Coextruded multilayer cellulosic film and its method of manufacture and products made therefrom

Abstract

Disclosed is a coextruded multilayer cellulosic film comprising at least one first film layer A comprising at least one first cellulosic polymer and at least one second polymer. The film further comprises at least one seal layer B, which is an outer and / or middle layer of the film, and at least one slip additive. Furthermore, the film is produced by a film extrusion process. Also disclosed are packaging materials comprising the film and related methods.

Description

[Technical Field]

[0001] The present disclosure relates to a coextruded multilayer cellulosic film, the film comprising at least a first film layer A and at least one seal layer B. Packaging materials comprising the coextruded multilayer cellulosic film and related manufacturing methods are also disclosed. [Background technology]

[0002] There are various methods for producing cellulose-based films. Films can be made from cellulose esters and aliphatic or aromatic polyesters or copolyesters. However, materials with high cellulose content have poor properties. To be able to produce these materials on an industrial scale and use them in various packaging applications, several requirements must be met. Existing solutions are unable to meet these requirements. Summary of the Invention [Problem to be solved by the invention]

[0003] Therefore, the present inventors have discovered a need to develop higher quality materials to meet the demands of more applications, and in particular a need to develop higher quality multilayer cellulosic films. [Means for solving the problem]

[0004] This Summary is provided to introduce a selection of concepts in a simplified form that are further described below in the Detailed Description. This Summary is not intended to identify key features or essential features of the claimed subject matter, nor is it intended to be used to limit the scope of the claimed subject matter.

[0005] A coextruded multilayer cellulosic film is described. The film comprises a first film layer A comprising at least one first cellulosic polymer and at least one second polymer. The film further comprises at least one seal layer B, which is an outer layer and / or an intermediate layer of the film. Additionally, the film comprises at least one slip additive. The coextruded multilayer film may be produced by a film extrusion process.

[0006] Additionally, a method for making a coextruded multilayer cellulosic film is described.

[0007] Also described is a packaging material comprising the coextruded multilayer cellulosic film. DETAILED DESCRIPTION OF THE INVENTION

[0008] The present disclosure provides a coextruded multilayer cellulosic film, the film comprising: a first film layer A comprising at least one first cellulosic polymer and at least one second polymer; At least one sealing layer B, which is an outer layer and / or an intermediate layer of the film; at least one slip additive; Including, The film relates to a film produced by a film extrusion process.

[0009] Further disclosed is a packaging material comprising the above-described coextruded multilayer cellulosic film.

[0010] 1. A method of making a coextruded multilayer cellulosic film, the method comprising: i. providing a first polymer composition for forming a first film layer A, the first polymer composition comprising at least one first cellulosic polymer and at least one second polymer; ii. providing a sealing polymer composition for forming at least one seal film layer B; iii. forming a co-extruded multi-layer film comprising the first film layer A and the seal film layer B by a film extrusion process; wherein the film comprises at least one slip additive.

[0011] The above-described method for making a coextruded multilayer cellulosic film may be used to make any of the coextruded multilayer cellulosic films described herein.

[0012] According to one embodiment, the coextruded multilayer cellulose-based film has a cellulose content of at least 20% by weight. The cellulose content may typically be in the range of 20-60% by weight, or 30-60% by weight, or 35-55% by weight, or 40-45% by weight, based on the total weight of the film. The cellulose content may be at least 25% by weight, or at least 30% by weight, or at least 35% by weight, or at least 40% by weight. The weight percentages are based on the total weight of the film. Preferably, the cellulose content is in the range of 30-50% by weight, or 35-45% by weight.

[0013] In this specification, the expression "cellulose content" should be understood to mean the cellulose content calculated based on the cellulose polymer present in the composition unless otherwise specified.For example, the cellulose polymer derivative used in the composition can be in the form of cellulose ester, in which case the amount of cellulose (wt%) is calculated as if there is no ester group covalently bonded to the cellulose polymer.Therefore, the cellulose content is not equal to the weight of the cellulose derivative content.Since the cellulose-based polymer derivative is usually in the form of ester or is substituted in other ways, the cellulose content of the film is typically not more than 55 wt%.

[0014] In this specification, unless otherwise specified, expressions such as "cellulose-based film" should be understood to mean a film in which a significant portion of the raw material is based on cellulose polymers or cellulose polymer derivatives. The cellulose content of a cellulose-based film may typically be at least 20% by weight. Cellulose polymers can be chemically modified, for example, to obtain thermoplastic properties.

[0015] As used herein, the expressions "coextruded multilayer" or "coextruded multilayer film" should be understood to refer to a material or film produced by coextrusion, unless otherwise specified. Coextrusion is a manufacturing process that involves pressing two or more materials together through the same die to produce a single piece. When multiple films or materials are combined by coextrusion, the result can have properties that differ from those of a single film or material. Coextruded multilayer films are typically produced by a technique in which thermoplastic resins are simultaneously extruded by multiple extruders and passed through a single die to build layers of molten resin on both the inside and outside of the film.

[0016] This disclosure describes coextruded multilayer cellulosic films that are suitable for a variety of packaging solutions.

[0017] In many packaging applications, it is very important to be able to seal the packaging film. To achieve this, good sealability is required. There are many sealing techniques, the most common of which is heat sealing. The novel coextruded multilayer cellulosic films described herein have excellent sealability, particularly heat sealability, provided by the defined coextruded multilayer structure.

[0018] As used herein, the expressions "sealable" or "seal" should be understood to mean the ability to attach two or more separate films to one another by the introduction of heat, unless otherwise specified.

[0019] Films produced by extrusion processes can have a layered structure. This structure is typically produced by the extrusion process by having several feed screws or extruders. A film line can have, for example, 1, 3, 5, or 7 extruders, and the resulting film can contain a corresponding number of layers.

[0020] The layered structure technology of the film extrusion process can be used to produce multilayer films, which offers several advantages because the individual layers may have different properties. However, this technology has not previously been utilized with cellulosic raw materials as described herein. The cellulosic films described herein have not been produced using industrial film extrusion processes for producing coextruded multilayer films.

[0021] In this disclosure, several film structures are described. The structure can be AB, where A and B represent different film layers. The film structure can also be, for example, ABA, where the middle film layer B is different from the outer film layer A. The film structure can also be ABC, or for example, ABCBA, where three different layers are used in various configurations. This can be further elaborated to ABCDCBA, etc.

[0022] As mentioned above, in many applications, it is important that films intended for packaging applications be able to be sealed. Otherwise, the film cannot be used at all in many packaging applications. Typically, to add heat-sealability to traditional cellulosic films, polyvinylidene dichloride (PVDC) is used as a coating. While PVDC provides heat-sealability, it is a chlorinated polymer. Therefore, the use of PVDC as a coating makes the entire package unsuitable for recycling, even by incineration. The coextruded multilayer cellulosic films described herein do not require the use of a PVDC coating.

