Masking film with improved adhesive stability

Abstract

The masking film comprises an adhesive layer comprising at least one hydrogenated styrene block copolymer and an adhesive surface having a surface roughness (Sa) of greater than about 2.0 μm. The masking film has an adhesion strength of less than about 2.0 after the adhesive layer is attached to a textured polycarbonate substrate and heated to 85°C for 30 minutes.

Description

[Technical Field]

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS This application claims the benefit of priority to U.S. Provisional Patent Application No. 62 / 978,602, filed February 19, 2020, the entire contents of which are incorporated herein by reference.

[0002] The present invention generally relates to masking films for protecting substrates with improved adhesive stability at elevated temperatures. [Background technology]

[0003] Masking films, also known as surface protection films, are commonly used to provide a physical barrier and prevent damage, contamination, scratches, abrasions, and / or other infringement of the substrate to which they are adhered. Masking films are applied to sensitive and delicate substrates used as components in electronic displays and may protect the substrate during manufacturing, as well as during shipping and / or storage of the substrate prior to use and through one or more subsequent processing steps.

[0004] Commonly used masking films, for example, achieve adhesion to the substrate through van der Waals forces, which requires that the masking film and the substrate each have at least one very flat and uniform surface, allowing the masking film to come into intimate contact with the substrate.

[0005] As referred to herein, "adhesion" means attachment to the surface of the substrate to be protected by intimate contact via the natural blocking adhesion that exists between a very smooth surface and another smooth surface via polar bonds, ionic bonds, and, in some cases, hydrogen bonds and / or van der Waals secondary bonds. "Adhesiveless" adhesion, as used herein, is intended to encompass peelable adhesion, where the adhesion is reversible so as not to modify or damage the film or the substrate to which it is applied. "Adhesion," as used herein, does not include the thermal bonding or crosslinking function of the adhesive as the adhesive force between the substrate surface and a film comprising a pressure-sensitive adhesive, or the thermal bonding or crosslinking function of the adhesive where the peel strength required to remove such a film exceeds the tensile strength of such a film itself, to the point where it tears or breaks before peeling from the substrate.

[0006] The amount of adhesion can be increased or decreased by softening or hardening the composition on the masking film surface. If the adhesion is too great, it will be difficult to remove the masking film from the substrate at the end of the process. If the adhesion is too low, the masking film may separate from the substrate prematurely and the substrate may no longer be protected. If the surface of the substrate to be protected has a textured surface, it may be necessary to increase the adhesion to prevent the masking film from separating from the substrate prematurely.

[0007] A suitable masking or surface protection film for protecting surfaces, including textured surfaces, is disclosed in commonly owned U.S. Patent No. 10,150,896. The adhesive layer of the surface protection film disclosed therein comprises a blend of hydrogenated styrene block copolymer, high-density polyethylene (HDPE), and low-density polyethylene (LDPE). Table 3 of U.S. Patent No. 10,150,896 lists adhesion test results for a series of films after the films were laminated to polycarbonate substrates and exposed to different temperatures. The data listed in Table 3 of U.S. Patent No. 10,150,896 indicate that the adhesion of the surface protection film to the polycarbonate substrate increases after the laminate is exposed to high temperatures, thereby making removal of the surface protection film more difficult, which may be undesirable for some applications. The increase in adhesion is expressed by the "Adhesion Build Value," which is the ratio of the peel test result at high temperature to the peel test result at room temperature. Summary of the Invention [Problem to be solved by the invention]

[0008] It is desirable to have a masking film that provides the desired surface protection of the substrate without damaging the surface of the substrate during use or removal of the masking film, even when the masking film and substrate are exposed to elevated temperatures. It is also desirable for the masking film to have a low adhesion success value, thereby demonstrating that the adhesive properties of the masking film do not increase substantially at elevated temperatures. [Means for solving the problem]

[0009] According to one aspect of the present invention, a masking film for protecting a substrate is provided. The masking film comprises an adhesive layer including at least one hydrogenated styrene block copolymer and an adhesive surface having a surface roughness (Sa) of greater than about 2.0 μm. The masking film has an adhesion strength of less than about 2.0 after the adhesive layer is attached to a textured polycarbonate substrate and heated to 85°C for 30 minutes.

[0010] In one embodiment, the adhesive surface is about 3.0 μm 3 / μm 2 The void volume (Vv) is greater than

[0011] In one embodiment, the adhesive surface is about 1.0 μm 3 / μm 2 The core void volume (Vvc) is greater than

[0012] In one embodiment, the masking film has an initial peel strength of greater than about 5 grams / inch at room temperature.

