Organotitanates as adhesion promoters for anti-noise shims to brake pads, related brake pads, and methods

Abstract

By pasting the anti-noise film (6) onto the surface with acrylic paste, in order to promote the adhesion of the anti-noise film (6) to the surface (7) of the metal support (2) of the braking element (1) usually painted with epoxy resin, the surface (7) is pretreated by applying a primer onto the epoxy resin paint layer (9), and the primer consists of an organotitanate (10) diluted in an organic solvent, preferably an alcoholic polar solvent; the organotitanate (10) is preferably tetra-alkoxytitanium(IV) represented by the general formula Ti(OR)4.

Description

Technical Field

[0001] Cross - reference to related applications This patent application claims priority from Italian Patent Application No. 102022000012896, filed on June 17, 2022, the entire disclosure of which is incorporated herein by reference.

[0002] The present invention relates to the use of a primer compound specifically selected to promote adhesion between an anti - noise sheet element known as a "shim" and a first face of a metal support, wherein the metal support holds a friction material block or pad on its second face opposite the first face, and the metal support, together with the friction material block and the shim, forms an automotive braking element, particularly a brake pad, such as a brake shoe or a brake pad.

[0003] The present invention further relates to a related method for securely and substantially permanently fixing a flat covering element, particularly an anti - noise sheet element or a shim, to the metal surface of a support, especially when the metal surface is coated with an organic resin, such as an epoxy resin.

[0004] The present invention also further relates to a related automotive braking element comprising an anti - noise element or a shim having improved adhesion.

Background Art

[0005] Braking elements commonly used in modern automobiles consist of brake pads comprising a friction material block and a support therefor, the support consisting of a metal plate bounded by a first face and a second opposite face.

[0006] The first face generally comprises a sheet element or foil called a "shim" that covers most or all of the first face, while the second face holds a friction material block attached to the second face, for example, by gluing or other means.

[0007] During use, a frictional material block carried by the second face is pressed against an element to be braked, e.g., a brake disk of a motor vehicle, by a direct or indirect thrust acting on the first face.

[0008] During this operation, noise and vibrations can occur due to the thrust acting on the metal surface of the first face of the support, also known as the "backplate". Therefore, the first face is provided with an anti-noise element called a shim, which is designed to absorb or at least reduce such noise and vibrations by virtue of its elastomeric properties.

[0009] Therefore, there is the problem of ensuring a secure attachment of the anti-noise shim to the first face of the support in order to avoid accidental detachment during use.

[0010] Unfortunately, to date, brake pads (both the frictional material block and the metal backplate) are generally coated with a protective paint, usually an epoxy resin, so that it can be difficult to securely fix the shim to the coated (painted) metal surface of the backplate.

[0011] Generally, the anti-noise shims normally applied on the backplate are attached to the backplate using an acrylic resin as an adhesive.

[0012] However, due also to the presence of the epoxy coating, the adhesiveness between the shim and the epoxy resin-coated backplate can be low, entailing the subsequent risk of detachment of the shim during use due to the mechanical stresses to which the shim is normally subjected.

[0013] In fact, the reduction in the presence of polar groups on the metal support surface results in a lower surface tension, and thus also a reduced ability of the anti-noise shim acrylic adhesive to adhere to the metal support surface. The low interaction between the metal surface and the adhesive leads to the easy detachment of the anti-noise element (shim) from the backplate.

[0014] To solve this problem, a surface flame treatment designed to accept anti-noise shims has been used to date. This treatment is known to be able to actually polarize the surface by forming functional groups such as -OH and -COOH.

[0015] However, in some cases, this treatment is of low effectiveness (therefore, this treatment does not solve the problem of the risk of shim detachment), is dangerous, complicated, and costly to implement, and thus it is considered preferable to avoid it.

[0016] To avoid the aforementioned drawbacks, the backplate can be provided with mechanical attachment points to the anti-noise shim, as schematically shown in FIG. 1.