[0023] Furthermore, the present inventors have recognized that it is very important to be able to efficiently manufacture films for packaging applications. Commonly used techniques for film manufacturing are different extrusion processes, such as blown film extrusion and cast film extrusion. Cellulose-based film products are commercially available and are manufactured by solvent casting or viscose processes. These traditional cellulosic films are typically acetate and cellophane-type products and are not thermally processable due to their poor or non-existent heat resistance. Therefore, the solvent casting or viscose processes require unique machinery and technology, making them very expensive and difficult to scale up.

[0024] The novel films described herein offer a scalable manufacturing process, and the granules used to make the films can be processed at high output and processing efficiency. The film compositions have high heat resistance, which are advantages since high processing efficiency is typically difficult to provide with new materials and new bio-based plastics.

[0025] Packaging films should preferably be clear, transparent, and glossy so that the product packaged within is attractive. Packaging films should also preferably have sufficient rigidity and puncture resistance to protect the packaged product. The described coextruded multilayer film provides these properties to packaging materials made from the film. The novel film may be clear, transparent, and glossy, as well as rigid and highly puncture-resistant.

[0026] Traditionally, the goal in multilayer film manufacturing is to obtain a film with properties that are optimal for the intended application. Properties such as grease, oxygen or vapor barrier, mechanical resistance, UV protection, sealing, chemical resistance, etc. can be incorporated into the final film structure through multilayer film technology.

[0027] While multi-layering is practical for obtaining good properties for various film applications, it is detrimental to recycling. Multi-layer films are known to be a challenge for plastic recycling processes. Typically, multi-layer films can be recycled simply as energy by incineration or, in some cases, as feedstock for some chemical recycling processes, but the yields obtained in these cases are low. Mechanical plastic recycling is not practical because the layers cannot be separated from each other during the recycling process.

[0028] The coextruded multilayer cellulose-based film described herein offers a sustainable alternative to multilayer films, in which cellulose-based raw materials are manufactured into a film structure using an industrial-scale extrusion process. The heat-sealing layer is introduced into the extrusion process as film layer B in a layer structure, including, for example, an AB, AAB, ABC, or ABA film layer structure. The coextruded multilayer structure of the present disclosure, including the sealing layer, can be recycled using mechanical plastic recycling. The sealing agent used may be easily recycled along with the film, and the resulting recycled material has very high quality properties.

[0029] Apart from good processability and heat sealability, the films are clear, transparent and glossy, therefore they are very well suited for packaging films.

[0030] In this invention, film structures are presented that include layers such as AB, AAB, ABC, and ABA, etc. Of course, the films can also be produced with many other layered structures depending on the configuration of the film extrusion line.

[0031] According to one embodiment, the process temperature for the film extrusion process is in the range of 200-240° C. The temperature may also be in the range of 210-230° C. Other suitable ranges are, for example, 205-235° C., or 215-225° C. The most suitable temperature range depends on the composition and number of layers.

[0032] According to one embodiment, at least one outer layer of the coextruded multilayer film comprises at least one slip additive in an amount of 0.5 to 5 wt. %. The amount of slip additive is typically 1 to 3 wt. %, or, for example, 1.5 to 4.5 wt. %, or 2 to 4 wt. %, based on the total weight of the layers. These amounts of slip additive have been shown to provide the necessary processability to produce a smooth, clear film that can be easily wound into a film roll without compromising the heat sealability of the film of the present disclosure.

[0033] Typically, slip additives (or slip agents) are divided into two classes: migrating and non-migratory. Slip additives may be inorganic compounds such as silica or talc. Slip additives may be organic compounds such as fatty acid amides (e.g., erucamide and oleamide), fatty acid esters, metal stearates, or waxes. Often, combinations of several slip additives are used. Often, slip additives are in the form of masterbatches. Often, formulations contain both slip additives and antiblock additives.

[0034] According to one embodiment, the slip additive is selected from the group consisting of migratory slip additives, non-migratory slip additives, inorganic slip additives, organic slip additives, and masterbatch slip additives, or any combination or mixture thereof. Masterbatch-type slip additives typically comprise a carrier material, such as a polymer, and an active material.

[0035] According to one embodiment, the coextruded multilayer cellulose-based film is produced by a film extrusion process at an output of 200 to 500 kg / h. The amount of slip additive described above has been shown to provide the capability to provide this range of output. Output refers to processing speed. Cellulose-based films with high cellulose content (such as cellophane and acetate) often require unique technologies for their production. However, by far the most common production method for flexible or rigid packaging is film extrusion, such as blown film extrusion and cast film extrusion processes. It is advantageous that cellulose-based film products can be produced by these film extrusion methods, which is possible for the coextruded multilayer cellulose-based film of the present disclosure.

[0036] According to one embodiment, the film extrusion process is a blown film extrusion process or a cast film extrusion process.

[0037] In this specification, unless otherwise specified, the expressions "recycle" or "recycled" should be understood to mean a process of reprocessing and reusing a material, or the result of that process, so that the molecules in the material are returned for reuse as either polymers, monomers, or smaller chemical building blocks. Recyclability refers to the ability to recycle a material for reuse. Preferably, films and materials for plastic packaging should be recyclable, either mechanically or chemically, to enable the reuse of molecular materials. This is clearly stated in the European Commission report (Plastics Strategy 2018) and the basic principles of the circular economy. Films with a high cellulose content are not known to be recyclable for reuse. Films with a high cellulose content are composed of cellulose acetate or regenerated cellulose, and these types of films are not susceptible to mechanical recycling due to their lack of thermal properties. Furthermore, recyclability is lost when PVDC is used as a sealing layer. Even if plastic film materials can be reprocessed into new pellets, it is not clear that the resulting pellets are suitable for the manufacture of new films. However, the coextruded multilayer cellulosic films of the present disclosure may be both chemically and mechanically recyclable.

[0038] "Mechanical recycling" is the process of, for example, taking a roll of plastic film, feeding it into a shredder, melting it, compounding it into strands, and then pelletizing the strands. These recycled pellets can then be made into new film products.

[0039] "Chemical recycling" is the process of taking, for example, a roll of plastic film and processing the material into smaller chemical components, such as syngas, a mixture of hydrogen, H2, and carbon monoxide, CO. These chemical building blocks can then be used directly to make new monomers for new plastic products.

