BR102016008523A2 - BRONZINA COVERED WITH POLYMERIC COVERAGE FOR REDUCTION OF DAMAGE IN INTERNAL COMBUSTION ENGINES AND PROCESS FOR SAME PRODUCTION - Google Patents

Abstract

Polymer-coated friction reducing bearing in internal combustion engines and process for producing the same invention relates to the polymeric-coated friction reducing bearing in internal combustion engines. furthermore, the present invention relates to the process for producing friction-reducing polymer-coated bronzine in internal combustion engines, particularly by introducing an adhesion layer between the metal surface of the bronzin and the polymeric coating, said layer obtained from the previous immersion of the bronzine in a hydroalcoholic solution of organo silanes and subsequent thermal curing, resulting in the formation of a polysiloxane film containing chemical groups capable of diverse interactions with the subsequent polymeric coating.

Description

(54) Title: BRONZINE WITH POLYMERIC COVER FOR REDUCING FRICTION IN INTERNAL COMBUSTION ENGINES AND PROCESS FOR THE PRODUCTION OF THE SAME (51) Int. Cl .: B29C 63/00; B29C 63/48; C07F 7/12 (52) CPC: B29C 63/0065, B29C 63/48, B29C 63/486, C07F 7/12, B29C 2063/483 (73) Holder (s): INSTITUTO NACIONAL DE TECNOLOGIA, MAHLE METAL LEVE S.A.

(72) Inventor (s): MÁRCIA GOMES DE OLIVEIRA; DJANIRA MARIA DE REZENDE COSTA; FERNANDA CRISTINA DE SOUZA COELHO DOS SANTOS; ELLEN GUIMARÃES OLIVEIRA GRANCE; DENISE DE SOUZA FREITAS; LISIANE GONÇALVES LIMA; CASSIO BARBOSA; IBRAHIM DE CERQUEIRA ABUD; MATHEUS DE SANTOS FERREIRA; SANDRA MATOS CORDEIRO COSTA; PAULO ROBERTO VIEIRA DE MORAIS (57) Abstract: Bearing with polymeric cover to reduce friction in internal combustion engines and process for producing the sameThe present invention refers to bearing with polymeric cover for reducing friction in internal combustion engines. In addition, the present invention relates to the process for the production of polymer-coated bearings to reduce friction in internal combustion engines, particularly by introducing an adhesion layer between the metallic surface of the bearing and the polymeric coating, the referred to being layer obtained from the previous immersion of the bearing in hydro-alcoholic solution of organosilanes and subsequent thermal curing, resulting in the formation of a polysiloxane film containing chemical groups capable of various interactions with the subsequent polymeric coating.

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Polymeric coated bearing for friction reduction in internal combustion engines and process for producing it

Fields of the invention [0001] The present invention relates to the field of friction in combustion engines. More specifically, the present invention relates to the bearing with polymeric cover for reducing friction in internal combustion engines. In addition, the present invention relates to the process for the production of polymer-coated bearings to reduce friction in internal combustion engines.

Description of the invention [0002] The present invention concerns the process of coating aluminum or bronze alloy bearings, consisting of: a first degreasing step of the metal surface, using water, neutral detergent and organic solvent; a second stage of basic surface activation with sodium hydroxide solution; a third stage of pre-treatment of the metallic surface with hydro-alcoholic solutions of mono and bifunctional silanes, aiming at the formation of a polysiloxane film with the function of anchoring the polymeric coating, later applied to the surface of the bearing; a fourth stage of condensation of the silanes to form the polysiloxane film; a fifth stage of application of the polymeric coating composed of poly (amide-imide), poly (tetrafluoroethylene) and aluminum flakes; and a sixth stage of thermal curing of the polymeric coating applied to the bearing. The composition of mono and bifunctional silane hydro-alcoholic solutions were also the object of development of this invention, as well as the curing time and temperature conditions for the formation of the polysiloxane film.

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Background of the invention [0003] The adhesion of polymeric coatings to metal surfaces requires their activation. This activation can be chemical, usually by basic attacks, acid attacks, phosphating, chrome plating and also by the deposition of oxides via sol-gel, whose main function is to generate chemically active groups and roughness that favor the adhesion of a polymeric coating. There is also mechanical activation, usually by blasting the metal surface with oxides, which mainly promotes the roughness of the metal surface by providing physical anchor points for the polymeric coating. Currently, aluminum or bronze bearings with polymeric coating generally have their surface activated by sandblasting with oxides, prior to the application of such coating. This operation has as main drawback the generation of residues on the metallic surface, which, later, can cause a premature failure of the coating. By replacing this step with a pre-treatment with silane, it is possible to promote a chemical adhesion of the polymeric coating, eliminating the problem of depositing blasting residues and a possible premature failure of the bearing in the engine.