[0017] The backplate A is provided integrally with a piece of the backplate A and is provided on its metal surface S facing the shim SH using pins P arranged in shallow grooves R made on the metal surface S. The shim SH is similarly provided with a hollow raised portion B that mechanically couples with the pins P.

[0018] However, it is clear that such a solution is complicated and costly to implement.

Summary of the Invention

[0019] The object of the present invention is to provide a method for fixing a coating sheet element such as an anti-noise shim to the surface of a metal support for a braking element such as the backplate of an automotive brake pad, which has no drawbacks of the prior art, and in particular, is highly reliable, easy to implement, and cost-effective.

[0020] A further object of the present invention is to provide a braking element, particularly a brake pad, comprising a support for a friction material block and an anti-noise shim applied on the opposite side of the friction material block of the support, wherein the shim is attached to the support in a reliable and simple manner.

[0021] According to the present invention, therefore, a method for fixing a covering sheet element, such as an anti-noise shim, to the surface of a metal support for a braking element, such as the backplate of an automotive brake pad, and a related braking element are provided, as defined in the appended claims.

[0022] The present invention also relates to the use of a specifically selected chemical compound as a primer for promoting the chemical adhesion of a covering sheet element, such as an anti-noise shim, to the metal surface of the support, in particular to the surface of the metal backplate of a brake pad on the side opposite to its friction material block.

[0023] According to an embodiment of the present invention, preferably, a covering sheet element made of any type of anti-noise shim known in the art is fixed / applied to the surface of a metal support for a braking element, such as a backplate, by a method comprising pasting the covering sheet element to such a surface and pretreating the surface before the pasting step; the step of pretreating the surface consists of applying a primer compound composed of an organotitanate diluted in an organic solvent to the surface.

[0024] In a preferred embodiment, the organotitanate is of the general formula [1]Ti(OR)4 (wherein R may be the same or different and is selected from the group consisting of an unsubstituted alkyl group having either a single-chain or a branched-chain, and a substituted alkyl group having either a single-chain or a branched-chain, and the substituent is selected from the group consisting of amino, phosphorus, ether, and unsaturated hydrocarbon groups) and is tetra-alkoxytitanium(IV).

[0025] In a preferred embodiment, the organic solvent is an alcoholic polar solvent.

[0026] The alcoholic polar solvent may be selected from the group consisting of isopropyl alcohol, ethanol, acetone, and mixtures thereof.

[0027] In the most preferred embodiment, the polar alcoholic solvent is isopropyl alcohol.

[0028] In an embodiment of the method of the present disclosure, the following steps are performed on the surface of the coated sheet element, i.e., the metal support designed to receive the anti-noise film: a) Coating the surface with an epoxy resin; b) Applying an organotitanate in an organic solvent to such a surface already coated with an epoxy resin in order to form a uniform layer of organotitanate in solution on the surface and the epoxy resin; c) Gluing the coated sheet element to the surface already coated and pretreated with organotitanate diluted in an organic solvent by applying an adhesive based on acrylic paste or acrylic resin between the coated sheet element and the uniform layer of organotitanate in solution.

[0029] In a preferred embodiment, the coated sheet element consists of an anti-noise film, the metal support consists of the back plate of an automotive brake pad, and the aforementioned surface defines the extent of its first surface on the side opposite to the second surface of the back plate carrying the friction material block.

[0030] In a preferred embodiment, the organotitanate is diluted in an alcoholic polar solvent at a dilution of 0.5% - 5% v / v (volume per volume).

[0031] In a preferred embodiment, the organotitanate diluted in an organic solvent is - by spraying the organotitanate solution, - by a roller coated with the organotitanate solution, - by non-uniformly dropping the organotitanate solution onto the surface and then uniformly distributing it by a cloth or an applicator covered with a cloth, such as a rotating disk applied to the aforementioned surface using a technique selected from the group consisting of.