[0040] Different parts of polymers can be recycled in different ways. Cellulose derivatives can undergo chemical recycling. Furthermore, many types of organic polymers can be used as feedstocks for chemical recycling. Traditional cellulosic polymers and films, such as cellophane, cellulose acetate, and other esters, are usable feedstocks for chemical recycling. Typically, the output of a chemical recycling process is a combination of, for example, synthesis gas, i.e., hydrogen (H2) gas and carbon monoxide (CO) gas.

[0041] However, the cellulose polymer structure itself is not currently regenerated as a result of chemical recycling. However, the chemicals used to modify cellulose can be produced from chemically recycled feedstocks. For example, the acetate groups in cellulose acetate or the propionate groups in cellulose acetate propionate can be produced from chemically recycled feedstocks.

[0042] Furthermore, some polymers, such as polyesters, can be used as feedstocks for chemical recycling. The outcome of these recycling processes can vary depending on the process used. Polyesters can be hydrolyzed into oligomers, dimers, or monomers. The polymers can also be reconstructed using an esterification process. Polyesters can also be used in thermochemical recycling processes, for example, to produce synthesis gas. This mixture can then be further used to build monomers or other chemical building blocks. Therefore, polymers such as polyesters can be used as feedstocks in chemical recycling processes. In addition, polymers such as polyesters can be produced from materials that are the outcome of chemical recycling processes.

[0043] According to one embodiment, the coextruded multilayer cellulosic film comprises chemically recycled material.

[0044] According to one embodiment, the coextruded multilayer cellulosic film contains 5-80 wt%, or 20-70 wt%, or 30-60 wt%, or 40-50 wt%, of chemically recycled material, based on the total weight of the film. This amount may be, for example, 10-80 wt%, or 30-50 wt%, of chemically recycled material, based on the total weight of the film. The amount of chemically recycled material may be, for example, 40-80 wt%, or 50-70 wt%, or 60-75 wt%. Preferably, the amount of chemically recycled material is 5-40 wt%.

[0045] Currently, cellulose polymer derivatives cannot be made entirely from chemically recycled materials. Typically, the ester moieties in cellulose acetate, cellulose acetate propionate, or cellulose acetate butyrate can be made from chemically recycled materials. Therefore, in practice, the maximum content of chemically recycled materials in a cellulose derivative is defined by the weight percent of the ester moieties relative to the total weight of the cellulose polymer derivative. This may typically vary from 20% to 55% by weight depending on the ester moieties and degree of substitution. This is the range for the maximum content of chemically recycled materials in a cellulose polymer derivative as a weight percent of the total weight of the cellulose polymer derivative.

[0046] For other polymers, such as aliphatic polyesters, the polyester portion can be made entirely of chemically recycled feedstock, so the maximum chemically recycled content for polyester, for example, is 100% by weight.

[0047] When the films according to the present disclosure are produced, the chemical recycle content may typically range from 50% up to 80% by weight if all ester groups in the cellulosic polymer, such as a cellulose polymer derivative, and the second polymer, such as a polyester, are made from chemically recycled materials.

[0048] According to one very specific embodiment, the chemical recycle in the coextruded multilayer cellulosic film is incorporated into a cellulosic polymer. Preferably, this polymer is cellulose acetate propionate. The propionate obtained via chemical recycle is more environmentally friendly than alternative known methods.

[0049] According to one embodiment, the coextruded multilayer cellulosic film comprises a mechanically recycled cellulosic blend.

[0050] According to one embodiment, the coextruded multilayer cellulosic film contains 5 to 100 wt. % mechanically recycled material, based on the total weight of the film. The amount of mechanically recycled material may be, for example, 10 to 95 wt. %, or 15 to 90 wt. %, or 20 to 85 wt. %, or 25 to 80 wt. %, or 30 to 75 wt. Mechanically recycled films have been shown to exhibit good sufficient puncture resistance, making them suitable for packaging applications.

[0051] According to one embodiment, the coextruded multilayer cellulosic film contains both mechanical and chemical recycle.

[0052] According to one embodiment, the sealing layer B is at least one intermediate layer of the film.

[0053] According to one embodiment, the sealing layer B is at least one outer layer of the film.

[0054] According to one embodiment, the coextruded multilayer cellulosic film comprises at least one sealing layer B, which is at least one of the middle and / or outer layers of the coextruded multilayer film, and which is introduced during the film extrusion process, which provides an efficient process for producing cellulosic films, where the films can be produced on an industrial scale.

[0055] According to one embodiment, the coextruded multilayer cellulosic film comprises a film layer structure selected from the group consisting of AB, ABA, ABC, ACB, and AAB. The expression "film layer structure" refers to the order in which the layers are placed on top of each other and extruded.

[0056] According to one embodiment, the sealing layer B comprises at least one polymer having heat-sealing properties. Herein, a polymer having heat-sealing properties may be referred to as a heat-sealing polymer. Thus, the sealing layer may provide the necessary sealing properties for the coextruded multilayer cellulosic film of the present disclosure. Suitable heat-sealing polymers are polymers or blends having a relatively low melting point. According to one embodiment, the sealing layer B comprises at least one polymer having heat-sealing properties, and the melting point of the heat-sealing polymer is 50°C to 210°C, or 60°C to 200°C, or 70°C to 190°C, or 80°C to 180°C.

[0057] According to one embodiment, a suitable heat-sealable polymer is a polymer or polymer blend having a suitable melt flow rate (MFR). According to a specific embodiment, the sealing layer B comprises at least one polymer having heat-sealability, and the MFR of this heat-sealable polymer is 1 g / 10 min to 20 g / 10 min (190°C; 2.16 kg) as measured by the ISO 1133 method. The MFR of the heat-sealable polymer may be 2 g / 10 min to 15 g / 10 min (190°C; 2.16 kg), or 3 g / 10 min to 10 g / 10 min (190°C; 2.16 kg), or 4 g / 10 min to 6 g / 10 min (190°C; 2.16 kg).

[0058] For example, the heat-sealable polymer may be polybutylene succinate (PBS), polybutylene adipate terephthalate (PBAT), and / or polylactic acid (PLA). Preferably, the heat-sealable polymer is PBS. The heat-sealable polymer may be a hot melt adhesive.

[0059] According to one embodiment, sealing layer B comprises at least one polymer coextruded with sealing layer B. This coextruded polymer is preferably an aliphatic and / or aliphatic-aromatic polyester or made by ring opening of a lactone. The use of aliphatic and / or aliphatic-aromatic polyesters in sealing layer B has been shown to provide good sealing properties.

[0060] According to one embodiment, the polymer co-extruded into the sealing layer is an aliphatic polyester.