[0004] The formation of metal oxides and hydroxides, in addition to other corrosion products at the interface between the metal and a coating, can compromise the mechanical and electrical stability of the assembly. This formation is particularly pronounced in humid environments. In the case of aluminum, its surface is naturally protected by a thin oxide layer, which provides passivation to the metal at room temperature and moderate relative humidity. Exposure to higher temperature and humidity induces the transformation of aluminum oxide into aluminum oxide-hydroxide (AlO (OH)) and finally, if the transformation is complete, to hydroxide of aluminum.

Petition 870160014263, of 4/15/2016, p. 12/34 / 19 aluminum (Al (OH) ₃ ).

[0005] The changes in the chemical composition of the surface are accompanied by changes in the original morphology of the thin oxide layer, passing to a flake structure and finally to a plate structure. These changes are associated with layers that are mechanically weaker and non-passivated. As it is possible to change the thickness of the oxide layer by these transformations, the mechanical integrity of the interface with the coating becomes weaker, which can lead to mechanical separation between the substrate and the coating.

[0006] The change in the roughness of the metallic surface is a device to improve the adhesion of polymeric coatings and thus obtain structural durability in humid or corrosive environments. The most common practices for inserting or accentuating the roughness on the metal surface are: blasting, chemical activation or anodizing and each technique has its limitations.

[0007] In the last 20 years the number of studies and technologies developed with organic coupling agents has grown considerably, which are able to chemically bond to the metallic surface and also to a subsequent layer of polymeric coating of the type epoxy resin, polyamides, silicones and others.

[0008] The main examples of such coupling agents are organo-silanes, organo-titanates and organo-zirconates. Typically, these compounds have a terminal group capable of reacting with one or more families of polymers, examples of which groups are amino, mercapto and epoxy. In addition, these compounds have one or more groups capable of binding to the metallic substrate, such as alkoxy, aryloxy or halides. [0009] In this context, it is known in the state of the art that most metals, when exposed to the atmosphere, form oxides on their surface.

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Hydroxide groups begin to associate with the oxides formed on the surface, especially when the metal is exposed to water, either in the atmosphere or by chemical reaction or by adsorption via hydrogen bonding or van der Waals force. When the organic coupling agent (organo-silane, organo-titanate, organo-zirconate) comes into contact with this metal surface, the hydrolysis of the alkoxy group occurs, for example, attached to the Si or Ti or Zr atom forming alcohol and the bond (Si or Ti or Zr) -O-Metal. This reaction anchors the organic portion of the coupling agent to the metallic substrate and allows another functional group at the end of the chain to be available to react with a polymeric coating. Among the organic coupling agents mentioned, organo-silanes are the most studied and have the largest number of developed applications.

[00010] Silanes are hybrid molecules containing functional organic groups such as methoxy and ethoxy, attached to the silicon atom. Some types of silanes have other functional groups in addition to those already mentioned, especially chlorine, amine, sulfur and epoxide. These are called functional silanes, in which additional functional groups promote adhesion with organic films, such as coating paints. [00011] The ethoxy or methoxy groups are hydrolyzed when water is added to the system, forming the silanol groups -Si-OH, which react with the hydroxide groups on the metal surface, creating a film at the interface with covalent chemical bonds of the type - Si-OM. Unlike chemical conversion treatments such as “chrome plating” or zirconium / titanium conversion, in which metal oxidation and species reduction govern surface conversion, silanes do not require the metal to participate electrochemically in the deposition mechanism of movie.

Petition 870160014263, of 4/15/2016, p. 14/34 / 19 [00012] The curing of the silane layer is considered essential considering its purpose of anti-corrosive protection. The heating of the coated substrates results in the crosslinking between the silane molecules inside the deposited film. The silanol groups, which did not react with the metallic surface, undergo condensation forming siloxane chains Si-O-Si. The crosslinking and branching produce dense networks, which limit the access of electrolytes to the adjacent metal surface and, therefore, an effective barrier against corrosive attack is formed.

