Equipment and methods for controlling bow in laminate structures

Abstract

Various methods provide embodiments for processing a large batch of asymmetric laminates with bow, including controlling or changing a bow or curvature in laminated glass structures by configuring the laminates in a laminate assembly, heating the assembly, optionally with force, to induce a change to the curvature of the initial laminates in the assembly to a reduced or eliminated curvature / bow in the final laminate product, once the laminate assembly is cooled.

Description

Attorney Docket No. SP24-298PCTEQUIPMENT AND METHODS FOR CONTROLLING BOW IN LAMINATE STRUCTURESCROSS-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 / 726,114 filed November 27, 2024, the content of which is incorporated herein by reference in its entirety.TECHNICAL FIELD

[0002] The present invention generally relates to glass laminates having outer sheets of material with different coefficients of thermal expansion that may result in bowing.BACKGROUND

[0003] Laminate structures may be used for a wide range of applications in a variety of industries. For example, laminate structures may be used in architectural applications such as siding, decorative panels, cabinet installations, wall coverings, and the like. Laminate structures may also be used for furniture items and / or household appliances. For instance, laminate structures may be incorporated as outer panels for a cabinet, furniture item, and / or household appliance.

[0004] Automotive, transportation, aviation, and architectural windows are often made from laminate structures comprising two glass sheets of similar thickness and composition. However, for various applications it may be desirable to provide laminate structures comprising dissimilar substrates, e.g., substrates of different composition and / or thickness. For instance, metal -glass laminates, plastic-glass laminates, glass-ceramic laminates, and other similar laminates may be desirable for aesthetic or structural qualities.

[0005] In addition, glass-glass laminates comprising dissimilar glass substrates may also be desirable for various applications, for example, laminates comprising glasses having different compositions, thicknesses, and / or other properties such as coefficient of thermal expansion (CTE). By way of a non-limiting example, a thin sheet of ion-exchanged glass may be laminated on a thicker soda lime glass sheet to provide enhanced damage resistance.Attorney Docket No. SP24-298PCT Electrochromic windows and mirrors may comprise a thin, alkali-free glass substrate upon which an electrically active thin film is deposited, which may be laminated to a thicker soda lime glass substrate for enhanced structural rigidity.SUMMARY

[0006] According to an aspect of the present disclosure is a method of forming a laminated sheet of glass. The method includes positioning thermoplastic polymer material between first and second layers of glass to form a stack. The first layer of glass comprises a first glass material having a first coefficient of thermal expansion (CTE), and the second layer of glass comprises a second glass material having a second CTE, wherein the second CTE is greater than the first CTE. The polymer material is heated to a lamination temperature to soften the thermoplastic polymer material to form a stack structure. The stack structure is cooled whereby the thermoplastic polymer material hardens and forms a first sheet structure having a first curvature. The first curvature results from a difference between the first CTE and the second CTE. This is followed by heating the first sheet structure to soften the thermoplastic polymer material. The method further includes utilizing a force to change a shape of the first sheet structure while the thermoplastic polymer material is softened to thereby form a second sheet structure. The second sheet structure is cooled, whereby the thermoplastic polymer material hardens to form a laminated sheet of glass having a second curvature that is not identical to the first curvature.

[0007] 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.

[0008] 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. 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 embodiments, and together with the description serve to explain principles and operation of the various embodiments.Attorney Docket No. SP24-298PCTBRIEF DESCRIPTION OF THE DRAWINGS

[0009] In the drawings:

[0010] FIG. 1 is a partially schematic cross-sectional view of a laminate structure according to an aspect of the present disclosure;

[0011] FIG. 2 is a partially schematic cross-sectional view of the laminate structure of FIG. 1 showing expansion of the layers due to changes in temperature;

[0012] FIG. 3 is a partially schematic cross-sectional view of a laminate structure that is bowed upon cooling; and

[0013] FIG. 4 depicts various images for incorporating an embodiment of a laminate assembly, here shown is a frame with plurality of affixing members (pegs), such that the frame is configured to retain a plurality of initial laminates having bowed / out of plane distortion, in accordance with one or more aspects of the present disclosure. As shown in detail in the left, center, and right images, a frame includes a fixture devices, comer support pin, and sag / distortion limiter pins.

