Patent Publication Number: US-2013240306-A1

Title: Brake shims and methods of forming same

Description:
TECHNICAL FIELD 
     The present disclosure generally relates to brake shims and methods of forming brake shims. 
     BACKGROUND 
     Brake shims diminish noise, vibration, and harshness generated during vehicle braking, and may dissipate energy by mechanisms such as material damping, isolation, and/or frictional damping. For example, brake shims may dissipate vibrational energy via constrained-layer damping wherein a viscoelastic material is sandwiched between two metal layers. 
     SUMMARY 
     A brake shim includes a metal substrate having a first surface and a second surface spaced opposite the first surface. The brake shim also includes a first film formed from a viscoelastic material and disposed on the first surface and the second surface, wherein the first film has a first elastic modulus, a primary surface spaced opposite the first surface, and a secondary surface spaced opposite the primary surface. In addition, the brake shim includes a second film formed from a polymer composition including a resin component and a curing agent reactive with the resin component. The resin component has at least one epoxide functional group, and the curing agent has at least one amine functional group. The second film is disposed on the primary surface and the secondary surface and has a second elastic modulus that is from about 10 times to about 1,000 times greater than the first elastic modulus. 
     In one embodiment, the metal substrate has a thickness of from about 0.25 mm to about 0.75 mm. Further, the first film is formed from a nitrile butadiene rubber. In addition, the first film is compressible and has a first thickness of from about 0.025 mm to about 0.10 mm. Further, the second film is formed from an epoxy coating composition, and has an engagement surface spaced opposite the primary surface and an attachment surface spaced opposite the engagement surface. The second film has a second thickness of from about 0.025 mm to about 0.075 mm. 
     A method of forming a brake shim includes applying a viscoelastic material to a metal substrate, wherein the metal substrate has a first surface and a second surface spaced opposite the first surface. After applying the viscoelastic material, the method includes at least partially curing the viscoelastic material to form a first film disposed on the first surface and the second surface. The first film has a first elastic modulus, a primary surface spaced opposite the first surface, and a secondary surface spaced opposite the primary surface. The method further includes applying a polymer composition to the first film, and, after applying the polymer composition, curing the polymer composition to form a second film disposed on the primary surface and the secondary surface and having a second elastic modulus that is from about 10 times to about 1,000 times greater than the first elastic modulus to thereby form a composite material. The polymer composition includes a resin component having at least one epoxide functional group, and a curing agent reactive with the resin component and having at least one amine functional group. The method further includes stamping the composite material to thereby form the brake shim. 
     The detailed description and the drawings or Figures are supportive and descriptive of the disclosure, but the scope of the disclosure is defined solely by the claims. While some of the best modes and other embodiments for carrying out the claims have been described in detail, various alternative designs and embodiments exist for practicing the disclosure defined in the appended claims. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a schematic exploded illustration of a perspective view of a brake shim attached to a backing plate; 
         FIG. 2  is a schematic illustration of a cross-sectional view of the brake shim of  FIG. 1  taken along section line  2 - 2 ; and 
         FIG. 3  is a schematic illustration of a method of forming the brake shim of  FIGS. 1 and 2 . 
     
    
    
     DETAILED DESCRIPTION 
     Referring to the Figures, wherein like reference numerals refer to like elements, a brake shim is shown generally at  10  in  FIG. 1 , and a method of forming the brake shim  10  is shown generally at  12  in  FIG. 3 . The brake shim  10  or brake insulator may be useful for a brake assembly of a vehicle (not shown), and may, for example be a component of a brake pad (not shown). However, the brake shim  10  and method  12  may also be useful for non-vehicular applications requiring excellent noise, vibration, and harshness dissipation and/or damping characteristics. 
     Referring again to  FIG. 1 , the brake shim  10  described herein may be formed from a composite material  14 , and may be attached to a backing plate  16  during use. By way of one non-limiting example, an adhesive  18  may be sandwiched between the brake shim  10  and the backing plate  16  to thereby attach the brake shim  10  to the backing plate  16 . However, the brake shim  10  may be fixedly attached to the backing plate  16  by any suitable method or material. For example, the brake shim  10  may be mechanically joined to the backing plate  16  via a clip or bracket. 
     Referring now to  FIGS. 1 and 2 , the brake shim  10  includes a metal substrate  20  having a first surface  22  ( FIG. 2 ) and a second surface  24  ( FIG. 2 ) spaced opposite the first surface  22 . The metal substrate  20  may be selected according to the desired operating conditions of the brake shim  10 , and may, for example, provide strength, stiffness, and/or support to the brake shim  10 . The metal substrate  20  may be formed from any suitable metal, such as, but not limited to, aluminum, steel, e.g., cold rolled steel, galvanized steel, and stainless steel, and combinations of aluminum and steel. Further, the brake shim  10  may include only one metal substrate  20 . That is, the brake shim  10  may not include two or more metal substrates  20 . 
