Security film and forced invasive

Abstract

A security film, the security film comprising a substrate comprising a thermoplastic polyurethane; an optically transparent pressure sensitive adhesive layer disposed on the substrate; and a polymer liner peelably attached to the substrate via an optically transparent pressure sensitive adhesive layer. The substrate, the optically transparent pressure sensitive adhesive layer, and the polymeric liner are substantially coextensive with one another. The substrate comprises an outermost major surface of the security film, and the thickness of the substrate is in the range of 480 microns to 760 microns and differs, as determined according to ASTM D1004-21, by an initial jig pitch of 3.8 cm, a strain rate of 1.27 m / min, a Graves tear resistance of the substrate of greater than 2.75 Joules, and a maximum extension of greater than 7.5 cm. The safety film may enhance the resistance to forced invasion of the window. A forced intrusion resistant window includes a security film laminated to a glass pane, the polymer liner of which has been removed.

Description

Technical Field

[0001] This instruction manual pertains to safety films that can be used to enhance the resistance of windows to forced intrusion. Background Technology

[0002] Security film can be used to provide an additional base for glass windows, offering extra protection against breakage and burglary. Summary of the Invention

[0003] In some respects, this specification provides a safety film for enhancing the resistance of windows to forced intrusion. The safety film comprises a substrate comprising thermoplastic polyurethane; an optically clear pressure-sensitive adhesive layer disposed on the substrate; and a polymeric backing peelably attached to the substrate via the optically clear pressure-sensitive adhesive layer. The substrate, the optically clear pressure-sensitive adhesive layer, and the polymeric backing may substantially co-extend with each other. The substrate comprises the outermost main surface of the safety film, and the thickness of the substrate is in the range of 480 micrometers to 760 micrometers, and differs from those measured according to ASTM D1004-21, except that the initial clamping spacing is 3.8 cm, the strain rate is 1.27 m / min, the Graves tear resistance of the substrate is greater than 2.75 Joules, and the maximum elongation is greater than 7.5 cm.

[0004] In some respects, this specification provides a safety film for enhancing the resistance of windows to forced intrusion. The safety film comprises a substrate comprising thermoplastic polyurethane; an optically clear pressure-sensitive adhesive layer disposed on the substrate; and a polymer backing peelably attached to the substrate via the optically clear pressure-sensitive adhesive layer. The substrate, the optically clear pressure-sensitive adhesive layer, and the polymer backing may substantially coexist with each other. The substrate comprises the outermost main surface of the safety film, and the thickness of the substrate is in the range of 480 micrometers to 760 micrometers. When the polymer backing is removed and the substrate is laminated to glass via the optically clear pressure-sensitive adhesive layer to form a laminate, as determined according to ASTM F1233-21, except that a 0.7 kg smooth-surfaced frame hammer is used as a blunt impact tool, and the smooth surface of the frame hammer strikes the glass side of the laminate along a Z-shaped pattern, the horizontal edges of which are each 76 cm wide and the diagonal length is 102 cm, the blunt impact forced intrusion time of the laminate is at least 100 seconds. Forced intrusion is defined as breaking through the laminate along the entire Z-pattern. The glass has in-plane dimensions of 86cm × 86cm and a thickness of 3.2mm. The substrate can be substantially co-linear with the glass. The glass is tempered glass as specified in ASTM C1048-18.

[0005] In some respects, this specification provides an intrusion-resistant window comprising at least one glass pane; and a safety film laminated to the outermost primary surface of the at least one glass pane. The safety film comprises a substrate containing thermoplastic polyurethane. The substrate comprises the outermost primary surface of the safety film. The thickness of the substrate is in the range of 480 micrometers to 760 micrometers, and differs from that measured according to ASTM D1004-21 in that the initial clamping spacing is 3.8 cm, the strain rate is 1.27 m / min, the substrate has a Graves tear resistance greater than 2.75 Joules, and a maximum elongation greater than 7.5 cm.

[0006] These and other aspects will become apparent from the detailed description that follows. However, in no way should this brief overview be construed as limiting the subject matter for which protection may be claimed. Attached Figure Description

[0007] Figure 1 This is a schematic cross-sectional view of a safety membrane based on some implementation schemes.

[0008] Figure 2 This is a scatter plot of Graves tear resistance versus maximum elongation for various exemplary and comparative substrates.

[0009] Figure 3 These are graphs showing the tear force versus elongation of various exemplary and comparative substrates.

[0010] Figure 4 This is a schematic cross-sectional view of a window designed to resist forced intrusion, based on some implementation schemes.

[0011] Figure 5 It is a schematic diagram of a blunt impact pattern used to determine the time of forced penetration by blunt impact, according to some implementation schemes.

[0012] Figure 6 It is a graph showing the time to blunt impact forced intrusion of a window against various exemplary and comparative safety films and their substrate thickness.

[0013] Figures 7 to 8 It is a schematic cross-sectional view of the base of a safety membrane according to some implementation schemes. Detailed Implementation

[0014] Reference is made in the following description to the accompanying drawings, which form part of this disclosure and in which various embodiments are illustrated by way of example. The drawings are not necessarily drawn to scale. It should be understood that other embodiments may be conceived and practiced without departing from the scope or spirit of this specification. Therefore, the following detailed description should not be considered limiting.