[0013] In one embodiment, the textured polycarbonate substrate has a surface roughness Sa of about 0.60 μm.

[0014] In one embodiment, the hydrogenated styrene block copolymer comprises a tackifier.

[0015] In one embodiment, the hydrogenated styrene block copolymer is a styrene-butadiene-styrene (SEBS) block copolymer.

[0016] In one embodiment, the adhesive layer also includes low density polyethylene.

[0017] In one embodiment, the adhesive layer also includes a second hydrogenated styrene block copolymer, hi one embodiment, the second hydrogenated styrene block copolymer is a styrene-butadiene-styrene (SEBS) block copolymer.

[0018] In one embodiment, the masking film also includes a release layer, hi one embodiment, the release layer includes low density polyethylene.

[0019] In one embodiment, the masking film also includes a core layer between the adhesive layer and the release layer, hi one embodiment, the core layer includes a blend of high density polyethylene and low density polyethylene.

[0020] These and other aspects, properties, and characteristics of the present invention, as well as the method of operation and function of the associated elements of structure, combination of parts, and economies of manufacture, will become more apparent from a consideration of the following description and appended claims, taken in conjunction with the accompanying drawings, all of which form a part hereof. It is to be expressly understood, however, that the drawings are for the purpose of illustration and description only and are not intended as a definition of the limits of the invention. As used in this specification and claims, the singular forms "a," "an," and "the" include plural referents unless the context clearly dictates otherwise.

[0021] The components in the following figures are illustrated to emphasize the general principles of the present disclosure. [Brief explanation of the drawings]

[0022] [Figure 1] 1 is a schematic diagram illustrating a masking film according to an embodiment of the present invention adhered to a substrate. [Figure 2] 2 is a graph showing peel strength test results at room temperature as a function of surface roughness (Sa) of the adhesive surface of the masking film of FIG. 1 after being adhered to a textured polycarbonate substrate. [Figure 3] 2 is a graph showing peel strength test results after 30 minutes at 85°C as a function of surface roughness (Sa) of the adhesive side of the masking film of FIG. 1 after being adhered to a textured polycarbonate substrate. [Figure 4]2 is a graph showing adhesion establishment values ​​as a function of surface roughness (Sa) of the adhesive surface of the masking film of FIG. 1 after being adhered to a textured polycarbonate substrate. [Figure 5] 2 is a graph showing adhesion establishment values ​​as a function of adhesive surface void volume (Vv) of the masking film of FIG. 1 after being adhered to a textured polycarbonate substrate. [Figure 6] 2 is a graph showing the adhesion establishment value as a function of the core void volume (Vvc) of the adhesive surface of the masking film of FIG. 1 after being adhered to a polycarbonate substrate having a textured surface. DETAILED DESCRIPTION OF THE INVENTION

[0023] 1 schematically illustrates a masking film 100 according to an embodiment of the present invention. As illustrated, masking film 100 is a multilayer film including a release layer 110 having an outer release surface 112, a core layer 120, and an adhesive layer 130 on the opposite side of core layer 120 from release layer 110. Adhesive layer 130 includes an outer adhesive surface 132. Outer adhesive surface 132 of adhesive layer 130 is configured to contact surface 152 of a substrate 150 to be protected by masking film 100, e.g., an optical film for the display of an electronic device.

[0024] In one embodiment, the masking film 100 may have a thickness of between about 30 μm and about 70 μm. In one embodiment, the masking film 100 may have a thickness of between about 40 μm and about 60 μm. In one embodiment, the masking film 100 may have a thickness of about 50 μm. In one embodiment, the thickness ratio of the three layers 110, 120, 130 may be about 15:65:20, i.e., 15% release layer 110, 65% core layer 120, and 20% adhesive layer 130.

[0025] As discussed herein, surface roughness is defined as either the arithmetic mean height (Ra) of the micropeaks and microvalleys of a surface relative to the centerline of the surface as measured by a surface profilometer conforming to ANSI / ASME test method B46.1-1985, hereafter referred to as "surface roughness (Ra)," or the arithmetic mean height of a surface as measured by a 3D optical profilometer such as that manufactured by Zygo Corporation of Middlefield, Connecticut conforming to ISO 25178, hereafter referred to as "surface roughness (Sa)." Both surface roughness (Ra) and surface roughness (Sa) are typically measured in micrometers or microns (μm), or microinches (10 -6 It is expressed in units of inches.