[0061] According to one embodiment, the polymer co-extruded into the sealing layer is selected from the group consisting of polybutylene succinate (PBS), polypropylene succinate (PPS), polybutylene succinate adipate (PBSA), polybutylene adipate terephthalate (PBAT), polylactic acid (PLA), polycaprolactone (PCL), polybutylene adipate (PBA), polyhydroxyalkanoate (PHA), polyhydroxybutyrate (PHB), polyethylene furanoate (PEF), polybutylene terephthalate (PBT), polybutylene succinate terephthalate (PBST), and any polyester containing sebacic acid and / or azelaic acid and / or dodecanedioic acid as dicarboxylic acid, alone or in combination with terephthalic acid, and any combination thereof. According to one very specific embodiment, the polymer co-extruded into the sealing layer is selected from the group consisting of polybutylene succinate (PBS), polybutylene adipate terephthalate (PBAT) and polylactic acid (PLA) or any combination thereof.

[0062] According to one preferred embodiment, the polymer co-extruded into the sealing layer is polybutylene succinate.

[0063] According to one embodiment, the polymer co-extruded in sealing layer B constitutes 5 to 40 wt. %, or 10 to 30 wt. % of the total weight of sealing layer B.

[0064] According to one embodiment, the coextruded multilayer cellulosic film is heat-sealable, and the film is coated with a sealable coating, such as a dispersion coating or an adhesive coating.

[0065] According to one embodiment, the coextruded multilayer cellulosic film is coated with a coating selected from at least one of a barrier coating, a sol-gel coating, or a heat-resistant coating.

[0066] According to one embodiment, the coextruded multilayer cellulosic film is treated with a plasma or corona treatment before the coating is applied.

[0067] According to one embodiment, the first layer A comprises a first cellulose-based polymer selected from cellulose esters having an ester side chain length of C2 to C16. The side chains may be branched or unbranched. The side chains may comprise a mixture of several ester groups. Preferably, the side chain length of the branched or unbranched ester side chains is C3 to C10, or C3 to C8, or C3 to C5, or C2 to C4. The degree of substitution of the cellulose-based polymer may be 0.5 to 3. Preferably, the degree of substitution is 1 to 3. Most preferably, the degree of substitution is 2 to 3. The cellulose ester may be a mixed cellulose ester having multiple types of ester side chains. Alternatively or additionally, several different cellulose esters may be mixed in the polymer composition.

[0068] According to one embodiment, the first layer A comprises a first cellulose-based polymer, which is cellulose acetate propionate (CAP) and / or cellulose acetate butyrate (CAB), and a polymer selected from the group consisting of polybutylene succinate (PBS), polypropylene succinate (PPS), polybutylene succinate adipate (PBSA), polybutylene adipate terephthalate (PBAT), polylactic acid (PLA), polycaprolactone (PCL), polybutylene adipate (PBA), polyhydroxyalkanoate (PHA), polyhydroxybutyrate ( and a second polymer selected from the group consisting of polyesters containing sebacic acid and / or azelaic acid and / or dodecanedioic acid as dicarboxylic acids, alone or in combination with terephthalic acid, and any combination thereof, wherein the total amount of the first and second polymers is at least 80 wt. % based on the total weight of the first layer A. According to one very specific embodiment, the first cellulosic polymer is cellulose acetate propionate (CAP) and / or cellulose acetate butyrate (CAB). Preferably, the cellulosic polymer is cellulose acetate propionate. According to one very specific embodiment, the second polymer is polybutylene succinate (PBS), polypropylene succinate (PPS), and / or polybutylene succinate adipate (PBSA).

[0069] According to one embodiment, the sealing layer B comprises a first cellulose-based polymer selected from cellulose esters having an ester side chain length of C2 to C16. The side chains may be branched or unbranched. The side chains may comprise a mixture of several ester groups. Preferably, the side chain length of the branched or unbranched ester side chains is C3 to C10, or C3 to C8, or C3 to C5, or C2 to C4. The degree of substitution of the cellulose-based polymer may be 0.5 to 3. Preferably, the degree of substitution is 1 to 3. Most preferably, the degree of substitution is 2 to 3. The cellulose ester may be a mixed cellulose ester having multiple types of ester side chains. Alternatively or additionally, several different cellulose esters may be mixed in the polymer composition.

[0070] According to one embodiment, the sealing layer B comprises a first cellulose-based polymer which is cellulose acetate propionate (CAP) and / or cellulose acetate butyrate (CAB) and a second cellulose-based polymer which is selected from the group consisting of polybutylene succinate (PBS), polypropylene succinate (PPS), polybutylene succinate adipate (PBSA), polybutylene adipate terephthalate (PBAT), polylactic acid (PLA), polycaprolactone (PCL), polybutylene adipate (PBA), polyhydroxyalkanoate (PHA), polyhydroxybutyrate ( and a second polymer selected from the group consisting of cellulose acetate propionate (PHB), polyethylene furanoate (PEF), polybutylene terephthalate (PBT), polybutylene succinate terephthalate (PBST), and any polyester containing sebacic acid and / or azelaic acid and / or dodecanedioic acid as a dicarboxylic acid, alone or in combination with terephthalic acid, and any combination thereof, wherein the total amount of the first and second polymers is at least 80 wt % based on the total weight of sealing layer B. Preferably, sealing layer B comprises cellulose acetate propionate and polybutylene succinate.

[0071] According to one very specific embodiment, sealing layer B consists solely of a polymer with heat-sealing properties. According to one very specific embodiment, sealing layer B consists of polybutylene succinate (PBS).

[0072] According to one embodiment, the first layer A comprises at least one first cellulosic polymer in an amount of 55 to 95 wt % and at least one second polymer in an amount of 5 to 45 wt %, based on the total weight of the first layer A. The amount of the first cellulosic polymer may be 60 to 90 wt %, or 65 to 85 wt %, or 70 to 80 wt %. The amount of the second polymer may be 10 to 40 wt %, or 15 to 35 wt %, or 20 to 30 wt %.

[0073] According to one embodiment, in the first layer A, the total amount of the first cellulosic polymer and the second polymer is at least 80 wt. %, or at least 90 wt. %, or at least 95 wt. %, based on the total weight of the first layer A, with the remainder being other polymers and / or additives such as slip additives, softeners, pigments, stabilizers or other additives for use in plastic compositions.

[0074] According to one embodiment, the coextruded multilayer cellulosic film can be oriented. The film can be oriented in the longitudinal (machine) direction or the transverse direction. The film can also be oriented in both directions for biaxial orientation to provide heat shrinkage, improve tensile strength, or improve the impact strength of the product.

[0075] Also described is a packaging material comprising the coextruded multilayer cellulosic film.

