High-performance Anti-noise shim and its production method

Abstract

Anti-noise shim (400) or (500) comprising a structurally discontinuous or inhomogeneous support layer in the form of a perforated metal foil or made of fiber, respectively, said support layer embedded / sandwiched / inserted between two damping material layers, different to each other, coupled and linked to each other and to the support layer by chemical binder and / or by applying pressure and / or temperature, wherein one damping material layer comprises fibers selected from organic natural and / or artificial and / or synthetic fibers or inorganic fibers, a binder and a filler and the other damping material layer comprises fibers selected from organic natural and / or artificial and / or synthetic fibers or inorganic fibers, a binder with the exclusion of filler or wherein the filler is excluded.

Description

[0001] " High-Performance anti-noise shim and its production method" DESCRIPTION

[0002] Technical field of the invention

[0003] The present invention relates to an even more improved anti-noise shim. More in detail the invention relates to an improved anti-noise shim comprising at least a damping material layer, more preferably comprising structurally discontinuous or inhomogeneous support layer, said support layer selected from the group comprising a perforated metal foil support layer or support layer made of fibers, continuous or discontinuous, long, medium or short fibers, organic or inorganic fibers, with different structural options: fibers distributed randomly to form a compact but inhomogeneous support layer, fibers in the form of a woven "mesh" support layer, fibers arranged in a network wherein the fiber are welded together at the overlapping points to give the network structure support layer, said support layer embedded / sandwiched / inserted between two damping material layers, different to each other, coupled and linked to each other by chemical binder and / or by applying pressure and / or temperature, preferably by chemical binding, such as adhesive.

[0004] State of the art

[0005] Shims are widely used in automotive industry as a measure to reduce noise, vibration and harshness (NVH). This makes the use of shims especially interesting for the brake system, where shims are applied to the brake pads to reduce NVH during a braking event.

[0006] A typical shim is a functional multilayer compound. The number of layers, their thickness as well as the chemical composition of each layer varies between the numerous types of shims available to the market. The chemical composition, the structural characteristics, such as the thickness, the arrangement and the mutual connection of the components constituting a multilayer shim are currently the only variables that influence its NVH relevant properties.

[0007] Typically, a shim is used for dampening reasons. The shim is bonded to the backplate of the brake pad by an adhesive layer and / or with rivets or clips. This is essential to maximize the dampening effects of the shim. Due to its excellent dampening properties as well as its elasticity different kind of rubbers may be used.

[0008] Further type of shim comprises a support metal layer which typically serves both as a carrier for the rubber as well as adding strength to the product in the XY-plane. Also, different types of support metal layers are used depending on the requirementsof the target application and cost requirements (see the Patent no. 102020000011902 granted in the name of the Applicant).

[0009] In order to improve the performance of the anti-noise shim already available the Applicant has developed a new cost competitive anti-noise shim with improved properties comparable to higher quality higher price already available on the market.

[0010] Summary of the invention

[0011] Aspects of the invention are described here, which form an integral part of the technical content of this patent. These aspects may be used to limit the claims and / or define additional claims during the term of this patent.

[0012] The Applicant, continuing research in this technical field, surprisingly and unexpectedly created the following as the subject of this invention: a new anti-noise shim which represents a further improvement of the anti-noise shim already available.

[0013] This is achieved by the anti-noise shim comprising at least a damping material layer comprising fibers selected from organic natural and / or artificial and / or synthetic fibers or inorganic fibers, a filler and a binder, and an anti-noise shim comprising at least a damping material layer comprising fibers selected from organic natural and / or artificial and / or synthetic fibers or inorganic fibers, and a binder, with the exclusion of filler or wherein the filler is excluded, said anti-noise shim (400) or (500) further comprising structurally discontinuous or inhomogeneous support layer, said support layer selected from the group comprising:

[0014] - a perforated metal foil support layer or

[0015] - support layer made of fibers, continuous or discontinuous, long, medium or short fibers, organic or inorganic fibers, with different structural options:

[0016] * fibers randomly distributed to form a compact but inhomogeneous support layer, ® fibers in the form of a woven "mesh" support layer,

[0017] * fibers arranged in a network wherein the fiber are welded together at the overlapping points to give the network structure support layer, i.e., to provide to the support layer a network structure,

[0018] said support layer embedded / sandwiched / inserted between two damping material layers, different to each other, coupled and linked to each other and to the support layer by chemical binder and / or by applying pressure and / or temperature, preferably by chemical binder, such as an adhesive, to give the corresponding anti¬ noise shim (400) and (500) as herewith disclosed according to the present invention,as well as the related methods for the production thereof as defined in the enclosed independent claims.

