Single material film and method for producing same

Abstract

A film (1) comprising a carrier substrate (10, 110) substantially comprising an oriented and at least partially crystalline thermoplastic polymer; and a coating (20, 120) which is an unoriented thermoplastic polymer coated on at least one side of the carrier substrate (10); wherein the combined carrier substrate (10) and coating (20) consist essentially of at least 70%, preferably at least 75%, more preferably at least 80%, more preferably at least 85%, more preferably at least 90%, most preferably at least 95% of the same polymer compounds.

Description

Technical Field

[0001] The present invention relates to a film, such as a film used in conjunction with a release liner, comprising a carrier layer and a coating. In particular, the present invention relates to the composition and type of the materials of each layer, as well as its production method. Background Art

[0002] The increasing globalization goes hand in hand with the increasing waste disposal. In many other industrial sectors, the packaging industry and / or the industry providing product decoration aim to reduce waste generation while maintaining or even improving the performance and function of products.

[0003] For example, release liners can be used in a variety of different applications, such as graphic arts, tapes, envelopes, industrial-use containers, fiber composites, medical, hygiene, labels, etc., which are provided with an adhesive layer, where the release liner can be peeled off (or also referred to as exposed / shed). Such film-based release liners should have certain properties to provide consistent release performance, such as being safe and stable, easy to use, and having low manufacturing costs. Therefore, it is desirable that the components of these products can be easily recycled without compromising their mechanical properties.

[0004] In the prior art, attempts have been made to meet these requirements.

[0005] For example, there are release liners based on polyethylene (PE), paper, and silicone. In addition, some release liners may be based on primers or polyethylene terephthalate (PET). Other examples include structured films based on PE, polypropylene (PP), PET, or polyamide (PA) silicone. Further known examples of structured release liners are based on biaxially oriented (BO) polymers (such as BOPP, BOPET, BOPA, or BOPE films and silicone).

[0006] However, according to the prior art, the proposed solutions have several disadvantages. For example, some of them are hybrid materials and / or multi-layered different types of polymer materials. This poses difficulties for recycling, reducing the recycling efficiency and increasing the cost. In addition, some of the proposed solutions require chemical or energy recycling. Moreover, due to different required manufacturing processes, some of them exhibit different mechanical properties. In addition, some of them cannot be processed, for example, cannot be embossed as required, or at least cannot be embossed sufficiently, nor can they be embossed in a flexible manner.

[0007] Refer to CN112250897A, CN106432768A, US2015 / 259563Al, and WO2022 / 056095Al.

[0008] In view of the above disadvantages, it is very important to provide improved films (for example, films used as release liners).

[0009] Therefore, an object of the present invention is to overcome the above disadvantages at least in part. Summary of the Invention

[0010] According to the subject matter of the independent claims, these objects are achieved at least in part by a film and a method for manufacturing a film. Further aspects of the present disclosure are defined in the dependent claims. Since both the film and the method for manufacturing the film are related to the film, it should be understood that the advantages and / or features of the film are also applicable to the method, and vice versa.

[0011] Film

[0012] Specifically, this object is achieved by a film comprising: a carrier substrate substantially comprising an oriented and at least partially crystalline thermoplastic polymer; and a coating which is an unoriented thermoplastic polymer coated on at least one side of the carrier substrate; wherein the combined carrier substrate and coating consist essentially of at least 70%, preferably at least 75%, more preferably at least 80%, more preferably at least 85%, more preferably at least 90%, most preferably at least 95% of the same polymer compound.

[0013] A particular advantage of the film is that the use of substantially the same polymer compound can improve recyclability. In particular, the film can be easily recycled because there is no need for the cumbersome separation of different polymer compounds coated on each other as in the prior art films. In particular, no chemical or energy recovery is required. The film can be recycled by mechanical means, which are well-established, easy to handle and inexpensive. Therefore, the efficiency of recycling is greatly improved.

[0014] In addition, since at least the carrier substrate comprises an oriented and at least partially crystalline thermoplastic polymer, the film has sufficient mechanical strength and structural integrity. This brings advantages in terms of mechanical properties and lifespan and increases the uses of the film. In particular, the tensile strength may be significantly higher compared to an unoriented film with the same polymer.

[0015] The coating is an unoriented thermoplastic polymer coated on at least one side of the carrier substrate and has the advantage of facilitating structuring or embossing. This allows for the creation of a structure, thereby improving, for example, the release properties of the coating. In addition, compared to coatings that only allow "holographic" films, it is beneficial that this coating allows for larger embossing structures. The holographic films are typically limited to micro-embossing (e.g., the depth of the embossing structure is low). As another example, sufficient structuring may help to promote the repositioning of the film. It is noted that when applied to oriented polymers, it is generally not possible to achieve such a high degree of embossing. Generally, the crystallinity of such oriented polymers may only allow embossing structures to a lesser extent (e.g., less than about 5 μm).

