Wiper frame coating composition for wiper blades

Abstract

The present invention relates to a coating composition for a wiper blade of a wiper frame, wherein the composition is an aqueous phase composition comprising at least one resin and at least one solid lubricant, and further comprising a colloidal silica solution and cellulose fibers. The present invention further relates to a method for obtaining such a composition and to a wiper blade obtained by using the composition.

Description

Technical Field

[0001] The present invention relates to a coating composition for a wiper blade of a vehicle front glass wiper, a method for using the same, and a method for manufacturing the same. Further, it relates to a wiper blade for a front glass wiper, and the wiper blade is at least partially coated with the composition.

Background Art

[0002] Automobiles are generally equipped with a wiper system for cleaning and / or wiping the front glass to prevent the driver's field of vision from being obstructed. The wipers of this system have conventionally been driven by an arm that performs a reciprocating motion with an angle. These blades are pressed against the outer surface of the window (e.g., the front glass), wipe off the water, and discharge it out of the driver's field of vision. In the conventional type, the wiper is manufactured in the form of an articulated crossbar that holds the wiper blade at multiple locations. In the newer "flat blade" form, the wiper blade is manufactured in the form of a semi-rigid assembly that fixes the wiper blade over its entire length.

[0003] Generally, the wiper blade is composed of an elastically deformable material based on an elastomer blended with additives, particularly to improve mechanical properties, elasticity, wear resistance, resistance to external attacks, or to facilitate the implementation of the manufacturing process. For example, reinforcing fillers, plasticizers, vulcanizing agents, or protective agents against ultraviolet rays, oxidation, ozone, and / or wear are applicable.

[0004] In the case of the wiper blade of an automotive front glass wiper, these blades must have the property of effectively wiping the moving front glass while ensuring noise comfort during use for vehicle occupants. That is, it is required not to generate sound waves or noise. In fact, during wiper use, the continuous friction of the blade against the front glass causes the blade to wear out early, resulting not only in a decrease in wiping performance but also in the generation of noise.

[0005] Blade wear necessitates the replacement of the entire front wiper, even if other parts and elements of the wiper are still functioning. To extend the life of wiper blades, patent US5447645 describes a rubber lubricating and preservative composition containing graphite, butyl titanate, and isopropanol. This composition may also contain other products such as UV stabilizers and binders. However, this composition is inherently highly flammable and requires special storage conditions, making it unsuitable for direct use by non-professionals.

[0006] French Patent No. 2977258 describes a composition used for repairing wiper blades. This is an aqueous composition containing 5% to 25% of a lubricating filler (preferably graphite powder). [Overview of the Initiative] [Problems that the invention aims to solve]

[0007] There remains a need to improve the performance characteristics of windshield wiper blades, particularly their wear resistance, and to achieve a longer lifespan. Furthermore, it is desirable to have a coating composition available that can improve these performance characteristics, is easy to use, and exhibits good adhesion to the wiper blade. [Means for solving the problem]

[0008] These and other objectives are achieved by the compositions according to the present invention.

[0009] This is because, in the context of the present invention, it has been found that the abrasion resistance of a coating composition can be improved by adding fibers and silica to the coating composition. [Brief explanation of the drawing]

[0010] [Figure 1] The wiper blade of a windshield wiper according to the present invention is shown. [Figure 2] The dustproof histograms for the control composition and compositions with increased cellulose fiber content are shown. Fiber content is expressed as a percentage on the right y-axis. [Figure 3] The dustproof histograms for the control composition and the composition with increased colloidal silica content are shown. The colloidal silica content is shown as a percentage on the right y-axis. [Figure 4] The histograms of dustproof properties are shown for a control composition and a composition containing a fixed amount of cellulose fibers (1.7%) with an increasing colloidal silica content. The colloidal silica content is shown in percentage on the right y-axis. [Modes for carrying out the invention]

[0011] Therefore, the subject of the present invention is a coating composition for the wiper blade of a windshield wiper, the composition being an aqueous phase composition in which at least one resin and at least one solid lubricant are dispersed, and the composition further comprises the following: (i) a colloidal silica solution containing 40% to 50% solids at a concentration of 0.1% to 10%, particularly 1.1% to 9.3%, and (ii) 0.5% to 5%, especially 0.5% to 3% cellulose fibers, The above percentages are expressed as weight percentages relative to the total weight of the composition.