[0015] Safety films can be used to provide an additional substrate for window panes to, for example, slow down attempts to break in, provide protection against physical impacts, and / or reduce the number of free-flying fragments in the event that would otherwise result in a glass breakage incident. For example, a safety film may comprise a polymer substrate that can be laminated to the inner surface of the window pane to form a forced-intrusion resistant window, for example, with a significantly increased forced-intrusion time compared to an unprotected window. According to some embodiments of this specification, it has been unexpectedly found that when the substrate comprises a thermoplastic polyurethane having the properties described elsewhere herein, the forced-intrusion time to break through the forced-intrusion resistant window increases rapidly if the substrate thickness is increased to at least 480 micrometers. When Graves tear resistance and maximum elongation are determined according to a modified ASTM D1004-21 test, as further described elsewhere herein (e.g., modified to use an initial clamp spacing of 3.8 cm and a strain rate of 1.27 m / min), thermoplastic polyurethane properties that have been found to contribute to increased forced penetration time include high Graves tear resistance (e.g., greater than 2.75 joules) and high maximum elongation (e.g., greater than 7.5 cm). Other useful properties of thermoplastic polyurethanes have been found to include, for example, high elongation at break (e.g., at least 500%) and low tensile stress at 300% elongation (e.g., not exceeding 15 MPa).

[0016] Figure 1 This is a schematic cross-sectional view of a safety film 100 according to some embodiments. In some embodiments, the safety film 100 includes a substrate 110 comprising thermoplastic polyurethane; an optically transparent pressure-sensitive adhesive layer 120 disposed on the substrate 110; and a polymer liner 140 peelably attached to the substrate 110 via the optically transparent pressure-sensitive adhesive layer 120. In some embodiments, the substrate 110, the optically transparent pressure-sensitive adhesive layer 120, and the polymer liner 140 are substantially co-extended with each other. In some embodiments, the substrate 110 includes the outermost main surface 112 of the safety film 100. In some embodiments, the thickness T of the substrate 110 is in the range of 480 micrometers to 760 micrometers. In some embodiments, the thickness T is at least 500 micrometers, 520 micrometers, 540 micrometers, 560 micrometers, 580 micrometers, 590 micrometers, 600 micrometers, or 610 micrometers. Figure 1In this context, the safety film typically extends in the xy-plane, and its thickness is measured along the z-axis. Generally, a larger thickness (e.g., 480 micrometers or even more) is preferred to improve blunt impact penetration time. In some embodiments, the thickness T does not exceed 740 micrometers, 720 micrometers, 700 micrometers, 680 micrometers, 660 micrometers, 640 micrometers, or 620 micrometers. Generally, for example, a smaller thickness (e.g., 760 micrometers or even less) is preferred to improve manufacturability and cost. In some embodiments, the thickness T is, for example, in the range of 500 micrometers to 740 micrometers, or 520 micrometers to 720 micrometers, or 540 micrometers to 700 micrometers, or 560 micrometers to 680 micrometers, or 580 micrometers to 660 micrometers, or 590 micrometers to 640 micrometers. In some embodiments, the thickness T is, for example, about 610 micrometers. It has been found, for example, that when the substrate has high Graves tear resistance with high maximum elongation, compared to a thinner substrate (see, for example...),... Figure 6 Compared to [previous methods], substrate thicknesses in the range of 480 to 760 micrometers, or in another range within these ranges, provide significantly improved time to blunt impact forced intrusion. The safety film 100 can be used to enhance the resistance of windows to forced intrusion. For example, the polymer backing can be removed, and the substrate layer can be pressed to the glass panes of the window via an optically clear pressure-sensitive adhesive to produce a forced intrusion-resistant window as further described elsewhere herein.

[0017] A layer or element can be described as substantially co-extending with each other if at least about 60% of its area is co-extended with at least about 60% of the area of ​​each other layer or element. Here, area refers to the area of ​​the main surface of the layer or element (e.g., the area in the xy plane). In some embodiments, for layers or elements described as substantially co-extending, at least about 70%, or at least about 80%, or at least about 90%, or at least about 95% of the area of ​​each layer or element is co-extended with at least about 70%, or at least about 80%, or at least about 90%, or at least about 95% of the area of ​​each other layer or element. Layers or elements substantially co-extending with each other can be co-extending with each other, with possible exceptions being edge regions of layers or elements. For example, in some embodiments, for a security film substantially co-extending with a glass pane, the security film is co-extending with the glass pane, except for the edge of the pane, which may not include the security film and can be concealed below the window frame.

[0018] The polymer liner 140 can be made of any suitable polymer such as polyester. In some embodiments, the polymer liner is, for example, a surface-treated polyethylene terephthalate (PET) liner. The PET or other polymer layer may include an anti-stick coating (located on the side of the liner 140 facing the adhesive layer 120). For example, the anti-stick coating may be a silicone or natural wax coating. The surface of the polymer liner 140 facing the adhesive layer 120 can be smooth. For example, the surface can be optically smooth (e.g., having a surface roughness Ra that is small compared to the wavelength of visible light), such that the liner does not transfer optically significant roughness to the adhesive layer. For example, the surface roughness Ra may be less than 200 nm, 150 nm, 100 nm, or 50 nm. For example, the thickness of the polymer liner 140 may be between 25 micrometers and 100 micrometers.

[0019] In some embodiments, an optically clear pressure-sensitive adhesive 120 is selected such that it is compatible with both the substrate 110 and the intended glass surface to which it will be applied. In some embodiments, the optically clear pressure-sensitive adhesive 120 may be selected based on its physical properties, such as its softness or hardness (modulus of elasticity) or its flowability. In some embodiments, the optically clear pressure-sensitive adhesive 120 may be selected based on its optical properties, such as its transparency, or more specifically, its optical clarity (high), optical transmittance (high), and optical haze (low). For example, the light transmittance of the optically clear pressure-sensitive adhesive layer 120 may be greater than 80%, 85%, or 90%, and / or the haze may be less than 5%, 4%, 3%, or 2%. For example, light transmittance and haze can be measured according to ASTM D1003-13. In some embodiments, the optically clear pressure-sensitive adhesive 120 may be an acrylic adhesive. In some embodiments, the thickness of the optically clear pressure-sensitive adhesive 120 may be between 1 micrometer and 25 micrometers, between 25 micrometers and 50 micrometers, between 50 micrometers and 75 micrometers, between 75 micrometers and 100 micrometers, or between 100 micrometers and 500 micrometers. This adhesive layer can be formed by any suitable means and then dispensed or provided onto the substrate by any suitable method, such as by solvent or extrusion coating, or by lamination via transfer tape or a release liner carrying the adhesive layer. Suitable optically clear pressure-sensitive adhesives with polymer liners include 3M optically clear adhesives 8211, 8212, 8213, 8214, and 8215.