[0032] An embodiment of the present invention is a braking element, particularly a brake pad, comprising a support for a friction material block and an anti-noise shim applied on the side of the support opposite to the friction material block, wherein the shim is attached to a first surface of the support on the side opposite to the friction material block; i) - the first surface of the support is coated with a first layer of epoxy resin; ii) - a second layer of organotitanate is spread on the first layer of epoxy resin, the organotitanate containing alkoxy groups; iii) - the shim is attached to the first surface by a third layer of acrylic resin on the second layer of organotitanate; iv) - at least a part of each alkoxy group is hydrolyzed by both the acrylic resin and the epoxy resin to form a chemical bond between the first layer and the third layer, which consists of a braking element.

[0033] In a preferred embodiment of the braking element according to the present invention, the organotitanate forming the second layer is tetra-alkoxytitanium(IV) represented by the general formula Ti(OR)4, wherein R is the same or different, preferably a non-substituted alkyl group having either a single chain or a branched chain, or a substituted alkyl group having either a single chain or a branched chain, and the substituent is selected from the group consisting of amino, phosphorus, ether, and unsaturated hydrocarbon groups.

[0034] An embodiment of the present invention is the use of a primer compound for promoting the adhesion of an anti-noise sheet element or shim to the surface of a metal support of a braking element, particularly the backplate of an automotive brake pad, - the surface is coated with an epoxy resin, - the anti-noise shim is pasted to the surface with an acrylic paste or an adhesive based on an acrylic resin, - The primer compound is spread on an epoxy resin paint that coats the surface such that it is inserted between the epoxy resin and the acrylic resin paste or adhesive; - The primer compound consists of an organotitanate diluted in an organic solvent, preferably an alcoholic polar solvent; - The organotitanate is tetra-alkoxytitanium(IV) represented by the general formula Ti(OR)4, where R is the same or different, preferably an unsubstituted alkyl group having either a single chain or a branched chain, or a substituted alkyl group having either a single chain or a branched chain, and the substituent is selected from the group consisting of amino, phosphorus, ether, and unsaturated hydrocarbon groups; It consists of the use.

[0035] In a preferred embodiment of the use according to the present invention, the organotitanate is diluted in an alcoholic polar solvent at a dilution of 0.5% - 5% v / v, then applied to the painted surface of the metal support and allowed to air dry at room temperature.

[0036] Preferred but non-limiting embodiments of the present invention are described in more detail below with reference to some actual examples of its implementation, which are only intended to disclose some features that are part of the content of this disclosure in a non-exhaustive and non-limiting manner, and with reference to the figures in the accompanying drawings.

Brief Description of the Drawings

[0037]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

DETAILED DESCRIPTION OF THE INVENTION

[0038] Referring to FIGS. 2, 5, 6 and 7, reference numeral 1 consists of a brake pad of any shape in the non-limiting embodiment shown, and is shown schematically only for illustrative purposes and not to scale, and shows as a whole (FIG. 5) the braking element for an automobile.

[0039] The braking element 1 comprises a metal support 2, also known as a "back plate", which consists of a flat metal plate defined between two substantially flat surfaces on opposite sides that are substantially parallel to the surface 3, i.e., the first surface 3 and the second surface 4.

[0040] The braking element 1 further comprises a friction material block (or pad) 5 attached in any suitable manner to the second surface 4 designed to face an element to which the brake is applied during use, such as a brake disc (not shown for the sake of brevity), in the art, and a well-known anti-noise element 6 carried by the first surface 3 and covering all or at least a part of the latter.

[0041] The anti-noise element 6, usually called a "shim", is fixed to the surface 3 in a stable manner such that the anti-noise shim 6 is applied on the side opposite to the friction material block 5 of the support 2.