[0014] FIG. 5 depicts an embodiment of a laminate assembly including a rack design, configured to include a set of corner supports and central supports, where the altitude difference between the central supports and the comer supports set the sag value (e.g. the amount of movement permitted in the laminates when the are retained and processed in accordance with one or more of the present aspects. As shown, the rack design is composed of a set of corner supports and central supports, while the altitude difference between the central supports and the comer supports set the sag value. The corner supports can be punctual but to limit the optical deformation and the risk to break the laminate, the corners of the laminates are linear supports. Moreover, corner supports are configured to ease the loading and stacking of the laminates.

[0015] FIG. 6 depicts an embodiment of a frame assembly, shown as a horizontal rack design that is configured to support a plurality of laminates positioned at the comer of each, in accordance with one or more of the present aspects. As shown, a tube is inserted in two C shape supports. The first laminate is placed on the rack. Two spacers are then added, and a new tube is inserted in these C profiles. This design is a tool-free arrangement, which is a configuration of the frame to handle large quantities of laminates to be processed in the autoclave in a minimum amount of time.Attorney Docket No. SP24-298PCT

[0016] FIG. 7 is a schematic depiction of an embodiment of a frame assembly, where there is a central support provided, where the central support can be a post in a pillar form, with a plurality of interspaced holes along the height of the pillar, where the holes are configured to accept and retain a support. As a non-limiting example, the support can include a tube covered with a flexible material (e.g. rubber), and the post can be inserted into the pillar at varying heights to tailor a plurality of initial laminates to the frame, forming the laminate assembly where the initial laminates are accommodated with their initial bow / out of plane distortion, in accordance with aspects of the present disclosure.

[0017] FIG. 8 and 9 show a schematic of an embodiment of an adjustable, telescoping integral frame module that incorporates adjustable frame components to accommodate laminates of varying sizes and a pair of telescoping edge retaining frame members, so that the rack can customize and adjust to accommodate multiple laminate sizes, in accordance with aspects of the present disclosure.

[0018] FIG. 10 depicts an embodiment of a frame assembly incorporating multiple stacked sizes of the frames, such that multiple batches of varying sized laminates can be configured in laminate assembly for processing in accordance with one or more aspects of the present disclosure. Using multiple sets of comer supports enable a customized mix of sizes or SKUs on the rack and process a batch of varying sizes as one laminate assembly in accordance with one or more aspects of the present disclosure.

[0019] FIGS. 11-14 depict an alternative embodiment, a frame / rack design configured with removable spacer tubes, where the rack is configured to tilt the loaded batch of laminates, a tapered top plate for tube insertion and reconfiguration, as well as optionally cooperation with a universal support so that the frame is modular, enabling bath processing and minimal operator configuration of specific layers / frame builds.

[0020] In this embodiment, the rack is a tilted configuration composed of a series of tubes located on a radius, for example 12.5 meters. A plurality of tubes are removably insertable and connectable into a frame that is inclined by 0 to 90° (horizontal), or preferably by 30 or 45°. As shown, the first series of tubes are placed in between the two plates, and the first laminate is configured in place. Then, a second series of tubes is installed, and a second laminate is placed onto them, and multiple additional laminates are configured in this way to build out the laminate assembly. The tubes are inserted in the top plate by sliding them up in the funnel shape, and then translated vertically in the bottom plate. Some non-limiting advantages of this design include, the ability to handling different laminates sizes on theAttorney Docket No. SP24-298PCT SAME rack; separating laminates; minimizing the handling of spacers which are composed of simple tubes (covered with a silicone sleeve for example); and limiting the complexity of numerous parts and build scenarios, to avoid build variations and modifications of the laminate assembly.

[0021] Depending on the process results, the number of tubes can be limited to 13 tubes per laminate but, some of these tubes can be removed and a fewer number of tubes, like 3 tubes, could be sufficient for support, even with large laminate parts (e.g. 10x5 feet size).

[0022] These figures show 10 laminates retained in a stacked configuration in spaced relation, separated by individual tubes to form a laminate assembly. In this example, the radius of curvature defines the amount of counter bow that is applied to the laminates, which is a function of the laminated long axis (e.g. about 40 mm for 2 m, less for shorter parts, 100 mm for 3 m long parts).