[0026] Various volumetric parameters of the surface may also be measured with a 3D optical profilometer conforming to ISO 25178 and are typically expressed in units of cubic micrometers per square micrometer of area (μm / μm). Typical filtering techniques may be used with software associated with the 3D optical profilometer to filter out high-frequency readings ("noise") and / or low-frequency readings ("waviness"). The software may also calculate a material ratio curve (also known as an Abbott-Firestone curve) by integrating the 3D optical profilometer trace, and from the material ratio curve, determine the void volume below a selected material ratio that was 10% of the measured value, reported herein as "void volume (Vv)." The void volume at 80% material ratio is referred to herein as the "Dales void volume (Vvv)," and the difference between the void volume at 10% material ratio (Vv) and the Dales void volume at 80% material ratio (Vvv) is referred to herein as the "core void volume (Vvc)."

[0027] peeling layer The release layer 110 may comprise one or more polyolefins, such as low-density polyethylene (LDPE), linear low-density polyethylene (LLDPE), high-density polyethylene (HDPE), medium-density polyethylene (MDPE), polypropylene (PP), random copolymer polypropylene, polypropylene impact copolymer, or metallocene linear low-density polyethylene, plastomer, poly(ethylene-co-vinyl acetate), poly(ethylene-co-acrylic acid), poly(ethylene-co-methyl acrylate), cyclic olefin polymers, polyamide, poly(ethylene-co-n-butyl acrylate), and mixtures thereof. In one embodiment, the release layer 110 may comprise a suitable polyolefin blend of low-density polyethylene (LDPE) and high-density polyethylene (HDPE) in a weight ratio of 60:40 to 40:60. In one embodiment, the release layer 110 may comprise LDPE but not HDPE. In one embodiment, one or more additives, such as antioxidants, may be included in the release layer 110.

[0028] The thickness of the release layer 110 may be between about 1 μm and about 20 μm, for example, between about 5 μm and about 12 μm, for example, about 1 μm, about 2 μm, about 3 μm, about 4 μm, about 5 μm, about 6 μm, about 7 μm, about 8 μm, about 9 μm, about 10 μm, about 11 μm, or about 12 μm.

[0029] Core layer The core layer 120 may comprise one or more polyolefins, such as low-density polyethylene (LDPE), linear low-density polyethylene (LLDPE), high-density polyethylene (HDPE), medium-density polyethylene, polypropylene (PP), random copolymer polypropylene, polypropylene impact copolymer, metallocene linear low-density polyethylene, plastomer, poly(ethylene-co-vinyl acetate), poly(ethylene-co-acrylic acid), poly(ethylene-co-methyl acrylate), cyclic olefin polymers, polyamide, poly(ethylene-co-n-butyl acrylate), and mixtures thereof. One suitable polyolefin blend comprises low-density polyethylene (LDPE) and high-density polyethylene (HDPE) in a weight ratio of 60:40 to 40:60. The core layer 120 may also comprise one or more additives, such as antioxidants.

[0030] The thickness of the core layer 120 of the masking film 100 according to embodiments of the present invention may be between about 10 μm and about 50 μm, for example, between about 20 μm and about 40 μm, for example, about 20 μm, about 21 μm, about 22 μm, about 23 μm, about 24 μm, about 25 μm, about 26 μm, about 27 μm, about 28 μm, about 29 μm, about 30 μm, about 31 μm, about 32 μm, about 33 μm, about 34 μm, about 35 μm, about 36 μm, about 37 μm, about 38 μm, about 39 μm, or about 40 μm.

[0031] adhesive layer The adhesive layer 130 according to embodiments of the masking film 100 comprises a blend of one or more hydrogenated styrene block copolymers and, optionally, one or more polyolefins, such as low-density polyethylene (LDPE) and / or high-density polyethylene (HDPE). Suitable hydrogenated styrene block copolymers have a polystyrene block-polydiene block polymer structure prior to hydrogenation. The hydrogenated block copolymers may be linear or radial prior to hydrogenation. Suitable polydienes for the hydrogenated styrene block copolymer include polybutadiene (1,3-butadiene), polyisoprene, and mixtures thereof. Hydrogenation of the polystyrene block-polydiene block structure can result in, for example, a styrene-ethylene-butylene-styrene polymer structure, or "SEBS," or a styrene-ethylene-propylene-styrene structure, or "SEPS." In embodiments of the present invention, the styrene content of the hydrogenated styrene block copolymer may be between 10% and 70% by weight.

