FR2977258A1 - Aqueous composition, useful for renovation of a wiper of windshield wiper brush, comprises black filler, preferably graphite powder, binder comprising polyurethane acrylic resin, dispersing agent, spreading agent and thickening agent - Google Patents

Abstract

Aqueous composition comprises 5-25 wt.% of a black filler, preferably graphite powder, a binder comprising polyurethane acrylic resin, a dispersing agent, a spreading agent and a thickening agent. Independent claims are included for: (1) a renovation device of a wiper, comprising a container (22, 34, 44) containing the composition and an applicator; and (2) renovation of a wiper, comprising applying the composition to the wiper, followed by drying.

Description

Renovation composition of a wiper member

The present invention relates to a composition for renovating a wiper member and in particular a wiping blade wiper blade. It also relates to a renovation device comprising said composition and a method of renovating a wiper member. Most motor vehicles such as trains, cars, boats or airplanes are equipped with a windscreen wiper blade, which eliminates rainwater and any debris that obstructs the driver's view. pilot through the windshield. A wiper blade is usually composed of two parts, an arm and a blade.

Depending on the type of arm used, there are two types of wiper blades: the conventional broom or the flat broom. A "conventional broom" is a broom whose pressure distribution printed by the arm supporting the blade is provided by spreaders distributed along the blade, unlike a "flat broom", the distribution of the pressure printed by the arm The broom is supported by a metallic vertebra having a curvature and a calculated pressure. In this second type of brush, we can remove the pedals of the arm which allows a reduction of the height of the blade. A wiper blade wiper usually comprises three elements: a lip ensuring contact with the windshield and providing the seal for wiping water, a generally rectangular shaped heel for insert the blade in the support and a hinge (optional) formed by a thin rubber band between the lip and the heel and ensuring the correct positioning of the lip on the windshield, especially when changing direction of the broom to turning points.

To ensure its mechanical performance and its compatibility with various climatic environments, the wiper blade of a wiper blade is generally made of elastomer material (s) also comprising different fillers and / or additives. By "based on" is meant a material comprising at least 100/0 of elastomer (s), preferably at least 200/0, and more preferably at least 35 ° / U.

By "elastomer (s)" is meant a polymer having "hyper-elastic" properties, obtained after crosslinking the polymer. These elastomers comprise natural or synthetic elastomers, alone or as a mixture, in particular the elastomers chosen from the group consisting of natural rubbers (NR), polychloroprenes (CR), ethylenepropylene-diene monomers (EPDM), nitrile rubbers ( NBR, HNBR, XNBR), polybutadienes (BR), styrene butadiene rubbers (SBR) butyl rubbers, epichlorohydrins (ECO / GECO), ethylene-acrylate copolymers (VAMAC type), polyurethanes (PU), fluorinated elastomers and silicone elastomers (VMQ / FMQ). These elastomers can be used alone or in mixture. By way of example, mention is made of the NR / EPDM, NR / CR, EPDM / PP mixtures or other mixtures known to those skilled in the art. Preferably, the elastomers are selected from the group consisting of NR, EPDM, CR and mixtures based on these elastomers. The fillers used are generally carbon black, graphite, silica, talc or chalk and their derivatives and / or mixtures. The additives include, inter alia, protective agents, for example para-phenylenediamine derivatives which trap UV. The additives also include waxes that migrate to the surface to protect the material. In addition, the additives may comprise plasticizers to improve the cold resistance and the use of the elastomer. The most commonly used plasticisers are naphthenic oil, aromatic oil, paraphenic oil or ester oil. The additives comprise a vulcanization system, for example comprising sulfur and / or different molecules improving the reaction efficiency or peroxide derivatives. In the field of technical materials based on elastomer (s), research is often oriented towards improving the mechanical properties and more particularly the surface properties of the parts shaped from these materials. In the case of wiper blades for a motor vehicle wiper blade, these blades must have characteristics that effectively wipe the windshield on which they move while presenting a sound comfort in use for the occupant of the vehicle. , that is to say to avoid generating sound waves or noise. However, when using the wiper blade, the incessant friction blade on the windshield causes premature wear thereof, having the effect not only to lose wiper quality but also to generate the noise. The wear of the blade requires the replacement of the entire wiper blade, although the other parts and elements thereof are still functional. In order to increase the service life of a wiper blade, US Pat. No. 5,447,645 therefore describes a composition for lubricating and preserving a rubber, comprising graphite, butyl titanate and isopropanol. This composition may also include other products such as UV stabilizers, a binder, etc. Such a composition, however, has a high flammable nature, which requires special storage conditions and is therefore not very suitable for direct use by a nonprofessional.