[0023] FIG. 15 depicts an embodiment of a heating and cooling cycle, in accordance with one or more aspects of the present disclosure. FIG. 15 provides a non-limiting example of one such autoclave cycle; however time, temperature, and pressure may vary, depending upon the capability of the equipment, the composition of the laminate, the configuration of the laminate assembly, and the initial bow in the initial laminate, among other factors.DETAILED DESCRIPTION

[0024] In the following detailed description, for purposes of explanation and not limitation, example embodiments disclosing specific details are set forth to provide a thorough understanding of various principles of the present disclosure. However, it will be apparent to one having ordinary skill in the art, having had the benefit of the present disclosure, that the present disclosure may be practiced in other embodiments that depart from the specific details disclosed herein. Moreover, descriptions of well-known devices, methods and materials may be omitted so as not to obscure the description of various principles of the present disclosure. Finally, wherever applicable, like reference numerals refer to like elements.

[0025] Ranges can be expressed herein as from “about” one particular value, and / or to “about” another particular value. As used herein, the term “about” means that amounts, sizes, formulations, parameters, and other quantities and characteristics are not and need not be exact, but may be approximate and / or larger or smaller, as desired, reflecting tolerances,Attorney Docket No. SP24-298PCT conversion factors, rounding off, measurement error and the like, and other factors known to those of skill in the art. When the term “about” is used in describing a value or an endpoint of a range, the disclosure should be understood to include the specific value or endpoint referred to. Whether or not a numerical value or endpoint of a range in the specification recites “about,” the numerical value or endpoint of a range is intended to include two embodiments: one modified by “about,” and one not modified by “about.” It will be further understood that the endpoints of each of the ranges are significant both in relation to the other endpoint, and independently of the other endpoint.

[0026] The terms “substantial,” “substantially,” and variations thereof as used herein are intended to note that a described feature is equal or approximately equal to a value or description. For example, a “substantially planar” surface is intended to denote a surface that is planar or approximately planar. Moreover, “substantially” is intended to denote that two values are equal or approximately equal. In some embodiments, “substantially” may denote values within about 10% of each other, for example within about 5% of each other, or within about 2% of each other.

[0027] As used herein, the term “dispose” includes coating, depositing and / or forming a material onto a surface. The disposed material may constitute a layer, as defined herein. The phrase “disposed on” includes the instance of forming a material onto a surface such that the material is in direct contact with the surface and also includes the instance where the material is formed on a surface, with one or more intervening material(s) between the disposed material and the surface. The intervening material(s) may constitute a layer, as defined herein.

[0028] Directional terms as used herein - for example up, down, right, left, front, back, top, bottom - are made only with reference to the figures as drawn and / or to any specific orientation described herein and are not intended to imply absolute orientation.

[0029] 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 an order be inferred, in any respect. This holds for any possible non-express basis for interpretation, including: matters of logic with respect to arrangement of steps or operational flow; plain meaning derived from grammaticalAttorney Docket No. SP24-298PCT organization or punctuation; the number or type of embodiments described in the specification.

[0030] As used herein, the singular forms “a,” “an” and “the” include plural referents unless the context clearly dictates otherwise. Thus, for example, reference to a “component” includes embodiments having two or more such components, unless the context clearly indicates otherwise.

[0031] Laminate structures comprising dissimilar substrates may be referred to herein as "asymmetric" laminates. While asymmetric laminates may present one or more advantages as compared to symmetric laminates, these laminates can also present various challenges. For example, asymmetric laminates can comprise two or more substrates with different CTEs. During the lamination process, the substrates can be heated to a lamination temperature and subsequently cooled, e.g., to room temperature. When the laminate structure cools, the CTE mismatch between the substrates can lead to out-of-plane deflection (often referred to as "bow"). Bow in laminate structures can interfere with subsequent processing steps such as film deposition, can result in unwanted optical distortion in the final product, and / or can result in a product that is unsuitable for the intended application and / or does not meet the desired target shape.