[0032] The melt flow rate ("MFR") of a thermoplastic resin, such as a styrene block copolymer, is inversely related to the viscosity of the thermoplastic resin. A high MFR means that the thermoplastic resin has a low viscosity, and vice versa. As used herein, "MFR" means the melt flow rate, measured in grams per 10 minutes, determined in accordance with ASTM D-1238 at 230°C under a mass of 2.16 kg, unless otherwise specified. Hydrogenated styrene block copolymers suitable for adhesive layer 130 may have a melt flow rate of between about 0.1 g / 10 min and about 100 g / 10 min.

[0033] In various embodiments of the present invention, adhesive layer 130 may comprise 50% to 100% by weight of a hydrogenated styrene block copolymer. In these embodiments, adhesive layer 130 may also comprise 0% to 50% by weight of LDPE and / or HDPE.

[0034] The thickness of the adhesive layer 130 of the masking film 100 according to embodiments of the present invention may be between about 1 μm and about 20 μm, for example, between about 3 μm and about 15 μm, for example, about 3 μm, about 4 μm, about 5 μm, about 6 μm, about 7 μm, about 8 μm, about 9 μm, about 10 μm, about 11 μm, about 12 μm, about 13 μm, about 14 μm, or about 15 μm.

[0035] Base material While the masking film 100 of the present invention can be applied to any substrate 150, typical substrates include, by way of example only, polycarbonate, acrylic, polyvinyl chloride, polyethylene terephthalate (PET), glycol-modified polyethylene terephthalate (PETG), polyimide, glass, ceramic, and metal. Such substrates typically have an average surface roughness (Ra) ranging from about 0 microinches (0 μm) to about 150 microinches (3.81 μm). The substrate 150 may have a smooth surface 152 (i.e., a surface having an average surface roughness (Ra) ranging from about 0 microinches (0 μm) to about 5 microinches (0.127 μm), or a textured surface 152 having an average surface roughness (Ra) ranging from about 5 microinches (0.127 μm) to about 150 microinches (3.81 μm).

[0036] Applying masking film to substrates Any of a variety of conventional methods can be utilized to apply the multilayer masking film 100 to the substrate 150 and to press the applied masking film 100 against the surface 152 of the substrate 150. Generally speaking, the masking film 100 may be removed from a roll and applied directly to the substrate 150 by a nip roll or similar system through which the masking film 100 and substrate 150 pass. As the masking film 100 is pulled from the roll, the helical orientation of the masking film 100 on the roll separates the outer adhesive surface 132 of the adhesive layer 130 from the outer surface 112 of the release layer 110 without damaging either layer or the masking film 100 as a whole. [Example]

[0037] A series of three-layer masking films 100 were extruded on a coextrusion cast film line using the same conditions. The target total thickness of each film 100 was approximately 50 μm, with 15% of the total thickness attributed to the release layer 110, approximately 65% ​​of the total thickness attributed to the core layer 120, and approximately 20% of the total thickness attributed to the adhesive layer 130. The release layer 110 of each film 100 consisted essentially of LDPE. The core layer 120 of each film 100 was a blend of approximately 60% by weight HDPE and approximately 40% by weight LDPE. For the adhesive layer 130, different hydrogenated styrene block copolymers were used. Specifically, Kraton™ MD6951, a styrene-butadiene-styrene (SEBS) type hydrogenated styrene block copolymer manufactured by Kraton Performance Polymers, Inc., and Versaflex™ PF MD6666N, a styrene-butadiene-styrene (SEBS) type hydrogenated styrene block copolymer manufactured by PolyOne Corporation, were used for adhesive layer 130. Versaflex™ PF MD6666N also contains a pressure-sensitive adhesive.

[0038] Two formulations were investigated for use as the adhesive layer 130. "Formulation A" was a blend of 55 wt% Versaflex™ PF MD6666N, 20 wt% Kraton™ MD6951, and 25 wt% LDPE. "Formulation B" was a blend of 75 wt% Versaflex™ PF MD6666N and 25 wt% Kraton™ MD6951. For a comparative example, a blend of 55 wt% Versaflex™ PF MD6666N, 20 wt% Kraton™ MD6951, 15 wt% LDPE, and 10 wt% HDPE ("Formulation C") was used for the adhesive layer.

