Microstructured foam rolls

Abstract

The present disclosure is directed to a multilayer foam material comprising a foam layer, a support layer, an adhesive layer, and a liner, in that order. The disclosure is also directed to rolls comprising the multilayer foam material, including level wound rolls. The multilayer foam material and the rolls made therefrom are useful in various applications, such as tapes for materials used inside battery modules or battery packs, and other applications that require precise placement of materials.

Description

PA103145W002MICROSTRUCTURED FOAM ROUES

[0001] The present disclosure is directed to a multilayer foam material comprising a foam layer, a support layer, an adhesive layer, and a liner, in that order. The disclosure is also directed to rolls comprising the multilayer foam material, including level wound or planetary rolls. The multilayer foam material and the rolls made therefrom are useful in various applications, such as tapes for materials placed inside battery modules or battery packs, and other applications that require precise placement of materials.BACKGROUND

[0002] In battery assembly manufacturing, the precise placement of certain materials, such as cushioning foams, is essential for maintaining the performance and longevity of battery cells. The process demands placement rates faster than one part per second in order for the process to remain economically viable. Cushioning foam exerts pressure on the battery when installed, and only certain locations on prismatic cells can tolerate this pressure without decreasing performance.

[0003] Traditional pick-and-place systems, commonly used in manufacturing, often lack the precision required for handling soft, flexible cushioning materials. These systems struggle to place cushioning foam accurately within the tight tolerances needed.

[0004] Additionally, it is important during assembly that the cushioning material remains firmly attached between adjoining battery cells to prevent movement during cell stacking into an array. The foam material must adhere sufficiently to the adjoining cell to allow movement of the assembled cell array without any relative motion of the foam material. This type of stability is needed to maintain the structural integrity and long term performance of the battery pack.

[0005] Economic considerations are also significant in the manufacturing process. Minimizing the number of steps in the fabrication and assembly of the cushioning foam is preferred to decrease costs. Inline fabrication of the cushioning foam, as opposed to secondary offline die-cutting or fabrication steps, offers advantages in terms of cost and efficiency.

[0006] Overall, the field of battery assembly manufacturing faces challenges in achieving precise, high-speed placement of cushioning foam materials, ensuring firm attachment during cell stacking, and balancing the cushioning force exerted on battery cells. Consequently, there is a need for materials and methods that allow for the direct application of flexible materials to the battery with high precision. Those needs are addressed by the materials and methods described in the present disclosure.SUMMARY

[0007] The present description relates to materials and methods that address the need for precise placement and firm attachment of articles in certain environments where placement stability is important for maintaining performance of certain components. Although the present description refers to materials and methods for the placement of cushioning materials in certain processes, such as battery assembly manufacturing, the present materials and methods are suitable for the manufacture of rolls of tape forapplications in other fields. For instance, the present materials and methods can be used in any environment where precision placement of a tape from a wound roll is needed. Examples of other applications outside of battery assembly such as gasketing & sealing, noise & vibration solutions, and impact absorber applications.

[0008] The present description relates to a foam roll that includes a multilayer foam material designed for fast application to substrates. The multilayer foam material has a microstructured foam layer, a support layer with a specified minimum thickness adjacent, preferably immediately adjacent, to the foam layer, and a high shear-strength adhesive layer with a significant loop tack adjacent, preferably immediately adjacent, to the support layer. In certain preferred embodiments, the foam roll includes a liner adjacent, preferably immediately adjacent, to the adhesive layer.

[0009] All scientific and technical terms used herein have meanings commonly used in the art unless otherwise specified. The definitions provided herein are to facilitate understanding of certain terms used frequently in this application and are not meant to exclude a reasonable interpretation of those terms in the context of the present disclosure.

[0010] Unless otherwise indicated, all numbers in the description and the claims expressing feature sizes, amounts, and physical properties used in the specification and claims are to be understood as being modified in all instances by the term “about.” Accordingly, unless indicated to the contrary, the numerical parameters set forth in the foregoing specification and attached claims are approximations that can vary depending upon the desired properties sought to be obtained by those skilled in the art utilizing the teachings disclosed herein. At the very least, and not as an attempt to limit the application of the doctrine of equivalents to the scope of the claims, each numerical parameter should at least be construed in light of the number of reported significant digits and by applying ordinary rounding techniques. Notwithstanding that the numerical ranges and parameters setting forth the broad scope of the invention are approximations, the numerical values set forth in the specific examples are reported as precisely as possible. Any numerical value, however, inherently contains certain errors necessarily resulting from the standard deviations found in their respective testing measurements.

[0011] The recitation of numerical ranges by endpoints includes all numbers subsumed within that range (e.g. a range from 1 to 5 includes, for instance, 1, 1.5, 2, 2.75, 3, 3.80, 4, and 5) and any range within that range.

[0012] As used in this specification and the appended claims, the singular forms “a”, “an”, and “the” encompass embodiments having plural referents, unless the content clearly dictates otherwise. As used in this specification and the appended claims, the term “or” is generally employed in its sense including “and / or” unless the content clearly dictates otherwise.

[0013] The term “adjacent” refers to the relative position of two elements, such as, for example, two layers, that are close to each other and may or may not be necessarily in contact with each other or that may have one or more layers separating the two elements as understood by the context in which “adjacent” appears.

[0014] The term “immediately adjacent” refers to the relative position of two elements, such as, for example, two layers, that are next to each other and in contact with each other and have no intermediate layers separating the two elements. The term “immediately adjacent,” however, encompasses situations where one or both elements (e.g., layers) have been treated with a primer, or whose surface has been modified to affect the properties thereof, such as etching, embossing, etc., or has been modified by surface treatments, such as corona or plasma treatment, etc. that may improve adhesion.