[0016] Surprisingly, the inventors have found that the combination of the carrier substrate and the coating provides a novel combination that offers excellent material properties and recyclability.

[0017] Another advantage of the film is that it can be soft and elastic (although essentially a single material), enabling it to conform to the structural components of any shape to which it is to be applied. It can be understood that if it is used for packaging industrial products (such as cars), it may smoothly conform to the round and / or angular contours of the car.

[0018] The film can be used as part of, for example, a release liner, as further described herein. Specific examples of applications are graphic arts, tapes, envelopes, industrial-use containers, fiber composites, medical, hygiene, labels, etc. Examples of graphic arts may be advertising films, traffic signs, car packaging, and structured liners. In terms of fiber composites, suitable uses may be aerospace building components and consumer leisure products.

[0019] Optionally or additionally, the film can be used in different fields of industry, not particularly limited to release liners. In some fields, adding a barrier layer is desirable. More use cases of the film described herein include the food industry, pet care, and household and personal care. The film can be part of the products used therein, such as products related to cheese and dairy products, potato chips and snacks, fresh and processed meats, fish and poultry, frozen foods, sugar and confectionery, tea and coffee, dry pet foods, pet care snacks and treats, wet pet foods, cleaning products, detergents, hygiene, personal care, and cosmetics.

[0020] The term "same" polymer can be understood as follows: for example, if PP (as defined elsewhere herein) is used for the carrier substrate, then essentially PP is also used for the coating. The term "essentially" herein is understood to generally include at least 70% of PP. It should be noted that impurities and / or minor manufacturing differences may be considered when determining the percentage value. Therefore, the percentage value may deviate slightly from the preferred percentage value. The polymer compounds used for the carrier substrate and the polymer compounds used for the coating can have different chain lengths (i.e., the number of monomers can be different). This may result in the polymer compounds used for the carrier substrate and the polymer compounds used for the coating having different melt flow indices.

[0021] The term "oriented" polymer can at least include the uniaxially and biaxially oriented polymers described elsewhere herein.

[0022] Preferably, the combination of the carrier substrate and the coating has a thickness that enables it to be structured or embossed to a depth between 5 μm and 50 μm.

[0023] Preferably, the combined carrier substrate and coating may have a thickness that enables it to be structured of at least 5 μm, preferably at least 10 μm, more preferably at least 15 μm, more preferably at least 20 μm, more preferably at least 25 μm, more preferably at least 30 μm, more preferably at least 35 μm, more preferably at least 40 μm, more preferably at least 45 μm, and most preferably at least 50 μm.

[0024] Alternatively or additionally, the combined carrier substrate and coating may have a thickness that enables it to be structured of at most 90 μm, more preferably at most 85 μm, more preferably at most 80 μm, more preferably at most 75 μm, more preferably at most 70 μm, more preferably at most 65 μm, more preferably at most 60 μm, more preferably at most 55 μm, and most preferably at most 50 μm.

[0025] The advantage of this is that a sufficient depth of structure can be imparted to the carrier substrate. This makes the film particularly useful in many of the applications described herein.

[0026] In one example, the depth can be measured along a substantially straight line perpendicular to the main surface of the film. This conforms to the typical understanding of depth by those skilled in the art.

[0027] Preferably, the coating has a thickness that enables it to be structured or embossed to a depth between 5 μm and 50 μm.

[0028] Preferably, the coating may have a thickness that enables it to be structured of at least 5 μm, preferably at least 10 μm, more preferably at least 15 μm, more preferably at least 20 μm, more preferably at least 25 μm, more preferably at least 30 μm, more preferably at least 35 μm, more preferably at least 40 μm, more preferably at least 45 μm, and most preferably at least 50 μm.

[0029] Alternatively or additionally, the coating may have a thickness that enables it to be structured of at most 90 μm, more preferably at most 85 μm, more preferably at most 80 μm, more preferably at most 75 μm, more preferably at most 70 μm, more preferably at most 65 μm, more preferably at most 60 μm, more preferably at most 55 μm, and most preferably at most 50 μm.

[0030] The advantage of this is that, in particular, the coating can be provided with an embossed structure. Since the coating is unoriented, this is easily achieved. Thus, embossing can be carried out, for example, using a thermally driven embossing process. This may be a cost-effective process.