[0020] The Graves tear resistance and corresponding maximum elongation of a substrate can be determined according to the ASTM D1004-21 tear resistance test. This test standard specifies a sample geometry in which the sample has an approximately V-shaped portion between approximately rectangular ends, with a sample width of 1.9 cm (0.75 inches). Clamps are attached to the ends and pulled apart at a specific strain rate, causing the sample to tear; the tear typically occurs in the V-shaped portion. The force-displacement relationship is measured, and the area under this force-displacement relationship is determined as the Graves tear resistance. The maximum elongation at the point of final tear can also be determined. The maximum elongation is the change in clamp spacing from the initial spacing to the final tear spacing (e.g., a change from an initial spacing of 3.8 cm to a final tear spacing of 11.3 cm indicates a maximum elongation of 7.5 cm). In some embodiments, this ASTM standard is modified by specifying different strain rates, different initial clamp spacings, and / or different sample widths. Two such modifications have been found to be useful in characterizing the substrates of safety films. In one modification, ASTM D1004-21 is used, differing only in that the initial clamp spacing is 3.8 cm and the strain rate is 1.27 m / min. In another modification, ASTM D1004-21 is used, differing only in that the initial clamp spacing is 5.1 cm, the strain rate is 1.27 m / min, and the sample width is 3.8 cm. When the sample width is increased, the shape of the approximately V-shaped portion remains as specified in ASTM D1004-21.

[0021] In some embodiments, as determined according to ASTM D1004-21, the difference lies in the initial clamp spacing being 3.8 cm, the strain rate being 1.27 m / min, and the Graves tear resistance of substrate 110 being greater than 2.75 joules, 3 joules, 3.25 joules, 3.5 joules, 3.75 joules, 4 joules, 4.25 joules, 4.5 joules, 4.75 joules, 5 joules, 5.25 joules, 5.5 joules, 5.75 joules, 6 joules, or 6.25 joules, and the maximum elongation being greater than 7.5 cm. For example, in some embodiments, the Graves tear resistance can be as high as 15 joules, 12 joules, 10 joules, or 8 joules. In some embodiments, the maximum elongation is greater than 8 cm, 8.5 cm, 9 cm, 9.5 cm, 10 cm, 10.5 cm, 11 cm, 11.5 cm, or 12 cm. For example, in some implementations, the maximum extension can be up to 18cm, 16cm or 14cm. Figure 2This is a scatter plot of Graves tear resistance versus maximum elongation in the Graves tear resistance test for various exemplary and comparative substrates with thicknesses ranging from 124 micrometers (4.9 mils) to 699 micrometers (27.5 mils), as further described in the embodiments. According to some embodiments, it has been found that substrates in the upper right portion of this scatter plot (e.g., Graves tear resistance greater than 2.75 joules and maximum elongation greater than 7.5 cm, or Graves tear resistance greater than 3 joules and maximum elongation greater than 8.5 cm) provide better resistance to breakage and intrusion than substrates in other portions of the scatter plot. Graves tear resistance can be enhanced from the values ​​shown in the plot by increasing the substrate thickness, as tearing a thicker substrate typically requires greater energy. As further described elsewhere in this article, maximum elongation can be adjusted by regulating the relative amount and type of hard and soft segments in the polyurethane (e.g., increasing the soft segment content can increase maximum elongation, but may sacrifice tear strength unless the substrate is also made thicker; and it has been found that soft segments based on polycaprolactone or polycarbonate provide the desired tear resistance and the desired maximum elongation).

[0022] In some embodiments, as determined according to ASTM D1004-21, the difference lies in the initial clamp spacing being 5.1 cm, the strain rate being 1.27 m / min, and the sample width being 3.8 cm. The Graves tear resistance of the substrate 110 is greater than 9 joules, 9.5 joules, 10 joules, 10.5 joules, 11 joules, 11.5 joules, 12 joules, 12.5 joules, 13 joules, 13.5 joules, 14 joules, 14.5 joules, or 15 joules, and the maximum elongation is greater than 9 cm. For example, in some embodiments, the Graves tear resistance can be as high as 30 joules, 25 joules, 20 joules, or 18 joules. In some embodiments, the maximum elongation is greater than 9.5 cm, 10 cm, 10.5 cm, 11 cm, 11.5 cm, 12 cm, 12.5 cm, or 13 cm. For example, in some implementations, the maximum extension can be as high as 22cm, 20cm, 18cm, 17cm, 16cm or 15cm. Figure 3 The graphs are force versus elongation curves of various thermoplastic polyurethane substrates as further described in the examples, as determined in the Graves tear resistance test.

[0023] For example, according to some embodiments, other useful properties of the substrate include elongation at break and / or tensile stress at 300% elongation. In some embodiments, the elongation at break of the substrate is at least 500%, 550%, 600%, 650%, 675%, or 700%. In some such embodiments, or in others, the tensile stress of the substrate at 300% elongation does not exceed 15 MPa, 14 MPa, 13 MPa, 12 MPa, or 11 MPa. For example, the elongation at break can be as high as 1200%, 1100%, 1000%, 950%, or 900%. For example, the tensile stress at 300% elongation can be at least 5 MPa, 6 MPa, 7 MPa, 8 MPa, 9 MPa, or 10 MPa. For example, Figure 3 The thermoplastic polyurethane labeled as substrate C has an elongation at break of 741% and a tensile stress of 10.7 MPa (1550 psi) at 300% elongation. For example, the elongation at break and / or the tensile strength at a given elongation (e.g., 300%) can be determined according to ASTM D882-18 or according to D882-18, but modified to use a test speed of 30.5 cm / min (12 in / min), a sample width of 1.3 cm (0.5 inch), and an initial clamp spacing of 2.5 cm (1 inch).

