durable and resistant to tearing. id="p-109"

[00109] Thermal stabilization. After stretching, the film undergoes thermal treatment to stabilize the new mechanical properties. id="p-110"

[00110] Cutting and winding. The finished film is cut into rolls of a specified width. id="p-111"

[00111] Final processing. BOPE films can be printed, metallized, laminated, or coated with functional layers.

EXAMPLES EXAMPLE id="p-112"

[00112] The inventors successfully manufactured LDPE films having a printable ABS-based outer layer, as described below. Equipment: [00113] Twin screw extruder, Coperion, ZSK 18MegaLab , D=18mm, 48L/D [00114] Flat film / sheet line, JWELL, JWZN30, D=30mm, 28L/D [00115] Melt flow indexer, Wance Testing Machine [00116] Hot air circulation oven, 0.1°C Temperature readout [00117] Pro-Dyne pens – Vetaphone [00118] Dyne level (dyne/cm): 38, 42 & 48 Test methods: [00119] Compound preparation by twin screw extruder. [00120] Raw materials were not dried before compound [00121] Compounds & virgin ABS were dried for >4hr @ 80°C prior to MFI & cast film. [00122] Film preparation by Calender process [00123] ➢ Target: 50µm, 3m [00124] MFI, ISO 1133 @ 220⁰C / 5 & 10 Kg [00125] Surface tensions measurements with Dyne pens Raw Materials: [00126] LDPE, ALCUDIA PE003 (similar to Ipethene 320) – Repsol [00127] ABS, Polylac PA747S – Chimei Sample description id="p-128"

[00128] Table 1: sample description Results & Discussion id="p-129"

[00129] Typical Properties Properties Unit Standard LDPE NMO- 191224- C2 ABS MFI (220°C / 5Kg) gr/10min ISO 1133 14 16 1.

MFI (220°C / 10Kg) gr/10min ISO 1133 72 - 7. id="p-130"

[00130] Table 2: Typical properties Surface Tension %wt Sheet Comp.# Film # LDPE ABS Film Thickness [µm] Notes - NMO-221224-S1 100 - 60 Transparent & sticky film NMO-191224-C2 NMO-221224-S4 20 80 120 Opaque & rigid film - NMO-221224-S5 - 100 180 Opaque & rigid film id="p-131"

[00131] Some variation in droplets' appearance was observed between both sides of the film, hence both sides were tested. No difference was observed in terms of the film's dyne level. id="p-132"

[00132] The surface tension of the samples is summarized in Table 3 below. NMO-221224- Properties Unit S1, LDPE S4, 20%PE S5, ABS Surface tension Dyne/cm < 38 38 ≤ x < 42 42 ≤ x < Table 3: Surface tension Conclusions & Remarks: [00133] Surface tension of LDPE film (S1) is below the threshold minimum required for printing. [00134] For film with 80% ABS (S4), higher surface tension was observed, allowing for printing. For ABS film (S5), its surface tension conforms with the typical value for ABS films (e.g. 42 dyne/cm).

EXAMPLE id="p-135"

[00135] Additional exemplary films according to the invention can be manufactured as follows. id="p-136"

[00136] Objective: The goal is to create a film with surface energy suitable for printing and thereby avoid using a primer. id="p-137"

[00137] Printable films will be produced using varying ratios of polyethylene (PE) and acrylonitrile-butadiene-styrene (ABS). The films will be evaluated for their physical, chemical, optical, and processing properties to understand how different PE-ABS ratios influence the overall performance of the film.

Materials id="p-138"

[00138] Polyethylene (PE): LLDPE MG200024 id="p-139"

[00139] Acrylonitrile Butadiene Styrene (ABS): Select an appropriate grade of ABS with properties as sartex HF-0660I or as SD-0150 from LOTTE Chemical Experimental Design id="p-140"

[00140] Film Preparation: id="p-141"

[00141] Prepare films with different ratios of PE and ABS: id="p-142"

[00142] 100% PE (control sample) id="p-143"

[00143] 80% PE / 20% ABS id="p-144"

[00144] 50% PE / 50% ABS id="p-145"

[00145] 20% PE / 80% ABS id="p-146"

[00146] 100% ABS (control sample) id="p-147"

[00147] Processing Method: id="p-148"

[00148] Mix the polymers at different ratios, melt them in an extruder, and then form the film using either a casting or blown film process. Adjust the processing conditions like temperature and extrusion speed. The target is to reach the same films thickness. id="p-149"