[0031] Preferably, the combined carrier substrate and coating are a single material having at least 90%, preferably 95% of the same polymer compound.

[0032] The advantage of doing this is that it can improve recycling because it allows for mechanical recycling, which can be a very efficient recycling process.

[0033] Preferably, the same polymer compound is composed of the same monomer units or the same combination of a plurality of monomer units and is selected from the list including polyesters and polyolefins.

[0034] They have the advantage that the monomers are relatively inexpensive and readily available. Thus, the quality of film production is improved.

[0035] The monomer units of polyesters can include aromatic polyesters such as PEF. PEF is becoming increasingly popular due to its bio-based characteristics and advantages in terms of thermal and barrier properties. In addition, it is understood that biodegradable polyesters can also be used according to the present invention. The term "biodegradable" as used herein can be understood as plastics that can be decomposed by the action of organisms. An example of such a biodegradable polyester may be PHB, which is particularly attractive due to its compostable properties. It is noted that the use of PLA as another example of a biodegradable polyester is also becoming increasingly important as it can be produced economically from renewable resources.

[0036] More examples of polyesters include PET and PBT. In addition, examples of polyolefins include PE and PP.

[0037] Overall, the monomers used in the films according to the present disclosure can facilitate a more economically efficient process and can make a valuable contribution to higher sustainability.

[0038] In one embodiment, the oriented and at least partially crystalline thermoplastic polymer can be a uniaxially oriented or biaxially oriented thermoplastic polymer.

[0039] The uniaxially oriented thermoplastic polymer can be a polymer that has been stretched to make the polymer chains parallel to each other (e.g., in a first direction). Preferably, the chains are oriented towards the machine direction (MD).

[0040] The advantage of such uniaxially oriented polymers is that they can be produced in an economically efficient and simple manner. In addition, for certain applications, the property of being easily tearable in one direction may be required, and uniaxially oriented polymers have proven to be beneficial.

[0041] Preferably, the oriented and at least partially crystalline thermoplastic polymer is a biaxially oriented thermoplastic polymer.

[0042] The biaxially oriented (BO) thermoplastic polymer can be a polymer that has been stretched to make the polymer chains parallel to each other (e.g., in a first direction). The chains can be parallel to the plane of the film. In addition, the chains of the biaxially oriented polymer can be oriented in a direction substantially perpendicular to the first direction.

[0043] This orientation exhibits improved clarity, high tensile properties, improved flexibility and toughness. Additionally, the improved barrier properties may be attributed to this orientation. Moreover, the oil and grease resistance can also be enhanced.

[0044] It should be noted that if a polymer is a BO polymer, it can still be referred to as the "same" polymer within the meaning of the present disclosure.

[0045] In a preferred embodiment, the film further comprises a release layer applied on the side opposite to the carrier substrate on the unoriented polymer layer (the coating).

[0046] The advantage of the film is that it provides a layer that can conveniently be used as part of a release liner. For example, a release layer can provide a releasable surface such that additional layers (which may include printing and adhesives) can be applied to the film rather than being permanently attached to the film. Such additional layers can be easily removed from the remaining layers of the film through the releasable surface.

[0047] Preferably, the release layer comprises a layer of silicone coating.

[0048] The advantage of this is that mature technologies can be used to fabricate the film. Silicone facilitates the manufacturing process. Additionally, colored silicone can also be used. Moreover, silicone helps to provide a releasable surface such that any additional layers applied to the film can be more easily removed from the film, as described herein.

[0049] In a specific example, the release layer can comprise PDMS (as described elsewhere herein).

[0050] In another embodiment, printing is preferably provided between the carrier substrate and the coating.

[0051] The advantage is that the appearance is improved and is appreciated by users / consumers. The printing is not restricted and includes any type of printing. The printing may be specifically designed for special applications and / or uses. In one example, the printing can include one or more and / or combinations of graphic elements, graphemes, pictures, artworks, letters, symbols, etc. In one example, a natural appearance can be provided if desired. In a further example, the printing can include a company logo, advertising slogan or warning symbol. Some of these prints may be particularly useful for the packaging industry.

[0052] Alternatively or additionally, printing can be provided on top of the coating, for example, printing can be provided on the side of the coating opposite to the side facing the carrier substrate.

[0053] The printing can be a separate layer or applied on a certain layer. Any type of printing technology can be used for printing, such as rotogravure printing, flexographic printing, digital printing, offset printing, inkjet printing, and / or laser marking. In this way, high-quality prints can be obtained. The advantage of digital printing is that the printing is basically non-contact.