[0015] The term “substantially circular shape” refers to a shape that can fit within two concentric circles when the outer circle has a diameter 50% greater than the inner circle. In some embodiments, the difference between the outer and inner diameters is 15 microns. For instance, a substantially circular shape for the microstructures is a shape that fits within two concentric circles when the outer diameter is 40 microns and the inner diameter is 10 microns. This definition allows for the measurement of the diameter in cases where the shape may have irregularities or deviations from a perfect circle.

[0016] In the context of a substantially circular shape, the “diameter” of the shape is the longest straight-line distance between two points on the outline of the shape wherein the shape is aligned with a horizontal plane. This measurement represents the maximum width of the shape. An average diameter is obtained by the arithmetic average of 20 measurements.

[0017] The term “substantially spherical” in the context of a cell within a foam material refers to a shape that can fit within two concentric spheres when the outer sphere has a diameter 50% greater than the inner sphere. In some embodiments, the difference between the outer and inner diameters is 15 microns. This definition allows for the measurement of the diameter in cases where the cell may have irregularities or deviations from a perfect sphere.

[0018] In the context of a substantially spherical cell, the “diameter” of the cell is measured by averaging the cell diameter measured from a cross-sectional slice of the foam embodiment as described in detail in the Examples section. An average diameter is obtained by the arithmetic average of 20 measurements.

[0019] In the context of microstructures on a surface, a "non-repeating pattern" refers to an arrangement of microstructures that do not exhibit regular, periodic repetition. Unlike a repeating pattern, where the same geometric shapes or structures are consistently spaced and oriented in a predictable manner, a non-repeating pattern is characterized by irregularity and randomness in the placement and size of the microstructures. That is, the distances between individual microstructures vary, with no consistent interval or alignment, and, although the microstructures can be considered to have a substantial circular shape when viewed from a top plane, the microstructures differ in their spatial dimensions.

[0020] The term “loop tack” refers to the initial tack or stickiness of an adhesive surface when it first come into contact with another surface. A loop tack value is measured as described in the experimental section following ASTM method at D6195 at 20” / min.

[0021] The term “shear strength” of an adhesive bond between two surfaces as measured under the overlap shear test refers to the maximum stress that an adhesive bond can withstand when subjected to shear forces. These forces act parallel to the plane of the adhesive bond, causing the bonded surfaces toslide relative to each other. The overlap shear test is measured following method ASTM DI 002 as described in the Examples section.

[0022] The term “roll” refers to an item having a core around which a flexible material is wound. In the context of the present disclosure, the flexible material is preferably a multilayer foam material. Typically, a roll allows for convenient storage, handling, and dispensing of the flexible material, e.g., the multilayer foam material.

[0023] The term “level-wound roll” refers to roll in which the material is wound in a helical manner such that each layer is aligned and substantially evenly distributed across the width of the core or spool. This results in a uniform roll with parallel layers, minimizing gaps and overlaps.

[0024] The term “satellite roll” refers to a roll in which the material is wound directly on a core or spool from a wider roll (a planetary roll) that is being slit into smaller rolls. In a satellite roll, the width of the material being wound is typically the same as the width of the core onto which it is being wound.

[0025] In the context of cavities on a surface, the term “maximum depth” of a cavity or depression on the surface of a foam material refers to the greatest vertical distance measured from a reference plane on the surface of the foam material to the lowest point within the cavity or depression. This measurement is taken along a line perpendicular to the reference plane. Maximum depth is measured as described in the Examples below.

[0026] A surface is considered “not tacky to the touch” if, when a human finger is pressed against the surface and then removed, the surface does not exhibit any adhesion to the finger. Specifically, the surface does not feel sticky, and there is no residue or resistance felt upon removal of the finger. For purposes of this determination, the human finger can be considered to have a surface roughness (Ra) greater than 90 microns when measured across contiguous lines of a fingerprint.

[0027] The term “surface roughness (Ra)” refers to the arithmetic average roughness over 10 separate linear measurements as described in the Example section. Surface roughness is a measurement of the average difference between the peaks and valleys of a surface

[0028] The term “closed-cell foam structure” in the context of a foam material refers to a material comprising cells, or bubble, completely enclosed by its walls and not connected to other cells.BRIEF DESCRIPTION OF THE DRAWINGS

[0029] FIG. 1 shows an exemplary embodiment of a multilayer foam material of the present disclosure.

[0030] FIG. 2 shows a diagram for the preparation of an array of battery cells comprising the multilayer foam material of the present disclosure.

[0031] FIG. 3 shows a micrograph of a portion of a microstructured surface of this disclosure.

[0032] FIG. 4 shows a micrograph of a portion of a regular foam surface, without identifiable microstructures or cavities.

[0033] FIG. 5 shows a micrograph of a microstructured surface having cavities.

[0034] FIG. 6 shows a representation of the depth of cavities within a microstructured surface.

[0035] FIG. 7 shows a compression force to deflection graph for a multilayer foam material of this disclosure.

[0036] FIG. 8 shows a plot of shear force vs displacement for a multilayer foam material of the present disclosure.DETAILED DESCRIPTION

[0037] The present description relates to a foam roll that includes a multilayer foam material designed for fast application to substrates, while maintaining precision placement. The multilayer foam material has unique properties that provide cushioning, support, and distinctive adhesive properties that make this material especially suitable for use in automated processes that require precision placement and robust attachment to the substrate.