[0032] With reference to FIG. 1, a laminated structure 1 according to an aspect of the present disclosure includes a first layer of material 2, a second layer of material 3, and a thermoplastic polymer material (“interlayer”) 4 disposed between the first layer 2 and the second layer 3. The first layer 2 may comprise a first glass material having a thickness “Tl” and second layer 3 may comprise a glass material having a second thickness “T2.” The first thickness Tl may, optionally, be less than the second thickness T2. For example, the first thickness Tl may be thin glass (e.g. 0.5 mm, or 0.7 mm, or 1 mm), and the second thickness T2 may be thick glass (e.g. about 2 mm, about 3 mm, or about 4 mm, or about 5 mm). The polymer interlayer 4 may, optionally, have a thickness “T3” that is between the thickness Tl and T2. For example, the thickness T3 may be about 2.3 mm. However, the present disclosure is not limited to specific thicknesses, and the thicknesses Tl, T2, and T3 may be larger or smaller than the examples noted above as required for a particular application.

[0033] The first layer 2 may, optionally, comprise an Architectural Technical Glass (ATG) such as EAGLE XG® available from Coming Incorporated of Coming NY. More specifically, the material of first layer 2 may comprise an Alkaline Earth Boro-Attorney Docket No. SP24-298PCT Aluminosilicate. This material may have a coefficient of thermal expansion (CTE) of about 3.2 X 10’6 / K.

[0034] The second glass of second layer 3 may, optionally, comprise a tempered soda lime glass wherein T2 is about 4 mm to about 6 mm, and wherein the glass has a CTE of about 9.2 X 10’6 / K.

[0035] The polymer interlayer 4 may comprise, for example, PVB RA41 or other suitable material. In general, the thickness, softening temperature, melting temperature, and other properties of the polymer interlayer 4 may be selected as required for a particular application.

[0036] With reference to FIG. 2, during fabrication, the polymer interlayer 4 is positioned between the first layer 2 and the second layer 3 to form an intermediate assembly or stack 10. The stack 10 is then heated to soften the polymer interlayer 4, and a force such as pressures Pl and P2 may be applied to upper and lower sides 12 and 14, respectively, of stack 10 to pretreat stack 10. Various suitable pretreatment processes are known in the art. As discussed in more detail below, several hot press operations may be utilized during the fabrication process. Following pretreatment, the stack 10 may be further heated and additional pressure Pl and P2 may be applied in one or more additional hot press steps. Various suitable hot press processes are known in the art. During the hot press operation(s), the first and second layers of glass 2 and 3 expand at different rates as shown by the arrows “El” and “E2.” It will be understood that FIG. 2 is schematic in nature. At elevated temperatures (e.g. during the hot press operations), the material of polymer interlayer 4 is soft such that minimal shear force is transmitted through polymer interlayer 4 between the first and second layers 2 and 3, respectively.

[0037] With further reference to FIG. 3, following the hot press operations, the stack 10 is allowed to cool. Due to the cooling and differences in CTE between the materials of layers 2 and 3, layers 2 and 3 contract as shown by the arrows “Cl” and “C2.” As noted above, the material of second layer 3 may have a CTE that is significantly greater than the CTE of the material of first layer 2. Upon cooling, this may result in greater contraction of layer 3 compared to layer 2, leading to a bowed initial (first) laminated sheet structure 15 as shown in FIG. 3. The initial (first) laminated sheet 15 has a convex surface 16 and a concave surface 17. As the polymer interlayer 4 cools, shear forces are transferred between layers 2 and 3 leading to the bowed shape of initial laminated sheet 15. It will be understood that the curvature of the initial laminated sheet 15 shown in FIG. 3 is exaggerated, and the actual curvature of initial laminated sheet 15 may be less than the amount shown in FIG. 3.Attorney Docket No. SP24-298PCT

[0038] In general, differential cooling of stack 10 may reduce or eliminate bow (curvature) as described in U.S. Patent No. 10,189,228, the entire contents of which are incorporated herein by reference. In general, bow may be measured per ASTM Cl 172. However, initial laminated sheet structure 15 may have at least some significant bow or out of plane deformation. In general, the first (bowed) sheet structure 15 may be formed by various known lamination processes.

