Glass article with adhesive layer configured for delamination of glass substrate in response to headform impact

Abstract

Disclosed are embodiments of a glass article. The glass article includes a glass substrate having a first major surface and a second major surface. The second major surface is opposite to the first major surface. The glass article also includes a frame with a frame surface and an adhesive structure disposed between the glass substrate and the frame that bonds the glass substrate to the frame. After impact with a headform according to FMVSS 201, the glass substrate at least partially delaminates from the adhesive structure and the glass substrate does not break across the first major surface or the second major surface.

Description

Attorney Docket No.: SP24-229PCTGLASS ARTICLE WITH ADHESIVE LAYER CONFIGURED FOR DELAMINATION OF GLASS SUBSTRATE IN RESPONSE TO HEADFORM IMPACTCROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims the benefit of priority under 35 U.S.C. § 119 of U.S. Provisional Application No. 63 / 687,960 filed August 28, 2024, the content of which is incorporated herein by reference in its entirety.BACKGROUND

[0002] The disclosure relates to a glass article and, more particularly, to a glass article having a glass substrate configured to at least partially delaminate during headform impact testing.

[0003] Vehicle interiors include various display and non-display surfaces that incorporate glass. Glass is desirable over plastics, for example, because the optical properties and durability of glass are often superior. However, glass does not plastically deform in the same way as plastic, and as a result, glass subject to stress associated with vehicle collisions may break in a way that forms sharp or jagged edges. Thus, vehicles incorporating glass articles are subject to certain safety standards as well as customer requirements to minimize the risk of injury caused by such glass articles during an accident.SUMMARY

[0004] The following summary is a brief description of certain aspects of the present disclosure. The summary should not be considered as limiting of the breadth, scope, or applicability of the present disclosure.

[0005] According to aspect (1), a glass article is provided. The glass article includes a glass substrate comprising a first major surface and a second major surface. The second major surface is opposite to the first major surface. The glass article also includes a frame comprising a frame surface and an adhesive structure disposed between the glass substrate and the frame that bonds the glass substrate to the frame. After impact with a headform according to FMVSS 201, the glass substrate at least partially delaminates from the adhesive structure and the glass substrate does not break across the first major surface or the second major surface.Attorney Docket No.: SP24-229PCT

[0006] According to aspect (2), the glass article of aspect (1) is provided, wherein the adhesive structure comprises a first adhesive having a first tensile strength that is 1.0 MPa or less.

[0007] According to aspect (3), the glass article of aspect (2) is provided, wherein the first adhesive comprises at least one of pressure sensitive tape or acrylic resin.

[0008] According to aspect (4), the glass article of aspect (2) or aspect (3) is provided, wherein the first adhesive extends around at least 80% of a periphery of the second major surface of the glass substrate.

[0009] According to aspect (5), the glass article of aspect (4) is provided, wherein the first adhesive extends around the entire periphery of the second major surface of the glass substrate.

[0010] According to aspect (6), the glass article of aspect (4) is provided, wherein the adhesive structure comprises a second adhesive having a second adhesive strength, the second adhesive strength being greater than the first adhesive strength.

[0011] According to aspect (7), the glass article of aspect (6) is provided, wherein the second adhesive is disposed in discrete sections around the periphery of the second major surface of the glass substrate.

[0012] According to aspect (8), the glass article of aspect (7) is provided, wherein the periphery includes a first longitudinal side, a second longitudinal side, a first lateral side, and a second lateral side; wherein the first lateral side forms a first corner with the first longitudinal side and a second corner with the second longitudinal side and the second lateral side forms a third comer with the first longitudinal side and a fourth comer with the second longitudinal side; and wherein a respective midpoint of at least one discrete section of the plurality of discrete sections is disposed on each of the first longitudinal side, the second longitudinal side, the first lateral side, and the second lateral side in a range of 10% to 40% of a respective side length as measured from each of the first comer, the second corner, the third corner, and the fourth corner.

[0013] According to aspect (9), the glass article of any of aspects (6) to (8) is provided, wherein the second adhesive comprises at least one of a urethane or an epoxy.Attorney Docket No.: SP24-229PCT

[0014] According to aspect (10), the glass article of aspect (1) is provided, wherein the adhesive structure comprises a first adhesive having a first adhesive strength that is greater than 1.0 MPa.

[0015] According to aspect (11), the glass article of aspect (10) is provided, wherein the first adhesive is disposed in a plurality of discrete sections around a periphery of the second major surface of the glass substrate.

[0016] According to aspect (12), the glass article of aspect (11) is provided, wherein the plurality of discrete sections cover from 5% to 50% of the periphery.

[0017] According to aspect (13), the glass article of aspect (11) or aspect (12) is provided, wherein the periphery includes a first longitudinal side, a second longitudinal side, a first lateral side, and a second lateral side; wherein the first lateral side forms a first corner with the first longitudinal side and a second comer with the second longitudinal side and the second lateral side forms a third comer with the first longitudinal side and a fourth corner with the second longitudinal side; and wherein a respective midpoint of at least one discrete section of the plurality of discrete sections is disposed on each of the first longitudinal side, the second longitudinal side, the first lateral side, and the second lateral side in a range of 10% to 40% of a respective side length as measured from each of the first corner, the second corner, the third comer, and the fourth corner.