[0076] According to one embodiment, the packaging material comprises a coextruded multilayer cellulosic film, which is selected from the group consisting of bags, cone-shaped bags, bags with perforations, bags with tear elements, pouches, sachets, flowpack packaging, packaging with narrow seals, packaging with wide seals, sealable packaging, resealable packaging, bags with wide side seals, bags with laminated side seals, flexible packaging of any kind, semi-rigid or rigid packaging, thermoformed products such as trays or trays and top layers, clamshell packaging, blister packaging, cardboard-plastic combination packaging, protective packaging, barrier packaging, laminating films, greenhouse films, agricultural films such as crop forcing films, silage films or silage stretch films, protective films, cushioning films such as bubble wrap or bubble packing, shrink films, and shrink sleeves.

[0077] The films may be used in packaging materials for semi-rigid or rigid packaging in thermoforming applications such as trays, trays and top layers, clamshell packaging, blister packaging, packaging made from a combination of cardboard and plastic, protective packaging, barrier packaging, and the like.

[0078] The films may be used, for example, to package fresh produce, perishable food, dry food, cosmetics, electronics, hygiene products, cleaning products, tools, toys, medical products, and other household, consumer, and industrial products.

[0079] The film may also be used as a laminate film, for example, laminated to paper, paperboard, cardboard, aluminum, composites, or plastics.

[0080] Furthermore, the film may be used in agricultural films such as greenhouse films, crop enforcing films, silage films, silage stretch films, and the like.

[0081] A further possible use is as a protective film, a cushioning film, such as bubble wrap, air bubble wrap, etc.

[0082] According to one embodiment, the packaging material is selected from the group consisting of a bag, a pouch or a sachet with a narrow seal. In addition, the film comprises a film layer structure ABA.

[0083] According to one very specific embodiment, the packaging material is a resealable bag. A resealable bag typically includes a rectangular bag sealed on three sides and a closure mechanism for the open side. The closure mechanism may be a zipper or zipper, a top zipper, a press to close the zipper, or a closure that can be opened and closed several times by pressing the seal or pulling the zipper pull to close the seal. The closure mechanism is typically sealed within the plastic bag to tightly close the bag.

[0084] The closure mechanism or zipper can be made in an extruder or zipper profile extruder. The closure mechanism or zipper can be made as a long strand or as a single piece. The zipper is made from a thermoplastic material.

[0085] According to one embodiment, the zipper material comprises a first cellulose-based polymer selected from cellulose esters having an ester side chain length of C2 to C16. The side chains may be branched or unbranched. The side chains may comprise a mixture of several ester groups. Preferably, the side chain length of the branched or unbranched ester side chains is C3 to C10, or C3 to C8, or C3 to C5, or C2 to C4. The degree of substitution of the cellulose-based polymer may be 0.5 to 3. Preferably, the degree of substitution is 1 to 3. Most preferably, the degree of substitution is 2 to 3. The cellulose ester may be a mixed cellulose ester having multiple types of ester side chains. Alternatively or additionally, several different cellulose esters may be mixed in the polymer composition.

[0086] According to one embodiment, the zipper material comprises a first cellulosic polymer that is cellulose acetate propionate (CAP) and / or cellulose acetate butyrate (CAB) and a second cellulosic polymer that is selected from the group consisting of polybutylene succinate (PBS), polypropylene succinate (PPS), polybutylene succinate adipate (PBSA), polybutylene adipate terephthalate (PBAT), polylactic acid (PLA), polycaprolactone (PCL), polybutylene adipate (PBA), polyhydroxyalkanoate (PHA), polyhydroxybutyrate and a second polymer selected from the group consisting of cellulose acetate propionate (PHB), polyethylene furanoate (PEF), polybutylene terephthalate (PBT), polybutylene succinate terephthalate (PBST), and any polyester containing sebacic acid and / or azelaic acid and / or dodecanedioic acid as a dicarboxylic acid, alone or in combination with terephthalic acid, and any combination thereof, wherein the total amount of the first and second polymers is at least 80 wt % based on the total weight of the sealing layer B. Preferably, the sealing layer comprises cellulose acetate propionate and polybutylene succinate.

[0087] The recyclability of resealable bags having the described closure mechanism may be preserved since the zipper may be reused along with the bag. [Example]

[0088] Reference will now be made in detail to the various embodiments, examples, of the described coextruded multilayer films of the present disclosure.

[0089] The following description discloses some embodiments in such detail that one skilled in the art can utilize the embodiments based on this disclosure. Not every step or feature of the embodiments is discussed in detail, as many steps or features will be apparent to one skilled in the art based on this specification.

[0090] Materials used in the examples: CAB is cellulose acetate butyrate grade CAB-381-20 (Eastman), product number 419044 (Sigma Aldrich). TOFA methyl esters are tall oil fatty acid methyl esters (various suppliers). CAP is cellulose acetate propionate from Eastman, grade CAP-482-20, Treva Engineering Bioplastic GC6011 clear, Treva Engineering Bioplastic TR6012FPNAT Natural. GS Pla is GS Pla AZ91T polymer from Mitsubishi. TEC is triethyl citrate (various suppliers). FZ91 is BioPBS FZ91PM from PTT MCC Biochem. FD92PM is BioPBS FD92PM from PTT MCC Biochem. S723 is SUKANO PBS ao S723. S724 is SUKANO PBS dc S724. IM100 is Croda IncroMax 100 as a 5% masterbatch in FZ91 polymer. S547 is SUKANO PLA uv S547. IncroMold S is IncroMold™ S polymer additive from Croda. Incroslip SL is Incroslip™ SL polymer additive from Croda. IncroMax PS is IncroMax PS from Croda as a 5% masterbatch in FZ91 polymer. S511 is SUKANO PLA dc S511. 4060D is a PLA resin Ingeo Biopolymer 4060D heat seal layer. Biomelt 2K is Kiilto Biomelt 2K from Kiilto Oy (Kiilto). Carbobond 1995 is Carbobond 1995 acrylic copolymer from Lubrizol. Carbobond 3005 is Carbobond 3005 acrylic copolymer from Lubrizol. Hycar 26084 is a carboxy-modified reactive acrylic latex from Lubrizol. Hycar 26288 is Hycar 26288 acrylic copolymer from Lubrizol. Hycar 26349 is Hycar 26349 acrylic copolymer from Lubrizol. Hycar 26548 is Hycar 26548 acrylic copolymer from Lubrizol. ACTEseal HSC-426-WK is a heat seal lacquer for polyester film from Actega. ACTEseal HM-194-AFP is a heat seal coating from Actega.

[0091] Example 1 - Reference Example Cellulosic Blend and Film Compositions [Table 1]

[0092] The blends in Table 1 were prepared using a melt mixing process at the temperatures indicated.