     Referring to  FIG. 3 , in one non-limiting embodiment of the method  12 , as set forth in more detail below, the metal substrate  20  may be provided in the form of a payoff coil or roll (illustrated generally at  26  in  FIG. 3 ), but may be coated and processed as a sheet (denoted generally at  30  in  FIG. 3 ) having a thickness  32  ( FIG. 2 ) of from about 0.25 mm to about 0.75 mm, e.g., from about 0.4 mm to about 0.6 mm. However, the metal substrate  20  may be rolled upon itself into the payoff coil or roll  26  that is suitable for unrolling, processing, and re-rolling. In addition, although not shown, the payoff coil or roll  26  of metal substrate  20  may include an interleaf between each successive layer of the payoff coil or roll  26 . Alternatively, for other non-limiting embodiments of the method  12 , the metal substrate  20  may not be provided in the form of the payoff coil or roll  26  but may rather be provided, for example, in sheet form  30  or in the form of shaped workpieces (not shown). 
     In addition, although not shown, it is to be appreciated that the metal substrate  20  may include a primer layer formed from a primer composition. In such embodiments, the primer layer may be disposed on the metal substrate  20  and thereby form the first surface  22  ( FIG. 2 ) and the second surface  24  ( FIG. 2 ). In particular, the primer composition may be selected to coat and protect the metal substrate  20 . In addition, the primer composition may chemically and/or physically prepare the metal substrate  20  to accept an additional film  36  ( FIGS. 1 and 2 ) or layer, as set forth in more detail below. For example, the primer composition may be selected to bond with a viscoelastic material  40  ( FIG. 3 ). Although optional, a suitable example of a primer composition is a phenolic resin, which may be commercially available under the trade name Chemlok®  205  from Lord Corporation of Cary, N.C. 
     Referring again to  FIGS. 1 and 2 , the brake shim  10  also includes a first film  36  formed from the viscoelastic material  40  ( FIG. 3 ) and disposed on the first surface  22  ( FIG. 2 ) and the second surface  24  ( FIG. 2 ). The first film  36  has a primary surface  42  spaced opposite the first surface  22  and a secondary surface  44  spaced opposite the primary surface  42 . Further, the first film  36  has a first thickness  46  of from about 0.025 mm to about 0.10 mm. For example, the first thickness  46  may be from about 0.05 mm to about 0.8 mm. As used herein, the terminology “thickness” refers to a depth of a film (e.g., the first film  36 ) after the film has cured, set, dried, cross-linked, and/or hardened. In addition, the first film  36  may be compressible and may be generally characterized as elastic. 
     Further, the primary surface  42  and the secondary surface  44  may not be tacky. As used herein, the terminology “tacky” refers to a material that retains a sticky feel to the touch. That is, a tacky material may not be fully cured or dried, or may be inherently sticky based upon its chemical constituents, and as such, exhibits a gummy and/or gluey surface, appearance, and/or characteristic. As such, the first film  36  may not be a mastic, and may therefore be applied to the metal substrate  20  with conventional coil coating equipment (illustrated generally in  FIG. 3  and set forth in more detail below). That is, since the primary and secondary surfaces  42 ,  44  may not be tacky or sticky, conventional coil coating equipment does not require modification in order to dispose the viscoelastic material  40  on the metal substrate  20 . 
     In addition, the first film  36  has a first elastic modulus. As used herein the terminology “elastic modulus” may refer to a Young&#39;s modulus or a shear modulus. Further, the first film  36  may have a hardness of from about 40 Shore A to about 90 Shore A. 
     Without intending to be limited by theory, the viscoelastic material  40  ( FIG. 3 ) may impart excellent damping and isolation properties to the brake shim  10  ( FIG. 2 ). For example, the viscoelastic material  40  may be selected as an isolation material to minimize transmission of vibration to the metal substrate  20  ( FIG. 2 ) during, for example, vehicle braking operations, as set forth in more detail below. As such, the first film  36  ( FIG. 2 ) may assist in isolating the metal substrate  20  from a source of vibrational energy, e.g., a brake pad (not shown) that is engaged with a rotor (not shown) of a vehicle (not shown). Such damping may occur as a result of extension and compression of the first film  36  formed from the viscoelastic material  40  during vehicle braking operations and/or from micro-shearing of the first film  36 . 