[0038] The multilayer foam material has a foam layer, a support layer with a specified minimum thickness adjacent, preferably immediately adjacent, to the foam layer, and a high shear-strength adhesive layer with a significant loop tack adjacent, preferably immediately adjacent, to the support layer. In certain preferred embodiments, the foam roll includes a liner adjacent, preferably immediately adjacent, to the adhesive layer.

[0039] The foam layer has a microstructured surface in a non-repeating pattern that is non-tacky to the touch but has adhesiveness towards a surface that has a surface roughness of less than 0.7 microns. In preferred embodiments, the multilayer foam material is wound into a roll for ease of use and application, and does not include a liner on the microstructured surface.

[0040] Multilayer Foam Material

[0041] FIG. 1 shows an embodiment of the multilayer foam material. A first surface on the foam layer (110) is a microstructured surface (120) featuring ruptured closed cells, which provide nonchemical adhesion to other surfaces. Immediately adjacent to the second surface of the foam layer is a support layer (130), which enables the foam layer to maintain its dimensions during tensioning. A high shear strength adhesive layer (140) is immediately adjacent the support layer, offering adhesion to the substrate to facilitate tensioning and increase application of the multilayer foam material to a substrate (not shown). Finally, the release liner (150,) optional but preferred, is immediately adjacent to the adhesive layer. The liner protects the adhesive layer until it is ready for application, preserving its integrity.

[0042] In a preferred embodiment, the multilayer foam material is wound into a roll, and in a most preferred embodiment, the multilayer foam material is wound into a level-wound roll.

[0043] Foam Laver

[0044] The foam layer provides cushioning, certain structural support to the multilayer foam material, and a microstructure adhesive surface that is non-tacky to the touch. The foam layer may be made out of polyurethane, silicone, or acrylic materials.

[0045] In general, the foam layer is made of polymer matrix comprising voids, also known as “cells,” typically in an amount of at least 5% by volume, typically from 10% to 95% by volume or from 60% to 90% by volume. The cells of the present foam layer are closed, which means that the cells arecompletely enclosed by their walls and not connected to other cells. In other embodiments not exemplified here, the cells may be reticulated or partially reticulated either by chemical means or crushing. The cells may be obtained by any of the known methods such as using a gas or other foaming agents. Alternatively, the cells may result from the incorporation of hollow fillers, such as hollow polymeric particles, hollow glass or hollow ceramic microspheres.

[0046] In a typical aspect, the foam layer for use herein, comprises a polymer base material selected from the group chosen from polyacrylates, polyurethanes, polyolefins, polystyrenes, polyvinyls, silicones, natural rubbers, synthetic rubbers, polyvinylpyrrolidone, and any combinations, copolymers, or mixtures thereof. In preferred embodiments, the foam layer comprises a polymer base material selected from the group chosen from polyurethanes, silicones, and polyacrylates, and any combinations, copolymers, or mixtures thereof. In more preferred embodiments, the polymeric foam layer comprises a polymer base material chosen from polyurethanes and polyacrylates, and any combinations, copolymers or mixtures thereof.

[0047] The foam layer comprises two distinct types of cells: “central” cells and “surface” closed cells. The central cells are located around the center of the foam layer in the thickness direction. Central cells may be closed or open and form the core of the foam layer and are characterized by their larger size compared to the cells near the surface. The central cells have an average diameter greater than 100 microns, with some cells reaching greater than 300 microns in diameter.

[0048] Without being limited to theory, the larger size of the central closed cells allows them to act as the primary cushioning component of the foam layer. They provide significant volume and resilience, enabling the foam to compress under load and recover effectively when the pressure is removed. This characteristic is particularly beneficial in applications where the multilayer foam material needs to accommodate and distribute substantial forces, such as in battery cell cushioning when battery cells expand and contract during the charging and discharging processes.

[0049] The surface closed cells are located at least within 50 microns of the foam layer's surface that features the microstructures, but they may also be located at distances greater than 50 microns from the surface. These cells are smaller in size compared to the central cells and are distributed more densely near the surface. The surface closed cells have an average diameter smaller than 100 microns, with specific embodiments having diameters smaller than 100 microns, smaller than 80 microns, or even smaller than 50 microns.

[0050] These surface cells contribute to the creation of a non-repeating pattern of microstructures on the foam’s surface. As these cells rupture or partially collapse during the manufacturing process, they form cavities on the foam's first major surface. This microstructured surface provides adhesion and prevents relative motion of the multilayer foam material when applied to smooth surfaces. Unlike central cells, which are typical of known foam layers, the microstructured surface of the foam layer is a unique characteristic of the present foam layer.

[0051] The microstructured surface has adhesive properties but is not tacky to the touch. The adhesiveness of the microstructured surface is inherently non-chemical, meaning it does not rely onchemical adhesives to bond with other surfaces. This unique property allows the microstructured surface to adhere effectively without the need for any activation methods such as heat, pressure, or other forms of treatment.

[0052] Without being limited to theory, the present inventors discovered that the adhesiveness of the microstructured surface is primarily attributed to the vacuum effect created between the cavities of the microstructures and the substrate to which they are adhered. When the foam layer is applied with force to a surface, the microstructures form tiny, enclosed spaces with the substrate that create a vacuum. This vacuum generates a suction force that enhances the adhesion between the foam layer and the substrate. This mechanism allows the foam layer to adhere sufficiently to the substrate to prevent the multilayer foam material from sliding or moving out of place.