[0039] According to an aspect of the present disclosure, the initial (first) laminated sheet structure 15 may be heated to soften the material of the polymer interlayer 4, and a force “F” may then be utilized to reduce the curvature of the laminated sheet structure while the polymer interlayer 4 is soft, and the polymer interlayer 4 may then be cooled while the force F is applied while the polymer interlayer 4 is allowed to cool, thereby reducing the curvature of the initial (first) laminated sheet 15 to form a final (flat) laminated structure 1 (FIG. 1). In general, the force F may comprise a pressure “P3” that is applied to convex surface 16, or the force F may be a gravitational force resulting from the mass of the sheets 2, 3, and 4. One ore more weights such as flat (first) or curved sheets of material (not shown) may also be placed on convex surface 16 while polymer material is soft due to heating, whereby the weights create or increase force F. The laminated sheet structure 15 may, optionally, have a quadrilateral perimeter with four corners, and a support 18 may be positioned at one or more of the comers of the concave lower side 14. Supports 18 support the sheet structure 15 on a surface 20 as the sheet structure 15 is heated to soften polymer interlayer 4. Supports 18 may comprise resilient blocks or other suitable structures. Also, supports 18 may comprise elongated members that extend along opposite edges 22 and 23 of intermediate structure 15. In general, supports may have virtually any size and configuration as required for a particular application.

[0040] As the polymer interlayer 4 is heated and a force F is applied, the sheet structure 15 will begin to deform due to the force F. Depending on the temperature and the amount of force F, the lower side 14 of intermediate structure or sheet 15 may become planar, or it may sag below a plane 24 whereby lower side 14 has a convex shape as shown by the dashed line 17A. The sheet structure 15 is then allowed to cool (e.g. at room temperature) while the force F is applied. During cooling, the first and second layers 2 and 3 then contract. This contraction may cause the lower side 14 to shift upwardly from the position 17A due to differences in the CTE of layers 2 and 3. The contraction may cause the lower side 14 to shiftAttorney Docket No. SP24-298PCT to a flat position shown by the dashed line 24, whereby a substantially flat final sheet 1 (FIG. 1) is produced.

[0041] One or more systems as described herein are utilized with a plurality of laminate stacks, to secure a batch of laminate stacks in a lay-up for post processing, to further reduce and / or eliminate bow in the resulting asymmetrical laminate structures.

[0042] Any conventional lamination processing can be utilized with asymmetrical laminates and the resulting bowed laminates can be post-processed with the systems and methods set forth herein to reduce and / or eliminate bow, providing asymmetrical laminate products that are within the target limits of out-of-plane distortion or bow.

[0043] In one aspect, a method of processing bowed asymmetrical laminates is provided, comprising: configuring a laminate assembly, comprising a plurality of initial laminates where at least one of the plurality of laminates exhibit bow above a threshold target and a frame assembly, where the frame assembly is configured to enable spaced, stacked retention of the initial laminates; and heating at least one laminate assembly to soften a thermoplastic polymer material between a first glass layer and a second glass layer in each of the initial laminates, whereby, via the heating, the amount of bow in the laminate stack has reduced as compared to the initial bow.

[0044] In some embodiments, the method includes cooling the laminate assembly, to harden the thermoplastic polymer material in each of the laminate stacks, thereby forming a final laminate product having a final bow, wherein the final bow is different from and / or less than the initial bow.

[0045] In some embodiments, the method includes using at least one pressure member on each initial laminate in the stacked configuration of the laminate assembly to apply force to that initial laminate and promote reduction in bow (e.g. promote gravity force to act on the initial laminate to change a first shape / curvature / out of plane distortion of the initial laminate while the thermoplastic polymer material is softened to form a second shape / curvature / out of plane distortion of the laminate product.

[0046] In some embodiments, the second CTE is at least twice the first CTE; and the first layer of glass is thinner than the second layer of glass.

[0047] In some embodiments, the second layer of glass is at least five times as thick as the first layer of glass.Attorney Docket No. SP24-298PCT

[0048] In some embodiments, the first glass material comprises an alkaline earth boro- aluminosilicate glass; the second glass material comprises soda lime glass; and the thermoplastic polymer material comprises a layer of polyvinyl butyral.

[0049] In some embodiments, the initial laminate is configured with a stack design comprising: the first layer of glass is at least 0.4 to not greater than 1.6 mm thick; the second layer of glass is at least 2 mm to not greater than 5 mm thick; and the layer of thermoplastic polymer material is at least 0.5 to not greater than 2.5 mm thick.