[00149] Parameters to Control: id="p-150"

[00150] Temperature: Ensure processing temperature is optimal for both PE and ABS. id="p-151"

[00151] Extrusion speed (if using extrusion): Keep constant or adjust according to polymer ratios. id="p-152"

[00152] Thickness: Measure and control the thickness of the films to ensure consistency across samples. The target thickness is ~50 micron. id="p-153"

[00153] Characterization Methods: id="p-154"

[00154] Processing Properties id="p-155"

[00155] Melt Flow Index (MFI): Measure the Melt Flow Index (MFI) of the mixtures to assess their flow behavior under heat. This is an important parameter for the extrusion process. id="p-156"

[00156] Extrusion Behavior: During the extrusion process, monitor parameters like extrusion speed, temperature, and die pressure to assess how well the mixture flows and forms a film. id="p-157"

[00157] After fabricating the films, evaluate them through various tests to assess the effects of the PE/ABS ratio on their properties. id="p-158"

[00158] Optical Properties: id="p-159"

[00159] Transparency and Haze: Measure the light transmittance using a spectrophotometer. id="p-160"

[00160] Glossiness: Use a gloss meter to measure the surface gloss of the films, as different polymer ratios may affect the surface finish. id="p-161"

[00161] Surface Properties: id="p-162"

[00162] Measures the surface tension and the wettability of the film surface. id="p-163"

[00163] The target surface tension US 42+ Dynes, preferably 48+ id="p-164"

[00164] Mechanical Properties: id="p-165"

[00165] Tensile Strength: Perform a tensile test to measure the force required to break the film and its elongation at break. This will indicate the film’s strength and flexibility. id="p-166"

[00166] Elongation at Break: Measure how much the film stretches before breaking, which is especially important for determining flexibility. id="p-167"

[00167] Impact Resistance: Use an Izod impact test or drop weight test to assess how well the film resists breaking under sudden forces. id="p-168"

[00168] Thermal Properties: id="p-169"

[00169] Melting Temperature (Tm): Use Differential Scanning Calorimetry (DSC) to determine the melting points of PE, ABS, and their mixtures. id="p-170"

[00170] Glass Transition Temperature (Tg): Measure the glass transition temperatures using DSC for both ABS and the mixtures to understand their thermal stability. id="p-171"

[00171] Thermal Stability: Use Thermogravimetric Analysis (TGA) to assess the film’s stability at elevated temperatures, which is important for processing and end-use performance. id="p-172"

[00172] Data Analysis: id="p-173"

[00173] Compare the performance of the films across different PE/ABS ratios. id="p-174"

[00174] Analyze how the properties vary with the ratio of the two polymers.

General id="p-175"

[00175] As used herein the term "about" refers to  10 %. id="p-176"

[00176] The terms "comprises", "comprising", "includes", "including", "having" and their conjugates mean "including but not limited to". id="p-177"

[00177] The term "consisting of means "including and limited to". id="p-178"

[00178] The term "consisting essentially of" means that the composition, method or structure may include additional ingredients, steps and/or parts, but only if the additional ingredients, steps and/or parts do not materially alter the basic and novel characteristics of the claimed composition, method or structure. id="p-179"

[00179] The word "exemplary" is used herein to mean "serving as an example, instance or illustration". Any embodiment described as "exemplary" is not necessarily to be construed as preferred or advantageous over other embodiments and/or to exclude the incorporation of features from other embodiments. id="p-180"

[00180] The word "optionally" is used herein to mean "is provided in some embodiments and not provided in other embodiments". Any particular embodiment of the invention may include a plurality of "optional" features unless such features conflict. id="p-181"

[00181] As used herein, the singular form "a", "an" and "the" include plural references unless the context clearly dictates otherwise. For example, the term "a compound" or "at least one compound" may include a plurality of compounds, including mixtures thereof. id="p-182"

[00182] As used herein, the term "substantially" refers to at least 80%, at least 85%, at least 90%, at least 92%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99%, including any range or value therebetween. Throughout this application, various embodiments of this invention may be presented in a range format. It should be understood that the description in range format is merely for convenience and brevity and should not be construed as an inflexible limitation on the scope of the invention. Accordingly, the description of a range should be considered to have specifically disclosed all the possible subranges as well as individual numerical values within that range. For example, description of a range such as from 1 to 6 should be considered to have specifically disclosed subranges such as from 1 to 3, from 1 to 4, from 1 to 5, from 2 to 4, from 2 to 6, from 3 to 6 etc., as well as individual numbers within that range, for example, 1, 2, 3, 4, 5, and 6. This applies regardless of the breadth of the range. id="p-183"