[00013] DE GREAVE et al. (Progress in Organic Coatings 59, 224-229. 2007) investigated the healing influence of bis-1,2- (triethoxysilyl) ethane (BTSE) on aluminum substrate (AA1050 99.5% Al ), using complementary techniques such as ellipsometry (ES), electrochemical impedance spectroscopy (EIS), exploratory differential calorimetry (DSC) and thermogravimetric analysis combined with mass spectrometry (TGA-MS). The silane films were deposited on aluminum by immersion in methanolic solution with acidic pH. The temperature range in which curing can take place ranges from 100 to 300 ° C, with maximum rates being obtained at 200 ° C. The infrared spectra revealed an increase in the absorption band relative to the Si-O-Si group, while the band relative to the Si-OH group has its absorption reduced by the curing process. The silane film initially formed is densified and shrunk by curing, as demonstrated by the ellipsometry data, resulting in barrier properties, according to the electrochemical impedance spectroscopy data.

[00014] Bis-1,2- (triethoxysilyl) ethane (BTSE) is the most common compound and found in several commercial silane mixtures for the deposition of thin films. However, the BTSE molecule is poorly soluble in water,

Petition 870160014263, of 4/15/2016, p. 15/34 / 19 As a result, the use of BTSE methanolic solutions was very common. From an industrial point of view, these solutions had their use discontinued, in view of the toxicity arising from the high content of methanol and silane itself. Thus, the aqueous solutions of BTSE started to be supplied commercially and used within the industry. However, its stability is limited, since the addition of excess water can lead to the anticipated hydrolysis of the ethoxy groups, generating an undesirable competition between the reaction of the silanol groups with the metal and the condensation reaction. The formation of long chain species as a result of the condensation reaction reduces the reactivity with the metal surface.

[00015] Compared to the methanolic solution of BTSE the aqueous solution has less monomer and more condensed polymers, which affects the structure of the silane layer deposited on the metal. In the uncured condition, the silane layer from the aqueous solution already has polymerized species. The electron microscopy images revealed similarities between the two silane films, but the properties of the layers can be affected in another way. The curing kinetics of these films will be different, since crosslinking has already started in a previous way in the aqueous solution and thus larger species can combine, which is important with regard to the barrier property of the film. Therefore, after a short curing time, the barrier performance of the film from the aqueous solution of BTSE is superior. In fact, the results of electrochemical impedance spectroscopy reveal this behavior (DE GREAVE et al, Progress in Organic Coatings 63, 38-42. 2008).

[00016] It is worth mentioning that another important factor regarding the morphology of the formed film is the concentration of the silane solution. The more diluted the silane solution, the less compact the layers of the

Petition 870160014263, of 4/15/2016, p. 16/34 / 19 deposited film (DE GREAVE et al, Progress in Organic Coatings 63, 38-42. 2008).

[00017] FRIGNANI and collaborators (Corrosion Science 48, 2258-2273. 2006) studied the inhibitory effects of silane compounds (with 3 or 8 or 18 long aliphatic carbon atoms) for the corrosion of aluminum alloy AA7075 in solutions 0.1N Na2SO4 or NaCl compared to those provided by BTSE. Polarization curves were recorded using the electrochemical impedance spectroscopy technique. [00018] The aluminum was previously sanded, washed with distilled water, degreased with acetone, activated in a basic medium and washed again before immersion in the methanolic solution of the organo-silanes. The cure was carried out at 100 ° C for 1 hour (FRIGNANI et al, Corrosion Science 48, 2258-2273. 2006).

[00019] The presence of a long aliphatic chain in the silane molecule sharply increases the protective action of these films. The greater the alkyl chain, the greater the action. This improvement is related to the increase in the thickness of the film, which causes a noticeable impediment to the penetration of aggressive aqueous solutions. Such layers completely cover the aluminum surface, although not uniformly. While all silane layers inhibit the cathodic reaction, only organo-silane with C ₁₈ chain can inhibit the anodic reaction, even in the presence of chlorides (FRIGNANI et al, Corrosion Science 48, 2258-2273. 2006).

[00020] CORREA-BORROEL and collaborators (Journal of Applied Electrochemistry 39, 2385-2395. 2009) evaluated the effect of the size of the alkyl radical of non-functional organo-silanes in films deposited on the AA2024 aluminum surface (92.5% Al) and with organic coating

Petition 870160014263, of 4/15/2016, p. 17/34 / 19 adjacent polypyrrole. The organo-silanes studied were propyl (C3), octyl (C8) and octadecyl (C18) trimethoxysilane. The silane film was deposited by immersion in methanolic solution and curing was carried out at 80 ° C for 1 hour. Polypyrrole coating was performed by electrodeposition. The aluminum surface was previously sanded and degreased. It was observed that the corrosion protection was only limited and decays when subjected to highly corrosive environments, such as saline fog cabins, for prolonged periods. The combination of the silane film and the polypyrrole coating produces a structure that provides better protection over time. The best performance is achieved with the deposition of polypyrrole on silanes, due to the excellent bond between the silane adsorbed on the aluminum surface and the polypyrrole film. Of the three organosilanes used, the one with the smallest chain has the best performance. When long chain organo-silanes are used, the polypyrrole film becomes independent, due to less interaction between the layers. Electrochemical impedance spectroscopy and layer morphological studies also revealed greater adhesion and less deterioration of polypyrrole deposits in silane layers.