[0019] As a further embodiment of the anti-noise shim (400) and (500) as herewith disclosed according to the present invention, the fibers and / or the binder of the two damping material layers are equal or different to each other.

[0020] Description of the drawings

[0021] Figs. 1 shows the structurally discontinuous or inhomogeneous support layer from a structural point of view according to the present invention wherein the fibers are distributed randomly to form a compact but inhomogeneous support layer.

[0022] Figs. 2a and 2b show the structurally discontinuous or inhomogeneous support layer from a structural point of view according to the present invention wherein the fibers are in the form of a woven "mesh" support layer.

[0023] Fig. 3 shows the structurally discontinuous or inhomogeneous support layer from a structural point of view according to the present invention wherein the fibers arranged in a network, with meshes of different sizes (w), always the same or variable in the same structure, with the fibers having the same diameter (Ø) or even different diameters, are welded together at the overlapping points to give the network structure forming the support layer, that is, to provide the support layer with the network structure.

[0024] Figs. 4a to 4b show the structurally discontinuous or inhomogeneous support layer from a structural point of view according to the present invention in the form of a perforated metal foil.

[0025] Detailed description of the invention and embodiments thereof

[0026] It is therefore an object of the present invention an anti-noise shim (400) or (500) comprising a structurally discontinuous or inhomogeneous support layer in the form of a perforated metal foil or made of fiber, respectively, said support layer embedded / sandwiched / inserted between two damping material layers, different to each other, coupled and linked to each other and to the support layer by chemical binder and / or by applying pressure and / or temperature, preferably by chemical binder, such as an adhesive, wherein one damping material layer comprises fibers selected from organic natural and / or artificial and / or synthetic fibers or inorganic fibers, a binder and a filler and the other damping material layer comprises fibers selected from organic natural and / or artificial and / or synthetic fibers or inorganic fibers, a binder with the exclusion of filler or wherein the filler is excluded.As a preferred embodiment of the present invention, the Applicant surprisingly and unexpectedly developed a new anti-noise shim 400 comprising structurally discontinuous or inhomogeneous support layer in the form of a perforated metal foil, preferably wherein the perforated area is at least 30%, more preferably at least 50% of the entire surface of the foil, said support layer embedded / sandwiched / inserted between two damping material layers, different to each other, coupled and linked to each other and to the support layer by chemical binder and / or by applying pressure and / or temperature, preferably by chemical binder, such as an adhesive, wherein one damping material layer comprises fibers selected from organic natural and / or artificial and / or synthetic fibers or inorganic fibers, a binder and a filler and the other damping material layer comprises fibers selected from organic natural and / or artificial and / or synthetic fibers or inorganic fibers, a binder with the exclusion of filler or wherein the filler is excluded.

[0027] As a further preferred embodiment of the present invention, the Applicant surprisingly and unexpectedly developed a new anti-noise shim 500 comprising structurally discontinuous or inhomogeneous support layer made of fiber, such as * fibers randomly distributed to form a compact but inhomogeneous support layer,

[0028] * fibers in the form of a woven "mesh" support layer,

[0029] * fibers arranged in a network wherein the fiber are welded together at the overlapping points to give the network structure support layer,

[0030] said support layer embedded / sandwiched / inserted between two damping material layers, different to each other, coupled and linked to each other and to the support layer by chemical binder and / or by applying pressure and / or temperature, preferably by chemical binder, such as an adhesive, wherein one damping material layer comprises fibers selected from organic natural and / or artificial and / or synthetic fibers or inorganic fibers, a binder and a filler and the other damping material layer comprises fibers selected from organic natural and / or artificial and / or synthetic fibers or inorganic fibers, a binder with the exclusion of filler or wherein the filler is excluded.