In addition, in order to reduce the ecological impact of certain products, it would be advantageous to propose aqueous alternatives to organic solvent compositions where possible in order to reduce their impact on the environment in terms of toxicity and generation of volatile compounds. organic.

However, an aqueous solvent composition has never been proposed because it is poorly suited to the intended application. Indeed, a worn blade, made of elastomer material (s), has a potentially dirty, heterogeneous and hydrophobic surface. An aqueous solution thus has little affinity for this type of support and will spread with difficulty, unlike the organic solvent. The present invention therefore aims to provide a composition that does not require any particular precaution in its handling, and in particular that can be used by a non-professional, this composition not having an organic solvent in its formulation.

It therefore relates to an aqueous composition comprising: 5 to 25% by weight of sliding fillers, preferably 5 to 20% by weight, more preferably 7 to 15% by weight, a binder chosen from acrylic resins or polyurethanes, a dispersing agent, a spreading agent, and a thickening agent, the percentages by weight being given on the total weight of the composition. The composition according to the invention is more particularly adapted to the renovation of a wiper member and in particular a wiper blade of a wiper blade.

It has thus been possible to produce a composition exhibiting both: a good capacity for spreading or wetting, a good adhesion capacity on a surface based on elastomer (s) not prepared, a good dispersion and homogeneity of the sliding charges in the composition, a viscosity suitable for the intended use and in particular the means used to apply the composition, while using water as the solvent of the composition. This is due in particular to the specific combination of the different ingredients used in the composition. By "wiper member", it is more particularly a wiper blade for wiper blade, for windshield or squeegee.

By "acrylic resin" is meant any thermoplastic polymer or copolymer having as monomer a compound selected from acrylic acid, methacrylic acid, their esters or acrylonitrile. Advantageously, the copolymer is chosen from acrylic styrene copolymers and their derivatives. By "polyurethane" is meant any thermoplastic polymer or copolymer resulting from a polymerization reaction involving an isocyanate function with an alcohol function so as to form a urethane unit. The term "slippery charges" refers mainly to molybdenum disulphide powder, talc, PTFE powder, glass or silicone microbeads and graphite powder.

The sliding loads introduced will help restore the sliding qualities of the wiper member. Preferably, the sliding charges are graphite powder. Advantageously, when the sliding charges are in the form of powder and in particular, in the case of graphite powder, the particles of the powder have a size of between 0.1 and 20 μm, preferably between 1 and 10 μm. This size makes it possible to better control the spreading and the homogeneity of the composition. This has the effect of avoiding the formation of agglomerates of particles, which would cause subsequent defects during wiping. The binder makes it possible to increase the adhesion capacity of the composition on the surface of the wiper member based on elastomer (s). Preferably, the binder is introduced in an amount of from 1 to 10% by weight. Advantageously, self-crosslinking binders will be used, preferably those having a glass transition temperature between -10 and -40 ° C, more preferably between -20 and -30 ° C.