[0053] The present inventors have discovered that the microstructured surface of this disclosure will show adhesion to surfaces that have a surface roughness of less than 0.7 microns. The microstructured surface is referred to in some embodiments in the claims as the first major surface of the foam layer. In one embodiment, the microstructured surface exhibits a shear strength of at least 25 KPa when applied against a surface with a roughness of less than 0.7 microns.

[0054] In a most preferred embodiment, the microstructures are cavities that can have various shapes and sizes, with some having a substantially circular shape when viewed from the top. The depth of these cavities ranges from 1.5 microns to 30 microns, with specific embodiments having depths from 2 microns to 10 microns or even 2 microns to 5 microns. The diameter of the cavities can range from 5 microns to 75 microns, with certain embodiments specifying diameters from 10 microns to 40 microns or 20 microns to 30 microns.

[0055] In preferred embodiments, the portion of the microstructured surface that lacks microstructures is smooth. The microstructured surface in areas where there are no microstructures has a maximum surface roughness (Ra) of less than 1 micron. In preferred embodiments, the maximum surface roughness of those regions is less than 0.4 microns.

[0056] The microstructured surface of the foam layer is characterized by a certain density of microstructures, with the number of microstructures ranging from 40 to 225 per square millimeter (mm2,) 60 to 200 microstructures per mm2, or even from 100 to 150 microstructures per mm2in other embodiments.

[0057] Support Layer

[0058] The support layer in the multilayer foam material provides structural integrity and dimensional stability to the foam layer. In preferred embodiments, the support layer is positioned immediately adjacent to the foam layer, typically has a thickness greater than 0.25 mils (6.35 microns). The choice of material for the support layer is not particularly limited, allowing for a wide range of known materials to be utilized, including polyester, polypropylene, polyolefin, coated polyvinyl chloride, polyethylene terephthalate (PET), polyethylene terephthalate glycol (PETG), polyimide, polycarbonate, ethylene vinyl acetate, thermoplastic polyurethane, and various combinations thereof.

[0059] The support layer may have a range of thicknesses to accommodate various application needs. In general, the support layer has a thickness greater than 0.25 mils. In one embodiment, the support layer has a thickness from 0.25 mils to 5 mils, or from 0.25 mils to 2 mils, or from 0.25 mils to 1.25 mils. In other embodiments, the support layer may have a thickness from 0.3 mils to 1.1 mils.

[0060] In specific embodiments, the support layer can have a thickness of about 0.5 mils. Alternatively, the support layer may have a thickness of about 1.0 mils.

[0061] The inventors have discovered that the presence of the support layer provides unexpected benefits on the performance of the multilayer foam material. For example, compare the results of Comparative Example 3 (CE3), which did not have a support layer, with the results of Examples 1, 2, & 3 (EXI, EX2 and EX3) shown on Tables 4 and 5 in the Examples section. Even though CE3 had microstructures similar to those of EXI, EX2, & EX3 (Table 4), the shear strength of CE3 is about 19 kPa, which is not sufficient for a suitable bond with the desired substrate (Table 5).

[0062] This property is also on display in FIG. 8, which compares the shear strength performance of two types of multilayer foam materials: one with a support layer and one without. The graph clearly demonstrates that the multilayer foam materials with a support layer (represented by the solid lines in the figure) exhibit superior performance to the multilayer foam material without a support layer. These supported multilayer foam materials can withstand a shear force exceeding 25 kPa at significant lower displacement before experiencing delamination or breaking. In contrast, multilayer foam materials without a support layer (represented by the dashed lines) show a significantly lower shear strength, and markedly longer displacement, before breaking or tearing at less than 20kPa.

[0063] This property of supported multilayer foam materials indicates a higher resistance to shear stress than multilayer foam materials without a support layer, even though both materials have similar microstructures on their respective surfaces.

[0064] Adhesive Layer

[0065] In preferred embodiments, the adhesive layer is immediately adjacent to the support layer and is designed to provide high initial shear strength, facilitating effective tensioning and application of the multilayer foam material. The choice of adhesive for this layer is not particularly limited, allowing for a wide range of known adhesives to be utilized based on specific application requirements.

[0066] In some embodiments, the adhesive used is a pressure sensitive adhesive (PSA.) Common adhesives include acrylic, rubber, and various combinations thereof. In preferred embodiments, the PSA is an acrylic PSA.

[0067] Liner

[0068] The liner of the foam roll protects the adhesive layer and maintains the integrity of the multilayer foam material until it is ready for application. The liner is not particularly limited and is typically made from materials such as silicone-coated paper, polyethylene, or other release-coated substrates. The liner ensures that the adhesive layer remains uncontaminated and retains its tackiness until the tape is ready to be used. The liner is positioned immediately adjacent to the adhesive layer, providing a barrier that prevents premature adhesion and facilitates easy handling and storage of the foamroll. When the foam roll is ready to be applied, the liner can be easily removed by automated equipment, exposing the adhesive layer for immediate bonding to the target surface.

[0069] The surface roughness of the side of the liner that is in direct contact (immediately adjacent) to the microstructured surface is high enough that the microstructured surface has lower adhesion to the back side of the release liner than the adhesive has to the release liner. In some embodiments, the surface roughness of the side of the liner that is in direct contact (immediately adjacent) to the microstructured surface has a surface roughness greater than 0.7 microns.