[0039] The surface roughness (Ra) of the cast rolls used in the production of the masking film 100 and the resulting surface characteristics of the adhesive surface 132 of the masking film 100 were also investigated. Specifically, samples were produced using cast rolls with surface roughness (Ra) values ​​of 24 microinches (0.61 μm), 100 microinches (2.54 μm), 207 microinches (5.26 μm), and 600 microinches (15.24 μm). A relatively smooth cast roll with a surface roughness (Ra) of 0.5 microinches (0.0127 μm) was used for the comparative example. A summary of the cast roll formulations and surface roughness (Ra) used to produce the nine different samples, including the comparative example, is provided in Table I below.

[0040] [Table 1]

[0041] Each of the film samples listed in Table I was tested for surface roughness (Sa), void volume (Vv), and Dales void volume (Vvv) using the test methods described above, and the core void volume (Vvc) was calculated by subtracting the Dales void volume (Vvv) from the void volume (Vv). Table II below lists the surface characteristics of the adhesive side of each film sample, including surface roughness (Sa), void volume (Vv), Dales void volume (Vvv), and core void volume (Vvc).

[0042] [Table 2]

[0043] Each of the films was aged for two weeks under ambient conditions (e.g., about 23° C.) before being laminated onto a polycarbonate substrate 150 having a textured surface 152 with a surface roughness (Sa) of about 23.6 microinches (0.60 μm), with the adhesive surface 132 of the adhesive layer 130 in contact with the textured surface 152 of the polycarbonate substrate 150. Laminate samples were cut to 1 inch wide and placed at room temperature (e.g., about 23° C.) for 1 hour or in an oven at 85° C. for 30 minutes. The 180° peel force ("peel force value") in grams / inch at a speed of 5 mm / sec was measured using a TA.XTPlus Texture Analyzer manufactured by Texture Technologies Corp.

[0044] The adhesion strength of each sample was calculated by dividing the peel force value after the sample was exposed to 85°C for 30 minutes by the peel force value at room temperature. Table III below lists the peel force test results, including the calculated adhesion strength. An adhesion strength of about 2.0 or less is desirable. It is also desirable for the peel force to be less than about 50 grams / inch.

[0045] [Table 3]

[0046] Figure 2 shows the room temperature peel force values ​​of the samples as a function of the surface roughness (Sa) of the adhesive surface 132 of each masking film 100, as well as the formulation used in the adhesive layer 130. As expected, Formulation B, with its higher content of Versaflex™ PF MD6666N adhesive, provided masking films with adhesive layers that exhibited greater peel strength than masking films with adhesive layers containing Formulation A or Formulation C. Additionally, increasing the surface roughness (Sa) of the adhesive surface decreased the peel strength of the corresponding masking films.

[0047] 3 shows the peel force values ​​of the masking films 100 after exposing the samples to 85° C. for 30 minutes as a function of the surface roughness (Sa) of the adhesive surface 132, as well as the formulation used in the adhesive layer 130. As shown, the peel strength of masking films with adhesive surfaces having a relatively low surface roughness (Sa), i.e., less than 1.0 μm, was much greater than the peel strength of masking films with adhesive surfaces having a surface roughness (Sa) greater than about 2.0 μm.

[0048] 4 shows the adhesion strength of the samples as a function of the surface roughness (Sa) of the adhesive surface 132 of each masking film 100, as well as the formulation used for the adhesive layer 130. As noted above, it is desirable for masking films to have an adhesion strength of less than about 2.0. Each of the masking films including an adhesive surface with a surface roughness (Sa) greater than about 2.0 μm, regardless of formulation, had an adhesion strength of less than about 2.0.

[0049] FIG. 5 shows the adhesion strength of each masking film 100 as a function of the void volume (Vv) of the adhesive surface 132, as well as the formulation used for the adhesive layer 130. As shown, 3 / μm 2 Each of the masking films containing adhesive surfaces with void volumes (Vv) greater than 1.0 had an adhesion success value of less than approximately 2.0, regardless of formulation.

[0050] FIG. 6 shows the sample adhesion values ​​as a function of the core void volume (Vvc) of the adhesive surface 132 of each masking film 100, as well as the formulation used for the adhesive layer 130. As shown, approximately 1.0 μm 3 / μm 2 Each of the masking films containing adhesive surfaces with a core void volume (Vvc) greater than 1.0 had an adhesion success value less than about 2.0, regardless of formulation.

[0051] The above test results indicate that the formulation for adhesive layer 130, as well as the surface roughness (Sa) and / or void volume (Vv) and core void volume (Vvc) of adhesive surface 132 can be adjusted to achieve desired initial peel strength and bond establishment values.