[0093] The films made from blends 5 to 11 in Table 1 were clear, transparent, and glossy. The stiffness of the films increased with increasing CAP content.

[0094] Films made with blends 1-8 were particularly suitable for laboratory or pilot scale blown film extrusion processes.

[0095] Films made with blends 7-11 were particularly suitable for laboratory or pilot scale cast film extrusion processes.

[0096] However, none of the blends in Table 1 were suitable for industrial production at high output and process efficiency. Films made with the blends in Table 1 had high friction, a property that made them unsuitable for industrial-scale processing.

[0097] In blown film extrusion processes at production rates above 20 kg / hr, the bubbles were unstable and the film roll was uneven due to high friction levels and stickiness. Similar problems were encountered in cast film extrusion processes at production rates above 50 kg / hr, as the film could not be rolled evenly due to high friction levels and stickiness.

[0098] Example 2 Cellulose-based compositions and films containing additives [Table 2]

[0099] The blends in Table 2 were produced using a melt mixing process at the temperatures indicated. Films made with the blends in Table 2 were produced using a cast film extrusion line at the temperatures indicated.

[0100] High friction means static friction above 1.8 and dynamic friction above 0.6, which are too high for film manufacturing and therefore film could not be efficiently manufactured. Moderate friction means static friction between 0.6 and 1.8 and dynamic friction between 0.3 and 0.6, so the film was processable for certain applications. Low friction means static friction below 0.6 and dynamic friction below 0.3, so the film was easily processable for various applications.

[0101] Different additives, anti-friction additives, slip additives, and anti-block additives, have been tested in cellulosic film manufacturing. Many additives failed to improve the friction properties of the blends. Many of the additives also reduced the transparency of the film to unacceptable levels. Some additives improved the friction level without affecting transparency.

[0102] Industrial production of cellulose-based films In a blown film extrusion process using three extruders, the innermost and outermost layers were fed with pre-blended Blend 6. 1-5 wt. % S724 was co-fed to this. The middle layer was fed with pre-blended Blend 6. This film was produced at an output of 200-400 kg / h. Therefore, industrial-scale processability was very good. The resulting film was transparent and clear, and easy to process.

[0103] Example 3 Cellulosic Blends and Films with Heat-Sealable Polymers (Third Polymers) [Table 3]

[0104] The blends in Table 3 were produced using a melt mixing process at the temperatures indicated. Films made with the blends in Table 3 were produced using a cast film extrusion line at the temperatures indicated.

[0105] To improve the heat sealability, different heat seal polymers were added to the cellulosic blends.

[0106] The melt flow rate (MFR) of heat seal polymers is typically 4-6 g / 10 min (190°C; 2.16 kg). For example, the MFR of FD92PM is 4 g / 10 min (190°C; 2.16 kg), and the MFR of FZ91PM is 5 g / 10 min (190°C; 2.16 kg).

[0107] Industrial production of heat-sealable cellulosic films: Film structure ABA In a three-extruder blown film extrusion process, the innermost and outermost layers were fed with pre-blended Blend 6, co-fed with 1-5% slip agent. The middle layer was fed with pre-blended Blend 6 and co-fed with 10-30% sealable polymer. The films were produced at an output of 200-400 kg / h. Therefore, industrial-scale processability was very good. The resulting films were transparent and clear, and easy to process.

[0108] The resulting film has very good heat sealability for narrow hot cut sealing of bags and sachets, as shown in Table 4. The film can be produced in thicknesses of 20 to 150 μm.

[0109] [Table 4]

[0110] Films of structure ABA have excellent puncture resistance as shown in Table 5.

[0111] [Table 5]

[0112] Industrial production of heat-sealable cellulosic films: Film structures AB In a three-extruder blown film extrusion process, the outermost layer was fed with pre-blended Blend 6, co-fed with 1-5 wt% slip agent. The middle layer was fed with pre-blended Blend 6. The innermost layer was fed with pre-blended Blend 6 and 10-30 wt% sealable polymer co-fed with 1-5 wt% slip agent. The films were produced at output rates of 200-400 kg / h. Thus, industrial-scale processability was very good. The resulting films were transparent and clear, and easy to process. The resulting films had excellent heat-sealing properties for flow-pack sealing with wide seals and as laminating films for cardboard and paper. The films could be produced in thicknesses of 20-150 μm using a blown film extrusion process.

[0113] Film structures AB and ABA can also be produced using a cast film extrusion process to produce thicker films, for example, 100-1000 μm.

[0114] Example 4 Cellulose-based film with coating Coatings, such as dispersion coatings, adhesive coatings, sol-gel coatings, heat-resistant coatings, barrier coatings, or matte coatings, can be used to achieve the desired film properties. For sustainability and recyclability, it is crucial that the coating layer be thin and contain only organic or inorganic components that do not interfere with further recycling processes. Various coatings have been tested. These films can be pretreated with plasma or corona treatment before applying the coating layer.

[0115] A film made from Blend 6 was coated with a heat seal coating according to Table 6.

[0116] [Table 6]

[0117] Films made from Blend 6 were coated with a sol-gel coating to obtain good barrier properties.

[0118] Films made from Blend 6 were coated with a barrier coat for high water vapor barrier.

[0119] Films made from Blend 6 were coated with a barrier coating for enhanced chemical resistance.

[0120] The film made from Blend 6 was coated with a heat resistant coating for better heat resistance.

[0121] The film made from Blend 6 was coated with a matte coating to give the film a matte effect.

[0122] Example 5 Manufacturing recycled cellulose-based films Mixed film waste containing blends 6 and 8 with additives was fed to a shredder, then melted, extruded into strands, and pelletized. The resulting granules were crystal clear and transparent. The recycled granules were then made into new film products in a cast film extrusion line. The resulting films were crystal clear and transparent, and films with thicknesses of 20 μm to 300 μm were successfully produced. No pores were detected in the recycled films, indicating good recyclability and extrusion properties for this recycled blend.

[0123] As shown in Table 7, this recycled film had excellent puncture resistance.

[0124] [Table 7]

[0125] The recycled blend can be mixed with a virgin cellulosic blend. The percentage of mechanically recycled material can vary, for example, from 5% to 100% by weight of the cellulosic film.

[0126] Example 6 NIR (near infrared spectroscopy) separation of cellulosic films Films made with Blend 6 containing additives were thermoformed into clamshell packaging. These packaging items were analyzed for their NIR spectra for plastic waste sorting. The samples showed clearly identifiable spectral curves and could be identified and sorted in a plastic waste sorting system.

[0127] Example 7 Cellulose-based film with chemical recycle The cellulose ester or polyester polymers suitable for the coextruded multilayer cellulosic system may contain chemical recycle.