[0018] According to aspect (14), the glass article of any of aspects (1) to (13) is provided, wherein the adhesive structure comprises: a polymer support disposed between the glass substrate and the frame, the polymer support comprising a first support surface and a second support surface, the second support surface being opposite to the first support surface; a first adhesive layer disposed between the frame surface and the second support surface; and a second adhesive layer disposed between the second major surface and the first support surface.

[0019] According to aspect (15), the glass article of any of aspects (1) to (14) is provided, wherein the glass substrate comprises a glass thickness between the first major surface and the second major surface, the glass thickness being 2 mm or less.

[0020] According to aspect (16), the glass article of any of aspects (1) to (15) is provided, wherein the frame surface defines a curvature, wherein the adhesive structure joins the glass substrate to the frame surface such that the glass substrate is elastically deformed to conform to the curvature.Attorney Docket No.: SP24-229PCT

[0021] According to aspect (17), the glass article of any of aspects (1) to (15) is provided, wherein the first major surface of the glass substrate is substantially flat.

[0022] According to aspect (18), a glass article is provided. The glass article includes a glass substrate comprising a first major surface and a second major surface. The second major surface is opposite to the first major surface. The glass article also includes a frame comprising a frame surface and an adhesive structure disposed between the glass substrate and the frame that bonds the glass substrate to the frame. The adhesive structure comprises: (i) a first adhesive having a first adhesive strength of 1.0 MPa or less that extends around an entirety of a periphery of the second major surface of the glass substrate; (ii) a second adhesive having a second adhesive strength of greater than 1.0 MPa that is disposed in a plurality of discrete sections around the periphery of the second major surface of the glass substrate; or (iii) a combination of the first adhesive and the second adhesive in which the second adhesive is disposed in a plurality of discrete sections around the periphery of the second major surface of the glass substrate and in which the first adhesive extends between the plurality of discrete sections of the second adhesive such that the first adhesive and the second adhesive together extend around the entirety of the periphery of the glass substrate. After impact with a headform according to FMVSS 201, the glass substrate at least partially delaminates from the adhesive structure and the glass substrate does not break across the first major surface or the second major surface.

[0023] According to aspect (19), the glass article of aspect (18) is provided, wherein the first adhesive comprises at least one of pressure sensitive tape or acrylic resin.

[0024] According to aspect (20), the glass article of aspect (18) or aspect (19) is provided, wherein the second adhesive comprises at least one of a urethane or an epoxy.

[0025] According to aspect (21), the glass article of any of aspects (18) to (20) is provided, wherein the periphery includes a first longitudinal side, a second longitudinal side, a first lateral side, and a second lateral side; wherein the first lateral side forms a first corner with the first longitudinal side and a second comer with the second longitudinal side and the second lateral side forms a third comer with the first longitudinal side and a fourth corner with the second longitudinal side; and wherein a respective midpoint of at least one discrete section of the plurality of discrete sections is disposed on each of the first longitudinal side, the second longitudinal side, the first lateral side, and the second lateral side in a range ofAttorney Docket No.: SP24-229PCT10% to 40% of a respective side length as measured from each of the first corner, the second corner, the third comer, and the fourth corner.

[0026] According to aspect (22), the glass article of any of aspects (18) to (21) is provided, wherein the glass substrate comprises a glass thickness between the first major surface and the second major surface, the glass thickness being 2 mm or less.

[0027] According to aspect (23), the glass article of any of aspects (18) to (22) is provided, wherein the frame surface defines a curvature and wherein the adhesive structure joins the glass substrate to the frame such that the glass substrate elastically deforms to conform to the curvature.

[0028] According to aspect (24), the glass article of any of aspects (18) to (23) is provided, wherein the first major surface of the glass substrate is substantially flat.

[0029] Additional features and advantages will be set forth in the detailed description which follows, and in part will be readily apparent to those skilled in the art from that description or recognized by practicing the embodiments as described herein, including the detailed description which follows, the claims, as well as the appended drawings.

[0030] It is to be understood that both the foregoing general description and the following detailed description are merely exemplary, and are intended to provide an overview or framework to understanding the nature and character of the claims.BRIEF DESCRIPTION OF THE DRAWINGS

[0031] The accompanying drawings are included to provide a further understanding, and are incorporated in and constitute a part of this specification. The drawings illustrate one or more embodiment s), and together with the description serve to explain principles and operation of the various embodiments. In the drawings:

[0032] FIG. 1A is a perspective view of a vehicle interior with vehicle interior systems incorporating glass articles, according to exemplary embodiments;

[0033] FIG. IB is a side view of a glass article for a vehicle interior system, according to exemplary embodiments;

[0034] FIGS. 2-4 are still images taken from a recording of a glass article undergoing headform impact testing, showing delamination of the glass substrate according to exemplary embodiments;Attorney Docket No.: SP24-229PCT

[0035] FIGS. 5 and 6 depict a glass article and headform impactor used to model stresses associated with headform impact testing for various adhesive conditions, according to exemplary embodiments;

[0036] FIGS. 7 and 8 depict fully bonded and partially bonded adhesive conditions, respectively, for modeling stresses on the glass substrate during headform impact testing, according to exemplary embodiments;

[0037] FIGS 9 and 10 depict the peak maximum principal stress and the maximum principal stress at peak headform impactor intrusion, respectively, for the fully bonded adhesive condition, according to exemplary embodiments;

[0038] FIGS 11 and 12 depict the peak maximum principal stress and the maximum principal stress at peak headform impactor intrusion, respectively, for the partially bonded adhesive condition, according to exemplary embodiments;