[0054] Preferably, in the films described herein, the coating is applied to the carrier substrate by an extrusion coating process and / or a lamination process.

[0055] The advantage of this is that the manufacturing process is simplified.

[0056] Different types of lamination processes may be applicable and are of course included in the present disclosure. For example, adhesive thermal lamination or ultrasonic lamination can be used.

[0057] Advantageously, a conventional embossing roll or cooling roll can be used for coating. For example, extrusion can be carried out with the aid of a structured cooling roll. The cooling roll can have an outer shell and an inner shell in order to cool the hot (and molten) polymer material with the aid of a cooling medium (such as water). The cooling medium can be guided through the cooling roll.

[0058] Preferably, the tensile strength of the combined carrier substrate and coating is at least 50 N / mm 2 preferably at least 60 N / mm 2 more preferably at least 70 N / mm 2 more preferably at least 80 N / mm 2 more preferably at least 85 N / mm 2 more preferably at least 90 N / mm 2 more preferably at least 95 N / mm 2 more preferably at least 100 N / mm 2 more preferably at least 105 N / mm 2 more preferably at least 110 N / mm 2 more preferably at least 115 N / mm 2 more preferably at least 120 N / mm 2 more preferably at least 125 N / mm 2 more preferably at least 130 N / mm 2 preferably measured in the cross direction (CD) of the carrier substrate.

[0059] The advantage of this is that the film has sufficient mechanical properties to withstand impacts due to handling and / or the environment.

[0060] In one example, the tensile strength can be the maximum stress that the carrier can withstand when it is stretched or pulled before breaking. This tensile strength may be measured along the machine direction (MD) or the cross direction (CD) of the carrier substrate. Exemplarily, the test conditions for films and sheets according to DIN EN ISO 527 / 3 and / or ASTM D882 can be used to derive the tensile strength as disclosed herein.

[0061] Preferably, the carrier substrate comprises two or more polymer layers.

[0062] Such carrier substrates can be manufactured by coextrusion (as described elsewhere herein). Specifically, the carrier substrate can comprise three or more polymer layers. For example, one of the layers comprised in the carrier substrate can be a sealing layer. This sealing layer can be made of a material similar to that used in the carrier substrate, such as PP or PE.

[0063] Furthermore, in a preferred embodiment, the carrier substrate layer comprises a barrier layer.

[0064] The barrier layer can be understood as any layer that at least partially prevents or hinders the passage of fluids, particles, etc. through the film. In one example, the barrier layer has the advantage of preventing any fluid and / or particle exchange of the goods (e.g., for food applications) to the outside. This may help to extend the shelf life. In addition, these barriers can also be used to prevent environmental impacts, such as wind, water, fire, rain, oil, etc.

[0065] In one example, the carrier substrate or film can be obtained by a coextrusion or lamination process. Coextrusion is particularly advantageous in that it can easily provide a film comprising multiple layers.

[0066] Preferably, the coating is provided on both sides of the carrier substrate.

[0067] Preferably, the film comprises one or more additional layers, wherein the one or more additional layers are any one of the following: polyester layer, polyolefin layer, adhesive lacquer layer, silicone layer. It is noted that the one or more additional layers can comprise any one of the polymer compounds used herein with respect to the "same" polymer compound.

[0068] Preferably, the ratio of the thickness of the carrier substrate to the coating is in the range of, for example, about 40% to 60% to about 95% to 5%, such as 56% to 44% or 80% to 20%. Those skilled in the art will understand that if "40% to 60% to about 95% to 5%" is mentioned, the first two percentage values and the last two percentage values may each belong to the same group, essentially representing one end of the thickness ratio "range" referred to herein respectively.

[0069] Preferably, the thickness ratio of the carrier substrate to the coating can be at least 40% to 60%, preferably at least 45% to 55%, more preferably at least 50% to 50%, more preferably at least 55% to 45%, more preferably at least 60% to 40%, more preferably at least 65% to 35%, more preferably at least 70% to 30%, more preferably at least 75% to 25%, more preferably at least 80% to 20%, more preferably at least 85% to 15%, more preferably at least 90% to 10%, and most preferably at least 95% to 5%.

[0070] Alternatively or additionally, the thickness ratio of the carrier substrate to the coating can be at most 95% to 5%, preferably at most 90% to 10%, more preferably at most 85% to 15%, more preferably at most 80% to 20%, more preferably at most 75% to 25%, more preferably at most 70% to 30%, more preferably at most 65% to 35%, more preferably at most 60% to 40%, more preferably at most 55% to 45%, more preferably at most 50% to 50%, more preferably at most 45% to 55%, and most preferably at most 40% to 60%.