     In one non-limiting embodiment, the viscoelastic material  40  may be a rubber. Suitable rubbers include, but are not limited to, natural rubbers, neoprene rubbers, isoprene rubbers, butadiene rubbers, styrene-butadiene rubbers, nitrile butadiene rubbers, urethane rubbers, silicone rubbers, fluorine rubbers, halogenated rubbers, butyl rubbers, and combinations thereof. In one non-limiting example, the viscoelastic material  40  may include a nitrile butadiene rubber (NBR). That is, the first film  36  ( FIG. 2 ) may be formed from a nitrile butadiene rubber. A suitable example of a viscoelastic material  40  is commercially available under the trade name MSC S5 from Material Sciences Corporation of Elk Grove Village, Ill. 
     In addition, referring again to  FIG. 2 , the brake shim  10  includes a second film  38  formed from a polymer composition  48  ( FIG. 3 ) and disposed on the primary surface  42  and the secondary surface  44 . In one embodiment, the second film  38  has an engagement surface  50  spaced opposite the primary surface  42  and an attachment surface  52  spaced opposite the engagement surface  50 . Further, the second film  38  may have a second thickness  54  ( FIG. 2 ) of greater than about 0.015 mm. As a non-limiting example, the second thickness  54  may be from about 0.025 mm to about 0.075 mm. That is, the second thickness  54  may be less than 1 mm, e.g., from about 0.04 mm to about 0.06 mm. 
     In addition, as described with continued reference to  FIG. 2 , the second film  38  has a second elastic modulus that is from about 10 times to about 1,000 times greater than the first elastic modulus. For example, the second elastic modulus of the second film  38  may be from about 100 times to about 1,000 times greater than the first elastic modulus of the first film  36 . As such, the second film  38  exhibits excellent stiffness and rigidity. Stated differently, the first elastic modulus of the first film  36  may be less than the second elastic modulus of the second film  38 . Therefore, the second film  38  may be substantially stiffer and less elastic than the first film  36 . As such, the viscoelastic material  40  may micro-shear upon exposure to vibrational energy, and the second film  38  may function as a constraining layer for the brake shim  10 , as set forth in more detail below. 
     As described with reference to  FIG. 3 , the polymer composition  48  includes a resin component (represented generally at  56 ) having at least one epoxide functional group. As used herein, the terminology “epoxide functional group” refers to a cyclic ether having three ring atoms. The resin component  56  may include more than one epoxide functional group and may be characterized as a polyepoxide resin or an epoxy resin. 
     In addition, the polymer composition  48  includes a curing agent (represented generally at  58  in  FIG. 3 ) reactive with the resin component  56  and having at least one amine functional group. As used herein, the terminology “amine functional group” refers to a functional group having a nitrogen atom and a lone pair of electrons. The curing agent  58  may include more than one amine functional group and may be characterized as a polyamine. The curing agent  58  may react with the resin component  56  to harden the polymer composition  48  and form the second film  38  ( FIG. 2 ), as set forth in more detail below. In particular, the at least one epoxide functional group may react with the at least one amine functional group to form a covalent bond. As such, upon cure, the polymer composition  48  may harden to form a cross-linked polymer, i.e., the second film  38 , wherein the cross-linked polymer may have a matrix or lattice structure (not shown). 
     The polymer composition  48  may further include a rubber component (not shown). More specifically, the rubber component may be embeddable within the cross-linked matrix or lattice structure (not shown) of the cured second film  38  ( FIG. 2 ) formed from the polymer composition  48 . The rubber component may be the same or different than the viscoelastic material  40  ( FIG. 3 ). Without intending to be limited by theory, the rubber component may complement the first film  36  ( FIG. 2 ) formed from the viscoelastic material  40  and may provide the brake shim  10  ( FIG. 2 ) with excellent damping and isolation properties. Suitable rubber components may include, but are not limited to, natural rubbers, neoprene rubbers, isoprene rubbers, butadiene rubbers, styrene-butadiene rubbers, nitrile butadiene rubbers, urethane rubbers, silicone rubbers, fluorine rubbers, halogenated rubbers, butyl rubbers, and combinations thereof. 
     Alternatively or additionally, the polymer composition  48  may further include an additive component (not shown). The additive component may be selected to impart texture, decrease surface area, and/or lower a coefficient of friction of the second film  38  ( FIG. 2 ) formed from the cured polymer composition  48 . Suitable additive components may include, but are not limited to, inorganic and/or organic fillers such as glass beads, e.g., hollow glass microspheres; fibers, e.g., carbon fibers; silicas; clays; and combinations thereof 
     The polymer composition  48  may be selected to provide the brake shim  10  ( FIGS. 1 and 2 ) with excellent stiffness and rigidity. That is, the polymer composition  48  may complement the viscoelastic material  40  ( FIG. 3 ) so that the brake shim  10  provides both isolation and shear damping characteristics, as set forth in more detail below. For example, the polymer composition  48  may be selected so that the brake shim  10  includes a coated constraining layer (i.e., the second film  38  (FIG.  2 )), as opposed to a metal constraining layer. That is, the polymer composition  48  may be selected so that the brake shim  10  does not include two or more metal substrates  20 , e.g., a second metal substrate (not shown) spaced apart from the metal substrate  20 . Rather, the polymer composition  48  may exhibit excellent stiffness and rigidity when cured, and may function as the second metal substrate (not shown). Therefore, the second film  38  may eliminate a requirement for the brake shim  10  to include more than one metal substrate  20 . 