[00021] COMYN and collaborators (International Journal of Adhesion & Adhesives 20, 77-82. 2000) compared the pretreatment of aluminum joints with glycidoxypropyltrimethoxysilane (GPTMS), 3-aminopropyltrimethoxysilane (APES) and anodization with phosphoric acid (PAA ). The aluminum used was AA1050 (99.5% Al), which was defatted with methyl ethyl ketone (MEK). The deposition of the silane films was performed by immersion in a 2% aqueous solution of GPTMS or APES and drying was carried out at room temperature. Anodization with phosphoric acid was carried out in a bath with phosphoric acid solution (10%)

Petition 870160014263, of 4/15/2016, p. 18/34 / 19 at 10V in stainless steel tank, which functioned as a cathode and drying was carried out at room temperature. After the pre-treatment, the sealant was applied based on a copolymer of nitrile rubber functionalized with amine groups and epoxy resin.

[00022] Both silanes chosen are functional, that is, they have groups capable of reacting chemically with the sealant, forming an interface with aluminum through covalent chemical bonds, since the silanol groups react with the metallic surface and the epoxy group of the GPTMS reacts with the amine groups of the nitrile rubber, while the amine groups of the APES react with the epoxy resin. The use of both GPTMS and APES promoted an increase in the strength of adhesion, as observed for PAA. In addition, the resistance to fluids such as gasoline, water and water and antifreeze mixture has been improved, that is, the joints maintained their adhesion strength for up to 15 weeks of immersion in these fluids (COMYN et al. International Journal of Adhesion & Adhesives 20, 77-82. 2000).

[00023] SETH and collaborators (Progress in Organic Coatings 58, 136-145. 2007) used bis [3- (triethoxysilyl) propyl] (BTESPT) tetrasulfide in conjunction with epoxy-acrylate or novolac-epoxy-polyurethane and phosphate resins of zinc within the concept of superprimers. All components of the formulation were mixed with high shear and deposited on aluminum surfaces AA2024-T3. The cure was carried out at room temperature for 14 days.

[00024] EP1097259, owned by the University of Cincinnati (2005), addresses the use of silane polysulfide solutions to obtain protective films deposited on a wide range of metallic substrates, including zinc, copper, aluminum and their alloys. O

Petition 870160014263, of 4/15/2016, p. 19/34 / 19 solvent of these solutions is a mixture of alcohol and water, the pH around 4 and the concentration of silane in the range of 1 to 5%. The deposition of the film can be by immersion, spray or another conventional technique. The results obtained after immersion in NaCl solution for 1000h were exceptional for substrates coated with silane films.

[00025] The US6827981 patent, also owned by the University of Cincinnati, presents a mixture of functional organo-silanes, more specifically vinyl-silane and bis-silyl-amino-silane, for the deposition of protective films on zinc substrates and their alloys. These films do not need to be removed for subsequent applications of paints, adhesives and other polymeric layers, on the contrary, it acts to favor the anchoring of these coatings. The solutions containing the functional organo-silanes is preferably aqueous, but it also contains organic solvents of the alcoholic class to increase the solubility of the hydrolyzed silanes. The pH of the solution can vary between 4 and 10, depending on the ratio between vinyl-silane and bis-silyl-amino-silane, preferably around 4. The metallic substrate must be cleaned with solvent or chemically activated in alkaline medium. The deposition of the film can be by immersion, spray or any other technique and drying is carried out at 90 ° C for 1 hour. The protection mechanism is the establishment of a dense polymeric network formed by the inter and intra silane reaction, in addition to an effective anchoring on the metal surface due to the action of Si-OH silanol groups, which are chemically bonded to the metal surface -Si-OM .

[00026] EP patent 1153089, filed by the company Chemetall PLC (2007), follows the same line as the patent of the University of Cincinnati, combining vinyl-silane with bis-silyl-silane in aqueous / alcoholic solutions. The ratio of vinyl-silane to bis-silyl-silane around 1: 2 and pH in the range

Petition 870160014263, of 4/15/2016, p. 20/34 / 19 from 3 to 6. The range of metallic substrates was expanded with the insertion of steel, iron and aluminum. The deposition was also carried out by methods known as immersion or spray. Drying is carried out in the range of 40 to 180 ° C for a sufficient time. The proposed mechanism is exactly the same as in the previous patent, that is, the formation of a dense polymeric network by the reaction between the silanes, and the affinity of bis-silyl-silane for the metal surface is greater compared to vinyl-silane.