[0024] Figure 4 This is a schematic cross-sectional view of an intrusion-resistant window 200 according to some embodiments. The intrusion-resistant window 200 includes at least one glass pane 160; a security film 100' laminated to the outermost main surface 162 of the at least one glass pane 160. The at least one glass pane 160 may be a single glass pane, or it may be, for example, two or three glass panes. The at least one glass pane may define an inner surface (e.g., a surface facing the interior of the house) and an outer surface (e.g., a surface facing the exterior of the house). The outermost main surface 162 may be an inner surface or an outer surface. Typically, the outermost main surface 162 is an inner surface (i.e., the security film 100' is laminated to the inner surface). However, in some cases, the outermost main surface 162 may be an outer surface. The security film 100' may substantially co-extend with the at least one glass pane 160 (e.g., the security film 100' may co-extend with the at least one glass pane 160, with the possible exception that the edge area of ​​the at least one glass pane 160 may not be covered by the security film 100').

[0025] Safety membrane 100' may correspond to safety membrane 100 with polymer liner 140 removed. Safety membrane 100' includes a substrate 110 comprising thermoplastic polyurethane. Substrate 110 includes the outermost main surface 112 of safety membrane 100', and the thickness T of the substrate is in the range of 480 micrometers to 760 micrometers (or within the range described elsewhere herein). The maximum elongation and Graves tear resistance of substrate 110 are within the corresponding ranges described elsewhere herein. For example, in some embodiments, as determined according to ASTM D1004-21, differing only in an initial clamping distance of 3.8 cm and a strain rate of 1.27 m / min, the Graves tear resistance of substrate 110 may be greater than 2.75 joules (or within the range described elsewhere herein), and the maximum elongation may be greater than 7.5 cm (or within the range described elsewhere herein). In some embodiments, the substrate 110 of the safety film 100' has an elongation at break of at least 500% (or within the range described elsewhere herein), and its tensile stress at 300% elongation does not exceed 15 MPa (or within the range described elsewhere herein). In some embodiments, the haze of the substrate 110 is less than 5%, 4%, 3%, or 2% (e.g., as determined according to ASTM D1003-13). In some embodiments, the haze of the intrusion-resistant window 200 is less than 5%, 4%, 3%, or 2% (e.g., as determined according to ASTM D1003-13). In some embodiments, the light transmittance of the substrate 110 is greater than 80%, 85%, or 90% (e.g., as determined according to ASTM D1003-13). In some embodiments, the light transmittance of the intrusion-resistant window 200 is greater than 80%, 85%, or 90% (e.g., as determined according to ASTM D1003-13).

[0026] In some implementations, the anti-forced intrusion window 200 is characterized by the time of blunt impact forced intrusion. Figure 5This is a schematic diagram of a blunt impact pattern used to determine the blunt impact forced penetration time according to some embodiments. In some embodiments, such as those determined according to ASTM F1233-21, the difference lies in the use of a 0.7 kg smooth-surfaced frame hammer 670 as the blunt impact tool, and the smooth surface 672 of the frame hammer strikes the glass side of the anti-forced penetration window (the side opposite the safety film 100') along a Z-shaped pattern. The horizontal edges of the Z-shaped pattern are each 76 cm wide (width W), and its diagonal length D is 102 cm. The blunt impact forced penetration time of the anti-forced penetration window 200 is at least 100 seconds, 110 seconds, 120 seconds, 130 seconds, 140 seconds, 150 seconds, 160 seconds, 170 seconds, or 180 seconds, where forced penetration is defined as breaking through the anti-forced penetration window along the entire Z-shaped pattern. The frame hammer typically includes an impact surface that can be milled (also called a grid or waffle) or smooth. A smooth surface typically does not include any textures that are intentionally formed in that surface.

[0027] In some embodiments, the safety film 100 is characterized by its passive impact forced intrusion time when a laminate is formed by removing the polymer backing 140 and laminating the substrate 110 to standardized glass (e.g., standardized tempered glass with standardized dimensions) via an optically clear pressure-sensitive adhesive layer 120. In some embodiments, when the polymer backing 140 is removed and the substrate 110 is laminated to glass 160 via an optically clear pressure-sensitive adhesive layer 120 to form a laminate (e.g., corresponding to a forced intrusion resistant window 200), as per ASTM... The determination, as specified in F1233-21, differs in that a 0.7 kg smooth-surfaced frame hammer is used as the blunt impact tool, and the smooth surface of the frame hammer strikes the glass side of the laminate along a Z-shaped pattern. The horizontal edges of the Z-shaped pattern are each 76 cm wide (width W), and its diagonal length D is 102 cm. The blunt impact forced penetration time of the laminate is at least 100, 110, 120, 130, 140, 150, 160, 170, or 180 seconds, where forced penetration is defined as breaking through the laminate along the entire Z-shaped pattern. The glass is tempered glass as specified in ASTM C1048-18, with in-plane dimensions of 86 cm × 86 cm and a thickness of 3.2 mm. The substrate 110 may be substantially co-extended with the glass 160 in the laminate.

[0028] In some embodiments, the anti-intrusion window 200 or laminate is characterized by the number of impacts that cause intrusion in a blunt impact intrusion test. In some embodiments, the number of impacts is at least 100, 120, 140, or 150. For example, the number of impacts can be up to 200, 180, or 170.