[0039] FIG. 13 provides a table of highest maximum principal stress on the glass substrate during headform impact testing based on adhesive strength as well as illustrations showing delamination of the glass substrate as predicted using finite element analysis, according to exemplary embodiments;

[0040] FIG. 14 depicts an analytical system for estimating delamination conditions based on material properties and dimensions of the adhesive structure joining two sheets, according to exemplary embodiments;

[0041] FIG. 15 is a graph of the adhesive width based on glass substrate thickness to achieve delamination of the glass substrate during headform impact testing, according to exemplary embodiments; and

[0042] FIG. 16 is a graph of the design space to provide delamination of the glass substrate during headform impact testing, according to exemplary embodiments.DETAILED DESCRIPTION

[0043] Reference will now be made in detail to various embodiments of a glass article with a glass substrate configured to delaminate during headform impact testing in order to relieve impact stress that might otherwise break the glass substrate, examples of which are illustrated in the accompanying drawings. Glass articles used in vehicle interior systems are designed not only for aesthetic functionality and utility but also for safety. Because vehicles may be involved in collisions in which the occupant’s momentum causes the occupant to come intoAttorney Docket No.: SP24-229PCT contact with various vehicle interior structures, those structures are tested to confirm compliance with certain safety standards and manufacturer requirements in order to minimize injury to the occupant. One such safety standard relates to the contact of an occupant’s head with vehicle interior displays. One aspect of this test is whether glass integrated into the display breaks, which might create sharp edges that could cut the occupant’s face or head. As will be discussed below, the inventors surprising and unexpectedly found that glass articles in which the glass substrate at least partially delaminates from the rest of the structure during headform impact testing experienced lower maximum principal stress than glass substrates that remained fully bonded to the structure. By lowering the stress on the glass to below the breaking strength of the glass, the chances of breaking the glass are greatly reduced. These and other aspects and advantages will be described in relation to the embodiments provided below and in the drawings. These embodiments are presented by way of example and not by way of limitation.

[0044] In order to provide context for the glass article described herein, exemplary embodiments of glass articles will be described in relation to the particular vehicle interior systems. Such vehicle interior systems are merely exemplary, and the glass article can be incorporated into other vehicle interior systems that are not depicted.

[0045] FIG. 1A shows an exemplary interior 10 of a vehicle that includes three different embodiments of vehicle interior systems 20, 30, 40. Vehicle interior system 20 includes a base, shown as center console base 22, with a curved surface 24 including a display 26. Vehicle interior system 30 includes a base, shown as dashboard base 32, with a curved surface 34 including a display 36. The dashboard base 32 typically includes an instrument panel 38 which may also include a display. Vehicle interior system 40 includes a base, shown as steering wheel base 42, with a curved surface 44 and a display 46. In one or more embodiments, the vehicle interior system includes a base that is an arm rest, a pillar, a seat back, a floorboard, a headrest, a door panel, or any portion of the interior of a vehicle that includes a curved or flat surface.

[0046] The embodiments of the glass articles described herein can be used in each of vehicle interior systems 20, 30, 40, among others. In one or more such embodiments, the glass article discussed herein may include a cover glass substrate that also covers non-display surfaces of the dashboard, center console, steering wheel, door panel, etc. In such embodiments, the glass material may be selected based on its weight, aesthetic appearance, etc. and may be provided with a coating (e.g., an ink or pigment coating) including a pattern (e.g., a brushed metal appearance, a wood grain appearance, a leather appearance, a colored appearance, etc.) to visually match the glass components with adjacent non-glass components. In specificAttorney Docket No.: SP24-229PCT embodiments, such ink or pigment coating may have a transparency level that provides for deadfront or color matching functionality when the display 26, 36, 38, 46 is inactive. Further, while the vehicle interior of FIG. 1 A depicts a vehicle in the form of an automobile (e.g., cars, trucks, buses and the like), the glass articles disclosed herein can be incorporated into other vehicles, such as trains, sea craft (boats, ships, submarines, and the like), aircraft (e.g., drones, airplanes, jets, helicopters and the like), and spacecraft.

[0047] FIG. IB depicts an example of a glass article 100, such as might be used for a display or non-display application in the vehicle interior systems 20, 30, 40 of FIG. 1A, according to the present disclosure. The glass article 100 includes a glass substrate 102 comprising a first major surface 104 and a second major surface 106. The second major surface 106 is opposite to the first major surface 104. A minor surface 108 connects the first major surface 104 to the second major surface 106 around a periphery of the glass substrate 102. The glass article 100 also includes a frame 110 comprising a frame surface 112. In one or more embodiments, the frame 110 is a backing plate defining a continuous frame surface 112. In one or more other embodiments, the frame 110 includes one or more apertures such that the frame surface 112 defines a bezel around the one or more apertures. In one or more such embodiments, the apertures may be configured to receive a display module (such as a liquid crystal display, a light emitting diode (LED) display, an organic LED (OLED) display, or a microLED display, amongst others), including a backlight structure if provided, and / or a touch panel. In one or more embodiments, the frame surface 112 is substantially flat (e.g., having a radius of curvature of greater than 10,000 mm). In one or more embodiments, the frame surface 112 comprises at least one curvature. The curvature may be convex or concave and may have a radius of less than 10,000 mm, in particular less than 5000 mm, and most particularly less than 3000 mm. In one or more embodiments, the radius of curvature may be in a range of 20 mm to 3000 mm, in particular in a range of 20 mm to 1500 mm.