     In one non-limiting embodiment, the polymer composition  48  may be an epoxy coating composition. That is, for this embodiment, the second film  38  is formed from an epoxy coating composition. A suitable example of a polymer composition  48  is commercially available under the trade name RC-1 from Material Sciences Corporation of Elk Grove Village, Ill. 
     Further, although not shown, it is to be appreciated that the brake shim  10  ( FIG. 2 ) may optionally include one or more additional layers, such as, but not limited to, an anti-friction layer (not shown) formed from an anti-friction coating composition. The anti-friction coating composition may be selected to ensure that the composite material  14  ( FIG. 3 ) has a low coefficient of friction for ease of processing. The anti-friction coating composition may also be selected to minimize noise during vehicle braking That is, the anti-friction coating composition may be characterized as a low-friction coating composition, such as graphite or polytetrafluoroethylene. Suitable examples of anti-friction coating compositions include graphite, commercially available from Whitford Corporation of Elverson, Pa. 
     Referring again to  FIG. 1 , in operation, the brake shim  10  may be attached to the backing plate  16 , which may be configured for use with a vehicle braking system (not shown), and may be formed from, for example, a metal and/or composite. The backing plate  16  may have any shape and size according to a desired function of the vehicle braking system (not shown). For example, the backing plate  16  may have a curved shape and may include one or more attachment elements  60  configured for attachment to a brake pad (not shown). 
     In addition, with continued reference to  FIG. 1 , the brake shim  10  may be attached to the backing plate  16  with, for example, the adhesive  18 . More specifically, the adhesive  18  may be applied to the attachment surface  52  of the brake shim  10  so that the brake shim  10  may join to the backing plate  16 . That is, in one non-limiting embodiment, the adhesive  18  may be sandwiched between the brake shim  10  and the backing plate  16  so that the adhesive  18  contacts the attachment surface  52  and the backing plate  16 . The adhesive  18  may be any suitable adhesive for attaching the brake shim  10  to the backing plate  16 . For example, the adhesive  18  may be a pressure-sensitive adhesive. 
     Referring now to  FIG. 3 , the method  12  of forming the brake shim  10  ( FIG. 1 ) is disclosed. As set forth in more detail below, the method  12  is cost-effective and forms the brake shim  10  having excellent isolation and damping characteristics. Further, conventional coil coating equipment (illustrated generally in  FIG. 3 ) does not require modification for the method  12 , as also set forth in more detail below. 
     Referring to  FIG. 3 , the method  12  includes applying  62  the viscoelastic material  40  to the metal substrate  20 . For the method, the viscoelastic material  40  may be applied to the metal substrate  20  via any suitable process. By way of non-limiting examples, the viscoelastic material  40  may be applied to the metal substrate  20  via rollers  64 ,  66 ,  68 ,  70  ( FIG. 3 ), knives (not shown), laminators (not shown), sprayers (not shown), extruders (not shown), and combinations thereof. Further, in one example, the viscoelastic material  40  may be applied in non-liquid or film form. In another example, the viscoelastic material  40  may be applied in liquid form. 
     In one non-limiting embodiment, the viscoelastic material  40  may be applied to the metal substrate  20  as part of a continuous coil coating process. That is, as used herein, the terminology “coil coating process” refers to a continuous, automated metal coating operation that applies one or more compositions to the metal substrate  20  via, for example, one or more rollers  64 ,  66 ,  68 ,  70  ( FIG. 3 ) to form layers or films  36 ,  38  ( FIG. 2 ) disposed on the metal substrate  20 . Coil coating processes do not include processing the metal substrate  20  in a non-continuous operation. Rather, for this embodiment of the method  12 , the metal substrate  20  may be coated continuously by rolling a material onto the metal substrate  20 , as set forth in more detail below. 
     For purposes of illustration,  FIG. 3  is a schematic representation of an exemplary continuous coil coating process. The continuous coil coating process may include one or more passes, and the metal substrate  20  may travel through the operations of the continuous coil coating process at one or more line speeds. 