[0029] Figure 6 This is a graph showing the time to impact versus the total substrate thickness. Data is shown for polyurethane (PU) substrates, polyethylene terephthalate (PET) substrates, substrates comprising PU and PET layers (mixed PET / PU), and PU substrates applied to both sides of the window glass (half inside / half outside). Results for conventional safety film substrates (e.g., PET substrates), and for PU substrates with a thickness of 460 micrometers or less, or with a thickness greater than that but without the desired properties described elsewhere herein (e.g., Graves tear energy and Graves tear extension), fall within a channel between two parallel lines 401 and 402. The two parallel lines 401 and 402 are separated by approximately 50.4 seconds along the impact time axis. In some embodiments, the safety film of this specification results in an impact time higher than the upper line 401. The formula for the upper line 401 is FET = 0.116T + 28.2, where FET is the impact time in seconds and T is the substrate thickness in micrometers. In some implementations, for laminates or for invasive windows including safety films, the blunt impact invasive time in seconds is greater than 0.116T+30, or greater than 0.116T+50, or greater than 0.116T+70, or greater than 0.116T+90, or greater than 0.116T+110, or greater than 0.116T+120, or greater than 0.116T+130, or greater than 0.116T+140, or greater than 0.116T+150, where T is the thickness of the substrate in micrometers.

[0030] In some embodiments, the thermoplastic polyurethane comprises at least 85%, 90%, 92%, 93%, 94%, or 95% of the total volume of the substrate 110. In some embodiments, the substrate 110 comprises a single layer of thermoplastic polyurethane with a thickness of at least 480 micrometers, 500 micrometers, 520 micrometers, 540 micrometers, 560 micrometers, 580 micrometers, 600 micrometers, or 610 micrometers. In other embodiments, the substrate 110 may comprise two or more layers of thermoplastic polyurethane, wherein each pair of adjacent polyurethane layers may be separated by an adhesive layer.

[0031] Figures 7 to 8This is a schematic cross-sectional view of the substrate of a safety film according to some embodiments. Substrates 210 and 310 may correspond to substrate 110 and may have any of the properties described elsewhere herein with respect to substrate 110 (e.g., Graves tear resistance, maximum elongation, elongation at break, and / or stress at 300% strain). In some embodiments, substrate 210 or 310 comprises at least one layer 211 or 314 of thermoplastic polyurethane and further comprises at least one other polymer layer 212 or 315. For example, at least one other polymer layer 212 may be or include another thermoplastic polyurethane layer. For example, the at least one other polymer layer may be a clear coating. In some embodiments, thermoplastic polyurethane 110 or 211 comprises the outermost main surface 112 or 212 of the safety film. In other embodiments, a different polymer layer 315 comprises the outermost main surface 312 of the safety film.

[0032] In some embodiments, substrate 210 includes at least two thermoplastic polyurethane layers 211, 212 separated by adhesive layer 220, and their total thickness (T1+T2) is at least 480 μm, 500 μm, 520 μm, 540 μm, 560 μm, 580 μm, 600 μm, or 610 μm. In some embodiments, T1 and T2 are substantially equal (e.g., differing by no more than 20%, 15%, or 10%). In some embodiments, T1 and T2 are significantly different. In some embodiments, each of the at least two layers 211, 212 is attached to an adjacent layer of the at least two layers via adhesive layer 220.

[0033] In some embodiments, the substrate 310 includes a transparent coating 315 that encompasses the outermost main surface 312 of the safety film. In some embodiments, the thickness of the transparent coating ( Figure 8 The thickness of the transparent coating (T2) is in the range of 0.5 micrometers to 10 micrometers, 0.5 micrometers to 8 micrometers, 0.5 micrometers to 6 micrometers, or 0.5 micrometers to 5 micrometers. For example, a thinner (e.g., no more than 10 micrometers thick) transparent coating can provide easy-to-clean functionality without sacrificing tear resistance or forced penetration time. For example, the transparent coating 315 may contain silicone or other low surface energy materials. A thicker (e.g., at least 0.5 micrometers thick) transparent coating can be easily manufactured by conventional methods. The haze of the transparent coating 315 and / or the entire substrate 310 may be less than 5% (or within the range described elsewhere herein), and the light transmittance may be greater than 80% (or within the range described elsewhere herein). In some embodiments, the thickness of the transparent coating is at least 1 micrometer. In some embodiments, the substrate 310 includes a thermoplastic polyurethane layer 314 with a thickness T1 of at least 480 micrometers, 500 micrometers, 520 micrometers, 540 micrometers, 560 micrometers, 580 micrometers, 600 micrometers, or 610 micrometers.

[0034] Thermoplastic polyurethanes can be formulated to provide the mechanical properties described herein. The principles of polyurethane formulation are known in the art and are described, for example, in *The Chemistry of Polyurethanes: Renewable Polyols and Isocyanates*, by Felipe M. de Souza, Pawan K. Kahol, and Ram K. Gupta (2021), Proceedings of the American Chemical Society, Vol. 1380. Polyurethane Chemistry: Renewable Polyols and Isocyanates Chapter 1 of ); and Elsevier's Natural and Synthetic Biomedical Polymers by Kumbar, Sangamesh G. Laurencin, Cato T. Deng, and Meng (2014) Natural and Synthetic Biomedical Polymers Chapter 7 of the document. Thermoplastic polyurethanes are typically block copolymers comprising multiple alternating hard and soft segments. The polyurethane can be formed as a reaction product of a formulation comprising at least one isocyanate and at least one polyol. The at least one isocyanate defines the hard segments of the polyurethane, and the at least one polyol may comprise a diol having long-chain molecules, such as polyethers, polyesters, polysiloxanes, and / or polycarbonates, to define the soft segments. The mechanical properties of the polyurethane can be altered by appropriately selecting the hard and soft segments and / or by changing the ratio of soft and hard segments. Generally, increasing the hard segment fraction increases the strength of the polyurethane, while increasing the soft segment fraction increases its elasticity. In some embodiments, the thermoplastic polyurethane comprises hard segments ranging from 30% to 60% by weight, or 35% to 50% by weight, or 40% to 45% by weight. For example, as described elsewhere herein, according to some embodiments, it has been found that polyurethanes with an appropriate thickness having a hard segment content within these ranges can provide desired Graves tear strength and maximum elongation.