[0052] The embodiments described herein represent multiple possible implementations and examples and are not intended to necessarily limit the disclosure to any particular embodiment. Instead, various modifications can be made to these embodiments as will be understood by those skilled in the art. Any such modifications are intended to be within the spirit and scope of the disclosure and are protected by the following claims.

Claims

1. A masking film for protecting a substrate, comprising: a release layer comprising one or more polyolefins selected from low density polyethylene, linear low density polyethylene, high density polyethylene, medium density polyethylene, polypropylene, random copolymer polypropylene, polypropylene impact copolymer, or metallocene linear low density polyethylene, plastomer, poly(ethylene-co-vinyl acetate), poly(ethylene-co-acrylic acid), poly(ethylene-co-methyl acrylate), cyclic olefin polymers, polyamide, poly(ethylene-co-n-butyl acrylate), and mixtures thereof; a core layer comprising one or more polyolefins selected from low density polyethylene (LDPE), linear low density polyethylene (LLDPE), high density polyethylene (HDPE), medium density polyethylene, polypropylene (PP), random copolymer polypropylene, polypropylene impact copolymer, metallocene linear low density polyethylene, plastomer, poly(ethylene-co-vinyl acetate), poly(ethylene-co-acrylic acid), poly(ethylene-co-methyl acrylate), cyclic olefin polymers, polyamide, poly(ethylene-co-n-butyl acrylate), and mixtures thereof; an adhesive layer comprising 50% to 100% by weight of at least one hydrogenated styrene block copolymer and low density polyethylene; the core layer is located between the release layer and the adhesive layer; the release layer has a release layer thickness between 1 μm and 20 μm; the core layer has a core layer thickness between 10 μm and 50 μm; the adhesive layer has an adhesive layer thickness between 1 μm and 20 μm; The adhesive layer has an adhesive surface with a surface roughness (Sa) of more than 2.0 μm, A masking film having an adhesion success value of less than 2.0 after attaching the adhesive layer to a textured polycarbonate substrate having a surface roughness Sa of 0.60 μm and heating to 85° C. for 30 minutes, the adhesion success value being calculated by dividing the peel force value after the sample is exposed to 85° C. for 30 minutes by the peel force value at room temperature.

2. The adhesive surface is 3.0 μm ３ / μm ２ 10. The masking film of claim 1, having a void volume (Vv) greater than 80%, wherein the void volume (Vv) at 80% material ratio is the Dales void volume (Vvv).

3. The adhesive surface is 1.0 μm ３ / μm ２ 3. The masking film of claim 2, wherein the masking film has a core void volume (Vvc) greater than 10%, and wherein the core void volume (Vvc) is the difference between the void volume (Vv) at a 10% material ratio and the Dales void volume (Vvv) at an 80% material ratio.

4. 10. The masking film of claim 1, wherein the masking film has a peel strength of greater than 5 grams / inch at room temperature.

5. The masking film of claim 1 , wherein the hydrogenated styrene block copolymer comprises an adhesive.

6. 10. The masking film of claim 1, wherein the hydrogenated styrene block copolymer is a styrene-butadiene-styrene (SEBS) block copolymer.

7. The masking film of claim 1 , wherein the adhesive layer further comprises a second hydrogenated styrene block copolymer.

8. 8. The masking film of claim 7, wherein the second hydrogenated styrene block copolymer is a styrene-butadiene-styrene (SEBS) block copolymer.

9. 10. The masking film of claim 1, wherein the release layer comprises low density polyethylene.

10. 10. The masking film of claim 1, wherein the core layer comprises a blend of high density polyethylene and low density polyethylene.

11. 10. The masking film of claim 1, wherein the release layer comprises low density polyethylene and high density polyethylene in a weight ratio of 60:40 to 40:

60.

12. The masking film of claim 1 , wherein the release layer further comprises an antioxidant.

13. 10. The masking film of claim 1, wherein the core layer comprises low density polyethylene and high density polyethylene in a weight ratio of 60:40 to 40:

60.

14. The masking film of claim 1 , wherein the core layer further comprises an antioxidant.

15. 10. The masking film of claim 1, wherein the styrene content of the hydrogenated styrene block copolymer is between 10% and 70% by weight.

16. 10. The masking film of claim 1, wherein the at least one hydrogenated styrene block copolymer has a melt flow rate between 0.1 g / 10 min and 100 g / 10 min.

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