[0128] The ester moieties in the cellulosic polymers, such as CAP and CAB, can be made in part or entirely using chemically recycled feedstocks.

[0129] Other polymers used in the blend, such as FD92PM or FZ91, can also be made partially or entirely from chemically recycled molecules. The percentage of chemically recycled material can vary, for example, from 10% to 80% by weight of the cellulosic film.

[0130] Example 8 Resealable bag manufacturing Zippers for resealing packaging bags were produced using a zipper extruder or zipper profile extruder with Blends 6, 7, 8, 9, 10, or 11. The zippers were successfully sealed to bags made from heat-sealable cellulosic films of film structure ABA or AB to produce resealable zipper-containing bags.

[0131] The zipper had good resealability, mechanical properties, and modulus, making it well suited for reseal applications.

[0132] It is obvious to those skilled in the art that with the advancement of technology, the basic idea may be implemented in various ways. Therefore, the embodiments are not limited to the above examples; instead, they may vary within the scope of the claims.

[0133] The embodiments described hereinbefore may be used in any combination with each other. Some of the embodiments may be combined to form further embodiments. An article, system, method, or use disclosed herein may include at least one of the embodiments described hereinbefore. It will be understood that the benefits and advantages described above may relate to one embodiment or to several embodiments. Embodiments are not limited to those that solve any or all of the stated problems or have any or all of the stated benefits and advantages. It will be further understood that reference to "an" item refers to one or more of those items. The term "comprising" is used herein to mean including the preceding described features or acts without excluding the presence of one or more additional features or acts.

Claims

1. 1. A coextruded multilayer cellulosic film, said film comprising: a first film layer A comprising at least one first cellulosic polymer and at least one second polymer; At least one sealing layer B, which is an outer layer and / or an intermediate layer of the film, comprises a first cellulose-based polymer which is cellulose acetate propionate (CAP) and / or cellulose acetate butyrate (CAB), and a second cellulose-based polymer which is polybutylene succinate (PBS), polypropylene succinate (PPS), polybutylene succinate adipate (PBSA), polybutylene adipate terephthalate (PBAT), polylactic acid (PLA), polycaprolactone (PCL), polybutylene adipate (PBA), polyhydroxyalkanoate (PHA), polyhydroxybutylene at least one sealing layer B comprising a second polymer selected from the group consisting of polyethylene terephthalate (PHB), polyethylene furanoate (PEF), polybutylene terephthalate (PBT), polybutylene succinate terephthalate (PBST), and any polyester containing sebacic acid and / or azelaic acid and / or dodecanedioic acid as a dicarboxylic acid, either alone or in combination with terephthalic acid, and any combination thereof, wherein the total amount of the first and second polymers is at least 80 wt % based on the total weight of the sealing layer B; at least one outer layer of the coextruded multilayer film, the at least one outer layer comprising at least one slip additive in an amount of 1 to 5 wt. %, based on the total weight of the outer layer; A coextruded multilayer cellulosic film comprising:

2. 10. The coextruded multilayer cellulosic film of claim 1, wherein the film has a cellulose content of at least 20 wt%, or 30-60 wt%, or 35-55 wt%, or 40-45 wt%, based on the total weight of the film.

3. 3. The coextruded multilayer cellulosic film of claim 1 or claim 2, wherein the film comprises chemically recycled material.

4. 4. The coextruded multilayer cellulosic film of any one of claims 1 to 3, wherein the film contains 5 to 80 wt%, or 20 to 70 wt%, or 30 to 60 wt%, or 40 to 50 wt%, or 5 to 40 wt% chemically recycled material, based on the total weight of the film.

5. 5. The coextruded multilayer cellulosic film of claim 3 or claim 4, wherein the chemical recycle is incorporated into the cellulosic polymer.

6. 6. The coextruded multilayer cellulosic film of any one of claims 1 to 5, wherein the film comprises mechanically recycled material.

7. 7. The coextruded multilayer cellulosic film of claim 1, wherein the film contains 5 to 100 wt. % mechanically recycled material, based on the total weight of the film.

8. 8. The coextruded multilayer cellulosic film of any one of claims 1 to 7, wherein the film contains both mechanical and chemical recycle.

9. 9. The coextruded multilayer cellulose-based film of claim 1, wherein the film comprises at least one sealing layer B, which is at least one of the intermediate and / or outer layers of the coextruded multilayer film, and the sealing layer B is introduced during the film extrusion process.

10. 10. The coextruded multilayer cellulosic film of any one of claims 1 to 9, wherein the film comprises a film layer structure selected from the group consisting of A-B, A-B-A, ABC, A-C-B, and A-A-B.

11. 11. The coextruded multilayer cellulosic film according to any one of claims 1 to 10, wherein the sealing layer B comprises at least one polymer having heat-sealability.

12. 12. The coextruded multilayer cellulosic film according to any one of claims 1 to 11, wherein the seal layer B comprises at least one polymer having heat-sealability, and the polymer having heat-sealability has a melting point of 50°C to 210°C, or 60°C to 200°C, or 70°C to 190°C, or 80°C to 180°C.

13. 13. The coextruded multilayer cellulosic film according to any one of claims 1 to 12, wherein the seal layer B comprises at least one polymer having heat-sealability, and the polymer having heat-sealability has an MFR of 1 g / 10 min to 20 g / 10 min (190°C, 2.16 kg), or 2 g / 10 min to 15 g / 10 min (190°C, 2.16 kg), or 3 g / 10 min to 10 g / 10 min (190°C, 2.16 kg), or 4 g / 10 min to 6 g / 10 min (190°C, 2.16 kg).

14. 14. The coextruded multilayer cellulosic film of claim 1, wherein the sealing layer B comprises a first cellulosic polymer selected from cellulose esters having an ester side chain length of C2 to C16, the side chains may be branched or unbranched and may comprise a mixture of several ester groups, and the degree of substitution of the cellulosic polymer may be from 0.5 to 3.

15. 15. The coextruded multilayer cellulosic film of any one of claims 1 to 14, wherein the sealing layer B comprises at least one polymer coextruded into the sealing layer B, the coextruded polymer being an aliphatic and / or aliphatic-aromatic polyester or made by ring opening of a lactone.

16. 16. The coextruded multilayer cellulosic film of claim 15, wherein the polymer coextruded into the seal layer is an aliphatic polyester.

17. 17. The coextruded multilayer cellulosic film of claim 15 or 16, wherein the polymer coextruded into the seal layer is selected from the group consisting of polybutylene succinate (PBS), polypropylene succinate (PPS), polybutylene succinate adipate (PBSA), polybutylene adipate terephthalate (PBAT), polylactic acid (PLA), polycaprolactone (PCL), polybutylene adipate (PBA), polyhydroxyalkanoate (PHA), polyhydroxybutyrate (PHB), polyethylene furanoate (PEF), polybutylene terephthalate (PBT), polybutylene succinate terephthalate (PBST), and any polyester containing sebacic acid and / or azelaic acid and / or dodecanedioic acid as dicarboxylic acid, alone or in combination with terephthalic acid, and any combination thereof.