[0035] In some embodiments, the thermoplastic polyurethane is or comprises an aliphatic polyurethane. In other embodiments, the thermoplastic polyurethane is or comprises an aromatic polyurethane. According to some embodiments, aromatic polyurethanes can provide better properties than many aliphatic polyurethanes (e.g., better damage resistance and / or better Graves tear resistance), but aliphatic polyurethanes may be preferred for some applications because such polyurethanes typically exhibit less yellowing upon exposure to ultraviolet (UV) light than aromatic polyurethanes. In some embodiments, the substrate 110 includes a light stabilizer, such as a UV absorber, that can be dispersed in the thermoplastic polyurethane. Alternatively or additionally, the adhesive layer 120 may include a light stabilizer. Suitable light stabilizers include those available under the trade name TINUVIN from BASF (Ludwigshafen, Germany). For example, the light stabilizer may be included in the thermoplastic polyurethane layer and / or the adhesive layer at a content of 0.2% to 4% by weight.

[0036] In some embodiments, the thermoplastic polyurethane comprises a reaction product containing at least one polyisocyanate and at least one polyol. In some embodiments, each of the at least one isocyanate is an aliphatic isocyanate. In some embodiments, each of the at least one polyol is an aliphatic polyol. In other embodiments, the at least one isocyanate comprises an aromatic isocyanate and / or the at least one polyol comprises an aromatic polyol. According to some embodiments, it has been found that the desired properties can be obtained by using polycarbonate and / or polycaprolactone polyols. Therefore, in some embodiments, the at least one polyol comprises a polycarbonate polyol, a polycaprolactone polyol, or a combination thereof.

[0037] In some embodiments, the at least one polyol comprises an aliphatic polyol. In some embodiments, the formulation comprises 20% to 75% by weight of a polycarbonate polyol. In some embodiments, the formulation comprises not less than 30%, 40%, 50%, or 55% by weight of a polycarbonate polyol. In some embodiments, the formulation comprises not more than 70% or 65% by weight of a polycarbonate polyol. In some embodiments, the polycarbonate polyol is a polycarbonate diol. In some embodiments, the polycarbonate polyol is an aliphatic polycarbonate polyol, such as an aliphatic polycarbonate diol. In other embodiments, an aromatic polycarbonate polyol is used. Suitable polycarbonate polyols include those available under the trade name ETERNACOLL from UBE Corporation (Tokyo, Japan). Such polycarbonate polyols include ETERNACOLL UH100, which is an aliphatic polycarbonate diol.

[0038] In some embodiments, the at least one polyol comprises at least one diol and at least one triol. The triol may be included to increase branching sites in the resulting polyurethane. For example, in some embodiments, the formulation comprises 20% to 75% by weight of at least one diol and 0.2% to 5% by weight of at least one triol. In some embodiments, the formulation comprises not less than 30%, 40%, 50%, or 55% by weight of at least one diol. In some embodiments, the formulation comprises not more than 70% by weight or 65% by weight of at least one diol. In some embodiments, the formulation comprises 0.3% to 2% by weight of at least one triol.

[0039] In some embodiments, the at least one polyol comprises a polycaprolactone polyol with a molecular weight of less than 2500 g / mol, 2000 g / mol, 1500 g / mol, 1200 g / mol, 1000 g / mol, 800 g / mol, 600 g / mol, or 400 g / mol. In some embodiments, the molecular weight is at least 100 g / mol, 150 g / mol, 200 g / mol, or 250 g / mol. In some embodiments, the formulation comprises 15% to 75% by weight, or 20% to 60% by weight, or 25% to 65% by weight of a polycaprolactone polyol. In some embodiments, the polycaprolactone polyol is an aliphatic polycaprolactone polyol. In some embodiments, the at least one polyol comprises a first polycaprolactone polyol with a molecular weight in the range of 800 g / mol to 2500 g / mol and a second polycaprolactone polyol with a molecular weight in the range of 200 g / mol to 400 g / mol. In some embodiments, the formulation comprises 45% to 70% by weight of a first polycaprolactone polyol and 0.2% to 5% by weight or 0.3% to 2% by weight of a second polycaprolactone polyol. In some embodiments, the first polycaprolactone polyol is a diol and the second polycaprolactone polyol is a triol. In some embodiments, each of the first and second polycaprolactone polyols is an aliphatic polycaprolactone polyol. In other embodiments, at least one of the first and second polycaprolactone polyols is an aromatic polycaprolactone polyol. Suitable polycaprolactone polyols include those purchased under the trade name CAPA from Ingevity (North Charleston, SC), North Charleston, South Carolina, USA. These polycaprolactone polyols include CAPA 2203A, which is a polycaprolactone diol with a molecular weight of 2000 g / mol; CAPA 2101A, which is a polycaprolactone diol with a molecular weight of 1000 g / mol; and CAPA 3031, which is a polycaprolactone triol with a molecular weight of 300 g / mol.

[0040] In some embodiments, the at least one isocyanate is a cyclic aliphatic diisocyanate. For example, the formulation may comprise 25% to 60% by weight, or 30% to 55% by weight, or 30% to 50% by weight, or 30% to 45% by weight of a cyclic aliphatic diisocyanate. Suitable cyclic aliphatic diisocyanates include dicyclohexylmethane diisocyanate, which may be available under the trade name DESMODUR W from Covestro LLC (Pittsburgh, PA), USA.

[0041] In some embodiments, the formulation comprises a prepolymer containing the reaction product of an isocyanate and a polyester polyol. Suitable prepolymers include those available under the trade name RUBINATE from Huntsman (The Woodlands, TX), USA. An example is RUBINATE 1234, a low-functionality prepolymer (functionality = 2.01) prepared by reacting 4,4'-diphenylmethane diisocyanate (pure MDI) with a polyester polyol. For example, the formulation may comprise 40% to 65% by weight of the prepolymer.