The dispersing agent will mainly make it possible to ensure the dispersion of the slippery-weight particles in the composition and in particular to break up the agglomerates of particles which tend to form in contact with a solvent such as water. Preferably, the dispersing agent is introduced in an amount of from 0.05 to 0.5% by weight and is selected from the group consisting of water-soluble polymeric dispersing agents. Preferably, the polymeric dispersing agents comprise an ionic form of the polymer or copolymer used as binder. By way of example, a polyacrylate will preferably be used when the binder is acrylic resin. The main purpose of the spreading agent is to reduce the surface energy of the composition. Advantageously, the leveling agent is introduced in an amount ranging from 0.05 to 0.5% by weight and is chosen from the group consisting of silicone surfactants, such as modified dimethylsiloxane polyethers. The thickening agent will more particularly make it possible to adjust the viscosity so as to obtain good spreading while avoiding sagging when the composition is applied to the wiper member. Preferably, the thickening agent is introduced in an amount ranging from 0.1 to 1.5% by weight and is selected from the group consisting of thickening agents having a thixothrope character such as colloidal clay or acrylic emulsions which can to swell in alkaline medium, modified to make them hydrophobic (HMASE, "hydrophobically modified alkali swellable acrylic emulsion"). The latter type of thickening agent has the advantage of not adding solid particles in the composition, which can affect the quality of wiping or the effectiveness of sliding loads as an element to restore the sliding qualities. Advantageously, the ratio of the weight of the sliding charges, and in particular graphite, to the total dry composition weight is greater than 4, preferably greater than 5. This ratio makes it possible to perfectly control the deposition of the composition on the organ. wiping, in particular by avoiding the formation of streaks (over-thickness). Finally, the composition may also comprise a co-solvent which improves the penetration of the composition into the elastomer-based material (s). Advantageously, this co-solvent is of alcoholic nature, introduced in a small amount. For example, the amount of alcoholic cosolvent is from 0 to 10%, preferably from 0 to 5%. The invention also relates to a device for renovating a wiper member and more particularly to a wiper blade of a wiper blade, comprising a reservoir comprising a composition according to the invention and an applicator.

Advantageously, the applicator of the device according to the invention is of the brush, felt, buffer, ball or spray type and optionally comprises a slot in which to slide the member or the wiper blade. The invention also relates to a method of renovating a wiper member and in particular a wiper blade of a wiper blade, comprising a step of applying a composition according to the invention, on the wiper member or blade followed by a drying step. This composition is advantageously applied to a member or a wiper blade having a certain wear. The wear of a member or wiper blade is generally in two forms: - wear due to a lack of graphite coating point or generalized on the part of the blade (lip?) Coming into contact with the windshield, over a certain thickness of the order of 100 μm to 3 mm, and / or - wear due to abrasion of the elastomer-based material (s) to a thickness of the order of 50 to 100 μm on the part of the blade (lip?) coming into contact with the windshield. This wear of the material takes the form of a triangular wear chamfer when looking at the rubber blade in cross section. More particularly, the composition according to the invention will be applied to the lip of the wiper blade. Advantageously, the organ will be cleaned prior to the application of the composition.

Finally, the invention relates to the use of the composition according to the invention or the device according to the invention for renovating a wiping blade wiper blade and more particularly a lip of a wiper blade. Other features and advantages of the invention are described in the following nonlimiting examples and with reference to the drawings in which: - Figure 1 is a perspective representation of a conventional wiper blade (1a 2) is a perspective representation of a wiper blade according to one embodiment of the invention; wiper blade according to three different embodiments; - Figure 6 is a series of photographs illustrating the effects of application of the composition on a used wiper blade, and - Figure 7 is a graph showing the effect of on the coefficient of friction of the application of the composition on a used wiper blade. Figure 1 shows a perspective view of a wiper blade 11 conventional (la) or flat (lb) comprising a wiper blade 10 according to the invention. FIG. 2 is a view of the wiper blade 10 which comprises a heel 12 which allows the blade to be inserted into a wiper blade 11. This blade 10 also comprises a lip 16 intended to come into contact with the surface to be wiped. wipe and a hinge 14 formed by a thin rubber strip connecting the lip 16 and the heel 12. This hinge 14 ensures the correct positioning of the lip 16 on the surface to be wiped, especially when changing the direction of the blade 11 at the points of turnaround. The surface to be wiped is in this case a windshield of a motor vehicle. FIGS. 3 to 5 show three devices for renovating a wiping blade according to three different embodiments. The device 20 shown in FIG. 3 comprises a reservoir 22 containing the composition C according to the invention and a plug 24. A brush-type applicator 26 is connected to the plug by a rod 28, which allows the applicator 26 to be immersed in the tank 22 to take a portion of the composition C and then apply it to the wiper blade of a wiper blade. When the cap 24 closes the reservoir 22, a portion of the rod 28 and the applicator 26 are immersed at least partially in the composition C. Alternatively, the applicator 26 may also be of foam.