[0042] According to a first aspect of the present invention, referring to FIG. 2 which shows a considerably enlarged and to-scale cross-section of FIG. 6, but limited to the back plate 2 and the anti-noise shim 6, the anti-noise shim 6 is specifically attached to the first surface 3 of the support 2 on the side opposite to the friction material block 5 of the shim 6, specifically, by means of a layer 8 (FIG. 2) of a known adhesive or glue, and is fixed to the metal surface 7 of the first surface 3 by pasting.

[0043] In a preferred embodiment of the present invention, the adhesive or glue forming the layer 8 is, for example, any commercially available type of acrylic adhesive or glue.

[0044] In a preferred embodiment of the present invention, the first surface 3 of the support 2 is coated with a first layer 9 of synthetic paint (FIG. 2).

[0045] In a preferred embodiment, the layer 9 is formed by, for example, any commercially available type of epoxy resin paint.

[0046] According to a main aspect of the present invention, in order to promote reliable adhesion between the anti-noise shim 6 and the metal surface 7 of the first surface 3 of the metal support 2, a second layer 10 of organotitanate is spread over the first layer of the epoxy resin 9.

[0047] According to an aspect of the present invention, the organotitanate 10 (i.e., forming the layer 10) contains an alkoxy group.

[0048] Thus, the anti-noise shim 6 is attached to the first surface 3 by a third layer 8 of acrylic resin on the second layer 10 of organotitanate, and the second layer 10 is, in the preferred embodiment shown, on the epoxy resin layer 9 of the synthetic paint.

[0049] This specifically selected sequence of specifically selected materials surprisingly, as confirmed by experiments by the technical staff of the applicant, can avoid accidental detachment during the use of the anti-noise shim 6 from the back plate 2 because the organotitanate forming the layer 10 acts as a primer that promotes adhesion.

[0050] In fact, at least a part of each alkoxy group of the organotitanate 10 is hydrolyzed by both the acrylic resin 8 and the epoxy resin 9 to form a chemical bond 11 (FIG. 2) between the first layer 9 and the third layer 8.

[0051] It should be noted that the presence of the epoxy resin layer 9, even if highly preferred, may not necessarily be required in some cases.

[0052] According to a preferred embodiment of the present invention, the organotitanate 10 forming the second layer has the general formula: [1] Ti(OR)4 (wherein R is the same or different based on the surface chemistry of the subtraction 8, 9) is tetra-alkoxytitanium(IV).

[0053] R is usually an alkyl group having a single chain or a branched chain, but may also have an amino, phosphorus, ether or unsaturated moiety.

[0054] Therefore, R in formula [1] is preferably - an unsubstituted alkyl group having either a single chain or a branched chain; - a substituted alkyl group having either a single chain or a branched chain selected from the group consisting of - the substituents are selected from the group consisting of amino, phosphorus, ether, unsaturated hydrocarbon groups.

[0055] Preferred but non-limiting examples of organotitanates suitable for acting as primers according to the present invention are commercially available organotitanates commonly used for quite different purposes (e.g., as catalysts): - Tyzor® TnBT - tetra-n-butyl titanate

[0056]

Chemical formula

[0057] - Tyzor® BTP - Polymer Butyl Titanate - Tyzor® TPT - (Tetra-isopropyl Titanate)

[0058]

Chem.

[0059] - Tyzor® TOT - Tetra-2-ethylhexyl Titanate

[0060]

Chem.

[0061] - Tyzor® TE - Triethanolamine Titanate

[0062]

Chem.

[0063] - Ken-React® KR® 44 - Isopropyl, tri(N-ethylenediamino)ethyl Titanate

[0064]

Chem.

[0065] - Ken-React® KR® TTS - Isopropyl, triisostearoyl Titanate

[0066]

Chem.