[0042] In some embodiments, the formulation comprises at least one chain extender with a molecular weight less than 250 g / mol, 200 g / mol, or 150 g / mol. For example, the molecular weight may be at least 40 g / mol, 50 g / mol, or 60 g / mol. In some embodiments, the formulation comprises 3% to 25% by weight, or 4% to 22% by weight, or 5% to 20% by weight of at least one chain extender. Suitable chain extenders include aliphatic diols, such as 1,4-butanediol.

[0043] In some embodiments, the formulation contains a crosslinking or gelling catalyst, such as dibutyltin dilaurate. For example, the formulation may include 0.01% to 0.1% by weight of the crosslinking or gelling catalyst.

[0044] Example

[0045] Test methods

[0046] Graves tear test method 1

[0047] Graves tear resistance and corresponding maximum elongation were determined according to ASTM D1004-21, except that the initial clamp spacing was 1.5 inches (3.8 cm) and the strain rate was 500 in / min (1.27 m / min).

[0048] Graves tear test method 2

[0049] Graves tear resistance and corresponding maximum elongation were determined according to ASTM D1004-21, with the difference being that the initial clamp spacing was 2 inches (5.1 cm), the strain rate was 500 in / min (1.27 m / min), and the sample width was 1.5 inches (3.8 cm).

[0050] Tensile stress and elongation at break

[0051] The elongation at break and tensile stress at various elongations were determined according to ASTM D882-18, except that the test speed was 12 in / min (30.5 cm / min), the sample width was 0.5 inches (1.3 cm), and the initial clamp spacing was 1 inch (2.5 cm).

[0052] Crack and Intrusion Test

[0053] The safety film substrate is laminated onto the glass via an optically transparent pressure-sensitive adhesive layer to form a laminate. The substrate and glass are co-extended. If the safety film includes a polymer backing, the backing is removed prior to lamination. The glass has in-plane dimensions of 33.75 inches × 33.75 inches (86 cm × 86 cm) and a thickness of 1 / 8 inch (3.2 mm). The glass is tempered glass as specified in ASTM C1048-18. The blunt impact forced penetration time and number of impacts are determined according to ASTM F1233-21, except that a 0.7 kg smooth-surfaced frame hammer is used as the blunt impact tool, wherein the smooth surface of the frame hammer strikes the glass side of the laminate along a Z-shaped pattern, the horizontal edges of which are each 30 inches (76 cm) wide and the diagonal length of which is 40 inches (102 cm). Forced penetration is defined as breaking through the laminate along the entire Z-shaped pattern.

[0054] Material

[0055] Unless otherwise stated, all parts, percentages, ratios, etc., in the examples and the remainder of this specification are by weight. Unless otherwise specified, the materials used in the examples are available from commercial suppliers and / or can be prepared by known methods.

[0056]

[0057] safety film

[0058] The materials listed in the table below are reacted and extruded into a polyurethane substrate.

[0059]

[0060] Various formulations were prepared into safety film substrates and tested according to "Graves Tear Test Method 1". Results are reported in the table below and... Figure 2 middle.

[0061]

[0062] A sample of thermoplastic polyurethane (TPU) spheres was obtained and extruded into a safety film substrate. The substrate had the thickness and properties shown in the table below. In some cases, the substrate was formed by laminating two extruded substrates together. The properties in the table below were measured according to the description in "Tensile Stress and Elongation at Break".

[0063]

[0064] Various substrate layers were pressed onto glass using an optically clear pressure-sensitive adhesive and tested according to the “Crack and Penetration Test”. The optically clear adhesive (PSA) layer was 3M window film PSA, with a thickness of 20 to 30 micrometers, and exhibited a 180-degree peel force on glass greater than 10 N / in (3.94 N / cm) at a peel rate of 12 in / min (30.5 cm / min). Results are provided in the table below and Figure 6 Three PET substrates were tested for comparison, as shown in the table.

[0065]

[0066] Some of these substrates were tested according to “Graves Tear Test Method 1”. The results are provided in the table below and... Figure 2 middle.

[0067]

[0068] Various substrates were tested according to “Graves Tear Test Method 2”. Results are provided in the table below and Figure 3 middle.

[0069]

[0070] Terms such as “about” will be understood in the context in which they are used and described by those skilled in the art. If it is unclear to those skilled in the art in the context of their use and description of “about” to express quantities of characteristic size, quantity, and physical properties, then “about” will be understood to mean within 10% of the specified value. A quantity given a specified value as “about” can be precisely the specified value. For example, if it is unclear to those skilled in the art in the context of their use and description of this specification, a quantity having a value of about 1 means that the quantity has a value between 0.9 and 1.1, and that the value can be 1.

[0071] The term “substantially” will be understood by those skilled in the art in the context of its use and description in this specification. If, in the context of its use and description in this specification, the use of “substantially” regarding a property or characteristic is not readily apparent to those skilled in the art, and when the opposite meaning of such property or characteristic is clear to those skilled in the art, the term “substantially” will be understood to mean that the property or characteristic is more pronounced than its opposite meaning.

[0072] All cited references, patents, and patent applications are incorporated herein by reference in their entirety in a consistent manner. In the event of any inconsistency or contradiction between the incorporated references and this application, the information in the foregoing description shall prevail.

[0073] Unless otherwise stated, the description of elements in the accompanying drawings should be understood to apply equally to corresponding elements in the other drawings. While specific embodiments have been illustrated and described herein, those skilled in the art will recognize that various alternative and / or equivalent embodiments may be used instead of the illustrated and described embodiments without departing from the scope of this disclosure. This application is intended to cover any modifications, variations, or combinations of the specific embodiments discussed herein. Therefore, this disclosure is intended to be limited only by the claims and their equivalents.