[0070] Rolls of multilayer foam material

[0071] The multilayer foam material is typically manufactured in the form of a tape, which is then wound into a roll for convenient handling, storage, and application. This tape format allows for precise and controlled application of the foam material to various substrates. Typically, the foam tape comprises a foam layer with a microstructured surface, a support layer, an adhesive layer, and a protective liner. Preferably, the foam tape is wound into a level-wound roll.

[0072] In one embodiment, the first major surface of the foam layer serves as the outermost surface of the multilayer foam material and a liner is present on the adhesive layer, on the opposite major surface of the multilayer foam material. This configuration eliminates the need for an additional liner immediately adjacent to the first major surface and prevents a double liner composite effect. This allows the tape to be fabricated in lengths that would otherwise would not be possible with double-liner tape. Moreover, the single liner and double adhesive configuration enable the rolling of thick cross-sectional materials without causing the foam tape to buckle, maintaining the integrity and performance of the tape.

[0073] The roll can be available in various lengths to accommodate different application needs, with options including lengths greater than 200 meters, and ranges from 200 meters to greater than 2km, and from 300 meters to 650 meters

[0074] FIG. 2 shows the process to create an array of battery cells with the foam roll integrated between them. Initially, the multilayer foam material is provided in roll at the required part width. The applicator first removes the release liner, exposing the adhesive layer. Under tension, the applicator then applies the foam to the battery cells, ensuring precision placement. The foam tape is cut to the desired length at the application point, adhering firmly to the battery cells. Once the foam is applied to each battery cell, the cells are stacked into an array.

[0075] When the battery cells are being placed inside the battery pack enclosure, the microstructured surface of the foam layer adheres to the surface of the next battery cell, preventing the relative motion of each battery cell.