[00183] Whenever a numerical range is indicated herein, it is meant to include any cited numeral (fractional or integral) within the indicated range. The phrases "ranging/ranges between" a first indicate number and a second indicate number and "ranging/ranges from" a first indicate number "to" a second indicate number are used herein interchangeably and are meant to include the first and second indicated numbers and all the fractional and integral numerals therebetween. id="p-184"

[00184] As used herein the term "method" refers to manners, means, techniques and procedures for accomplishing a given task including, but not limited to, those manners, means, techniques and procedures either known to, or readily developed from known manners, means, techniques and procedures by practitioners of the chemical, pharmacological, biological, biochemical and medical arts. id="p-185"

[00185] It is appreciated that certain features of the invention, which are, for clarity, described in the context of separate embodiments, may also be provided in combination in a single embodiment. Conversely, various features of the invention, which are, for brevity, described in the context of a single embodiment, may also be provided separately or in any suitable sub-combination or as suitable in any other described embodiment of the invention. Certain features described in the context of various embodiments are not to be considered essential features of those embodiments, unless the embodiment is inoperative without those elements.

Claims (19)

CLAIMS What is claimed is:

1. A film comprising an inner layer in contact with at least one outer layer, wherein: the inner layer comprises a first outer portion and a second outer portion; at least one of the first outer portion and the second outer portion faces the at least one outer layer; the inner layer is a single layer film or a multi-layer film and comprises a polyolefin; the at least one outer layer comprises ABS; and wherein a polymeric material of the at least one outer layer and a polymeric material of the inner layer are oriented.

2. The film of claim 1, wherein the inner layer and the at least one outer layer consist of extrudable polymeric material.

3. The film of claim 1 or 2, wherein said at least one outer layer is a single layer comprising at least 15%w/w of ABS.

4. The film of claim 3, wherein said at least one outer layer further comprises (i) a polyolefin compatible with ABS; or (ii) a polyolefin and a compatibilizer.

5. The film of claim 3 or 4, wherein ABS content of said single layer is between 50 and 90% by weight.

6. The film of any one of claims 3 to 5, wherein said single layer is between 0.5 and um thick; and wherein ABS content of said single layer is between 70 and 90% by weight.

7. The film of claim 1 or 2, wherein the at least one outer layer comprises a first layer comprising a polyolefin compatible with ABS; and a second layer comprising ABS; wherein the first layer and the second layer are consecutive layers; and wherein the first layer is in contact with the first outer portion and/or with the second outer portion of the inner layer.

8. The film of claim 7, wherein said first layer is between 0.5 and 30 µm thick; and wherein said second layer is between 1 and 150 µm thick.

9. The film of claim 7 or 8, wherein ABS content of said second layer is between and 100% by weight.

10. The film of any one of claims 4 to 9, wherein the polyolefin compatible with ABS is or comprises maleic anhydride grafted polyethylene.

11. The film of any one of claims 1 to 10, wherein the polyolefin is selected from PE and PP, including any co-polymer and blend thereof.

12. The film of any one of claims 1 to 11, wherein the inner layer and the at least one outer layer further comprises between 0.1 and 10% w/w of an additive.

13. The film of any one of claims 1 to 12, wherein the at least one outer layer is stably bound to the inner layer and wherein the film is characterized by peel strength above N/cm, as determined by ASTM D3330 peel test.

14. The film of any one of claims 1 to 13, wherein the at least one outer layer is devoid of a printable coating and further devoid of heat-sensitive particles.

15. The film of any one of claims 1 to 14, wherein the at least one outer layer is printable.

16. The film of claim 15, wherein said at least one outer layer is characterized by at least one of: (i) a score between 1B and 5B, as determined by ASTM D3359– 09 tape test, and (ii) a surface tension of at least 38 dynes/cm.

17. The film of any one of claims 1 to 16, wherein a weight portion of the inner layer relative to a total weight of the film is at least 50%.

18. The film of any one of claims 1 to 17, being an oriented co-extruded film.

19. The film of claim 18, wherein the inner layer and the outer layer are manufactured by extrusion.