[0071] On the one hand, these thickness ratios have proven sufficient to provide adequate mechanical properties (possibly requiring a higher thickness of the carrier), while on the other hand, the materials used remain at a moderate level and can provide sufficient structuring (possibly requiring a higher thickness of the coating). Therefore, the inventors have found that an optimal ratio should be found.

[0072] Preferably, the polymer compound of the carrier substrate and the polymer compound of the coating have different chain lengths, different degrees of polymerization, and / or different melt flow indices.

[0073] The advantage of this is that although the combined carrier substrate and coating are considered to be composed of the same polymer compound, the chain lengths and polymerization grades of the polymer compounds can be different, and / or they can have different melt flow indices. This allows the properties of the carrier substrate and the coating to be customized as needed.

[0074] Method

[0075] This object is also achieved at least in part by a method for manufacturing a film (such as the film described herein), the method comprising the following steps:

[0076] Providing a carrier substrate that substantially comprises an oriented and at least partially crystalline thermoplastic polymer, and applying a coating on at least one side of the carrier substrate, the coating being an unoriented thermoplastic polymer; wherein the combined carrier substrate and coating are substantially composed of at least 70%, more preferably at least 75%, more preferably at least 80%, more preferably at least 85%, more preferably at least 90%, and most preferably at least 95% of the same polymer compound.

[0077] It should be understood that the substantially same advantages and features mentioned with respect to the membrane equally apply to the method of manufacturing the membrane. Additionally, these features can be combined and / or applied interchangeably to aspects, embodiments, and examples of the membrane and the method, respectively.

[0078] The respective advantages of the method are described herein with respect to the membrane.

[0079] Preferably, the method includes further method steps to provide the features mentioned in the context of the membrane.

[0080] Brief Description of the Drawings

[0081] Preferred embodiments are described below only by way of example.

[0082] Reference is made to the following drawings:

[0083] Figure 1 A schematic cross-section of a membrane according to a preferred embodiment of the present invention is shown.

[0084] Figure 2 A schematic cross-section of a membrane according to another preferred embodiment of the present invention is shown.

[0085] Figure 3 A schematic flow chart of a method according to an embodiment of the present invention is shown. Detailed Description

[0086] Definition

[0087] The longitudinal direction (MD) as used herein can be understood as the direction in which the machine (e.g., a belt) runs during the manufacture of a layer, membrane, or similar material and / or the direction in which the manufactured material is wound.

[0088] The transverse direction (CD) can be understood as being substantially perpendicular to the MD direction. It can also be referred to as the traverse direction. To further illustrate MD and CD, the following may be helpful and will be readily understood by those skilled in the art: If a layer, membrane, or similar material has substantially the same physical properties in two directions (e.g., MD and CD), the layer, membrane, or similar material can be referred to as isotropic.

[0089] "Polyolefin" or "polyolefins" is a type of polymer with the general formula (CH2CHR) n , where R is an alkyl group. They can also be referred to as polyolefins.

[0090] "CoEx" as used herein refers to coextrusion.

[0091] "PE" as used herein refers to polyethylene.

[0092] "PP" used in this text refers to polypropylene.

[0093] "PA" used in this text refers to polyamide.

[0094] "BO" used in this text refers to biaxial orientation. For example, "BOPP" refers to biaxially oriented polypropylene.

[0095] "PET" used in this text refers to polyethylene terephthalate.

[0096] "PBT" used in this text refers to polybutylene terephthalate.

[0097] "PHB" used in this text refers to polyhydroxybutyrate.

[0098] "PLA" used in this text refers to polylactic acid.

[0099] "PEF" used in this text refers to polyethylene furanoate.

[0100] "PDMS" used in this text refers to polydimethylsiloxane.

[0101] "Sil" used in this text refers to silicone.

[0102] Drawing

[0103] Subsequently, currently preferred embodiments will be outlined mainly with reference to the above-mentioned drawings. It should be noted that further embodiments are of course feasible, and the following explanations are provided only by way of example and are not limiting. In addition, the present invention can also be applied to other embodiments not explicitly disclosed below. In addition, as described below, the embodiments are compatible with each other, and the individual features of one embodiment can also be applied to another embodiment.

[0104] Throughout the drawings and the specification, the same reference numerals denote the same elements. The drawings may not be drawn to scale, and for clarity, illustration, and convenience, the relative sizes, proportions, and descriptions of the elements in the drawings may be exaggerated.