[0031] According to one embodiment, the binder is an elastomeric binder, but it may also be a non-elastomeric resin type binder. Compared to conventional rubber materials, the fibers make the material stronger and less elastic in the plane without considerably affecting the compression characteristics in the normal direction. Moreover, the fibers and the fillers reduce the amount of elastomeric binder in the layer,thereby making the layer less expensive. According to one embodiment, the fibers content in the damping material layer is not less than 5%, or 10%, or 14%, and not more than 23% or 30% by weight. However, for some applications the fibers content may be higher than 30%, such as up to 50% or up to 80% or even up to 95 %.

[0032] The organic fibers are selected from organic fibers depending on the specific application. Examples of organic natural fibers include: cellulose fibers, cotton linters fibers (fibers coming from plants, in general); examples of organic artificial or synthetic fibers are: aromatic polyamide fibers, polyamide fibers other than aromatic polyamide fibers, polyolefine fibers, polyester fibers, polyacrylonitrile fibers, polyvinyl alcohol fibers, polyvinylchloride fibers, polyurea fibers, polyurethane fibers, polyfluorocarbon fibers, phenol fibers, or the like. According to one embodiment, the fibers comprise aromatic polyamide fibers. More preferably the fibers are selected from inorganic fiber such as carbon fibers, glass fiber, ceramic fiber, rock wool, mineral wool, fused quartz fiber, chemical processed high silica fiber, fused alumina silicate fiber, alumina continuous fiber, stabilized zirconia fiber, boron nitride fiber, alkali titanate fiber, whiskers, boron fiber, wollastonite, basalt fiber, aramid fiber, or mixtures thereof.

[0033] The filler may be an inorganic filler such as clay, ash, talc, barium sulfate, sodium bicarbonate, graphite, lead sulfate, tripoli, wollastonite, or an artificial / synthetic organic filler such as rubber crumbs, or natural organic filler such as cork or similar, or mixtures thereof.

[0034] The binder may be an elastomeric material of rubber type such as styrene¬ butadiene rubber (SBR), acrylonitrile-butadiene rubber (nitrile-butadiene rubber, NBR), isoprene rubber (IR), chloroprene rubber (CR), butadiene rubber (BR), isobutylene-isoprene rubber (IIR), ethylene propylene rubber (EPM), fluoro rubber (FPM), silicone rubber (Si), chlorosulfonated polyethylene (CSM), ethylene-vinylacetate copolymers (EVA), chlorinated polyethylene (CPE), chloro-isobutane-isoprene rubber (CIIR), epichlorohydrin rubber (ECO), nitrile isoprene rubber (NIR) or the like, or mixtures thereof. Elastomers other than rubbers may also be used. According to alternative embodiments the binder is a resin type material such as a rubber modified phenolic resin, a phenolic resin, an epoxy resin or the like, or mixtures thereof.

[0035] In one embodiment of the present invention the structurally discontinuous or inhomogeneous support layer is made of fiber, continuous or discontinuous, long, medium or short fibers, organic or inorganic fibers, such as carbon fiber, metal fiber, glass fiber, polymeric fiber providing to the support layer with different structuraloptions: fibers distributed randomly to form a compact but inhomogeneous support layer (example fig. 1), fibers in the form of a woven "mesh" support layer (example fig.

[0036] 2a and fig. 2b), fibers arranged in a network (example fig. 3), with meshes of different sizes (w), always the same or variable in the same structure, with the fibers having the same diameter (Ø) or even different diameters, wherein the fiber are welded together at the overlapping points to give the network structure forming the support layer.

[0037] Alternatively, as can be clearly deduced from figures 2a and 2b, the fibers forming the aforementioned support layer are arranged in a warp and weft weave or woven together using a knitting technique (Knitting weaving).

[0038] In particular, said fibers constituting the support layer, when of organic or inorganic polymeric nature, correspond to the fibers present in the damping-material layer, but in general, regardless of their chemical nature, said fibers constituting the support layer are preferably long fibers either non-uniform or regular in diameter and length.

[0039] As a further embodiment, the structurally discontinuous or inhomogeneous support layer according to the present invention is in the form of a perforated metal foil (example fig. 4a and fig. 4b), preferably wherein the perforated area is at least 30%, more preferably at least 50% of the entire surface of the foil.

[0040] In a further preferred embodiment said perforated metal foil has a perforated area not higher than 20%, more preferably not higher than 10%, even more preferably not higher than 5% of the entire surface of the foil.