[0012] The composition is preferably an aqueous phase composition, generally containing 10% to 75% aqueous solvent, particularly 20% to 75% aqueous solvent. “Aqueous solvent” means a medium containing water and optionally one or more hydrophilic cosolvents. Such cosolvents can be, for example, alcoholic, particularly glycol esters.

[0013] Preferably, the composition contains 12% to 50% of a dispersed solid lubricant. Generally, the composition contains 10% to 31%, particularly 10% to 30.6%, of a resin dispersion containing 40% to 50% solids. The percentages are expressed as a weight ratio to the total weight of the composition.

[0014] The content of the solid lubricant in the dispersion is adjusted to provide 3% to 15% solid lubricant in the composition. The dispersion is an aqueous phase dispersion.

[0015] The composition may further contain additives. The amount of additives is determined by those skilled in the art. If additives are present, their concentration is generally in the range of 0.01% to 1% by weight.

[0016] Another subject of the present invention is a method for producing such a paint composition. This method particularly includes the following steps: a) Add cellulose fibers to an aqueous dispersion of a solid lubricant to obtain a mixture of cellulose fibers and the aqueous dispersion lubricant. b) Introduce colloidal silica into the mixture of cellulose fibers and solid lubricant obtained in step a). c) Add at least one aqueous resin to the dispersion obtained in step b).

[0017] Another subject of the present invention is the use of such a coating composition, which can be obtained by the above process, to at least partially coat a wiper blade for a windshield wiper.

[0018] Another subject of the present invention is a windshield wiper blade coated with a coating composition.

[0019] In the present invention, the term "aqueous phase" is understood to mean, in particular, a composition in which the content of an organic solvent is 10% by weight or less relative to the total weight of the composition. Preferably, the content of the organic solvent is 5% by weight or less, and more preferably 0% by weight relative to the total weight of the composition.

[0020] The concentration of colloidal silica in the composition according to the invention can in particular be from 0.1% to 8%, in particular from 0.4% to 7% by weight, based on the total weight of the composition. This can be, for example, a concentration of colloidal silica of 0.1%, 0.2%, 0.3%, 0.4%, 0.5%, 0.6%, 0.7%, 0.8%, 0.9%, 1%, 1.1%, 1.2%, 1.3%, 1.4%, 1.5%, 1.6%, 1.7%, 1.8%, 1.9%, 2%, 2.1%, 2.2%, 2.3%, 2.4%, 2.5%, 2.6%, 2.7%, 2.8%, 2.9%, 3%, 3.1%, 3.2%, 3.3%, 3.4%, 3.5%, 3.6%, 3.7%, 3.8%, 3.9%, 4%, 4.1%, 4.2%, 4.3%, 4.4%, 4.5%, 4.6%, 4.7%, 4.8%, 4.9%, 5%, 5.1%, 5.2%, 5.3%, 5.4%, 5.5%, 5.6%, 5.7%, 5.8%, 5.9%, 6%, 6.1%, 6.2%, 6.3%, 6.4%, 6.5%, 6.6%, 6.7%, 6.8%, 6.9%, 7%, 7.1%, 7.2%, 7.3%, 7.4%, 7.5%, 7.6%, 7.7%, 7.8%, 7.9% or 8% by weight, based on the total weight of the composition. The concentration of colloidal silica can in particular be from 4% to 7% by weight, based on the total weight of the composition.

[0021] According to another embodiment of the invention, the concentration of amorphous silica can be from about 0.4% to about 4% by weight, in particular from 0.9% to 3.5% by weight. In particular, good results are obtained when the concentration of amorphous silica in the paint composition is about 2.8%.

[0022] Preferably, the silica is in the form of particles having a particle size of 2 nm or less.

[0023]

[0024] According to one embodiment of the paint composition of the invention, the silica is present in the form of a colloidal silica dispersion, in particular a colloidal silica dispersion having a solids content of from 40% to 50%. Colloidal silica is most frequently prepared in a multi-step process in which an alkaline silicate solution is partially neutralized, thereby forming a silica core.