[0076] EXEMPLARY EMBODIMENTS1. A foam roll, comprising a multilayer foam material, the multilayer foam material comprising: a foam layer, a support layer immediately adjacent the foam layer having a thickness greater than 0.25 mils (6.35 microns),an adhesive layer immediately adjacent the support layer, having a loop tack greater than 10Ibf / in (1.8 N / mm); a liner immediately adjacent the adhesive layer, wherein the foam layer has a first major surface and an opposing second major surface, wherein at least a portion of the first major surface of the foam layer is microstructured comprising microstructures in a non-repeating pattern, and wherein the multilayer foam material is wound in a roll. A foam roll, comprising a multilayer foam material, the multilayer foam material comprising: a foam layer, a support layer immediately adjacent the foam layer having a thickness greater than 0.25 mils(6.35 microns), an adhesive layer immediately adjacent the support layer, having a loop tack greater than 10Ibf / in (1.8 N / mm); a liner immediately adjacent the adhesive layer, wherein the foam layer has a first major surface and an opposing second major surface, wherein at least a portion of the first major surface of the foam layer is microstructured comprising microstructures in a non-repeating pattern, and wherein the multilayer foam material is wound in a roll, wherein the microstructures are cavities. A foam roll, comprising a multilayer foam material, the multilayer foam material comprising: a foam layer, a support layer immediately adjacent the foam layer having a thickness greater than 0.25 mils(6.35 microns), an adhesive layer immediately adjacent the support layer, having a loop tack greater than 10Ibf / in (1.8 N / mm); a liner immediately adjacent the adhesive layer, wherein the foam layer has a first major surface and an opposing second major surface, wherein at least a portion of the first major surface of the foam layer is microstructured comprising microstructures in a non-repeating pattern, wherein the multilayer foam material is wound in a roll, and wherein the multilayer foam material has no liner immediately adjacent to the first major surface of the foam layer and the first major surface of the foam layer is an outermost surface of the multilayer foam material. A foam roll, comprising a multilayer foam material, the multilayer foam material comprising: a foam layer, a support layer immediately adjacent the foam layer having a thickness greater than 0.25 mils (6.35 microns),an adhesive layer immediately adjacent the support layer, having a loop tack greater than 10Ibf / in (1.8 N / mm); a liner immediately adjacent the adhesive layer, wherein the foam layer has a first major surface and an opposing second major surface, wherein at least a portion of the first major surface of the foam layer is microstructured comprising microstructures in a non-repeating pattern, and wherein the multilayer foam material is wound in a roll, and wherein the microstructures are cavities, wherein the multilayer foam material has no liner immediately adjacent to the first major surface of the foam layer and the first major surface of the foam layer is an outermost surface of the multilayer foam material. A foam roll according to any of the preceding claims, wherein the microstructures are cavities. A foam roll according to any of the preceding claims, wherein the microstructures are cavities and at least some of the cavities have a substantially circular shape when viewed from a top view. A foam roll according to any of the preceding claims, wherein the microstructures are cavities and at least some of the cavities have a maximum depth from 1.5 microns to 30 microns. A foam roll according to any of the preceding claims, wherein the microstructures are cavities and at least some of the cavities have a maximum depth from 2 microns to 10 microns. A foam roll according to any of the preceding claims, wherein the microstructures are cavities and at least some of the cavities have a maximum depth from 2 microns to 5 microns. A foam roll according to any of the preceding claims, wherein the microstructures are cavities and at least some of the cavities have a diameter from 5 microns to 75 microns. A foam roll according to any of the preceding claims, wherein the microstructures are cavities and at least some of the cavities have a diameter from 10 microns to 40 microns. A foam roll according to any of the preceding claims, wherein the microstructures are cavities and at least some of the cavities have a diameter from 15microns to 25microns. A foam roll according to any of the preceding claims, wherein the first major surface of the foam layer is not tacky to the touch. A foam roll according to any of the preceding claims, wherein the first major surface of the foam layer is not tacky to the touch and has a shear strength of at least 25 KPa against a surface having a surface roughness of less than 0.7 microns. A foam roll according to any of the preceding claims, wherein the first major surface of the foam layer is an outermost surface of the multilayer foam material. A foam roll according to any of the preceding claims, wherein the multilayer foam material has no liner immediately adjacent to the first major surface of the foam layer and the first major surface of the foam layer is an outermost surface of the multilayer foam material.-I lA foam roll according to any of the preceding claims, wherein the first major surface of the foam layer, excluding the microstructures (i.e., in a portion of the surface where there is no microstructure) has a maximum surface roughness, Ra, of less than 0.05 microns. A foam roll according to any of the preceding claims, wherein the first major surface of the foam layer, excluding the microstructures (i.e., in a portion of the surface where there is no microstructure) has a maximum surface roughness, Ra, of less than 0.1 micron. A foam roll according to any of the preceding claims, wherein the first major surface of the foam layer has from 40 to 225 microstructures per mm2. A foam roll according to any of the preceding claims, wherein the first major surface of the foam layer has from 60 to 200 microstructures per mm2. A foam roll according to any of the preceding claims, wherein the first major surface of the foam layer has from 100 to 150 microstructures per mmA A foam roll according to any of the preceding claims, wherein the microstructures are cavities and the cavities are a ruptured closed cell on the surface of the foam layer. A foam roll according to any of the preceding claims, wherein the foam layer has a cell foam structure comprising a plurality of closed cells. A foam roll according to any of the preceding claims, wherein the foam layer has a cell foam structure comprising a plurality of substantially spherical closed cells. A foam roll according to any of the preceding claims, wherein the foam layer has a cell foam structure comprising a plurality of substantially spherical closed cells; wherein cells around the center of the multilayer foam material in the thickness direction have an average diameter larger than cells located within 50 microns of the surface that has the microstructures. A foam roll according to any of the preceding claims, wherein the foam layer has a cell foam structure comprising a plurality of substantially spherical closed cells; wherein cells around the center of the multilayer foam material in the thickness direction have an average diameter greater than 100 microns and cells located within 50 microns of the surface that has the microstructures have an average diameter smaller than 100 microns. A foam roll according to any of the preceding claims, wherein the foam layer has a cell foam structure comprising a plurality of substantially spherical closed cells; wherein cells around the center of the multilayer foam material in the thickness direction have an average diameter greater than 100 microns and cells located within 50 microns of the surface that has the microstructures have an average diameter smaller than 80 microns. A foam roll according to any of the preceding claims, wherein the foam layer has a cell foam structure comprising a plurality of substantially spherical closed cells; wherein cells around the center of the multilayer foam material in the thickness direction have an average diameter greater than 100 microns and cells located within 50 microns of the surface that has the microstructures have an average diameter smaller than 50 microns.A foam roll according to any of the preceding claims, wherein the foam layer has a cell foam structure comprising a plurality of substantially spherical closed cells; wherein microstructures have an average diameter smaller than the average diameter of the cells in the foam. A foam roll according to any of the preceding claims, wherein the support layer has a thickness from 0.25 mils to 5 mils. A foam roll according to any of the preceding claims, wherein the support layer has a thickness from 0.25 mils to 2 mils. A foam roll according to any of the preceding claims, wherein the support layer has a thickness from 0.25 mils to 1.25 mils. A foam roll according to any of the preceding claims, wherein the support layer has a thickness from 0.3 mils to 1.1 mils. A foam roll according to any of the preceding claims, wherein the support layer has a thickness of about 0.5 mils. A foam roll according to any of the preceding claims, wherein the support layer has a thickness of about 1.0 mils. A foam roll according to any of the preceding claims, wherein the roll is a level wound roll. A foam roll according to any of the preceding claims, wherein the roll is a level wound roll having a length greater than 200 m. A foam roll according to any of the preceding claims, wherein the roll is a level wound roll having a length from 200 m to greater than 2km. A foam roll according to any of the preceding claims, wherein the roll is a level wound roll having a length greater than 300 m. A foam roll according to any of the preceding claims, wherein the roll is a level wound roll having a length from 300 m to 650m, A foam roll according to any of the preceding claims, wherein the foam layer is chosen from a polyurethane foam layer, silicone foam layer, acrylic foam layer. A foam roll according to any of the preceding claims, wherein the multilayer foam material has a width from 5mm to 150mm. A foam roll according to any of the preceding claims, wherein the multilayer foam material has a width from 5mm to 15mm. A foam roll according to any of the preceding claims, wherein the multilayer foam material has a thickness greater than 1mm. A foam roll according to any of the preceding claims, wherein the multilayer foam material has a thickness from 1mm to 10mm. A foam roll according to any of the preceding claims, wherein the multilayer foam material has a thickness from 1mm to 6mm. A foam roll according to any of the preceding claims, wherein the multilayer foam material has a thickness from 1.5mm to 4mm.48. A foam roll according to any of the preceding claims, wherein the compression force to deflection at 25% strain is greater than 35kPa and at 50% strain is less than 600kpa.49. A foam roll according to any of the preceding claims, wherein the support layer is a film comprising one or more of the following materials polyester, polypropylene, polyolefin, coated polyvinyl chloride, polyethylene terephthalate, polyethylene terephthalate glycol (PETG), polyimide, polycarbonate, ethylene vinyl acetate, thermoplastic polyurethane, and combinations thereof.50. A foam roll according to any of the preceding claims, wherein the support layer is a polyethylene terephthalate film.51. A foam roll according to any of the preceding claims, wherein the adhesive is chosen from acrylic, rubber, and combinations thereof.52. A foam roll according to any of the preceding claims, wherein the adhesive is an acrylic adhesive.53. A battery assembly comprising a portion of a foam roll (without liner) as described in any of the preceding claims adhered to a battery component.54. A battery assembly comprising a portion of a foam roll (without liner) as described in any of the preceding claims adhered to a battery component, wherein the battery component is a battery cell or a wall of an enclosure encasing battery cells.