[0105] Figure 1 A film 1 including a carrier substrate 10 is shown. The carrier substrate 10 is substantially composed of an oriented and at least partially crystalline thermoplastic polymer. The film 1 also includes a coating 20, which is an unoriented thermoplastic polymer and is coated on at least one side of the carrier substrate 10. Thus, two coatings 20 can be coated on both sides of the carrier substrate 10 (in Figure 1 only a configuration with the coating 20 coated on one side is shown). Such coating can be carried out by an extrusion coating process or a lamination process.

[0106] The oriented and at least partially crystalline thermoplastic polymer of the carrier substrate is biaxially oriented. The tensile strength of the carrier substrate in the cross direction (CD) is at least 100 N / mm 2 . It is understood that this value may vary depending on the polymer used. Figure 1 The cross direction is marked by way of example in. In addition, those skilled in the art will understand that the CD can also be reversed by approximately 180°. In addition, the main direction (MD) is represented by a circle and a cross, such that the MD lies in the plane of the image. In addition, those skilled in the art will understand that the MD can also be reversed by approximately 180° (e.g., out of the plane of the image).

[0107] The partially crystalline and oriented polymer exhibits one or more of improved transparency, high tensile properties, improved flexibility and toughness. In addition, the improvement in barrier properties may be attributed to this orientation. In addition, the oil and grease resistance can also be improved.

[0108] On the other hand, coating an unoriented thermoplastic polymer on at least one side of the carrier substrate as a coating has the advantage of being conducive to structuring or embossing. In this way, a structure can be created, thereby improving the release properties of the coating and the like. In addition, the advantage of this coating is that it can achieve a larger embossed structure than in a "holographic" film.

[0109] The combination of the carrier substrate 10 and the coating 20 has such a thickness (denoted by "t" in the Figure 1 and Figure 2 thickness direction) that it can be structured or embossed to a depth of at least 5 μm and / or at most 50 μm. In addition, these layers can be arranged such that the coating 20 has a certain thickness such that structuring or embossing can be carried out at a depth between 5 μm and 50 μm.

[0110] The combined carrier substrate 10 and coating 20 are substantially composed of at least 70% of the same polymer compound.

[0111] The combined carrier substrate 10 and coating 20 can specifically be a single material having at least 90%, preferably 95% of the same polymer compound.

[0112] The same polymer compound is composed of the same monomer unit or a combination of the same multiple monomer units. The monomer unit can be selected from a list including polyesters (e.g., PET, PBT, PEF, PHB, PLA) and polyolefins (e.g., PE, PP).

[0113] The advantage of this is that recycling can be improved because it can be mechanically recycled, and mechanical recycling can be a very efficient recycling process.

[0114] Figure 2Also shown is a film according to another embodiment of the present invention. The film also includes a carrier substrate 110 and a coating 120, as Figure 1 described in the embodiment of. Figure 2 The reference numerals 110 and 120 of Figure 1 correspond to the elements referred to by the reference numerals 10 and 20 of

[0115] The release layer 130 is provided on an unoriented polymer layer on the opposite side of the carrier substrate 110. As described herein, the release layer 130 is optional.

[0116] In addition, as Figure 2 shown, the film further includes printing 112 located between the carrier substrate 110 and the coating 120. The printing 112 can include decals, decorative elements, different colors, inks, paints, pigments, symbols, words, letters, or any combination thereof. Any type of printing process can be applicable, such as rotogravure printing, flexographic printing, digital printing, offset printing, inkjet printing, and / or laser marking. The printing 112 can also be arranged on top of the coating 120 (e.g., arranged above the coating 120 in Figure 2 instead of being arranged below as shown in Figure 2 ). Thus, the printing 112 can be applied on the side of the coating 120 opposite to the side facing the carrier substrate 110.

[0117] As Figure 2 optionally shown in, the carrier substrate 110 can include two or more polymer layers 110a, 110b. Specifically, the carrier substrate 110 can include three polymer layers 110a, 110b, 110c (as optionally shown in Figure 2 ). In this case, it may be beneficial for one or more (preferably one) of the polymer layers 110a, 110b, 110c to be a sealing layer (such a sealing layer can be made of PE). The carrier substrate 110 can also include a barrier layer. In one example, the carrier substrate 110 including a barrier layer can be obtained by coextrusion or lamination. Coextrusion is particularly advantageous because it can easily provide a film containing multiple layers. This may be easily recognizable in the final product because coextrusion improves the product quality and robustness compared to single extrusion (while complying with strict restrictions regarding barrier properties). However, if fewer layers are only required, single extrusion may be particularly beneficial.

[0118] This embodiment of course covers other layers, and the film is not limited to the presented layers. For example, any other layers of polyester, polyolefin, adhesive paint, silicone, or the like can also be included in the film.