[0041] Preferably, the thickness of the support layer made of the metal foil is not higher than 1000 pm, preferably not higher than 400-500 pm, more preferably not higher than 250 pm.

[0042] Preferably, the thickness of the support layer made of fibers randomly distributed to form a compact but inhomogeneous support layer is not higher than 1000 pm, preferably not higher than 400-500 pm, more preferably not higher than 250 pm.

[0043] Preferably the thickness of the support layer made of fibers in the form of a woven "mesh" support layer is not higher than 1000 pm, preferably not higher than 400-500 pm, more preferably not higher than 250 pm.

[0044] More preferably, as a further embodiment of the damping material layer according to the present invention, said damping material layer comprises at least a filler, an organic or inorganic fiber, more preferably a cellulose fiber, and a binder comprising NBR and / or SBR, wherein the filler is present in an amount between 1 and85% by weight, preferably between 30 and 70% by weight, more preferably between 45 and 55% by weight, the organic fiber, more preferably cellulose fiber, or inorganic, is present in an amount between 3 and 90% by weight, preferably between 15 and 30% by weight, more preferably between 20 and 25% by weight, the binder comprising NBR and / or SBR is present in an amount between 1 and 60% by weight, more preferably between 15 and 30% by weight, preferably between 20 and 25% by weight, said percentage being based on 100 parts by weight of the combination of the filler, the organic or inorganic fiber and the binder selected from NBR and / or SBR.

[0045] More preferably, as a further embodiment of the damping material layer according to the present invention, wherein the filler is excluded, said damping material layer comprises an organic or inorganic fiber, more preferably a cellulose fiber, and a binder comprising NBR and / or SBR, wherein the organic fiber more preferably a cellulose fiber, or the inorganic fiber, is present in an amount between 2 and 98% by weight, preferably between 40 and 60% by weight, more preferably between 45 and 55% by weight, said percentage being based on 100 parts by weight of the combination of the organic or inorganic fiber and the binder selected from NBR and / or SBR.

[0046] Preferably, when both NBR and SBR are present, preferably they are present with a relative rate of percentage by weight NBR / SBR from 35 / 65 to 65 / 35 being 100% by weight the sum of NBR and SBR.

[0047] In a further preferred embodiment of the present invention, when both NBR and SBR are present, preferably they are present with a relative rate of percentage by weight NBR / SBR from 10 / 90 to 90 / 10, preferably from 20 / 80 to 80 / 20, from 25 / 75 to 75 / 25, from 30 / 70 to 70 / 30, being 100% by weight the sum of NBR and SBR.

[0048] The binder comprised in the damping material layer is preferably selected among: an elastomeric material of latex / rubber type such as styrene-butadiene rubber (SBR), acrylonitrile-butadiene rubber (nitrile-butadiene rubber NBR), or a combination thereof NBR / SBR, or an elastomeric material of latex / rubber type comprising styrene¬ butadiene rubber (SBR), acrylonitrile-butadiene rubber (nitrile-butadiene rubber NBR), or a combination thereof NBR / SBR, and when both NBR and SBR are present, preferably they are present with a relative rate of percentage by weight NBR / SBR from 10 / 90 to 90 / 10, preferably from 20 / 80 to 80 / 20, more preferably from 25 / 75 to 75 / 25, even more preferably from 30 / 70 to 70 / 30, the most preferred from 35 / 65 to 65 / 35, being 100% by weight the sum of NBR and SBR; or the binder comprised in the damping material layer is selected among: a resin type material or a materialcomprising resin, such as a rubber modified phenolic resin, a phenolic resin, an epoxy resin or the like.

[0049] The technical advantages due to the damping material layer according to the present invention, combined with the cost-saved advantages in view of the reduction of the amount of the more expensive material, are that the damping effect is achieved by the fiber material's ability to generate inner friction work and rubber deformation. Whereas rubber generally causes damping by only deformation, the majority of inner work can be expressed by the friction between the single fiber strains when deforming the bundle. Again, excitation energy is converted into heat, thus increasing the dampening effect. Since the damping material layer, according to the present invention, uses both fibers and rubber, the resulting damping is a combination of both effects.