[0048] An adhesive structure 114 joins the second major surface 106 of the glass substrate 102 to the frame surface 112 of the frame 110. In one or more embodiments, the adhesive structure 114 is a single layer of an adhesive material. In one or more other embodiments, the adhesive structure 114 is a composite of a first adhesive layer 116, a polymer support 118, and a second adhesive layer 120. In such an embodiments, the first adhesive layer 116 is disposed between the frame surface 112 and a first support surface 122 of the polymer support 118, and the second adhesive layer 120 is disposed between the second major surface 106 of the glass substrate 102 and a second support surface 124 of the polymer support 118. In embodiments where used,Attorney Docket No.: SP24-229PCT the polymer support 118 may provide a desired spacing (e.g., to accommodate a display module or provide an air gap) between the glass substrate 102 and the frame 110 that may be difficult to fill with a single layer of adhesive material.

[0049] As mentioned, the frame 110 may be flat or curved. In one or more embodiments in which the frame 110 is curved, the glass substrate 102 follows the curvature of the frame 110. In one or more such embodiments, the glass substrate 102 is hot-bent such that the glass substrate 102 is permanently curved through the application of heat above the softening point of the glass composition of the glass substrate 102 and force, such as from gravity or a die. In one or more other such embodiments, the glass substrate 102 is cold-bent to the curvature of the frame 110 by elastically deforming the glass substrate 102 and bonding the glass substrate 102 in the elastically deformed state to the frame surface 112 with the adhesive structure 114.

[0050] The glass article 100 is disposed in an interior of a vehicle, and such glass articles 100 should meet certain safety standards, such as head impact protection. One relevant standard for head impact protection is outlined in FMVSS 201. According to this standard, the glass article 100 is impacted with a headform impactor having a mass of 6.8 kg anddiameterof 165 mm and traveling at a velocity of 5.35 m / s to 6.69 m / s. During testing, the deceleration of the impactor should be 120 g (g-force) or less. Further, the deceleration of the impactor should not exceed 80 g for any 3 ms interval over the time of impact. According to the present disclosure, the glass substrate 102 at least partially delaminates from the frame 110 during testing according to FMVSS 201, and the glass substrate 102 does not break across the first major surface 104 or the second major surface 106. Applicant surprisingly and unexpectedly found that, when a substantial portion of the glass substrate 102 delaminates during impact, the impact energy is dissipated through bending of the glass substrate 102 without causing breakage of the glass substrate 102.

[0051] FIGS. 2-4 depict various frames during video capture of headform impact testing (HIT) according to FMVSS 201. For the tested system, the glass substrate 102 had a thickness of 1.1 mm, a length of 277 mm, and a width of 199 mm and was AutoGrade™ glass (available from Corning Incorporated, Coming, NY). The first and second adhesive layers 116, 120 were each a pressure sensitive adhesive tape (VHB™ Tape available from 3M Company, St. Paul, MN), and disposed between the adhesive layers 116, 120 was a polymer support 118 having a thickness of 6.35 mm. The polymer support 118 had a bezel width of 3 mm, a length of 277 mm, and a width of 199 mm. The frame 110 was an aluminum plate having a thickness of 4.8 mm, a length of 355 mm, and a width of 223 mm, and clamp supports that held the frame 110Attorney Docket No.: SP24-229PCT were stainless steel having a thickness of 4.8 mm, width of 19 mm, and a height of 65 mm. On both sides, the polymer support 118 was bonded to the frame 110 and glass substrate 102, respectively, around the entire perimeter using pressure sensitive adhesive tape. During testing, the inventors found that the pressure sensitive adhesive tape used was actually not strong enough to retain the glass substrate 102 in response to impact by the headform impactor 126. That is, the glass substrate 102 delaminated from the polymer support 120 (and thus, the frame 110), and the glass substrate 102 did not break in response to the impact from the impactor 126.

[0052] FIG. 2 shows a rear perspective view of the headform impactor 126 and glass article 100 during impact. As can be seen, the glass substrate 102 delaminates along the lateral side of the glass article 100. FIG. 3 shows a front view of the glass article 100 after impact, and as identified by the white arrow, it can be seen that a portion of the glass substrate 102 remained delaminated after HIT and that the glass substrate 102 did not break. FIG. 4 is a view of the glass article 100 during headform impact looking from above, and as identified by the white arrows, it can be seen that the glass substrate 102 delaminated along both lateral edges of the glass article 100. That the glass substrate 102 did not break despite the large bending allowed by delamination of the glass substrate 102 was surprising and unexpected. The inventors theorize that the separation from the weak pressure sensitive tape allowed the glass substrate 102 to respond to impact with enhanced flexibility, reducing the stress experienced by the glass substrate to below the breaking stress of the glass substrate 102.