[0067] - Ken-React® KR® 138S - Titanium Di (dioctylpyrophosphate) oxyacetate

[0068]

Chemical formula

[0069] - Ken-React® KR® 55 - Tetra (2,2 diallyloxymethyl) butyl, di (ditridecyl) - phosphite titanate

[0070]

Chemical formula

[0071] selected from

[0072] Based on the above, the present invention also relates to a method for fixing an (optional) covering sheet element 6 to such a surface 7 for a braking element 1 by gluing the covering sheet element 6 to the surface 7 of a metal support 2 for the braking element 1 in an anti-noise Shim of an exemplary case, the method comprising a step of pretreating such a surface 7 before the gluing step; i. The step of pretreating such a surface 7 consists of applying a primer compound to the surface 7; ii. The primer compound consists of an organotitanate 10 diluted in an organic solvent for easier application, It is clear that it extends to the method.

[0073] The organotitanate is tetra-alkoxytitanium (IV) represented by the general formula [1] mentioned above, and R is the same or different and is represented by one of the alkyl groups mentioned above.

[0074] In a preferred embodiment, the organic solvent is an alcoholic polar solvent.

[0075] In a preferred embodiment, the alcoholic polar solvent is selected from the group consisting of isopropyl alcohol, ethanol, acetone, and mixtures thereof.

[0076] Referring to Figure 7, the method of the present invention preferably comprises the following steps: a) A first step 100 of coating the surface 7 with an epoxy resin 9; b) A second step 200 of applying a selected organotitanate diluted in an organic solvent onto the surface 7 already coated with the epoxy resin 9 in order to form a uniform layer 10 of the organotitanate in solution on the surface 7 and the epoxy resin 9, and then allowing the layer 10 to stand and dry; c) A third step 300 of gluing the covering sheet element 6 to the surface 7 already coated and pretreated with the organotitanate 10 diluted in an organic solvent by applying an adhesive 8 based on an acrylic paste or an acrylic resin between the covering sheet element 6 and the uniform layer 10 of the organotitanate. comprises.

[0077] The organotitanate 10 can be diluted in an alcoholic polar solvent at a dilution of 0.5% - 5% v / v.

[0078] The organotitanate 10 diluted in an organic solvent - by spraying the organotitanate 10 solution, - by a roller (known and not shown for the sake of brevity) coated with the organotitanate 10 solution, - by non-uniformly dropping the organotitanate 10 solution onto the surface 7 and then uniformly distributing it by a cloth or any kind of applicator covered with a cloth, such as a rotating disk can be applied to the surface 7 using a technique selected from the group consisting of.

[0079] The present invention relates to a method for manufacturing a braking element 1 comprising a support 2, a friction material block 5 attached to the support 2, and an anti-noise element 6 also attached to the opposite side of the support 2 from the friction material block 5, which, in addition to all the above steps 100 to 300, includes a step 400 (Figure 7) of molding the friction material block 5 on the support 2, which is also clearly applicable to the method.

[0080] Of course, step 400 is shown in the sequence following step 300 only for illustrative purposes in Figure 7, but is normally carried out before step 100, i.e., upstream of step 100, and as a result, the friction material block 5 is also completely or partially coated with the epoxy resin 9. Conversely, steps 100 to 300 are carried out in the same sequence as shown in Figure 7.

[0081] Finally, the present invention also relates to the use of a primer compound for promoting the adhesion of an anti-noise sheet element or shim 6 to the surface 7 of the metal support 2 of the braking element 1, the backplate 2 of the automotive brake pad 1 in the preferred embodiment shown, - the surface 7 can be coated with an epoxy resin 9, - the anti-noise shim 6 can be pasted onto the surface 7 with an acrylic paste 8 or an adhesive 8 based on an acrylic resin, - the primer compound is spread over the epoxy resin paint 9 covering the surface 7 such that it is inserted between the epoxy resin 9 and the acrylic resin paste or adhesive 8; - the primer compound consists of an organotitanate 10 diluted in an organic solvent, preferably an alcoholic polar solvent, which is spread to form a uniform layer 10; - the organotitanate is tetra-alkoxytitanium(IV) represented by the general formula Ti(OR)4, where R is as defined above, which is clearly applicable to the use.