     Therefore, with continued reference to  FIG. 3 , applying  62  the viscoelastic material  40  may include transferring the viscoelastic material  40  in liquid form from at least a first roller  64  to the first surface  22  ( FIG. 2 ), and from at least a second roller  66  to the second surface  24  ( FIG. 2 ) wherein the at least first roller  64  is rotatable in a first direction (denoted by arrow  72 ) and the at least second roller  66  is rotatable in a second direction (denoted by arrow  74 ) that is opposite the first direction  72 . It is to be appreciated that the at least first roller  64  and the at least second roller  66  may each include a plurality of rollers (not shown), and may each be configured as, for example, a three-roller reverse coating apparatus or system. That is, as shown generally in  FIG. 3 , the metal substrate  20  may be supplied as the payoff coil or roll  26  and may be unwound for processing in sheet form (represented generally by  30 ). The viscoelastic material  40  may be transferred at a wet film thickness (not shown) of from about 0.03 mm to about 0.5 mm, e.g., about 0.25 mm. As used herein, the terminology “wet film thickness” refers to a thickness or depth of a composition (e.g., the viscoelastic material  40 ) as applied in the form of a solution or a dispersion before a carrier (e.g., a solvent or water) of the composition is evaporated. 
     The viscoelastic material  40  may be supplied to the at least first roller  64  and the at least second roller  66  via, for example, one or more storage vessels  76  disposed in fluid communication with each of the at least first and second rollers  64 ,  66 . For example, each of the at least first and second rollers  64 ,  66  may pick up the viscoelastic material  40 , rotate in opposite directions  72 ,  74 , and roll the viscoelastic material  40  onto the metal substrate  20  as the metal substrate  20  continuously travels or advances in the processing direction (represented generally by arrow  78  in  FIG. 3 ). That is, in this embodiment, the viscoelastic material  40  may not be applied to the metal substrate  20  via extrusion and/or a calendered film laminating process. Therefore, in this embodiment, the viscoelastic material  40  may be applied via the at least first and second rollers  64 ,  66  to achieve a comparatively higher first thickness  46  ( FIG. 2 ) than would be possible if the viscoelastic material  40  were applied via solution coating. 
     With continued reference to  FIG. 3 , after applying  62  the viscoelastic material  40 , the method  12  includes at least partially curing  80  the viscoelastic material  40  to form the first film  36  ( FIG. 2 ). As best shown in  FIG. 2 , the resulting first film  36  is disposed on the first surface  22  and the second surface  24 . That is, the first film  36  is disposed on both “sides” of the metal substrate  20 , i.e., the “top” surface (e.g., the first surface  22 ) and the “bottom” surface (e.g., the second surface  24 ) of the metal substrate  20 . Therefore, the resulting first film  36  has the primary surface  42  spaced opposite the first surface  22 , and the secondary surface  44  spaced opposite the primary surface  42 . 
     Referring again to  FIG. 3 , at least partially curing  80  the viscoelastic material  40  may include increasing a temperature of the viscoelastic material  40  from about 100° C. to about 260° C. for from about 1 minute to about 5 minutes. More specifically, at least partially curing  80  the viscoelastic material  40  may include first baking the viscoelastic material  40  in a first oven  82 , and subsequently baking the viscoelastic material  40  again. For at least partially curing  80  the viscoelastic material  40  to form the first film  36 , the first oven  82  may have a plurality of heating zones (not shown), e.g., three or four heating zones, configured to sequentially heat the metal substrate  20  and the viscoelastic material  40 . 
     As such, at least partially curing  80  the viscoelastic material  40  may form the first film  36  ( FIG. 2 ) such that the primary surface  42  ( FIG. 2 ) and the secondary surface  44  ( FIG. 2 ) are not tacky. That is, the first film  36  may not gum up or adversely stick to the first and second rollers  64 ,  66 , and may not be a mastic. Further, at least partially curing  80  the viscoelastic material  40  may form the first film  36  having the first thickness  46  ( FIG. 2 ) of from about 0.025 mm to about 0.10 mm. 
     With continued reference to  FIG. 3 , the viscoelastic material  40  may be optionally quenched (represented generally by  86 ) upon exit from the first oven  82  to, for example, further reduce any tackiness of the viscoelastic material  40 . For example, the viscoelastic material  40  may be exposed to a comparatively cooler fluid, such as, but not limited to water, air, or combinations thereof 
     It is to be appreciated that for the aforementioned embodiments including the optional primer layer (not shown), the method  12  may include applying the primer composition (not shown) to the metal substrate  20  ( FIG. 2 ). For example, the primer composition may be applied to the metal substrate  20  as part of the aforementioned continuous coil coating process. 
     More specifically, as described with reference to  FIG. 3 , applying the primer composition may include transferring the primer composition in liquid form from at least the first roller  64  to the metal substrate  20 , and from at least the second roller  66  to the metal substrate  20  to thereby form the first surface  22  ( FIG. 2 ) and second surface  24  ( FIG. 2 ). 