[0053] In order to more fully understand the how delamination of the glass substrate 102 affects breakage of the glass substrate 102, the stresses associated with an impact on the glass substrate 102 were modeled using finite element analysis (FEA). FIG. 5 depicts the components of the modeled system. As can be seen, the glass article 100 included the glass substrate 100 disposed over the frame 110 and joined to the frame 110 by the adhesive structure 114. The frame 100 was supported by clamps 128 at each corner of the frame 110. The headform impactor 126 was considered to have contacted a center of the glass article 100. A quarter of the glass article 100 was modeled, and it is assumed that the other three quarters of the glass article 100 would respond symmetrically. FIG. 6 depicts a detailed view of the glass article 100. As can be seen, the modeled glass article 100 includes an adhesive structure 114 having a polymer support 118 disposed between first and second adhesive layers 116, 120. The first adhesive layer 116 joined the polymer support 118 to the frame surface 112, and the second adhesive layer 120 joined the glass substrate 102 to the polymer support 118.Attorney Docket No.: SP24-229PCT

[0054] For the modeled system, the glass substrate 102, first and second adhesive layers 116, 120, polymer support 118, and frame 110 were as described above, and the clamps 128 were stainless steel. The first adhesive layer 116 bonded the polymer support 118 to the frame 110 around the entire perimeter. The second adhesive layer 120 joined the glass substrate 102 to the polymer support 118 in two different configurations as shown in FIGS. 7 and 8. As shown in FIG. 7, the first condition was fully bonded around the entire perimeter to represent a glass substrate 102 that could not delaminate during HIT, and as shown in FIG. 8, the second condition was partially bonded around the perimeter with sections of adhesive on each side of the perimeter comer to simulate a glass substrate 102 that could lift from the frame 110 along the edges of the glass article 100. The glass substrate 102 has a longitudinal side 102a with a width W and a lateral side 102b with a length L. In the embodiment modeled, the longitudinal side 102a had a width W of about 277 mm, and the lateral side 102b has a length L of about 199 mm. In the quarter of the glass article 100 depicted, a first adhesive section 120a was disposed on the longitudinal side 102a of the perimeter at 72 mm from the corner, and a second adhesive section 120b was disposed on a lateral side 102b of the perimeter at 48.5 mm from the comer. The adhesive sections 120a, 120b had a length of about 6.5 mm.

[0055] FIGS. 9 and 10 depict the maximum principal stress distribution on the glass substrate during modeled HIT for the configuration shown in FIG. 7 (fully bonded). As can be seen in FIG. 9, the highest maximum principal stress was experienced on the second major surface 106 (side opposite impact) at 7.6 ms into the impact, and the peak maximum principal stress on the second major surface 106 was 1091 MPa. It can be seen from FIG. 10 that the maximum principal stress at the point of highest intrusion was 1058 MPa at a time of 9.0 ms.

[0056] FIGS. 11 and 12 depict the maximum principal stress distribution on the glass substrate during modeled HIT for the configuration shown in FIG. 8 (partially bonded). As can be seen in FIG. 11, the peak maximum principal stress was 960.6 MPa, experienced on the second major surface 106 of the glass substrate 102 at 8.7 ms into the impact. FIG. 12 provides the maximum principal stress at the point of highest intrusion, which was 946.8 MPa at a time of 9.3 ms into impact.

[0057] By comparing the impact properties for each of the adhesive bonding conditions, it can be seen that both the peak maximum principal stress and the maximum principal stress at the point of furthest intrusion were higher for the fully bonded condition (1091 MPa and 1058 MPa, respectively) where the glass substrate 102 could not delaminate than for the partially bonded condition (960.6 MPa and 946.8 MPa, respectively), in which the glass substrate 102Attorney Docket No.: SP24-229PCT could lift along the edges of the glass article 100. Based on a review of the modeled data, the inventors noted that, for the partially bonded condition, the glass was able to flex or buckle in response to impact because it was not pinned around the entire perimeter to the polymer support 118 (and thus to the frame 110).

[0058] In order to facilitate delamination of the glass substrate 102 in response to a headform impact, the adhesive structure 114 can be configured in a variety of different ways. According to a first aspect, the adhesive structure 114 bonds to the glass substrate 102 using a strong adhesive in discrete sections around the periphery of the glass substrate 102. That is, the adhesive structure 114 is not continuous between the glass substrate 102 and the frame 110. For example, the discrete sections of the adhesive structure 114 can be positioned as shown in the partial bonding condition of FIG. 8. In this context, a “strong” adhesive has a high adhesive strength, in particular relative to the intended use. In one or more embodiments, a strong adhesive has a tensile strength of greater than 1.0 MPa as measured according to ASTM D2095. For cold-bent glass articles 100, the tensile strength is, in particular, 3.0 MPa or greater as measured according to ASTM D2095. As used herein, the tensile strength of the adhesive as measured according to ASTM D2095 will be used as the measure of adhesive strength unless otherwise noted. For example, an adhesive joining a flat glass substrate 102 to a flat frame 110 does not require as high of an adhesive strength as an adhesive that must hold an elastically deformed glass substrate 102 against a curved frame 110. A strong adhesive joining the glass substrate 102 to the frame 110 in discrete sections would allow the glass substrate to bend away from the frame in response to impact by a headform (such as discussed above with respect to FIG. 8).

[0059] In one or more embodiments, the discrete sections of adhesive extend discontinuously around, for example, 5% to 50% of the perimeter of the glass substrate 102. In one or more embodiments, a midpoint of each discrete section of adhesive is positioned on the longitudinal side 102a of the glass substrate 102 a distance in a range of 0.1W to 0.4W, in particular 0.2W to 0.3W, and most particularly about 0.25W, as measured from each respective corner where the longitudinal side 102a meets the lateral side 102b. In one or more embodiments, the discrete sections of adhesive are positioned on the lateral side 102b of the glass substrate 102 a distance in a range of 0.1L to 0.4L, in particular 0.2L to 0.3L, and most particularly about 0.25L, from the comer. In one or more embodiments, each discrete section of adhesive covers 1% to 10% of the respective width or length of the longitudinal side 102a or lateral side 102b.Attorney Docket No.: SP24-229PCTIn one or more embodiments, each longitudinal side 102a or lateral side 102b includes from one to ten, in particular two to four, discrete sections of adhesive.