[0024] Therefore, the coating composition may contain 1% to 20% of a colloidal silica dispersion with a solid content of 40% to 50%, preferably 1% to 10%, and particularly 1.1% to 9.5%. A colloidal silica dispersion with a solid content of 40% to 50%, and particularly 2.4% to 8%, can be included as a colloidal silica dispersion with a solid content of 40% to 50%.

[24] The concentration of cellulose fibers in the coating composition of the present invention can vary in particular from 0.5% to 3%, particularly from 0.8% to 2.5%, and particularly from 1.5% to 2% by weight relative to the total weight of the composition. This is, for example, when the concentration of cellulose fibers is 0.5%, 0.6%, 0.7%, 0.8%, 0.9%, 1%, 1.1%, 1.2%, 1.3%, 1.4%, 1.5%, 1.6%, 1.7%, 1.8%, 1.9%, 2%, 2.1%, 2.2%, 2.3%, 2.4%, 2.5%, 2.6%, 2.7%, 2.8%, 2.9%, or 3% by weight relative to the total weight of the composition.

[0025] The cellulose fibers used in the implementation of this invention preferably have a size of 6 to 12 μm.

[0026] Unexpectedly, the inventors demonstrated that while silica or cellulose fibers, when used as individual additives, have the effect of reducing the resistance of the coating composition, adding these two components to the coating composition improves its abrasion resistance.

[0027] This synergistic effect makes it possible to reduce the amount of coating removed during blade use by approximately 20%, and in some cases 25%, compared to a standard composition that does not contain these components. This effect can be demonstrated particularly through abrasion tests.

[0028] The paint composition of the present invention has good adhesion to rubber blades.

[0029] Solid lubricants can be selected from lubricants well known to those skilled in the art. In particular, natural lubricants such as graphite and molybdenum disulfide, as well as synthetic lubricants such as graphite fluoride, tungsten disulfide, boron nitride, tungsten diselenium, molybdenum diselenium, niobium diselenium, or titanium iodide and titanium disulfide, and various mixtures of these in any ratio.

[0030] Preferably, graphite and / or molybdenum disulfide, particularly powdered graphite, are used. Preferably, the particle size of the graphite is less than 10 μm.

[0031] The concentration of the solid lubricant is generally 1% to 15% by weight, particularly 3% to 15% by weight, and more preferably 6% to 11% by weight, relative to the total weight of the composition. The lubricant may be provided in the form of an aqueous dispersion, particularly a dispersion with a solid content of 30% to 40%. In this case, the dispersion accounts for 10% to 55%, particularly 12% to 50%, and more particularly 25% to 40% of the weight of the coating composition.

[0032] The resin may be an aqueous resin containing at least one acrylic, vinyl, styrene, or urethane aqueous polymer. The polymer may be a homopolymer or copolymer. These polymers may be used individually or mixed depending on compatibility or desired final properties. Preferably, the resin contains at least one aqueous acrylic polymer.

[0033] In particular, aqueous polymer dispersions or emulsions may fall into this category.

[0034] In order to maintain the flexibility of the coating film at low temperatures, it is desirable that the resin has a glass transition temperature of 0°C or lower, more preferably -20°C or lower.

[0035] The amount of resin in the composition is adjusted by those skilled in the art according to the desired properties. Generally, it is between 10% and 31% by weight of the total weight of the composition.

[0036] The resin can be introduced in particular in the form of an aqueous dispersion. It is especially preferable that the solids content is 40% to 50%. In this case, the dispersion can account for 10% to 31%, particularly 15% to 25%, of the total weight of the composition.

[0037] The composition of the present invention may further contain at least one additive selected from thickeners, spreaders, dispersants, and UV inhibitors. The content of the additive is generally about 0.01% to 1% of the total weight of the composition.

[0038] UV protection agents include UV stabilizers and UV inhibitors.

[0039] The thickener is preferably selected from modified cellulose and modified urethane polymers. The content is preferably 0.5% by weight or less relative to the total weight of the composition.

[0040] Spreading agents can reduce the surface energy of a composition. They can be selected from silicone-based surfactants, particularly dimethylsiloxane-modified polyethers.