18. 18. The coextruded multilayer cellulosic film of any one of claims 15 to 17, wherein the polymer coextruded into the sealing layer is selected from the group consisting of polybutylene succinate (PBS), polybutylene adipate terephthalate (PBAT), and polylactic acid (PLA), or any combination thereof.

19. 19. The coextruded multilayer cellulosic film of any one of claims 15 to 18, wherein the polymer coextruded into the sealing layer is polybutylene succinate.

20. 20. The coextruded multilayer cellulosic film of any one of claims 15 to 19, wherein the polymer coextruded into the seal layer is provided as 5 to 40 wt. %, or 10 to 30 wt. % of the total weight of the seal layer.

21. 21. The coextruded multilayer cellulosic film of any one of claims 1 to 20, wherein the coextruded multilayer cellulosic film is heat-sealable, and the film is coated with a sealable coating.

22. 22. The coextruded multilayer cellulosic film of any one of claims 1 to 21, wherein the film is coated with a coating selected from at least one of a barrier coating, a sol-gel coating, or a heat-resistant coating.

23. 23. The coextruded multilayer cellulosic film of claim 21 or claim 22, wherein the film is plasma or corona treated.

24. 24. The coextruded multilayer cellulosic film of any one of claims 1 to 23, wherein the first film layer A comprises a first cellulosic polymer selected from cellulose esters having an ester side chain length of C2 to C16, the side chains may be branched or unbranched and may comprise a mixture of several ester groups, and the degree of substitution of the cellulosic polymer may be 0.5 to 3.

25. The first film layer A comprises a first cellulose-based polymer which is cellulose acetate propionate (CAP) and / or cellulose acetate butyrate (CAB), and a polymer selected from the group consisting of polybutylene succinate (PBS), polypropylene succinate (PPS), polybutylene succinate adipate (PBSA), polybutylene adipate terephthalate (PBAT), polylactic acid (PLA), polycaprolactone (PCL), polybutylene adipate (PBA), polyhydroxyalkanoate (PHA), polyhydroxybutyrate (PHB), polyethylene furanoate (PEF), polybutylene adipate (PBA), polybutylene terephthalate (PBAT), polylactic acid (PLA), polycaprolactone (PCL), polybutylene adipate (PBA), polyhydroxyalkanoate (PHA), polyhydroxybutyrate (PHB), polyethylene furanoate (PEF), polybutylene terephthalate (PBAT), polybutylene succinate (PBA ...

25. The coextruded multilayer cellulosic film of claim 1, further comprising a second polymer selected from the group consisting of poly(ethylene terephthalate) (PBT), poly(butylene succinate terephthalate) (PBST), and any polyester containing sebacic acid and / or azelaic acid and / or dodecanedioic acid as a dicarboxylic acid, either alone or in combination with terephthalic acid, and any combination thereof, wherein the total amount of the first and second polymers is at least 80 wt. % based on the total weight of the first film layer A.

26. The first film layer A has a total weight of: the at least one first cellulosic polymer in an amount of 55 to 95 wt. %; said at least one second polymer in an amount of 5 to 45% by weight; 26. The coextruded multilayer cellulosic film of any one of claims 1 to 25, comprising:

27. 27. The coextruded multilayer cellulosic film of any one of claims 1 to 26, wherein in the first film layer A, the total amount of the first cellulosic polymer and the second polymer is at least 80 wt%, or at least 90 wt%, or at least 95 wt%, based on the total weight of the first film layer A, with the remainder being other polymers and / or additives for use in plastic compositions.

28. 28. A packaging material comprising the coextruded multilayer cellulosic film of any one of claims 1 to 27.

29. 29. The packaging material of claim 28 selected from the group consisting of bags, cone bags, bags with perforations, bags with tear elements, pouches, sachets, flow pack packaging, packaging with narrow seals, packaging with wide seals, sealable packaging, resealable packaging, bags with wide side seals, bags with laminated side seals, flexible packaging of any kind, semi-rigid or rigid packaging, thermoformed products, clamshell packaging, blister packaging, cardboard-plastic combination packaging, protective packaging, barrier packaging, laminating films, agricultural films, protective films, cushioning films, shrink films, and shrink sleeves.

30. 30. The packaging material of claim 28 or claim 29, which is a resealable bag including a zipper.

31. 1. A method for producing a coextruded multilayer cellulosic film, comprising: i. providing a first polymer composition for forming at least one first film layer A, the first polymer composition comprising at least one first cellulosic polymer and at least one second polymer; ii. Providing a sealing polymer composition for forming at least one seal film layer B; iii. Forming a co-extruded multi-layer film comprising the first film layer A and the seal film layer B by a film extrusion process; wherein the film comprises at least one slip additive; The sealing layer B comprises a first cellulose-based polymer which is cellulose acetate propionate (CAP) and / or cellulose acetate butyrate (CAB), and a second cellulose-based polymer selected from the group consisting of polybutylene succinate (PBS), polypropylene succinate (PPS), polybutylene succinate adipate (PBSA), polybutylene adipate terephthalate (PBAT), polylactic acid (PLA), polycaprolactone (PCL), polybutylene adipate (PBA), polyhydroxyalkanoate (PHA), polyhydroxybutyrate (PHB), polyethylene furanoate (PEF), polybutylene terephthalate (PBT), polybutylene succinate terephthalate (PBST), and any polyester containing sebacic acid and / or azelaic acid and / or dodecanedioic acid as a dicarboxylic acid, alone or in combination with terephthalic acid, and any combination thereof. and a polymer of the formula (I) wherein the total amount of the first and second polymers is at least 80 wt % based on the total weight of the sealing layer B; The method of claim 1, wherein at least one outer layer of said coextruded multilayer film comprises at least one slip additive in an amount of 1 to 5 weight percent based on the total weight of said layer.

32. 32. The method of claim 31, wherein the coextruded multilayer cellulosic film is a film according to any one of claims 1 to 27.

33. A method according to claim 31 or claim 32, characterized in that the process temperature of the film extrusion process is in the range of 200 to 240°C or in the range of 210 to 230°C.

34. A method according to any one of claims 31 to 33, characterized in that the film is produced by a film extrusion process with an output of 200 to 500 kg / h.

35. The method of any one of claims 31 to 34, wherein the film extrusion process is a blown film extrusion process or a cast film extrusion process.

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