[0050] In some embodiments, the first glass material comprises an alkaline earth boro- aluminosilicate glass; the second glass material comprises soda lime glass; and the thermoplastic polymer material comprises a layer of polyvinyl butyral.

[0051] In one aspect, a method is provided, the method comprising a method of reducing bow of a laminated sheet of glass comprising thermoplastic polymer material between first and second layers of glass. In this embodiment, the method comprises: heating the laminated sheet structure of glass to soften the thermoplastic polymer material; utilizing a force to reduce the bow of the laminated sheet of glass while the thermoplastic polymer material is softened; and cooling the laminated sheet of glass whereby the thermoplastic polymer material hardens and the bow of the laminated sheet of glass is reduced.

[0052] In some embodiments, the spacers and / or frame components are configured with a coating or material sufficient to enable deformation but promote controlled retention and limited movement in x,y.z dimensions during laminate assembly processing.

[0053] In some embodiments, a plurality of laminate retaining members, configured with a frame end and a laminate end are utilized to retain the plurality of laminates in a laminate assembly.

[0054] In some embodiments, an H-shaped member, having a cross beam intersecting with two posts, wherein the cross beam is configured with an upper edge to retain a generally planar edge of a substrate and further wherein, the inner portion of each of the first and second post are configured with a coating or material to retain in place the edges of the substrate.

[0055] In some embodiments, the H-shaped members are configured to stack in a vertical configuration to form a ladder shape. In some embodiments, the upper and lower portions of the first and second post of each member are configured with attachment or retaining devices, to connect the upper and lower portions of each post to one another in a stacked configurationAttorney Docket No. SP24-298PCT

[0056] In some embodiments, the upper and power portions of the first and second post of each member are configured with a through-hole or via, to enable a retaining device to slide through the respective inside posts of the first and second portion of the ladder to secure the ladder shape (end caps / retaining devices to keep in stacked configuration.)

[0057] In some embodiments, the laminate retaining device is configured with adjustable components to enable sliding in an x / y direction to be resized / reconfigurable to various sized or custom shaped laminates.

[0058] In some embodiments, the frame is configured with pre-spaced holes and plurality of peg assemblies. In some embodiments, the frame is configured as a plurality of H-spacers at each edge, to enable one integral component to interspace between each layer and interconnect between layers, where the H-spacer is sufficiently thin to enable air flow and distortion / bow / movement between stacked laminate layers.

[0059] In one aspect, a process for conditioning a batch of asymmetric glass laminates (with at least some laminates exhibiting bow or out of plane distortion), the method comprising: configuring a plurality of initial laminates in a stacked, spaced configuration with a frame to define an laminate assembly; and heating the laminate assembly for a sufficient time, temperature, and pressure (e.g. an autoclave at about 140° C, at about 180 psi for about 45 minutes).

[0060] Optionally, controlled cooling to provide the final laminate products. Given the frame configuration variations, the laminates can retain the plurality of laminates in various positions and / or angles, including: configuring the laminate assembly in a horizontal position; configuring the laminate assembly in a vertical position; and / or configuring the laminate assembly in an angled position. In some embodiments, the frame is configured with adjustable positions, to enable spacing configured to enable movement of the initial laminate and accommodate the initial bow in the initial laminate, while mitigating contact with adjacent initial laminates during configuration of the stacked array and / or during processing.

[0061] The present disclosure is not limited to any specific materials for the frame, or sizes, provided the frame is configured to undergo heating and processing in laminate assembly configuration. In some embodiments, heating can be completed in an oven or other device to suitably reheat the laminate assembly.

[0062] Numerous conventional lamination processes may result in initial laminates having bow or out of plane distortion that renders them unsuitable for commercial applications in architecture other areas. With one or more embodiments of the present disclosure, the initialAttorney Docket No. SP24-298PCT bow in the initial laminates can be reduced and / or eliminated, increasing yield rates and improving the through-put of lamination (with the understanding that bow need not be mitigated in initial lamination, as batch processing for removing bow from initial laminates can be completed, according to the present disclosure.

[0063] In some embodiments, cooling of the laminate assembly can occur in a cooling press or at room temperature.