[0041] Dispersants are intended to better disperse particles such as glass particles and solid lubricant particles. Dispersants are particularly water-soluble polymer agents, and preferably polymer dispersants containing the ionic form of a polymer or copolymer used as a resin. For example, when the resin is a polyacrylic acid resin, polyacrylate is preferred.

[0042] The coating composition according to the present invention can be represented in particular by the following compositional formula (percentages are expressed as weight ratios to the total weight of the composition): Resin (solids content 40-50%): 10-31%, Dispersed lubricating filler (solids content 30-40%): 12-51%, Cellulose fiber: 0.5-3%, Colloidal silica (solid content 40-50%): 1-10%, Additives: 0.01~1%, and Solvent: 15-75%.

[0043] Other compositions according to the present invention are represented by the following formula: Resin (solids content 40-50%): 15-25%, Dispersed lubricant filler (solid content 30-40%): 25-40%, Cellulose fiber: 0.80-2.5%, Colloidal silica (solid content 40-50%): 2.4-8%, Additives: 0.01~1%, and Solvent: 34-45%.

[0044] The present invention also relates to a process for preparing a coating composition as defined above. This process may beneficially include one or more additional steps after step c).

[0045] Any additives may be added after step c) as needed.

[0046] The solvent is also added after step c). This includes water in particular, and, if necessary, cosolvents such as glycol ethers (e.g., 2-butoxyethanol).

[0047] The amounts of each component are as described above.

[0048] The present invention also relates to using a coating composition as defined herein or obtained by the above process for at least a portion of a wiper blade for a windshield wiper.

[0049] The composition can be applied, for example, directly to the wiper blade or to a molded rubber strip, which can then be redistributed into two or three parts to obtain the wiper blade. The coating composition is applied by dipping the wiper blade or molded rubber strip in the composition, spraying the composition onto the wiper blade or molded rubber strip, or covering the wiper blade or molded rubber strip with the composition. The wiper blade or molded rubber strip is then dried. In the case of a rubber strip, it is finally redistributed into two or three parts to obtain the wiper blade.

[0050] Prior to the coating process, a preheating and curing step, particularly in an infrared oven or convection oven, may be included.

[0051] The thickness of the coating layer is 1 to 10 μm, preferably 3 to 7 μm, and more preferably 4 to 6 μm.

[0052] Another subject of the present invention is a wiper blade coated with the coating composition. The blade is coated with a composition comprising at least the solid lubricant, graphene, and resin, wherein the solvent in the composition is evaporated and removed.

[0053] The silica content in the coating (dry film form) of the blade surface covered in this manner is generally 0.4% to 4% by weight relative to the total weight of the coating, for example, 0.4% to 3.8% by weight relative to the dry film weight. The cellulose fiber content in this coating is generally 0.5% to 3% by weight relative to the weight of the coating in the dry film state.

[0054] The coating composition for a windshield wiper blade according to the present invention is, in particular, an aqueous phase composition comprising at least one resin and at least one solid lubricant, the composition further comprising (i) 0.4% to 4% amorphous silica and (ii) 0.5% to 3% cellulose fibers, the proportions of which are expressed as weight ratios to the total weight of the composition.

[0055] Another subject of the present invention is a coating composition obtained by coating a support. Accordingly, the subject of the present invention is a coating composition in the form of a dry film, containing 0.4% to 4%, particularly 0.4% to 3.8%, of silica and 0.5% to 3%, particularly 0.5% to 2.5%, of cellulose fibers, the proportions of which are expressed as weight ratios to the dry film weight.

[0056] Brief explanation of the drawing The present invention will be better understood by referring to the accompanying drawings and reading the following description, which is merely illustrative. In the drawings: Figure 1 shows the wiper blade of a windshield wiper according to the present invention. Figure 2 shows the dustproof histograms of the control composition and the composition with increased cellulose fiber content. Fiber content is shown as a percentage on the right y-axis. Figure 3 shows the dustproof histograms of the control composition and the composition with increased colloidal silica content. The colloidal silica content is shown as a percentage on the right y-axis. Figure 4 shows histograms of dustproof properties for a control composition and a composition containing a fixed amount of cellulose fibers (1.7%) with increasing colloidal silica content. The colloidal silica content is shown in percentage on the right y-axis. [Examples]

[0057] Example 1: Dustproof test of a composition containing only cellulose fibers.