Claims

1. A security film for enhancing the resistance to forcible entry of a window, the security film comprising: a substrate comprising a thermoplastic polyurethane; an optically transparent pressure sensitive adhesive layer disposed on the substrate; and a polymeric liner releasably attached to the substrate via the optically transparent pressure sensitive adhesive layer, the substrate, the optically transparent pressure sensitive adhesive layer, and the polymeric liner being substantially coextensive with one another, wherein the substrate comprises an outermost major surface of the security film; and wherein the substrate has a thickness in the range of 480 micrometers to 760 micrometers and a Graves tear resistance greater than 2.75 Joules and a maximum elongation greater than 7.5 cm as determined according to ASTM D1004-21, except that the initial grip separation is 3.8 cm and the strain rate is 1.27 m / min.

2. The security film of claim 1, wherein when the polymeric liner is removed and the substrate is laminated to glass via the optically transparent pressure sensitive adhesive layer to form a laminate, the laminate has a blunt impact forcible entry time of at least 100 seconds as determined according to ASTM F1233-21, except that a smooth surfaced frame hammer of 0.7 kg is used as the blunt impact tool and the smooth surface of the frame hammer strikes the glass side of the laminate along a Z-shaped pattern, the horizontal edges of the Z-shaped pattern each being 76 cm in width and the diagonal length thereof being 102 cm, the glass is tempered glass as specified in ASTM C1048-18, the glass has in-plane dimensions of 86 cm by 86 cm and a thickness of 3.2 mm, and the substrate is substantially coextensive with the glass.

3. The security film of claim 1 or 2, wherein the substrate has a Graves tear resistance greater than 9 Joules and a maximum elongation greater than 9 cm as determined according to ASTM D1004-21, except that the initial grip separation is 5.1 cm, the strain rate is 1.27 m / min, and the sample width is 3.8 cm.

4. The security film of any one of claims 1 to 3, wherein the substrate has an elongation at break of at least 500% and a tensile stress at 300% elongation of no more than 15 MPa.

5. The security film of any one of claims 1 to 4, wherein the thermoplastic polyurethane comprises a reaction product of a formulation containing at least one isocyanate and at least one polyol, the at least one polyol comprising a polycaprolactone polyol having a molecular weight of less than 2500 g / mol.

6. The security film of any one of claims 1 to 4, wherein the thermoplastic polyurethane comprises a reaction product of a formulation containing at least one isocyanate and at least one polyol, the at least one polyol comprising a polycarbonate polyol.

7. The security film of claim 5 or 6, wherein the formulation comprises at least one chain extender having a molecular weight of less than 250 g / mol.

8. The security film of any one of claims 1 to 7, wherein the thermoplastic polyurethane comprises hard segments in a range of 30 wt% to 60 wt%.

9. A security film for enhancing the resistance to forcible entry of a window, the security film comprising: a substrate comprising a thermoplastic polyurethane; an optically transparent pressure sensitive adhesive layer disposed on the substrate; and a polymeric liner releasably attached to the substrate via the optically transparent pressure sensitive adhesive layer, the substrate, the optically transparent pressure sensitive adhesive layer, and the polymeric liner being substantially coextensive with one another, wherein the substrate comprises an outermost major surface of the security film; and wherein the substrate has a thickness in a range of 480 micrometers to 760 micrometers, and wherein when the polymeric liner is removed and the substrate is laminated to glass via the optically transparent pressure sensitive adhesive layer to form a laminate, the laminate has a blunt impact resistance to forcible entry of at least 100 seconds as determined according to ASTM F1233-21, except that a smooth surfaced frame hammer having a mass of 0.7 kg is used as the blunt impact tool, and the smooth surface of the frame hammer strikes the glass side of the laminate along a Z-shaped pattern, the horizontal edges of the Z-shaped pattern each having a width of 76 cm, and a diagonal length of 102 cm, the glass is tempered glass as specified in ASTM C1048-18, the glass has in-plane dimensions of 86 cm by 86 cm, a thickness of 3.2 mm, the substrate is substantially coextensive with the glass.

10. The security film of claim 9, wherein the thermoplastic polyurethane comprises hard segments in a range of 30 wt% to 60 wt%.

11. The security film of claim 9 or 10, wherein the blunt impact resistance to forcible entry in seconds is greater than 0.116T + 30, T being the thickness of the substrate in micrometers.

12. A resistance to forcible entry window, the resistance to forcible entry window comprising: at least one glass pane; and a security film laminated to an outermost major surface of the at least one glass pane, the security film comprising a substrate comprising a thermoplastic polyurethane, wherein the substrate comprises an outermost major surface of the security film; wherein the substrate has a thickness in a range of 480 micrometers to 760 micrometers, and a Graves tear resistance of the substrate is greater than 2.75 Joules and a maximum elongation is greater than 7.5 cm as determined according to ASTM D1004-21, except that the initial grip separation is 3.8 cm, and the strain rate is 1.27 m / min.

13. The forced entry resistant window of claim 12, wherein the forced entry resistant window has a blunt impact forced entry time of at least 100 seconds as determined according to ASTM F1233-21, with the exception that a 0.7 kg smooth surfaced frame hammer is used as the blunt impact tool, and the smooth surface of the frame hammer strikes the glass side of the forced entry resistant window along a Z-shaped pattern, the horizontal edges of the Z-shaped pattern each being 76 cm in width, and the diagonal length thereof being 102 cm, the forced entry being defined as breaching the forced entry resistant window along the entire Z-shaped pattern.

14. The forced entry resistant window of claim 13, wherein the blunt impact forced entry time in seconds is greater than 0.116T + 30, T being the thickness of the substrate in microns.

15. The forced entry resistant window of any one of claims 12 to 14, wherein the substrate of the safety film has an elongation at break of at least 500%, and a tensile stress at 300% elongation of no more than 15 MPa.

Images