[0082] In a preferred embodiment of the use according to the present invention, the organotitanate is diluted in an alcoholic polar solvent at a dilution of 0.5% to 5% v / v, then applied to the surface 7, allowed to stand and dry at room temperature, and then pasted onto the shim 6.

[0083] The present invention will be further described below with reference to the following actual examples, which also serve as clear evidence of its effectiveness and demonstrate that the present invention works effectively.

Example

[0084] The organotitanate consisting of tetra-n-butyl titanate is diluted in isopropyl alcohol at a dilution of 1% v / v and applied to the surface of a commercially available backplate designed to receive an anti-noise shim during use.

[0085] The backplate is painted with a commercially available epoxy resin paint.

[0086] The organotitanate is applied by dropping 4 drops of the organotitanate alcohol solution onto the target surface and then manually spreading it over the entire surface using a cloth.

[0087] The applied organotitanate alcohol solution is allowed to stand and dry at room temperature for several seconds (less than 10 seconds).

[0088] Thereafter, a commercially available anti-noise shim pre-pasted with a commercially available acrylic adhesive is applied to the pre-pasted side of the organotitanate-treated surface with a pressing time of 1 to 5 seconds and a pressing force included between 1000 and 2000 Kg.

[0089] Thereafter, the adhesiveness is measured by lap shear strength and tensile tests, and the results are compared with the same tests applied to the same backplate that receives the same pre-pasted shim but without pretreatment of the receiving surface of the backplate with organotitanate.

Example

[0090] Tensile test The test is carried out as shown in Fig. 3. The shim 6 is attached to the surface 7 of both backplates 2 which are untreated (surface 7 without the organotitanate layer 10) and pretreated with the organotitanate primer 10. After 24 hours, a part of the shim 6 is folded at 90° as shown in Fig. 3.

[0091] The adhesiveness of the shim 6 to the backplate 2 (both pretreated and untreated) is measured by pulling the anti-noise shim 6 in a direction perpendicular to the surface 7 of the backplate 2 with a force F A The resulting force is given by the following formula: [2] pA = F A / l (where pA is the tensile force and l is the width of the shim 6) is calculated in N / mm by:

[0092] The results are reported in Table 1 below.

[0093]

Table 1

Example

[0094] Double shear test The test is carried out as shown in Fig. 4. The shim 6 is attached onto the surface 7 of both backplates 2 which are untreated (surface 7 without the organotitanate layer 10) and pretreated with the organotitanate primer 10 as in Example 2. After 24 hours, the anti-noise shim 6 is subjected to a shear stress pA by applying an axial force F A in a direction parallel to the surface 7 to the backplate 2. The resulting force is given by the following formula: [3] pA = F A / l*m (where pA is the double shear force, l is the width of the shim 6, and m is the length of the shim 6 pasted onto the backplate) is calculated in N / cm 2 by:

[0095] The results are reported in Table 2 below.

[0096] [Table 2]

Example

[0097] Tensile test vs. amount of primer Shim 6 is attached onto the backplate surface 7 pretreated with an organotitanate primer consisting of commercially available tetra-n-butyl titanate (Tyzor-TnBT) at different concentrations of 0.5%, 1%, 5% and 10 v / v in isopropyl alcohol. After 24 hours, a part of Shim 6 was folded at 90°.

[0098] The adhesion of Shim 6 to the backplate 2 is measured by pulling the anti-noise Shim 6 in a direction perpendicular to the backplate surface 7 as described in Example 2. The resulting force is calculated by Equation [2] and reported in Table 3 below.

[0099] [Table 3]

[0100] The use of the organotitanate primer can be seen to increase the adhesion of Shim 6 at all concentrations. However, the best performance is achieved at a concentration of 1%. In fact, dilutions of 0.5, 5 and 10% v / v show applied forces lower than the applied force obtained with the primer diluted at 1% v / v. Conclusion The use of the organotitanate primer results in chemical crosslinking between the underlying layer and the adhesive shim in such a way that the traditional flame treatment of epoxy paints can be eliminated.