[0077] EXAMPLES

[0078] Advantages of the disclosure are illustrated by the following non-limiting examples. Unless otherwise noted, all examples in the proceeding consist of the materials detailed in Tables 1 and 2 referencing FIG. 1 for construction details. All descriptive values are nominal independent of manufacturing variation.

[0079] Table 1: Materials

[0080] Table 2: Multilayer Foam Material

[0081] Test Methods

[0082] Microstructure Diameter: Optical images & laser confocal measurements of the Foam layer were taken via Keyence confocal microscope, Model VK-X, SN 9D0P000003.at 20x magnification. Laser was set to doubler scan, measurement quality was set to high precision to increase resolution, & gamma multiplier was set to 0.45% to level output intensity. Camera Shutter speed was established at 1 / 60 of a second. Image was post processed optically via Keyence VK-X3000 Multifile Analyzer Version 3.3.1.85 software to provide numerical quantification of features. Specific features such as microstructure geometry was visually observed. Image was post processed to determine topology (FIG. 5). Microstructure diameter was measured by fitting a three-point circle with points selected on the cell wall that fit the cell diameter. 20 measurements were averaged in the reported values.

[0083] Cavity Depth: Optical images & laser confocal measurements of the Foam layer were taken via Keyence confocal microscope, Model VK-X, SN 9D0P000003.at 20x magnification. Laser was set to doubler scan, measurement quality was set to high precision to increase resolution, & gamma multiplierwas set to 0.45% to level output intensity. Camera Shutter speed was established at 1 / 60 of a second. Image was post processed optically via Keyence VK-X3000 Multifde Analyzer Version 3.3.1.85 software to provide numerical quantification of features.. Depth of the microstructures in the first major surface of the foam was determined via laser confocal measurements. Line cross section depth measurements of the first primary surface were determined as distance from the primary surface top & the valley of the microstructure cavity. FIG. 6 shows the depth of the microstructures in the first major surface of the multilayer foam material EX3 at a magnification of 20x.Microstructure Density: Optical images & laser confocal measurements of the Foam layer were taken via Keyence confocal microscope, Model VK-X, SN 9D0P000003.at 20x magnification. Laser was set to doubler scan, measurement quality was set to high precision to increase resolution, & gamma multiplier was set ot 0.45% to level output intensity. Camera Shutter speed was established at 1 / 60 of a second. Image was post processed optically via Keyence VK-X3000 Multifile Analyzer Version 3.3.1.85 software to provide numerical quantification of features.. Number of features within a view area of 526.777pm x 701.273 pm. Microstructure density was calculated by dividing features count by the view area.

[0084] Surface Roughness: Optical images & laser confocal measurements of the Foam layer were taken via Keyence confocal microscope, Model VK-X, SN 9D0P000003.at 20x magnification. Laser was set to doubler scan, measurement quality was set to high precision to increase resolution, & gamma multiplier was set ot 0.45% to level output intensity. Camera Shutter speed was established at 1 / 60 of a second. Image was post processed optically via Keyence VK-X3000 Multifile Analyzer Version 3.3.1.85 software to provide numerical quantification of features.. Surface roughness was numerically measured along linear sections of the of the specified surfaces. Surface roughness was determined as the average difference between the peaks and valleys averaged over the measurement length. Reported values were averages of 10 measurements.

[0085] Foam Cell Diameter: Optical images & laser confocal measurements of the Foam layer were taken via Keyence confocal microscope, Model VK-X, SN 9D0P000003.at 20x magnification. Laser was set to doubler scan, measurement quality was set to high precision to increase resolution, & gamma multiplier was set to 0.45% to level output intensity. Camera Shutter speed was established at 1 / 60 of a second. Image was post processed optically via Keyence VK-X3000 Multifile Analyzer Version 3.3.1.85 software to provide numerical quantification of features. Specific features such as cell diameter was visually observed. Foam layer cell diameter was measured by fitting a three point circle with points selected on the cell wall that fit the cell diameter. 20 measurements were averaged in the reported values.

[0086] Shear Strength: The adhesion force between two substrates was measured via overlap shear testing to determine the bond strength between the microstructure surfaces and adhering substrate. The overlap shear was quantified via method ASTM DI 002. For multilayer foam material, the first major surface with microstructure cavities was applied to the surface as defined in the examples with an overlap area of 25x25mm. Multilayer foam material was separated from the adhered substrate in plane with theadhesion surface to create shear. The layers were separated at a rate of 12mm / min. Measured peak shear stress was averaged from three tests.

[0087] Compression Force to Deflection (CFD). Compression response of multilayer foam composites were quantified ASTM D3574 with modifications. Release liners were removed prior to testing. Method was modified to measure instantaneous stress at a continuous rate of deflection of Imm / min. 25 measurements were conducted and stress averaged at stated strain values.