[00027] Previously, Chemetall PLC (2002) had filed the US6361592 patent in the same way as described above, but using ureico-silane instead of vinyl-silane combined with bis-silyl-silane. The other variables were very similar if not the same, with the exception of the ratio between ureico-silane and bis-silyl-silane that around 1:10.

[00028] Still in the line of combining silanes, the company Shin-Etsu Chemical Co. (2006) filed the patent EP1705231 addressing the development of aqueous solutions for mixing amino-silane with bis-silyl-silane, aiming at the formation of films, via immersion, preferably in several steel substrates. The pH conditions of the solution and drying of the film are identical to those reported in the other patents.

[00029] BEXELL and OLSSON (Surface and Interface Analysis 35, 880-887. 2003) evaluated the use of mixtures of functional and non-functional organo-silanes for the formation of films on aluminum, zinc and aluminum and zinc alloys. For this purpose, 1,2-bis (triethoxysilyl) ethane (BTSE) and mercaptopropyltrimethoxysilane (MPS) were chosen. The deposition was carried out by immersion in two stages, the first being immersed in BTSE solution and the second in MPS solution, both containing methanol and water in the ratio 60%: 40%. The variables in this study were the pH of the bath and the composition of the metallic substrate. The metal surface was previously polished,

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12/19 defatted and activated in alkaline medium. After immersion, the substrates were dried in an inert atmosphere.

[00030] ToF-SIMS analyzes (Flight Time SIMS or static SIMS) revealed that BTSE was completely hydrolyzed, while MPS was only partially hydrolyzed. In addition, the presence of negative ions of the HSi _x O _y - type indicates that the two silanes formed a highly cross-linked film with Si-O-Si type bonds. The two-stage treatment resulted in a bilayer film, the upper one being basically composed of the MPS. However, the thickness of this bilayer film was less than the film obtained only by depositing the BTSE, suggesting that part of the BTSE is dissolved during the immersion stage in the MPS solution in the two-stage process. Finally, it was found that the MPS mercapto group was not oriented outside the molecule, which would be of interest for the deposition of a third layer of another organic substance (Surface and Interface Analysis 35, 880-887. 2003).

[00031] Currently, bearings have their surfaces mechanically activated with oxide blasting, which increases the surface roughness, providing physical anchoring points, in addition to favoring the formation of an aluminum oxide layer, which in contact with the humidity of the air generates aluminum hydroxide, which contributes to the chemical anchoring of the poly (amide-imide) coating that contains in its formulation a mixture of mono and bis-silane.

[00032] However, blasting has the inconvenience of accumulating tiny oxide particles on the bearing surface, which result in premature failure of the part, as they impair the adhesion of the coating. Such dirt on the surface significantly impairs the load capacity. The bearing being a hydrodynamic bearing, any dirt breaks

Petition 870160014263, of 4/15/2016, p. 22/34 / 19 the oil film leading to scratches and potential locking and rapid degradation of the part.

Detailed description [00033] The present invention relates to the bearing with polymeric cover for reducing friction in internal combustion engines. In addition, the present invention relates to the process for the production of polymer-coated bearings to reduce friction in internal combustion engines.

[00034] The present invention concerns the process of coating aluminum or bronze bearings, consisting of a first stage of degreasing the metal surface, using water, neutral detergent and organic solvent; a second stage of basic activation of the bearing surface with aqueous sodium hydroxide solution; a third stage of pre-treatment of the metallic surface with hydro-alcoholic solutions of mono and bifunctional silanes, aiming at the formation of a polysiloxane film with the function of anchoring the polymeric coating, later applied to the surface of the bearing; a fourth stage of condensation of the silanes to form the polysiloxane film; a fifth stage of application of the polymeric coating composed of poly (amide-imide), poly (tetrafluoroethylene) and aluminum flakes; and a sixth stage of thermal curing of the polymeric coating applied to the bearing. The composition of mono and bifunctional silane hydro-alcoholic solutions were also the object of development of this invention, as well as the curing time and temperature conditions for the formation of the polysiloxane film.

[00035] The bearings are produced by casting a bronze alloy on a steel strip or by joint lamination

Petition 870160014263, of 4/15/2016, p. 23/34 / 19 (cleavage) between an aluminum alloy strip and another steel strip, later stamping and finishing machining for the final curved shape.