     The primer composition may be supplied to the at least first roller  64  and the at least second roller  66  via, for example, the one or more storage vessels  76  disposed in fluid communication with each of the at least first and second rollers  64 ,  66 . For example, each of the at least first and second rollers  64 ,  66  may pick up the primer composition, rotate in opposite directions  72 ,  74 , and roll the primer composition onto the metal substrate  20  as the metal substrate  20  continuously travels or advances in the processing direction  78 . 
     With continued reference to  FIG. 3 , after applying the optional primer composition, the method  12  may include curing the primer composition to form the first surface  22  ( FIG. 2 ) and the second surface  24  ( FIG. 2 ). In particular, curing the primer composition may include heating the primer composition to a temperature of from about 150° C. to about 250° C. for from about 1 minute to about 5 minutes. The primer composition may be optionally quenched (represented generally by  86 ) upon exit from the first oven  82 . For example, the primer composition may be exposed to a comparatively cooler fluid, such as, but not limited to water, air, or combinations thereof 
     In addition, with continued reference to  FIG. 3 , it is to be appreciated that the method  12  may include pretreating  88  the metal substrate  20  prior to applying the primer composition  18  and/or applying  62  the viscoelastic material  40 . For example, the metal substrate  20  may be cleaned to remove grease, lubricants, oil, and dirt from the metal substrate  20 , and/or the metal substrate  20  may be chemically treated to promote film adhesion and/or impart corrosion protection. As a non-limiting example, the metal substrate  20  may be pretreated with a pre-cleaning agent such as Parco® Precleaner, commercially available from Henkel Corporation of Rocky Hill, Conn. Optionally, alternatively or additionally, the metal substrate  20  may be pretreated with one or more rinses  90  which may include rinsing the metal substrate  20  with water at elevated temperatures and/or pressures to provide corrosion protection and/or prepare the metal substrate  20  for bonding with the first film  36 . Optionally, alternatively or additionally, the metal substrate  20  may be pretreated with one or more cleaning agents such as, but not limited to, Scotch-Brite™, commercially available from 3M of St. Paul, Minn., and/or Parco® 1200, commercially available from Henkel Corporation of Rocky Hill, Conn. Optionally, alternatively or additionally, the metal substrate  20  may be pretreated with one or more protectants such as, but not limited to, Bonderite® from Henkel Corporation of Rocky Hill, Conn. 
     Referring again to  FIG. 3 , the method  12  also includes applying  92  the polymer composition  48  to the first film  36  ( FIG. 2 ). The polymer composition  48  may also be applied to the first film  36  as part of the aforementioned continuous coil coating process. As such, the polymer composition  48  may be applied to the first film  36  in liquid form. Alternatively, although not shown, the polymer composition  48  may be applied to the first film  36  in non-liquid form, such as a paste, via, for example, solution coating, extrusion, and/or a calendered film laminating process. 
     As best shown in  FIG. 3 , in one non-limiting embodiment, applying  92  the polymer composition  48  may include transferring the polymer composition  48  in liquid form from at least a third roller  68  to the primary surface  42  ( FIG. 2 ), and from at least a fourth roller  70  to the secondary surface  44  ( FIG. 2 ). It is to be appreciated that the at least third roller  68  and the at least fourth roller  70  may each include a plurality of rollers (not shown), and may each be configured as, for example, a three-roller reverse coating apparatus or system. 
     The polymer composition  48  may be supplied to the at least third roller  68  and the at least fourth roller  70  via, for example, the one or more storage vessels  76  disposed in fluid communication with each of the at least third and fourth rollers  68 ,  70 . For example, each of the at least third and fourth rollers  68 ,  70  may pick up the polymer composition  48 , rotate in opposite directions  72 ,  74 , and roll the polymer composition  48  onto the first film  36  ( FIG. 2 ) as the metal substrate  20  continuously travels or advances in the processing direction  78 . In particular, the polymer composition  48  may be transferred at a wet film thickness (not shown) of from about 0.038 mm to about 0.050 mm, e.g., about 0.045 mm. Therefore, in this embodiment, the polymer composition  48  is not applied to the first film  36  via extrusion and/or a calendered film laminating process. 