[0050] In view of the above-mentioned combined advantages, the Applicant developed a further anti-noise shim technology comprising the coupling of the damping material layer according to the present invention with a support layer structurally discontinuous or inhomogeneous, selected from the group comprising:

[0051] - a perforated metal foil support layer or

[0052] ■ support layer made of fibers, continuous or discontinuous, long, medium or short fibers, organic or inorganic fibers, with different structural options:

[0053] * fibers randomly distributed to form a compact but inhomogeneous support layer, « fibers in the form of a woven "mesh" support layer,

[0054] ® fibers arranged in a network wherein the fiber are welded together at the overlapping points to give the network structure support layer,

[0055] wherein, in all said support layers, the layer of damping material grips the support layer due to the fact that said support layer has a discontinuous or inhomogeneous structure having holes, meshes, or having an irregular texture such as randomly distributed fibers or fibers to form a woven mesh (woven mesh support layer).

[0056] The technical advantages due to the anti-noise shim comprising a support layer made of fiber with the different structural options embedded in two damping material layers according to the present invention are that said support layer adds strength to the anti-noise shim being solicited in radial (XY) direction by the piston.

[0057] The technical advantages due to the anti-noise shim comprising a support layermade of a perforated metal foil embedded in two damping material layers according to the present invention are that said support layer absorbs vibration waves better than solid metal (i.e., a foil of whole metal).

[0058] It is a further object of the present invention the method of production of the anti¬ noise shim 400 or 500 comprising damping material layers according to the present invention wherein the damping material layers provided are obtained according to the following methods of production:

[0059] a) preparation of the damping material slurry wherein organic fibers, mechanically dispersed with the addition of water, in a pulper, and subsequently defibrillated ("refined"), are initially mixed with the inorganic and / or synthetic fillers and fibers in water, being subsequently added with binder and vulcanizer;

[0060] b) preparation of the damping material layer wherein:

[0061] b1) the damping material slurry is loaded by a head box into a flow spreader with the following steps

[0062] i) Fourdrinier Table section

[0063] ii) Press section

[0064] iii) Dryer section

[0065] iv) Calendar stack section

[0066] v) Reel section

[0067] to obtain a semi-finished damping material layer,

[0068] b2) semi-finished damping material layer is calendared

[0069] b3) the calendared semi-finished damping material layer is vulcanized to obtain the damping material layer containing filler;

[0070] a’) preparation of the damping material slurry wherein organic fibers, mechanically dispersed with the addition of water, in a pulper, and subsequently defibrillated ("refined"), are initially mixed with the inorganic and / or synthetic fibers in water, excluding the presence of fillers, and being subsequently added with binder and vulcanizer;

[0071] b’) preparation of the damping material layer wherein:

[0072] b’1) the damping material slurry is loaded by a head box into a flow spreader with the following steps

[0073] i) Fourdrinier Table section

[0074] ii) Press section

[0075] iii) Dryer sectioniv) Calendar stack section

[0076] v) Reel section

[0077] to obtain a semi-finished damping material layer,

[0078] b’2) semi-finished damping material layer is calendared

[0079] b’3) the calendared semi-finished damping material layer is vulcanized to obtain the damping material layer wherein the filler is excluded.

[0080] By this process the damping material layer has density values equal to or less than 2.3 gr / cm3, preferably 1.7 gr / cm3or less, more preferably 1.6 gr / cm3or less.

[0081] It is a further object of the present invention the method of production of the anti¬ noise shim 400 comprising structurally discontinuous or inhomogeneous support layer, from the structural point of view, in the form of a perforated metal foil combined with damping material layer according to the present invention, said method comprising:

[0082] - provide a perforated metal foil according to the present invention,

[0083] - provide two damping material layers, different to each other, according to the present invention,

[0084] - embedding / sandwiching / inserting the perforated metal foil between the two damping material layer which are coupled and linked to each other and to the perforated metal foil by chemical binder and / or by applying pressure and / or temperature, preferably by chemical binder, such as adhesive.