[0060] According to a second aspect the adhesive structure 114 bonds to the glass substrate 102 using a weak adhesive that is continuous or substantially continuous around the periphery of the glass substrate 102. That is, the adhesive structure 114 is continuous between the glass substrate 102 and the frame 110, such as is shown in the fully bonded condition of FIG. 7, or the adhesive structure 114 is substantially continuous between the glass substrate 102 and the frame 110, covering at least 80%, in particular at least 90%, of the periphery between the adhesive structure 114 and the frame 110. In this context, a “weak” adhesive has a low adhesive strength, in particular relative to the intended use. In one or more embodiments, a weak adhesive has a tensile strength of 1.0 MPa or less as measured according to ASTM D897. A weak adhesive that continuously joins the glass substrate 102 to the frame 110 around a periphery of the glass substrate would allow the glass substrate to delaminate from the frame in response to impact by a headform (such as discussed above with respect to FIGS. 2-4). Advantageously, using a weak adhesive continuously bonded to the glass substrate 102 provides sealing of the glass article 100 between the glass substrate 102 and the frame 110 to provident dust or moisture intrusion. Further, the continuous bonding between glass substrate 102 and the frame 110 provided by the weak adhesive enhances the reliability and conformity of the bond between a cold-bent glass substrate 102 and a curved frame 110.

[0061] According to a third aspect, a combination of strong adhesive and weak adhesive can be used as the adhesive structure 114 bonding the glass substrate 102 to the frame 110. For example, discrete sections of the strong adhesive can be provided discontinuously around the periphery of the glass substrate 102 with gaps between the discrete sections filled with the weak adhesive. In this way, the glass substrate 102 can delaminate in the regions where the glass substrate 102 is joined to the frame 110 with the weak adhesive. Accordingly, the adhesive structure 114 continuously bonds the glass substrate 102 to the frame 110 to provide sealing against dust intrusion and moisture and enhanced reliability for cold-bonded glass articles 100.

[0062] Commercially available adhesives have a range of adhesive strengths. For example, commercially available pressure sensitive adhesive tapes may have an adhesive strength (tensile strength as measured according to ASTM D2095) of less than 1 MPa, such as in a range of 0.3 MPa to 0.7 MPa (e.g., 0.59 MPa for VHB™ tape). Certain commercially available acrylic adhesives may have an adhesive strength of less than 3 MPa (e.g., 2.1 MPa for Scotch- Weld™ DP8610NS available from 3M Company, St. Paul, MN). Further, certainAttorney Docket No.: SP24-229PCT commercially available urethane adhesives may have an adhesive strength of 3 MPa or greater, such as in a range of 3 MPa to 8 MPa (e.g., 3.6 MPa for BETASEAL™ X2500 and 5.8 MPa for BETAMATE™ 2810SV both available from DuPont de Nemours, Inc., Wilmington, DE).

[0063] FEA was used to study the impact of adhesive strength on the delamination behavior of a glass substrate 102 as well as the stress experienced by the glass substrate 102 during HIT. In the analysis, the adhesive material was modeled as having an adhesive strength in a range from 0.5 MPa to 5 MPa at the interface between the glass substrate 102 and the adhesive structure 114. In all of the modeled cases, the adhesive structure 114 included a polymer support 118 fully bonded to the frame 110. As was determined above, in the fully bonded, no delamination condition, the peak maximum principal stress on the glass substrate was 1091 MPa.

[0064] FIG. 13 provides a table of the peak maximum principal stress on the glass substrate 102 as well as whether / how the glass substrate 102 was able to delaminate as a function of adhesive strength (0.5 MPa, 1 MPa, 2 MPa, 3.5 MPa, 4 MPa, and 5 MPa), determined by the FEA modelling. As discussed above, each of the adhesives was modelled in a fully bonded configuration. As can be seen, for the adhesives with an adhesive strength of up to 3.5 MPa, the peak maximum principal stress was reduced below 1000 MPa, in particular in a range of 934.5 MPa to 959.3 MPa. In these configurations, as shown in FIG. 13, the glass substrate was able to delaminate over all or a substantial portion of the interface between the glass substrate 102 and adhesive structure 114. Where the adhesive strength was 4 MPa or above, the peak maximum principal stress was greater than 1000 MPa, in particular 1088 MPa (i.e., substantially equal to the no delamination condition determined above). As shown in FIG. 13, there was minimal or no delamination between the glass substrate 102 and the frame 110 where the adhesive strength was 4 MPa or above.

[0065] Having determined that delamination may help enhance the reliability of the glass substrate 102 against breaking by lowering the peak maximum principal stress, an analytical method was investigated to determine how the adhesive material property (including adhesive strength and dimension factors) will affect the delamination behavior of the glass article 100 during HIT.