[00036] Before pretreatment with organo-silane hydro-alcoholic solutions it is necessary to clean the surface, in order to eliminate the grease from this metallic surface, guaranteeing the access of the reagents involved in the basic attack and in the pretreatment with hydro-alcoholic solution of organo-silanes on the surface of aluminum or bronze. [00037] Cleaning the surface consists of washing the bearing in three stages:

(i) Washing with distilled water;

(ii) Washing with neutral detergent;

(iii) Washing with organic solvent (acetone or methylene chloride) in an ultrasound bath for 10 min.

[00038] After cleaning to remove grease, a basic activation is made with aqueous 0.5M sodium hydroxide solution. This activation is carried out by immersing the bearing in a bath of aqueous sodium hydroxide solution with molar concentration between 0.05 and 1M, more preferably 0.5M, for up to 15 minutes, more preferably 5 minutes. Afterwards, the bearing is washed with plenty of distilled water and dried with an air blower. This activation has the function of generating hydroxyl groups on the aluminum surface, capable of chemically reacting with organo-silanes, via the hydrolysis mechanism.

[00039] Subsequently, the chemically activated aluminum or bronze bearings are immersed in a bath with hydro-alcoholic solution of organo-silanes at room temperature for up to 5 minutes, more preferably 2 minutes. The pair of solvents in the hydro-alcoholic solution is

Petition 870160014263, of 4/15/2016, p. 24/34 / 19 water and an alcohol with a hydrocarbon chain of up to 4 carbons, more preferably 2 carbons, and the water / alcohol ratio can vary from 10% / 90% to 90% / 10%, more preferably 50% / 50% . This bath must be kept under constant agitation. The organo-silanes used can be monosilanes, bis-silanes or a mixture of both, being hybrid molecules that contain hydroxyl groups or functional organic groups such as, for example, methoxy and ethoxy, linked to the silicon atom and other functional groups in addition to already mentioned with emphasis on chlorine, amine, sulfur and epoxide.

[00040] The concentration of the organo-silane or the organo-silane mixture can vary from 4% to 8% by volume in the hydroalcoholic solution, more preferably 4%. Once prepared, the organo-silane hydroalcoholic solution must remain under light and constant agitation for up to 60 minutes, more preferably 30 minutes, before starting the immersion of the bearings, so that the hydrolysis of the alkoxy groups occurs with the formation of the groups hydroxyl, which are responsible for the chemical interaction with the metallic surface (aluminum or bronze) of the bearing and later for the formation of the polysiloxane film during curing [00041] The immersion bath in hydro-alcoholic solution can contain only one monosilane or a mixture of monosilanes or a mixture of mono and bis silanes. In a mixture of organo-silanes, whether these are mono- or bis-silanes, it can vary from 95% / 5% to 80% / 20% by volume. The bearings are immersed at room temperature for up to 6 minutes, more preferably 2 minutes.

[00042] After immersion in hydro-alcoholic solution of the organo-silanes, the bearings are dried with an air blower, proceeding to the curing stage in an oven heated by electric resistors or infrared lamps at a temperature of 80 to 120 ° C, more preferably 100 ° C. Curing time is

Petition 870160014263, of 4/15/2016, p. 25/34 / 19 dependent on oven temperature and heat source, when this is electrical resistance the curing period can vary up to 120 minutes and when this is medium-wavelength infrared lamp the curing period can vary up to 30 minutes, so that the condensation of the silanol groups occurs with the formation of the polysiloxane film.

[00043] Once the polysiloxane film is formed, the polymeric coating composed of the mixture of poly (amide-imide), poly (tetrafluorethylene) and aluminum in N-ethyl-pyrrolidone solvent is spray applied to the bearing over the polysiloxane layer, with thickness between 6 and 20pm, more specifically 12pm. Finally, the aforementioned coating applied to the aluminum or bronze bearing is cured in an oven heated with electrical resistances or infrared lamps at a temperature of 160 ° C for up to 120 minutes.

[00044] The invention, described above, will be illustrated in more detail by the following examples and appended claims.

Examples

Example 1: Use of γ-glidoxy-propyl-trimethoxy-silane (GPTES) as a precursor to the polysiloxane film [00045] Aluminum bearings were cleaned in three stages, namely: (i) washing with distilled water; (ii) washing with neutral detergent; (iii) washing with methylene chloride in an ultrasound bath for 10 minutes. [00046] After properly degreased and dried, the bearings were chemically activated by immersion in 0.5M sodium hydroxide solution in water for 5 minutes and then washed with distilled water.