     With continued reference to  FIG. 3 , after applying  92  the polymer composition  48 , the method  12  includes curing  94  the polymer composition  48  to form the second film  38  ( FIG. 2 ) to thereby form the composite material  14  ( FIG. 1 ). As best shown in  FIG. 2 , the resulting second film  38  is disposed on the primary surface  42  and the secondary surface  44 . That is, the second film  38  is disposed on both “sides” of the first film  36 , i.e., the “top” surface (e.g., the primary surface  42 ) and “bottom” (e.g., the secondary surface  44 ) surface of the first film  36 . In particular, the resulting second film  38  has the engagement surface  50  spaced opposite the primary surface  42 , and the attachment surface  52  spaced opposite the engagement surface  50 . In addition, as set forth above, the second elastic modulus of the second film  38  is from about 10 times to about 1,000 times greater than the first elastic modulus of the first film  36 . For example, in one embodiment, the second elastic modulus may be from about 100 times to about 1,000 times greater than the first elastic modulus. That is, the second film  38  exhibits excellent stiffness and rigidity. 
     Referring again to  FIG. 3 , curing  94  the polymer composition  48  may include heating the polymer composition  48  to a temperature of from about 200° C. to about 260° C. for from about 1 minute to about 5 minutes. More specifically, curing  94  the polymer composition  48  may include first baking the polymer composition  48  in a second oven  84 , and subsequently baking the polymer composition  48  again. For curing  94  the polymer composition  48  to form the second film  38 , the second oven  84  may have a plurality of heating zones (not shown), e.g., three or four heating zones, configured to sequentially heat the metal substrate  20 , the first film  36 , and the polymer composition  48 . 
     With continued reference to  FIG. 3 , in one non-limiting embodiment, the method  12  may include, after applying  92  the polymer composition  48 , curing  94  the polymer composition  48  and the viscoelastic material  40 . That is, curing  94  the polymer composition  48  may also simultaneously cure the viscoelastic material  40 . However, in another non-limiting embodiment of the method  12 , the viscoelastic material  40  may be substantially cured before the polymer composition  48  is applied to the first film  36 . That is, the viscoelastic material  40  and the polymer composition  48  may separately cure. As such, for the method  12 , the viscoelastic material  40  may be partially cured or substantially cured before applying the polymer composition  48  to the first film  36 . 
     Referring to  FIG. 3 , curing  94  the polymer composition  48  may form the second film  38  having the second thickness  54  ( FIG. 2 ) of greater than about 0.015 mm. That is, curing  94  the polymer composition  48  may form the second film  38  having the second thickness  54  of from about 0.025 mm to about 0.075 mm. 
     Referring again to  FIG. 3 , the polymer composition  48  may be optionally quenched (represented generally by  86 ) upon exit from the second oven  84 . For example, the polymer composition  48  may be exposed to a comparatively cooler fluid, such as, but not limited to water, air, or combinations thereof. Further, the metal substrate  20  including the first film  36  ( FIG. 2 ) and second film  38  ( FIG. 2 ) disposed thereon may be rewound into a rewind coil or roll  28  for storage and/or continuous processing. In particular, the metal substrate  20  including the first and second films  36 ,  38  may be overwound and may include an interleaf (not shown) between successive layers (not shown) of the rewind coil or roll  28 . 
     Referring again to  FIG. 3 , the method  12  also includes stamping (represented generally at  98 ) the composite material  14  to thereby form the brake shim  10 . That is, the composite material  14 , which may include at least the first film  36  and the second film  38  disposed on the metal substrate  20 , may be stamped and/or cut to any desired shape and size. As such, the composite material  14  is a stampable product that may be configured according to an end use of the brake shim  10 . For example, the composite material  14  may be stamped to form tabs  100  ( FIGS. 1 ) and 90° corners so that the brake shim  10  may have any desired shape. 
     Further, as described with reference to  FIG. 1 , the method  12  ( FIG. 3 ) may include, after stamping  98  ( FIG. 3 ) the composite material  14  to form the brake shim  10 , adhering  102  the brake shim  10  to the backing plate  16 . For example, the method  12  may include sandwiching the adhesive  18  between the brake shim  10  and the backing plate  16 . More specifically, the adhesive  18  may be applied to the attachment surface  52  so that the brake shim  10  may attach to the backing plate  16 . Since the composite material  14  ( FIG. 2 ) is stampable to any desired shape, the brake shim  10  may adhere or attach to the backing plate  16  in any configuration. Further, the brake shim  10  is flexible, bendable to form 90° corners, and can therefore include tabs  100  ( FIG. 1 ) and components having any shape or size. The brake shim  10  may also be substantially free from delamination and may sufficiently adhere to the backing plate  16 . 
     Referring again to  FIG. 3 , although not shown, the method  12  may also include applying the anti-friction coating composition to the engagement surface  50  ( FIG. 2 ) and the attachment surface  52  ( FIG. 2 ). In particular, applying the anti-friction coating composition may include transferring the anti-friction coating composition in liquid form from the at least third roller  68  to the engagement surface  50 , and from the at least fourth roller  70  to the attachment surface  52 . In particular, the anti-friction coating composition may be transferred to the second film  38  at a film thickness (not shown) of from about 0.001 mm to about 0.01 mm, e.g., about 0.013 mm. Alternatively, the anti-friction coating composition may be applied to the second film  38  in non-liquid form. Further, the anti-friction coating composition may not be applied to or disposed on the first film  36  ( FIG. 2 ), but may rather be applied to and disposed on the second film  38 , as set forth above. 