[0066] FIG. 14 provides an analytical structure 200 comprising a first sheet 202 and a second sheet 204 joined with an adhesive material 206. Each sheet 202, 204 is pulled in opposing directions as shown by arrows 208, 210. The adhesive sheet has a thickness (t), and theAttorney Docket No.: SP24-229PCT adhesive material has a thickness (r|). The adhesive material 206 has a bond length of 2c. According to literature, if it is assumed that the strain in jointed sheets 202, 204 is negligibly small compared with the strain in the adhesive material 206, then both the maximum normal and shear stress will be located at edge of the joint (point 212) as shown in FIG. 14. When the adhesive material 206 is relatively flexible compare with jointed sheets 202, 204, then the maximum value of shear stress (rmax) and normal stress (omax) at the edge of the joint is given by Equations 1 and 2, respectively, below:

[0067] In Equations 1 and 2, the parameters k, k’, P, y, and X are given by Equations 3-7, below: k _ 2MQpt2(3)

[0068] In Equations 1-7, the parameters E, G, Ee, and Gerepresent the Young’s modulus and shear modulus of the material of the sheets 202, 204 and of the adhesive material 206, respectively. As shown in FIG. 14, the parameters t, c, and r are dimension-related parameters of the sheets 202, 204 and of the adhesive material 206. The parameter F is the tensile force applied on the sheets 202, 204, and the parameters Mo, Vo, and p are moment, shear force, and tensile stress transmitted by the sheets to the edges of the joint.

[0069] Based on Equations 1-7, the shear and normal stress to initiate delamination between a glass substrate 102 and an adhesive structure 114 can be estimated using material data provided in a material datasheet or determined experimentally. In this way, delamination can be controlled by adjusting adhesive material dimensions or adhesive material selection, and by properly distributing the location of delamination at the interface between the glass substrateAttorney Docket No.: SP24-229PCT102 and the adhesive structure 114, the performance of the glass article 100 during HIT can be refined.

[0070] An example of utilizing the above analytical Equations 1-7 to determine the adhesive material design space is shown in FIGS. 15 and 16. In determining the design space of a glass article 100, there are many adjustable factors that will affect the behavior of adhesive material (which will then lead to the delamination) during HIT. For the example considered, the parameters of adhesive material modulus, adhesive material thickness, normal (tensile) adhesive strength, and shear adhesive strength were held constant at 0.6 MPa, 0.6 mm, 0.5 MPa, and 0.25 MPa, respectively. The elastic modulus of the glass sheets 202, 204 was also held constant at 71,000 MPa. The whole glass article 100 was modeled to be under 70 N external load. For the analysis, it was assumed that the normal adhesion strength was the delamination initiation criteria (i.e., if the normal adhesion strength was exceeded, then the glass substrate 102 would delaminate). FIG. 15 provides the relationship between the thickness (t) of the glass substrate 102 and the width (c) of the adhesive material obtained based on the analytical solution and above assumptions. That is, with all other factors held constant, the adhesive width (c) for delamination of the glass substrate 102 is the width required to cause the adhesive material to exceed the normal adhesive strength. From FIG. 15, it can be seen that the adhesive width is given by the curve shown in the graph. For example, the adhesive width is 6.25 mm for a glass substrate 102 having a thickness of 1.1 mm.

[0071] FIG. 15 alone does not necessarily establish the design space for adhesive width (i.e., higher than 6.25mm or lower than 6.25 mm) for causing delamination of the glass substrate 102 during HIT testing. FIG. 16 provides a graph of maximum adhesive normal stress as a function of adhesive width. It can be seen from FIG. 16 that the maximum normal adhesive stress exceeds the stress of 0.5 MPa for adhesive widths of 6.25 mm or less. That is, the glass substrate 102 will delaminate from the adhesive structure 114 during HIT where the width of the adhesive structure 114 is 6.25 mm or less for the glass article designed according to the parameters outlined above.

[0072] Unless otherwise expressly stated, it is in no way intended that any method set forth herein be construed as requiring that its steps be performed in a specific order. Accordingly, where a method claim does not actually recite an order to be followed by its steps or it is not otherwise specifically stated in the claims or descriptions that the steps are to be limited to a specific order, it is in no way intended that any particular order be inferred. In addition, asAttorney Docket No.: SP24-229PCT used herein, the article "a" is intended to include one or more than one component or element, and is not intended to be construed as meaning only one.

[0073] It will be apparent to those skilled in the art that various modifications and variations can be made without departing from the spirit or scope of the disclosed embodiments. Since modifications, combinations, sub-combinations and variations of the disclosed embodiments incorporating the spirit and substance of the embodiments may occur to persons skilled in the art, the disclosed embodiments should be construed to include everything within the scope of the appended claims and their equivalents.

Claims

1. Attorney Docket No.: SP24-229PCTWhat is claimed is:

1. A glass article, comprising: a glass substrate comprising a first major surface and a second major surface, the second major surface being opposite to the first major surface; a frame comprising a frame surface; an adhesive structure disposed between the glass substrate and the frame bonding the glass substrate to the frame; wherein, after impact with a headform according to FMVSS 201, the glass substrate at least partially delaminates from the adhesive structure and the glass substrate does not break across the first major surface or the second major surface.

2. The glass article of claim 1, wherein the adhesive structure comprises a first adhesive having a first tensile strength that is 1.0 MPa or less.

3. The glass article of claim 2, wherein the first adhesive comprises at least one of pressure sensitive tape or acrylic resin.

4. The glass article of claim 2 or claim 3, wherein the first adhesive extends around at least 80% of a periphery of the second major surface of the glass substrate.

5. The glass article of claim 4, wherein the first adhesive extends around the entire periphery of the second major surface of the glass substrate.