[0064] An aspect of the present disclosure is post-processing of asymmetrical glass laminates to reduce or eliminate bow that may result from an initial lamination process. The process (post-processing) may be beneficial if the laminate includes glass materials having different coefficients of thermal expansion that result in bowing of the laminate after the initial laminate fabrication process. In general, the polymer material (interlayer) is allowed to cool during the initial processing, thereby forming a bowed laminate upon cooling of the thermoplastic polymer material of interlayer 4. The bowed laminate is then heated to soften the thermoplastic polymer material of interlayer 4, and pressure or force may be applied while the polymer is softened to thereby reduce or eliminate the bow, and the laminate is again cooled. The laminate may optionally be cooled while the pressure or force is being applied, whereby the polymer interlayer 4 again hardens and forms a final laminate that is flat (planar) or substantially flat. The resulting laminated structure may be utilized in architectural windows for buildings or other such structures.

[0065] The present disclosure is not, however, limited to forming final laminated structures that are planar. For example, if a curved laminate is required for a particular application, the initial lamination process may be utilized to form a laminated structure having an initial curvature. The curved laminate may then be heated, and pressure may be applied to either increase or decrease the curvature as required to form a non-planar final laminate structure having a desired degree of bow or curvature, wherein the final (desired) bow / curvature is non-zero.

[0066] Many variations and modifications may be made to the above-described embodiments / aspects of the disclosure without departing substantially from the spirit and various principles of the disclosure. All such modifications and variations are intended to be included herein within the scope of this disclosure and protected by the following claims.

Claims

Attorney Docket No. SP24-298PCTClaims:What is claimed is:

1. A method of processing bowed asymmetrical laminates, comprising: configuring a laminate assembly, comprising a plurality of initial laminates where at least one of the plurality of laminates exhibit bow above a threshold target and a frame assembly, where the frame assembly is configured to enable spaced, stacked retention of the initial laminates; and heating at least one laminate assembly to soften a thermoplastic polymer material between a first glass layer and a second glass layer in each of the initial laminates, whereby, via the heating, the amount of bow in the laminate stack has reduced as compared to the initial bow.

2. The method of claim 1, further comprising cooling the laminate assembly, to harden the thermoplastic polymer material in each of the laminate stacks, thereby forming a final laminate product having a final bow, wherein the final bow is different from and / or less than the initial bow.

3. The method of claim 1, further comprising using at least one pressure member on each initial laminate in the stacked configuration of the laminate assembly to apply force to that initial laminate and promote reduction in bow (e.g. promote gravity force to act on the initial laminate to change a first shape / curvature / out of plane distortion of the initial laminate while the thermoplastic polymer material is softened to form a second shape / curvature / out of plane distortion of the laminate product.

4. The method of claim 1, wherein: the second CTE is at least twice the first CTE; and the first layer of glass is thinner than the second layer of glass.

5. The method of claim 1, wherein: the second layer of glass is at least five times as thick as the first layer of glass.

6. The method of claim 1, wherein:Attorney Docket No. SP24-298PCT the first glass material comprises an alkaline earth boro-aluminosilicate glass; the second glass material comprises soda lime glass; and the thermoplastic polymer material comprises a layer of polyvinyl butyral.

7. The method of claim 1, wherein each initial laminate is configured with a stack design comprising: the first layer of glass is at least 0.4 to not greater than 1.6 mm thick; the second layer of glass is at least 2 mm to not greater than 5 mm thick; and the layer of thermoplastic polymer material is at least 0.5 to not greater than 2.5 mm thick.

8. The method of claim 1, wherein: the first glass material comprises an alkaline earth boro-aluminosilicate glass; the second glass material comprises soda lime glass; and the thermoplastic polymer material comprises a layer of polyvinyl butyral.

9. A method of reducing bow of a laminated sheet of glass comprising thermoplastic polymer material between first and second layers of glass, the method comprising: heating the laminated sheet structure of glass to soften the thermoplastic polymer material; utilizing a force to reduce the bow of the laminated sheet of glass while the thermoplastic polymer material is softened; cooling the laminated sheet of glass whereby the thermoplastic polymer material hardens and the bow of the laminated sheet of glass is reduced.

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