[0101] Another advantage of using the method of the present invention is the reduction of the risk and cost of anti-noise sheet applications due to the low amount of organotitanate required.

[0102] The alkoxy groups of the selected organotitanate have actually been shown to be readily hydrolyzed by some of the groups present on the surface of epoxy and acrylic resins. Thus, the connection sites between the two resins are increased, and accordingly, a durable crosslink is formed between them.

[0103] The advantages of this solution are as follows: 1) Avoidance of flame treatment.

[0104] 2) Increase in the adhesiveness of the sheet for an indefinite period through chemical bonding by both the epoxy resin of the backplate and the acrylic resin of the anti-noise sheet.

[0105] 3) Reduction of the risk and cost of anti-noise sheet applications.

[0106] Therefore, all the objects of the present disclosure are fulfilled. Specific terms Although specific braking devices, systems, and methods are disclosed in the context of specific example embodiments, the scope of the present disclosure extends beyond the specifically disclosed embodiments, such as the brakes shown for braking systems based on brake drums, to other alternative embodiments and / or uses of the embodiments, as well as their specific variations and equivalents, which will be understood by those skilled in the art. Use in any structure is clearly within the scope of the present invention. The various features and aspects of the disclosed embodiments can be combined with each other or substituted to form various modes of assembly. The scope of the present disclosure should not be limited to the specific disclosed embodiments described herein.

[0107] Terms representing conditions, such as "can", "could", "might", or "may", generally convey that a particular embodiment includes or does not include a particular feature, element, and / or step, unless specifically stated otherwise or understood otherwise within the context in which they are used. Thus, such terms representing conditions are not generally intended to imply that such feature, element, and / or step is required in one or more embodiments.

[0108] Unless stated otherwise, the terms "about", "approximately", and "substantially", as used herein, still represent an amount close to the stated value that performs the desired function or achieves the desired result. For example, in some embodiments, as the context may describe, the terms "about", "approximately", and "substantially" may refer to an amount within or equal to 10% less than the stated value. Similarly, the term "generally", as used herein, represents a value, amount, or characteristic that mainly includes or tends towards a particular value, amount, or characteristic.

[0109] This disclosure clearly contemplates that the various features and aspects of the disclosed embodiments can be combined with or substituted for each other. Thus, the scope of this disclosure should not be limited by the above - specifically disclosed embodiments, but should be determined only by a fair reading of the following claims and their full scope of equivalents.

Claims

1. A method for fixing a coated sheet element (6) to a surface (7) of a metal support (2) for a braking element (1) by gluing the coated sheet element to the surface, comprising a step of pretreating the surface (7) before the gluing step; i. the step of pretreating the surface (7) consists of applying a primer compound to the surface; ii. the primer compound consists of an organotitanate (10) diluted in an organic solvent characterized in that it is a method.

2. wherein the organotitanate (10) is represented by the general formula Ti(OR) 4 (wherein all Rs are the same or different and are preferably selected from the group consisting of an unsubstituted alkyl group having either a single-chain or branched-chain structure; a substituted alkyl group having either a single-chain or branched-chain structure, and the substituent is selected from the group consisting of amino, phosphorus, ether, and unsaturated hydrocarbon groups) is tetra-alkoxytitanium (IV), and the method according to claim 1 is characterized in that.

3. The method according to claim 1 or 2, characterized in that the organic solvent is an alcoholic polar solvent.

4. The method according to claim 3, characterized in that the alcoholic polar solvent is selected from the group consisting of isopropyl alcohol, ethanol, acetone, and mixtures thereof.

5. The following steps: a) a step (100) of coating the surface with an epoxy resin (9); b) a step (200) of applying the organotitanate (10) in an organic solvent onto the surface (7) already coated with the epoxy resin (9) in order to form a uniform layer of the organotitanate (10) in solution on the surface and on the epoxy resin; c) a step (300) of gluing the coated sheet element (6) to the surface (7) already coated and pretreated with the organotitanate (10) diluted in an organic solvent by applying an adhesive (8) based on acrylic paste or acrylic resin between the coated sheet element (6) and the uniform layer of the organotitanate (10) in solution characterized in that it comprises the method according to any one of claims 1 to 4.