[00047] After drying, with the aid of a dryer with cold air, the bearings were immersed for 2 minutes in a GPTES solution in a 1: 1 ethanol / water mixture, with 4% (v / v) organo-silane concentration. Then the bearings

Petition 870160014263, of 4/15/2016, p. 26/34 / 19 were dried with the aid of a cold air dryer and stored in a conventional oven (heat source: electrical resistance) heated to 100 ° C for 30 minutes to form the polysiloxane film.

[00048] Then, on the polysiloxane film formed, a polymeric coating composed of the mixture poly (amide-imide), poly (tetrafluoroethylene) and aluminum in N-ethyl-pyrrolidone solvent with a thickness of 12 pm was deposited by spray . Finally, the aforementioned coating applied to the aluminum bearing was cured in a conventional oven (heat source: electrical resistance) at 160 ° C for 120 minutes.

[00049] The adhesion of the set formed by the polysiloxane film and the polymeric coating to the aluminum bearing was evaluated according to the standard NBR 11003/1990 - Paints - Determination of adhesions. All bearings tested showed adhesions classified as Gr ₀ , that is, no highlighted film area.

Example 2: Use of the mixture of (3-aminopropyl) triethoxy silane (APTES) with bis- (y-trimethoxysilylpropyl) amine (BTSPA) as a precursor to the polysiloxane film [00050] Aluminum bearings were cleaned in three stages, namely : (i) washing with distilled water; (ii) washing with neutral detergent; (iii) washing with methylene chloride in an ultrasound bath for 10 minutes. [00051] After properly degreased and dried, the bearings were chemically activated by immersion in 0.5M sodium hydroxide solution in water for 5 minutes and then washed with distilled water.

[00052] After drying with the aid of a cold air dryer, the bearings were immersed for 2 minutes in APTES / BTSPA 9: 1 mixture solution in a 1: 1 ethanol / water mixture, with 4% organo-silane concentration (v / v). Then, the bearings were dried with the aid of a cold air dryer and

Petition 870160014263, of 4/15/2016, p. 27/34 / 19 stored in a conventional oven (heat source: electrical resistance) heated to 100 ° C for 30 minutes to form the polysiloxane film. [00053] Then, on the polysiloxane film formed, a polymeric coating composed of a mixture of poly (amide-imide), poly (tetrafluorethylene) and aluminum in 12-thick N-ethyl-pyrrolidone solvent was sprayed on. qm. Finally, the aforementioned coating applied to the aluminum bearing was cured in a conventional oven (heat source: electrical resistance) at 160 ° C for 120 minutes.

[00054] The adhesion of the set formed by the polysiloxane film and the polymeric coating to the aluminum bearing was evaluated according to the standard NBR 11003/1990 - Paints - Determination of adhesions. All bearings tested showed adhesions classified as Gr ₀ , that is, no highlighted film area.

Example 3: Use of the mixture γ-glidoxy-propyl-trimethoxy-silane (GPTES) with tetraethoxy-silane (TEOS) as a precursor to the polysiloxane film [00055] Aluminum bearings were cleaned in three stages, namely: (i) washing with distilled water; (ii) washing with neutral detergent; (iii) washing with methylene chloride in an ultrasound bath for 10 minutes. [00056] After properly degreased and dried, the bearings were chemically activated by immersion in 0.5M sodium hydroxide solution in water for 5 minutes and then washed with distilled water.

[00057] After drying, with the aid of a cold air dryer, the bearings were immersed for 2 minutes in a 9: 1 GPTES / TEOS mixture solution in a 1: 1 ethanol / water mixture, with 4% organo-silane concentration ( v / v). Then, the bearings were dried with the aid of a cold air dryer and stored in a conventional oven (heat source: electrical resistance) heated to 100 ° C for 30 minutes to form the

Petition 870160014263, of 4/15/2016, p. 28/34 / 19 polysiloxane.

[00058] Then, on the polysiloxane film formed, a polymeric coating composed of a mixture of poly (amide-imide), poly (tetrafluorethylene) and aluminum in N-ethyl-pyrrolidone solvent with a thickness of 12 pm was deposited by spray. Finally, the aforementioned coating applied to the aluminum bearing was cured in a conventional oven (heat source: electrical resistance) at 160 ° C for 120 minutes.

[00059] The adhesion of the set formed by the polysiloxane film and the polymeric coating to the aluminum bearing was evaluated according to the standard NBR 11003/1990 - Paints - Determination of adhesions. All bearings tested showed adhesions classified as Gr ₀ , that is, no highlighted film area.