6. The glass article of claim 4, wherein the adhesive structure comprises a second adhesive having a second adhesive strength, the second adhesive strength being greater than the first adhesive strength.

7. The glass article of claim 6, wherein the second adhesive is disposed in discrete sections around the periphery of the second major surface of the glass substrate.Attorney Docket No.: SP24-229PCT8. The glass article of claim 7, wherein the periphery includes a first longitudinal side, a second longitudinal side, a first lateral side, and a second lateral side; wherein the first lateral side forms a first corner with the first longitudinal side and a second corner with the second longitudinal side and the second lateral side forms a third corner with the first longitudinal side and a fourth corner with the second longitudinal side; and wherein a respective midpoint of at least one discrete section of the plurality of discrete sections is disposed on each of the first longitudinal side, the second longitudinal side, the first lateral side, and the second lateral side in a range of 10% to 40% of a respective side length as measured from each of the first comer, the second corner, the third comer, and the fourth comer.

9. The glass article of any of claims 6-8, wherein the second adhesive comprises at least one of a urethane or an epoxy.

10. The glass article of claim 1, wherein the adhesive structure comprises a first adhesive having a first adhesive strength that is greater than 1.0 MPa.

11. The glass article of claim 10, wherein the first adhesive is disposed in a plurality of discrete sections around a periphery of the second major surface of the glass substrate.

12. The glass article of claim 11, wherein the plurality of discrete sections cover from 5% to 50% of the periphery.

13. The glass article of claim 11 or claim 12, wherein the periphery includes a first longitudinal side, a second longitudinal side, a first lateral side, and a second lateral side; wherein the first lateral side forms a first comer with the first longitudinal side and a second corner with the second longitudinal side and the second lateral side forms a third comer with the first longitudinal side and a fourth corner with the second longitudinal side; and wherein a respective midpoint of at least one discrete section of the plurality of discrete sections is disposed on each of the first longitudinal side, the second longitudinal side, the first lateral side, and the second lateral side in a range of 10% to 40% of a respective side length as measured from each of the first comer, the second corner, the third comer, and the fourth comer.Attorney Docket No.: SP24-229PCT14. The glass article of any of claims 1-13, wherein the adhesive structure comprises: a polymer support disposed between the glass substrate and the frame, the polymer support comprising a first support surface and a second support surface, the second support surface being opposite to the first support surface; a first adhesive layer disposed between the frame surface and the second support surface; and a second adhesive layer disposed between the second major surface and the first support surface.

15. The glass article of any of claims 1-14, wherein the glass substrate comprises a glass thickness between the first major surface and the second major surface, the glass thickness being 2 mm or less.

16. The glass article of any of claims 1-15, wherein the frame surface defines a curvature, wherein the adhesive structure joins the glass substrate to the frame surface such that the glass substrate is elasticaly deformed to conform to the curvature.

17. The glass article of any of claims 1-15, wherein the first major surface of the glass substrate is substantially flat.

18. A glass article, comprising: a glass substrate comprising a first major surface and a second major surface, the second major surface being opposite to the first major surface; a frame comprising a frame surface; an adhesive structure disposed between the glass substrate and the frame bonding the glass substrate to the frame; wherein the adhesive structure comprises:(i) a first adhesive having a first adhesive strength of 1.0 MPa or less that extends around an entirety of a periphery of the second major surface of the glass substrate;(ii) a second adhesive having a second adhesive strength of greater than 1.0 MPa that is disposed in a plurality of discrete sections around the periphery of the second major surface of the glass substrate; orAttorney Docket No.: SP24-229PCT(iii) a combination of the first adhesive and the second adhesive, the second adhesive being disposed in the plurality of discrete sections around the periphery of the second major surface of the glass substrate and the first adhesive extending between the plurality of discrete sections of the second adhesive such that the first adhesive and the second adhesive together extend around the entirety of the periphery of the glass substrate; and wherein, after impact with a headform according to FMVSS 201, the glass substrate at least partially delaminates from the adhesive structure and the glass substrate does not break across the first major surface or the second major surface.

19. The glass article of claim 18, wherein the first adhesive comprises at least one of pressure sensitive tape or acrylic resin.

20. The glass article of claim 18 or cliam 19, wherein the second adhesive comprises at least one of a urethane or an epoxy.

21. The glass article of any of claims 18-20, wherein the periphery includes a first longitudinal side, a second longitudinal side, a first lateral side, and a second lateral side; wherein the first lateral side forms a first comer with the first longitudinal side and a second corner with the second longitudinal side and the second lateral side forms a third comer with the first longitudinal side and a fourth corner with the second longitudinal side; and wherein a respective midpoint of at least one discrete section of the plurality of discrete sections is disposed on each of the first longitudinal side, the second longitudinal side, the first lateral side, and the second lateral side in a range of 10% to 40% of a respective side length as measured from each of the first comer, the second corner, the third comer, and the fourth comer.

22. The glass article of any of claims 18-21, wherein the glass substrate comprises a glass thickness between the first major surface and the second major surface, the glass thickness being 2 mm or less.

23. The glass article of any of claims 18-22, wherein the frame surface defines a curvature and wherein the adhesive structure joins the glass substrate to the frame such that the glass substrate elastically deforms to conform to the curvature.Attorney Docket No.: SP24-229PCT24. The glass article of any of claims 18-23, wherein the first major surface of the glass substrate is substantially flat.

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