The device 32 shown in FIG. 4 comprises a reservoir 34 of cylindrical shape containing the composition C according to the invention, a plug 36 and an applicator 38 of spherical shape (ball) directly connected to the reservoir 34. The ball 38 has a diameter about 1 to 3 cm, preferably about 1.5 cm. The diameter of the ball 38 is adapted to the diameter of the body of the cylinder of the tank 34. This ball thus makes it possible to almost completely close the tank 34 and to spread the composition C by rolling on the wiper blade. a wiper blade. To do this, the bottle 32 is inverted so as to contact the composition C with the ball 38 and the composition C is then applied by rolling the ball on the surface of the blade. The device 42 shown in FIG. 5 comprises a reservoir 44 comprising the composition C according to the invention and an applicator 46 made of felt. The applicator 46 is of generally parallelepipedal shape and is connected directly to the reservoir 44 to ensure the contacting of the applicator 46 with the composition C. One of the faces of the applicator 46 has a slot 48 separating the applicator 46 This felt slit 48 makes it possible to insert the lip 16 of the wiper blade 10 between the two parts 52, 54, impregnated with the composition C. Once the lip 16 has been inserted between the two parts parts 52, 54, the composition C is spread by a displacement of the applicator 46 on the lip 16 in the direction D.

Alternatively, the applicator 46 may also be of foam. If necessary, the composition can be applied by spraying (spray).

EXAMPLE 1 Composition According to the Invention Two compositions according to the invention are prepared, the first being intended to be applied with a brush while the second is intended to be applied in the form of a spray. Applicator Brush Spray Ingredient%% Graphite Powder 4 pm 10 10 Dispersing Agent - Solsperse ® 44000 (Lubrizol) 0.2 0.2 Thickener - Solthix ® A100 (Lubrizol) 0.3 0.7 Binder - Texycril ® - (Scott Bader 3.2 3.2 Floating agent - Byk ® 348 (Byk) 0.3 0.35 Distilled water 86 85.6 Solsperse ® 44000: Polymeric dispersant without alkylphenol ethoxylate. Solthix ® A100: Acrylic emulsions which can swell in an alkaline medium, modified to make them hydrophobic (HMASE). Texycril ®: acrylic styrene. Byk ® 348: polyether dimethylsiloxane.

Example 2 Effect of Applying the Composition on a Wiped Wiper Blade 1. Observation of the Surface In FIGS. 6A and B the effects of the composition of Example 1 on a glass slide are shown. wiping of natural rubber coated with a graphite coating during the manufacturing process and having undergone abrasive wear aging related to use under conventional conditions. In FIG. 6A, the surface of the damaged blade is observed whereas in FIG. 6B this same surface is observed after application of the composition. The surface condition becomes homogeneous and the damaged areas are covered by the composition. In FIGS. 6C and D, the effects of the composition of Example 1 on a natural rubber wiper blade coated with a graphite coating in the manufacturing process and subjected to bonded abrasive wear aging are shown in FIGS. to use in winter conditions in the presence of frost. In Figure 6AC, the surface of the damaged blade is observed. There is tearing of the coating by gel-bound plate. In FIG. 6D, this same surface is observed after application of the composition. It is found that the damaged surfaces are homogeneously covered by the composition. 2. Effect on the coefficient of friction between rubber and glass Three wiper blade wipers were taken from the vehicle after real-time use between 6 months and 1 year. These blades are made of natural rubber and have been coated with a graphite treatment during their initial manufacture. The objective of the test is to compare: - the coefficient of friction of these blades in their used state, - the coefficient of friction of these blades after application of the composition.