[0119] In the above embodiments, the thickness ratio of the carrier substrates 10, 110 to the coatings 20, 120 is in the range of, for example, 40% to 60% to about 95% to 5%, such as 56% to 44% or 80% to 20%. For example, this applies if one or both sides of the carrier substrates 10, 110 are covered by the coatings 20, 120.

[0120] Figure 3 A schematic flow chart of a method 1000 according to an embodiment of the present invention is shown.

[0121] The method 1000 is used to manufacture a film 1, such as the film 1 described herein, and the method 1000 includes the following steps.

[0122] Providing 1100 a carrier substrate 10 that substantially comprises an oriented and at least partially crystalline thermoplastic polymer; and

[0123] Applying 1200 a coating 20 on at least one side of the carrier substrate 10, the coating 20 being an unoriented thermoplastic polymer.

[0124] The resulting combined carrier substrate 10 and coating 20 are substantially composed of at least 70%, more preferably at least 75%, more preferably at least 80%, more preferably at least 85%, more preferably at least 90%, and most preferably at least 95% of the same polymer compound.

[0125] Embodiment of further layer

[0126] The following examples may further assist in understanding the films described herein, but are not intended to be bound by and / or limit these examples.

[0127] In the following examples, the symbol " / " represents the separation between two layers. The term "(Sil)" indicates that silicone may be optional. Additionally, the symbol "(PP)" indicates that the PP layer may be optional.

[0128] Example 1: (PP) / BOPP carrier / PP / (Sil).

[0129] Example 2: PP / BOPP carrier / PP / Sil.

[0130] Example 3: Sil / PP / BOPP carrier / PP / Sil.

[0131] Example 4: (Sil) / PP / adhesive paint / BOPP carrier / adhesive paint / PP / Sil.

[0132] Example 5: (Sil) / PP / CoEx BOPP (- outer PP layer) / PP / Sil.

[0133] Example 6: (Sil) / PP / CoEx BOPP carrier / PP / Sil.

[0134] Example 7: (Sil) / PP / adhesive paint / CoEx BOPP (- inner PP) / adhesive paint / PP / Sil.

[0135] Example 8: PET / BOPET carrier / PET / Sil.

[0136] Example 9: Sil / PET / BOPET carrier / PET / Sil.

[0137] Example 10: (Sil) / PET / adhesive paint / BOPET carrier / adhesive paint / PET / Sil.

[0138] In the above examples, the film may include a barrier layer. Such a barrier layer may be provided within the BOPP layer, which is preferably obtained by the CoEx process. Such a barrier layer may alternatively or additionally be provided between any of the layers in the above examples.

[0139] Further examples of the film of the present invention and their resulting physical properties are listed in Table 1 below:

[0140] Table 1: Further examples 11, 12, and 13 of the film according to the present invention.

[0141] The Fmax CD (transverse) value can be measured according to the DIN EN ISO 527 / 3 and / or ASTM D882 test protocols. It should be noted that the tensile strength used herein is the maximum stress that the probe can withstand during the tensile test (obtainable from DIN EN ISO 527 / 1). The "side 1" and "side 2" of the embossing depth respectively represent the depth of the coating on each side of the carrier substrate.

[0142]

[0143] The difference between the sum of the "thickness" in the above table and the total thickness is due to the film containing other layers.

[0144] In the above Examples 11, 12, and 13, the grammage of the carrier (such as BOPP) can be 52.5 g / m 2 .

[0145] In the above Example 11, the grammage of the coating (such as PP) is about 100 g / m 2 , and the content of the same polymer (such as PP) is at least 85% (by weight).

[0146] In the above Examples 12 and 13, the content of the grammage of the coating (such as PP) is about 27 g / m 2, the content of the same polymer (such as PP) is at least 90% (by weight).

[0147] It should be noted that the above-mentioned embodiments and examples can be combined with other aspects described herein, and details of the embodiments and examples can also be omitted, as understood by those skilled in the art. The scope of protection is determined by the claims and is not limited by the embodiments and examples disclosed in the above drawings.

[0148] It will be obvious to those skilled in the art that, according to the above teachings, various modifications and variations can be made to the described embodiments and implementations. The disclosed embodiments and implementations are for illustrative purposes only. Other embodiments may include some or all of the features disclosed herein. Therefore, the present invention is intended to cover all possible modifications and alternative implementations that may fall within the true scope of the present invention.