[0085] It is a further object of the present invention the method of production of the anti¬ noise shim 500 comprising structurally discontinuous or inhomogeneous support layer, from the structural point of view, in the form of support layer made of fibers selected from the group comprising:

[0086] * fibers randomly distributed to form a compact but inhomogeneous support layer, ® fibers in the form of a woven "mesh" support layer,

[0087] « fibers arranged in a network wherein the fiber are welded together at the overlapping points to give the network structure support layer

[0088] said process comprising:

[0089] - provide the support layer made of fibers according to the present invention, - provide two damping material layers, different to each other, according to the present invention,

[0090] - embedding / sandwiching / inserting the support layer made of fibers between the two damping material layer which are coupled and linked to each other and to thesupport layer made of fibers by chemical binder and / or by applying pressure and / or temperature, preferably by chemical binder, such as adhesive.

[0091] It is a further object of the present invention a further method of producing the damping material layers included in the anti-noise sheet 400 or 500, respectively; both the damping material layer comprising fibers, filler and binder, and the other layer comprising fibers and binder: i.e., a damping material layer comprising fibers, filler and binder and the other damping material layer comprising fibers and binder, with the exclusion of the filler(s) or in which the filler(s) is / are excluded.

[0092] For both production methods, these are discontinuous methods of producing in sheets said damping material layers, one comprising fibers, filler and binder, the other comprising fibers and binder, with the exclusion of the filler(s) or in which the filler(s) is / are excluded.

[0093] Said methods fall within the production methods commonly referred to as IT-sheets, or Jointing sheets, or similar names.

[0094] By this process the damping material layer has density values of at least 1 gr / cm3, preferably at least 2 gr / cm3, more preferably at least 3 gr / cm3.

[0095] The damping material layer comprising fibers, filler and binder, according to the present invention, in the form of sheets is obtained by preparing a mixture in which the fibers are mixed together with at least a filler and with at least a binder, according to the present invention, and subjecting the resulting mixture to pressure and optionally heating, in a two rotating roll sheeter machine, said rolls with the same or different diameter, preferably with opposite directions of rotation (such as a calendaring machine with two coupled rollers), positioned vertically one above the other, wherein optionally one of the two rollers is hotter.

[0096] To obtain the damping material layer comprising fibers, at least a filler and at least a binder, according to the present invention, in the form of sheet, the mixture comprising the fibers, at least a filler and at least a binder is initially deposited / built up on one of the rollers, if present the hotter one, until the entire surface of the roller is covered, and then, the remaining part of the mixture comprising the fibers, at least a filler and at least a binder, according to the present invention, is added in the nip between the two rotating rollers, thus varying, but in a homogeneous way, the thickness and density of the damping material layer comprising fibers, filler and binder, which is formed due to the pressure and optionally the heating between the rollers, remaining adherent to the roller, roller on which it was initially deposited / built up,optionally the hottest one if present, and from which subsequently the damping material layer comprising fibers and binder so obtained is detached.

[0097] The damping material layer comprising fibers and binder, with the exclusion of the filler(s) or in which the filler(s) are excluded, according to the present invention, in the form of sheets is obtained by preparing a mixture in which the fibers are mixed together with at least a binder, according to the present invention, and subjecting the resulting mixture to pressure and optionally heating, in a two rotating roll sheeter machine, said rolls with the same or different diameter, preferably with opposite directions of rotation (such as a calendaring machine with two coupled rollers), positioned vertically one above the other, wherein optionally one of the two rollers is hotter.

[0098] To obtain the damping material layer comprising fibers, and at least one binder, according to the present invention, in the form of sheet, the mixture comprising the fibers and at least a binder is initially deposited / built up on one of the rollers, if present the hotter one, until the entire surface of the roller is covered, and then, the remaining part of the mixture comprising the fibers and at least a binder, according to the present invention, is added in the nip between the two rotating rollers, thus varying, but in a homogeneous way, the thickness and density of the damping material layer comprising fibers and binder, which is formed due to the pressure and optionally the heating between the rollers, remaining adherent to the roller, roller on which it was initially deposited / built up, optionally the hottest one if present, and from which subsequently the damping material layer comprising fibers and binder, with the exclusion of the filler(s) or in which the filler(s) are excluded, so obtained is detached.

[0099] By this process the damping material layer has density values of at least 1 gr / cm3, preferably at least 2 gr / cm3, more preferably at least 3 gr / cm3.

[0100] There is also provided a disc brake arrangement comprising an anti-noise shim according to anyone of the above embodiments between the caliper and the brake pad, and the disc brake may be arranged in a suitable vehicle, such as a car, truck, train, motorbike, bicycle etc.