6. The coated sheet element consists of an anti-noise shim (6), and the metal support consists of a backplate (2) of an automotive brake pad (1), the surface (7) defining the extent of its first face (3) opposite to the second face (4) of the backplate (2) carrying the friction material block (5); the method according to any one of claims 1 to 5, characterized in that the organotitanate (10) is diluted in an alcoholic polar solvent at a dilution of 0.5% to 5% v / v.

7. The organotitanate (10) diluted in an organic solvent is by spraying the organotitanate solution by means of a roller coated with the organotitanate solution by dropping the organotitanate solution unevenly onto the surface and then distributing it evenly by means of an applicator covered with a cloth or a fabric The method according to any one of claims 1 to 6, characterized in that it is applied to the surface (7) using a technique selected from the group consisting of

8. A braking element (1), in particular a brake pad, comprising a support (2) for a friction material block (5) and an anti-noise shim (6) applied on the side of the support opposite to the friction material block, wherein the shim (6) is attached to a first face (3) of the support on the side opposite to the friction material block, and in combination i) - the first face (3) of the support is coated with a first layer of epoxy resin (9); ii) - a second layer of organotitanate (10) is spread over the first layer of epoxy resin (9), the organotitanate containing alkoxy groups; iii) - the shim (6) is attached to the first face (3) by a third layer of acrylic resin (8) on the second layer of organotitanate (10); iv) - at least a part of each of the alkoxy groups is hydrolyzed by both the acrylic resin and the epoxy resin (9, 8) to form a chemical bond (11) between the first layer and the third layer characterized braking element.

9. The organotitanate (10) for forming the second layer is represented by the general formula Ti(OR) 4 (wherein R is the same or different, preferably a non-substituted alkyl group having either a single-chain or branched-chain structure; a substituted alkyl group having either a single-chain or branched-chain structure, and the substituent is selected from the group consisting of amino, phosphorus, ether, and unsaturated hydrocarbon groups), and is tetra-alkoxytitanium (IV). The braking element according to claim 8, characterized in that it is as described above.

10. Use of a primer compound for promoting the adhesion of an anti-noise sheet element (6) or shim to the surface (7) of a metal support (2) of a braking element (1), in particular the backplate of an automotive brake pad, - the surface (7) is coated with an epoxy resin (9), - the anti-noise shim (6) is pasted onto the surface with an acrylic paste or an acrylic resin-based adhesive (8), i) - the primer compound is spread over the epoxy resin paint layer (10) covering the surface (7) so as to be inserted between the epoxy resin (9) and the acrylic resin paste or adhesive (8); ii) - the primer compound consists of an organotitanate (10) diluted in an organic solvent, preferably an alcoholic polar solvent; iii) - the organotitanate (10) is of the general formula Ti(OR) 4 wherein R is the same or different, preferably a non-substituted alkyl group having either a single-chain or branched-chain; a substituted alkyl group having either a single-chain or branched-chain, and the substituent is selected from the group consisting of amino, phosphorus, ether, and unsaturated hydrocarbon groups), and is tetra-alkoxytitanium(IV) represented by the formula characterized use.

11. The use according to claim 10, wherein the organotitanate (10) is diluted in an alcoholic polar solvent at a dilution of 0.5% to 5% v / v, then applied to the surface (7), and left to dry at room temperature.

12. A method for manufacturing a braking element (1) comprising a support (2), a friction material block (5) attached to the support, and an anti-noise element (6) also attached to the opposite side of the support from the friction material block, the method comprising, in addition to all the steps of the method according to claims 1 to 7, a step (400) of molding the friction material block (5) on the support (2).

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