[0149] List of reference numerals

[0150] 1, 100 film

[0151] 10, 110 carrier substrate

[0152] 100a, 100b, 100c polymer layer

[0153] 12, 112 printing layer

[0154] 20, 120 coating

[0155] 30, 130 release layer

[0156] MD Machine Direction

[0157] CD Cross Direction

[0158] t thickness

[0159] 1000 method

[0160] 1100 method step: providing

[0161] 1200 method step: applying

Claims

1. A film (1), comprising: - A carrier substrate (10, 110), which basically comprises an oriented and at least partially crystalline thermoplastic polymer; And - A coating (20, 120), which is an unoriented thermoplastic polymer coated on at least one side of the carrier substrate (10); Wherein, the combined carrier substrate (10) and coating (20) are basically composed of at least 70%, preferably at least 75%, more preferably at least 80%, more preferably at least 85%, more preferably at least 90%, and most preferably at least 95% of the same polymer compound.

2. The film (1) according to the preceding claim, wherein the combined carrier substrate (10) and coating (20) have a thickness such that they can be structured or embossed at a depth between 5 μm and 50 μm.

3. The film (1) according to any one of the preceding claims, wherein the coating (20) has a thickness such that it can be structured or embossed at a depth between 5 μm and 50 μm.

4. The film (1) according to any one of the preceding claims, wherein the combined carrier substrate (10) and coating (20) are a single material having at least 90%, preferably 95% of the same polymer compound.

5. The film (1) according to any one of the preceding claims, wherein the same polymer compound is composed of the same monomer unit or the same combination of a plurality of monomer units, and is selected from the list including polyesters and polyolefins, Among them, Optionally, the polyester includes polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polyethylene furanate (PEF), polyhydroxybutyrate (PHB), polylactic acid (PLA), etc., Wherein, optionally, the polyolefin includes polyethylene (PE), polypropylene (PP), etc.

6. The film (1) according to any one of the preceding claims, wherein the oriented and at least partially crystalline thermoplastic polymer is a biaxially oriented thermoplastic polymer.

7. The film (1) according to any one of the preceding claims, further comprising a release layer (130) applied on the side of the coating (120) opposite to the carrier substrate (10).

8. The film (1) according to claim 7, wherein the release layer (130) comprises a silicone coating.

9. The film (1) according to any one of the preceding claims, wherein printing (112) is provided, preferably between the carrier substrate (110) and the coating (120).

10. The membrane (1) according to any one of the preceding claims, wherein, The coating (20) is coated onto the carrier substrate (10) by an extrusion coating process or a lamination process.

11. The film (1) according to claim 6, wherein when measured in the cross direction (CD) of the carrier substrate (10), the tensile strength of the combined carrier substrate (10) and coating (20) is at least 50 N / mm 2 , preferably at least 60 N / mm 2 , more preferably at least 70 N / mm 2 , more preferably at least 80 N / mm 2 , more preferably at least 85 N / mm 2 , more preferably at least 90 N / mm 2 , more preferably at least 95 N / mm 2 , more preferably at least 100 N / mm 2 , more preferably at least 105 N / mm 2 , more preferably at least 110 N / mm 2 , more preferably at least 115 N / mm 2 , more preferably at least 120 N / mm 2 , more preferably at least 125 N / mm 2 , more preferably at least 130 N / mm 2 .

12. The film (1) according to any one of the preceding claims, wherein the carrier substrate (10, 110) comprises two or more polymer layers (110a, 110b).

13. The film (1) according to any one of the preceding claims, comprising one or more additional layers, wherein the one or more additional layers are any one of the following: a polyester layer, a polyolefin layer, an adhesive paint layer, a silicone layer.

14. The membrane (1) according to any one of the preceding claims, wherein the thickness ratio of the carrier substrate (10, 110) to the coating (20, 120) is in the range of from about 40% to 60% to about 95% to 5%.

15. The membrane (1) according to any one of the preceding claims, wherein the polymer compound of the carrier substrate (10) and the polymer compound of the coating (20) have different chain lengths, different degrees of polymerization and / or different melt flow indices.

16. A method (1000) for manufacturing a membrane (1), such as the membrane (1) according to any one of the preceding claims, the method (1000) comprising the steps of: - providing (1100) a carrier substrate (10, 110), the carrier substrate (10, 110) substantially comprising an oriented and at least partially crystalline thermoplastic polymer, and - applying (1200) a coating (20, 120) on at least one side of the carrier substrate (10), the coating (20) being an unoriented thermoplastic polymer; wherein the combined carrier substrate (10) and coating (20) consists essentially of at least 70%, preferably at least 75%, more preferably at least 80%, more preferably at least 85%, more preferably at least 90%, most preferably at least 95% of the same polymer compound.

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