     Although not shown, after applying the anti-friction coating composition, the method  12  may include curing the anti-friction coating composition to form a third film (not shown) disposed on the engagement surface  50  ( FIG. 2 ) and the attachment surface  52  ( FIG. 2 ) and thereby form the composite material  14 . That is, the third film may be disposed on both “sides” of the second film  38 , i.e., the “top” surface (e.g., the engagement surface  50 ) and “bottom” surface (e.g., the attachment surface  52 ) of the second film  38 . 
     Referring again to  FIG. 3 , curing the anti-friction coating composition may include heating the anti-friction coating composition to from about about 200° C. to about 260° C. for from about 1 minute to about 5 minutes. More specifically, curing the anti-friction coating composition may include baking the anti-friction coating composition in the second oven  84 . Curing the anti-friction coating composition may form the optional third film having a third thickness (not shown) of from about 0.001 mm to about 0.01 mm. For example, the third film may have a third thickness of about 0.013 mm. 
     The anti-friction coating composition may be optionally quenched (represented generally by  86 ) upon exit from the second oven  84 . For example, the anti-friction coating composition may be exposed to a comparatively cooler fluid, such as, but not limited to water, air, or combinations thereof 
     The aforementioned method  12  ( FIG. 3 ) is cost-effective and forms the brake shim  10  ( FIG. 1 ) having excellent isolation and damping characteristics. For the method  12 , each of the first film  36  ( FIG. 2 ) and the second film  38  ( FIG. 2 ) may be applied with a continuous coil coating process rather than a non-continuous operation. In addition, the first film  36  and the second film  38  may be applied with conventional coil coating equipment. That is, conventional coil coating equipment does not require modification for the method  12 . 
     Further, the composite material  14  ( FIG. 2 ) is stampable to any desired shape to thereby form the brake shim  10  ( FIG. 1 ), and the brake shim  10  is robust in harsh operating environments, e.g., at operating temperatures of from about 175° C. to about 205° C., upon exposure to salt spray and/or oil, and upon frequent cycling during repetitive vehicle braking operations. Further, the brake shim  10  is flexible, bendable to form 90° corners, and can therefore include tabs  100  and components having any shape or size. In addition, the brake shim  10  exhibits excellent oil- and wear-resistance, and excellent adhesion of the brake shim  10  to the backing plate  16  ( FIG. 1 ). That is, the brake shim  10  is substantially free from delamination in the aforementioned harsh operating environments. As such, the brake shim  10  is durable and suitable for vehicular and non-vehicular applications requiring excellent noise, vibration, and harshness dissipation and/or damping characteristics. 
     Without intending to be limited by theory, the second film  38  ( FIG. 2 ) of the brake shim  10  ( FIG. 2 ) may provide the brake shim  10  with excellent stiffness and shear damping properties since the second film  38  may act as a coated constraining layer as opposed to a metal constraining layer (not shown). That is, the second film  38  may complement the first film  36  ( FIG. 2 ) so that the brake shim  10  provides both isolation and shear damping characteristics. 
     In addition, upon inclusion of the optional additive component, the second film  38  ( FIG. 2 ) may be tailored to exhibit high- or low-friction properties to further aid in noise, vibration, and harshness dissipation. For example, the brake shim  10  may have an overall thickness  96  ( FIG. 2 ) of about 1 mm. 
     In addition, the second film  38  ( FIG. 2 ) provides scratch- and mar-resistance to the brake shim  10  ( FIG. 1 ). That is, the second film  38  protects the comparatively softer first film  36  ( FIG. 2 ) and provides a comparatively scratch- and mar-resistant outer layer. 
     In addition, the second film  38  ( FIG. 2 ) prevents the composite material  14  ( FIG. 1 ) from sticking to itself when the composite material  14  is rewound from the sheet form  30  ( FIG. 3 ) to the rewind coil or roll  28  ( FIG. 3 ) before stamping  98  ( FIG. 3 ) to form the brake shim  10  ( FIG. 1 ). That is, the second film  38  eliminates application of a non-stick, release coating composition to the first film  36  ( FIG. 2 ) formed from the viscoelastic material  40  ( FIG. 2 ), which also contributes to a cost-effectiveness of the method  12  based on material reduction. 
     While the best modes for carrying out the disclosure have been described in detail, those familiar with the art to which this disclosure relates will recognize various alternative designs and embodiments for practicing the disclosure within the scope of the appended claims.