[0101] In order to fully utilize the anti-noise shims according to anyone of the above embodiments according to the invention, there is further provided a method to prevent noise in a disc brake, comprising the step of arranging an anti-noise shim according to anyone of the above embodiments between the caliper and the brake pad.

Claims

CLAIMS1. Anti-noise shim (400) or (500) comprising a structurally discontinuous or inhomogeneous support layer in the form of a perforated metal foil or made of fiber, respectively, said support layer embedded / sandwiched / inserted between two damping material layers, different to each other, coupled and linked to each other and to the support layer by chemical binder and / or by applying pressure and / or temperature, wherein one damping material layer comprises fibers selected from organic natural and / or artificial and / or synthetic fibers or inorganic fibers, a binder and a filler and the other damping material layer comprises fibers selected from organic natural and / or artificial and / or synthetic fibers or inorganic fibers, a binder with the exclusion of filler or wherein the filler is excluded.

2. Anti-noise shim (400) according to claim 1 wherein the perforated area of the perforated metal foil is at least 30%, more preferably at least 50% or not higher than 20%, more preferably not higher than 10%, even more preferably not higher than 5% of the entire surface of the foil.

3. Anti-noise shim (500) according to claim 1 wherein the discontinuous or inhomogeneous support layer made of fiber is selected from the group comprising:• fibers randomly distributed to form a compact but inhomogeneous support layer,• fibers in the form of a woven "mesh" support layer,• fibers arranged in a network wherein the fiber are welded together at the overlapping points to provide the network structure of the support layer.

4. Anti-noise shim according to any one of the preceding claims wherein the damping material layer comprises fibers selected from the group comprising natural organic fibers, such as cellulose fibers cotton linters fibers (fibers coming from plants, in general), aromatic polyamide fibers, polyamide fibers other than aromatic polyamide fibers, polyolefine fibers, polyester fibers, polyacrylonitrile fibers, polyvinyl alcohol fibers, polyvinylchloride fibers, polyurea fibers, polyurethane fibers, polyfluorocarbon fibers, phenol fibers, and / or inorganic fibers such as, carbon fibers, glass fiber, ceramic fiber, rockwool, mineral wool, fused quartz fiber, chemical processed high silica fiber, fused alumina silicate fiber, alumina continuous fiber, stabilized zirconia fiber, boron nitride fiber, alkali titanate fiber, whiskers, boron fiber, wollastonite, basalt fiber, aramid fiber, or combinations thereof.

5. Anti-noise shim according to any one of the preceding claims wherein thebinder material is selected from the group comprising an elastomeric material of latex / rubber type such as styrene-butadiene rubber (SBR), acrylonitrile-butadiene rubber (nitrile rubber, NBR), isoprene rubber (IR), chloroprene rubber (CR), butadiene rubber (BR), isobutylene-isoprene rubber (IIR), ethylene propylene rubber (EPM), fluoro rubber (FPM), silicone rubber (Si), chlorosulfonated polyethylene (CSM), ethylene-vinylacetate copolymers (EVA), chlorinated polyethylene (CPE), chloro- isobutane-isoprene rubber (CIIR), epichlorohydrin rubber (ECO), nitrile isoprene rubber (NIR) or the like, or the binder material comprises a resin type material such as a rubber modified phenolic resin, a phenolic resin, an epoxy resin or the like or combinations thereof.

6. Anti-noise shim according to any one of the preceding claims wherein the filler is selected from the group comprising an inorganic filler such as clay, ash, talc, barium sulfate, sodium bicarbonate, graphite, lead sulfate, tripoli, wollastonite, or combinations thereof or a synthetic / artificial organic filler such as crumbs of rubber or a natural organic filler such as cork or similar or combinations thereof.

7. Anti-noise brake shim comprising an anti-noise shim according to any one of claims 1 to 6.

8. Method to prevent noise in a disc brake, comprising the step of arranging the anti-noise brake shim according to claim 7 between the brake caliper and the brake pad.

9. Disc brake arrangement comprising the anti-noise brake shim according to claim 7 between the caliper and brake pad.

10. Vehicle comprising a disc brake arrangement according to claim 9.

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