The coefficient of friction is that of the blade, measured on a flat and dry glass pane, under dynamic conditions and under a load of 15g / cm, simulating the usual load on the wiper blade on a vehicle. The test bench used makes it possible to position a piece of blade on a movable plate of glass movable and adjustable in speed. A sensor measures the resistive force related to the friction of the blade and calculates a coefficient of friction knowing the load applied to the blade. Parameters: - blade: 6cm, - load on blade: 15g / cm, - speed of movement of the glass plate: 100mm / s. The coefficient of friction is measured on both wiping sides of the blade (side + / side -). The blades are then renovated using the composition described in Example 1, for use with a brush-type applicator.

The measurements on the renovated slats are carried out again. The results are as follows: Blade Type 1 2 3 Front Side + 1.88 1.63 1.39 Treatment Side - 2.09 1.54 1.80 After Side + 0.99 0.67 0.69 Treatment Side - 1.44 0.81 0.90 These results are also presented in the form of a bar chart in Figure 7. In this figure, the black sticks represent the average of the values (quoted + and cot-) before treatment, while the gray sticks represent the average of the values (side + and side-) after treatment. On this diagram is also indicated the conformity limit (L) of the wiper blade, which has been set at 1.5 to ensure optimal blade operation in terms of noise generation, wear resistance and durability. dynamic operation on windshield These results show a reduction in the coefficient of friction obtained after application of the treatment on the aged blades. This reduction is of the order of 30 to 50%. It also results in a reduction of chatter, a reduction of the veil generated by the slump of the blade and a reduction of friction and rollover noises. By chatter, we mean a phenomenon of vibration of the blade. The source of the vibration can be a blade whose coefficient of friction is too high. The generated vibration is transmitted to the broom, the movement of the broom then losing its fluidity and becoming jerky. By "rollover noise" is meant the coming in contact during reversals of the wiper blade, which have the effect of creating shocks between different surfaces. Indeed, during the sweeping, there is a reversal of the pivoting direction of the wiper blade relative to the wiping heel during which a surface of the wiper blade comes into contact with the window to be wiped. 5 10 15 25 30 35

Claims (10)

REVENDICATIONS1. An aqueous composition comprising: - 5 to 25% by weight of sliding fillers, preferably graphite powder, - a binder chosen from acrylic resins or polyurethanes, - a dispersing agent, - a spreading agent, and - a thickening agent. 2. Composition according to claim 1, wherein the dispersing agent is introduced in an amount ranging from 0.05 to 0.5% by weight and is selected from the group consisting of water-soluble polymeric dispersing agents. 3. Composition according to claim 1 or 2, wherein the spreading agent is introduced in an amount ranging from 0.05 to 0.5% by weight and is selected from the group consisting of silicone surfactants. 4. Composition according to any one of the preceding claims, wherein the thickening agent is introduced in an amount ranging from 0.1 to 1.5% by weight and is selected from the group consisting of thickeners having a thixothrope character. or acrylic emulsions which can swell in alkaline medium, modified to make them hydrophobic (HMASE, "hydrophobically modified alkali swellable acrylic emulsion"). 5. A composition according to any one of the preceding claims, wherein the binder is introduced in an amount of from 1 to 10% by weight. 6. Composition according to any one of the preceding claims, wherein the ratio of the weight of sliding charges on the total weight of dry composition is greater than 4. 7. Device for renovating a wiper member, characterized in that it comprises a reservoir (22; 34; 44) containing a composition C according to any one of the preceding claims and an applicator (26; 38; ). 8. Device according to claim 7, wherein the applicator (26; 38; 46) is brush (26), felt (46), buffer, ball (38) or spray. 9. A method of renovating a wiper member, characterized in that it comprises a step of applying a composition according to any one of claims 1 to 6, on a wiper member followed by a drying step. 10. Use of a composition according to any one of claims 1 to 6 or the device according to claim 7 or 8, for renovating a wiping blade wiper blade.