Petition 870160014263, of 4/15/2016, p. 29/34 / 3

Claims (7)

1. Polymer coated bearing characterized by comprising mono- and bifunctional silanes, poly (amide-imide), poly (tetrafluoroethylene) and aluminum flakes. 2. Polymeric coated bearing according to claim 1, characterized in that mono and bifunctional silanes are present in hydro-alcoholic solutions during application, included in the group containing monofunctional silanes γ-glidoxy-propyl-trimethoxy-silane, (3-aminopropyl ) triethoxy-silane, N- [3 (trimethoxy-silyl) propyl] ethylenediamine, tetraethoxy-silane, ethyl-triethoxy-silane, chloro-methyl-triethoxy-silane, vinyl-methyl-diethoxy-silane, (3-methacryloxypropyl (-trimethoxy -silane, (3-mercaptopropyl) -triethoxysilane, but not restricted to such, and bifunctional silanes included in the group consisting of bis- (Y-trimethoxysilylpropyl) amine (BTSPA), bis- (triethoxysilylpropyl) disulfide, bis tetrasulfide - (triethoxysilylpropyl), but not restrictive to such. 3. Bearing, according to claims 1 and 2, characterized by the silanes being located at the interface of the metallic part with the polymeric cover. 4. Bearing, according to claims 1 and 2, characterized by the silanes being located both at the interface of the metallic part with the polymeric cover, and within the composition of the polymeric cover. 5. Process for the production of bearings with polymeric cover characterized by comprising the following steps: i. cleaning the metallic surface of the bearing with water solution and neutral detergent and organic solvent, Petition 870160014263, of 4/15/2016, p. 30/34 2/3 preferably in an ultrasound bath; ii. activation of the metal surface by immersing the bearing in aqueous sodium hydroxide solution, preferably with a molar concentration between 0.05 and 1M, more preferably 0.5M, for up to 15 minutes, more preferably 5 minutes; iii. rinse the bearing thoroughly in water; iv. drying the bearing in forced air; v. immersion of the chemically activated bearings in a bath with hydro-alcoholic solution of organo-silanes, comprising water and an alcohol with a hydrocarbon chain of up to 4 carbons, more preferably 2 carbons, and the water / alcohol ratio in volume varying from 10% / 90% up to 90% / 10%, more preferably 50% / 50%, organo-silane or mixture of organo-silanes in the concentration of 4% to 8% (v / v) at room temperature for up to 5 minutes. saw. keep the organo-silane hydroalcoholic solution under light and constant agitation before starting the immersion of the bearings, until the hydrolysis of the alkoxy groups occurs with the formation of the hydroxyl groups, preferably for 30 minutes; vii. drying the bearings with forced air; viii. curing the organo-silane at 80 ° C to 120 ° for up to 120 minutes, more preferably 30 minutes in an oven with heating by electric resistances and 15 minutes in an oven heated by infrared lamps with medium wavelength; ix. condensation of silanol groups with the formation of the polysiloxane film; x. application of the polymeric coating, comprising a mixture of poly (amide-imide), poly (tetrafluoroethylene) and aluminum Petition 870160014263, of 4/15/2016, p. 31/34 3/3 in N-ethyl-pyrrolidone solvent, by spray on the polysiloxane layer, with a thickness between 6 and 20μm, more specifically 8 to 12μm. xi. curing of the polymeric coating applied on the bearing between 120 ° C to 180 ° C for up to 120 minutes in an oven with heating by electric resistances or in an oven heated by infrared lamps with medium wavelength ;. Process for the production of polymer-coated bearings according to claim 3, characterized by immersion in a hydro-alcoholic solution containing a monosilane or a mixture of monosilanes or a mixture of mono and bis-silanes. 7. Process for the production of polymer coated bearings according to claim 4, characterized in that the mixture between monofunctional or monofunctional / bifunctional organo-silanes varies from 95% / 5% to 80% / 20%. Petition 870160014263, of 4/15/2016, p. 32/34 1/1 Polymeric coated bearing for friction reduction in internal combustion engines and process for producing the same The present invention relates to the bearing with polymeric cover for reducing friction in internal combustion engines. In addition, the present invention relates to the process for the production of polymer-coated bearings to reduce friction in internal combustion engines, particularly by introducing an adhesion layer between the metallic surface of the bearing and the polymeric coating, the referred to being layer obtained from the previous immersion of the bearing in hydro-alcoholic solution of organo-silanes and subsequent thermal curing, resulting in the formation of a polysiloxane film containing chemical groups capable of various interactions with the subsequent polymeric coating. Petition 870160014263, of 4/15/2016, p. 33/34