[0088] Example 1-3 (EX1-EX3) and Comparative Examples 1-3 (CE1-CE3)

[0089] Commercialized polyurethane foam formulas in non cured liquid precursor state were were metered by weightonto composite of support layer, adhesive & release liner as described in CE1-CE2 & EX1-EX3. Metered precursor was calendaring to uniformly spread precursor. Nominal calendar weights are shown in Table 3. In CE1-CE2 & EX1-EX3, multilayer foam material was transported into a thermal oven. Foam was cured at a nominal temperatures of 107°C to enable thermal cure. Dwell time was in oven was 4.2 minutes.

[0090] Table 3

[0091] For CE1-CE2, foam was allowed to free rise resulting in a natural foam finish. In EX1-EX3, Foam was cured with against siliconized film surface resulting in a microstructure layer.

[0092] Post oven cure, foam is wound into roll with an automated line speed matched winding unit.

[0093] FIG. 3 illustrates the first major surface of the multilayer foam material EXI at a magnification of 20x. Image illustrates circular microstructures (encased in a doted circle) in a nonrepeating, non regular or periodic pattern. FIG. 4 illustrates the first major surface of the multilayer foam material CE2 at a magnification of 20x. FIG. 4 illustrates random surface characteristic typical of a foam surface, without identifiable microstructure or cavities. Numerical representation of the Examples (EX1- EX3) and Counter Examples (CE1-CE3) are shown in Table 4.

[0094] Table 4

[0095] Shear Strength

[0096] Multilayer foam material EX1-EX3 & CE1-CE3 were tested for comparison for shear strength. Multilayer Foam Material was tested in overlap shear bonded to PET film. The PET film had an average surface roughness, Ra of 0.119 micron and a maximum measured surface roughness Ra of 0.314 micron.

[0097] In Table 5, CE1 & CE2 showed no appreciable overlap shear strength as expected from an absence of microstructure surface. CE3, shows low shear strength as no support layer is present and microstructure surface deforms, the deformation of the microstructure reduces the ability to adhere. EX1-EX3 show increased shear strength more than 25kPa with the support layer. The increase in shear strength with the presence of the support layer was completely unexpected and surprising.

[0098] For several useful applications of holding substrates together through movement in a manufacturing process, a minimum value of shear strength is required. In several application due to the mass, acceleration of objects, or other separating forces during manufacturing, a minimal load of 25kPa is established as the viable strength needed. Additionally, as strength increases, surface area & hence part size can be reduced further proving utility of high shear strength.

[0099] Table 5

[0100] FIG. 8 highlights the advantage of the support layer in enhancing the shear resistance of the multilayer foam materials with support layer vs multilayer foam material without support layer. This makes the supported multilayer foam materials more suitable for demanding applications where higher shear forces are expected or required.

[0101] Compression Force to Deflection

[0102] Multilayer foam material for EX3 was evaluated for compression force to deflection. Average Stress at 25% strain is 175kPa. Average stress measured at 50% Strain is 506kPa. Complete compression force to deflection is shown in FIG. 7.

Claims

We claim:

1. A foam roll, comprising a multilayer foam material, the multilayer foam material comprising: a foam layer, a support layer immediately adjacent the foam layer having a thickness greater than 0.25 mils (6.35 microns), an adhesive layer immediately adjacent the support layer, having a loop tack greater than 10 Ibf / in (1.8 N / mm); a liner immediately adjacent the adhesive layer, wherein the foam layer has a first major surface and an opposing second major surface, wherein at least a portion of the first major surface of the foam layer is microstructured comprising microstructures in a non-repeating pattern, and wherein the multilayer foam material is wound in a roll.

2. A foam roll according to any of the preceding claims, wherein the microstructures are cavities.

3. A foam roll according to any of the preceding claims, wherein the microstructures are cavities and at least some of the cavities have a maximum depth from 1.5 microns to 30 microns.

4. A foam roll according to any of the preceding claims, wherein the microstructures are cavities and at least some of the cavities have a diameter from 5 microns to 75 microns.

5. A foam roll according to any of the preceding claims, wherein the first major surface of the foam layer is not tacky to the touch.

6. A foam roll according to any of the preceding claims, wherein the first major surface of the foam layer is not tacky to the touch and has a shear strength of at least 25 KPa against a surface having a surface roughness of less than 0.7 microns.

7. A foam roll according to any of the preceding claims, wherein the first major surface of the foam layer is an outermost surface of the multilayer foam material.

8. A foam roll according to any of the preceding claims, wherein the multilayer foam material has no liner immediately adjacent to the first major surface of the foam layer and the first major surface of the foam layer is an outermost surface of the multilayer foam material.

9. A foam roll according to any of the preceding claims, wherein the first major surface of the foam layer, excluding the microstructures (i.e., in a portion of the surface where there is no microstructure) has a maximum surface roughness, Ra, of less than 0.1 micron.

10. A foam roll according to any of the preceding claims, wherein the microstructures are cavities and the cavities are a ruptured closed cell on the surface of the foam layer.

11. A foam roll according to any of the preceding claims, wherein the foam layer has a cell foam structure comprising a plurality of closed cells.

12. A foam roll according to any of the preceding claims, wherein the foam layer has a cell foam structure comprising a plurality of substantially spherical closed cells; wherein cells around the center of the multilayer foam material in the thickness direction have an average diameter larger than cells located within 50 microns of the surface that has the microstructures.

13. A foam roll according to any of the preceding claims, wherein the roll is a level wound roll having a length greater than 200 m.

14. A foam roll according to any of the preceding claims, wherein the multilayer foam material has a width from 5mm to 150mm.

15. A battery assembly comprising a portion of a foam roll (without liner) as described in any of the preceding claims adhered to a battery component.

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