[0058] Prepare the composition corresponding to the following formula: [Table 1]

[0059] Adhesion tests were passed for all compositions.

[0060] A dustproof test will be conducted. The test involves sliding a rubber blade coated with the composition on a dry, abrasive, flat surface under a predetermined load (15 N / m in this example) and a predetermined number of cycles (10 cycles in this example) to measure its dustproof performance.

[0061] After measuring the height of the coating removed by abrasion, compare it to the value observed in the reference composition.

[0062] The results of the dustproof test are shown in Figure 2 and the table below. [Table 2]

[0063] Resistance is expressed as the percentage of coating removal relative to the baseline value.

[0064] The presence of cellulose fibers alone weakens the coating. Specifically, adding 1.7% fibers drastically reduces the coating's resistance, changing the abrasion rate to approximately 67% of the standard value. Adding cellulose fibers alone does not provide any additional resistance.

[0065] Example 2: Dustproof test of a composition containing only colloidal silica

[0066] Prepare the composition corresponding to the following formula: [Table 3]

[0067] The silica content is the wet-process content.

[0068] The results are shown in Figure 3 and the table below. [Table 4]

[0069] The presence of colloidal silica reduces the durability of the coating. Specifically, adding 2% silica resulted in an approximately 54% increase in wear compared to the standard product.

[0070] Example 3: Dustproof test of the composition according to the present invention

[0071] The dustproof properties of a composition containing 1.7% cellulose fiber and colloidal silica in the range of 2.4% to 7% were measured.

[0072] The test involves sliding a rubber blade coated with the composition on a dry, abrasive flat surface under a predetermined load (15 N / m in this example) and a predetermined number of cycles (10 cycles in this example) to evaluate its resistance.

[0073] The height of the coating removed by abrasion was measured and compared with the value observed in the control composition.

[0074] The compositions under test are shown in the table below. [Table 5]

[0075] The results of the dustproof test are shown in Figure 4 and the table below. [Table 6]

[0076] When the cellulose fiber content remains constant, increasing the silica content reduces the percentage of the coating removed (i.e., less damage to the coating). This reflects an improvement in the dust resistance of the coating.

Claims

1. A coating composition for a windshield wiper blade, wherein the composition is an aqueous phase composition comprising at least one resin and at least one solid lubricant, and further comprises: (i) 0.1% to 10% of a colloidal silica solution containing 40% to 50% solids, (ii) Containing 0.5% to 3% cellulose fiber, The above percentages are expressed as weight ratios to the total weight of the composition.

2. The composition according to claim 1, characterized in that the silica is in the form of particles of 2 nm or less.

3. (i) containing 0.1% to 8% colloidal silica, particularly containing 0.4% to 7%, and (ii) The composition according to any one of claims 1 and 2, characterized in that it contains 0.5% to 3% cellulose fibers, and more particularly 0.8% to 2.5% cellulose fibers.

4. The composition according to any one or more of the preceding claims, characterized in that the silica is in the form of a colloidal silica dispersion.

5. The composition according to any one or more of the preceding claims, characterized by containing 3% to 15% of a solid lubricant.

6. The composition according to any one or more of the preceding claims, further comprising at least one additive selected from thickeners, spreaders, dispersants, and UV inhibitors.

7. The composition according to any one or more of the preceding claims, characterized by containing 10% to 31% by weight of a resin dispersion containing 40% to 50% solids.

8. The following stages: a) A step of adding cellulose fibers to an aqueous dispersion of a solid lubricant to obtain a mixture of cellulose fibers and an aqueous dispersion of lubricant. b) A step of introducing colloidal silica into the mixture of cellulose fibers and solid lubricant obtained in step a), c) Adding at least one aqueous resin to the dispersion obtained in step b), A method for producing the composition according to any one or more of the preceding claims, characterized by including the following:

9. Use of a composition according to any one of claims 1 to 7, or a composition obtained by the method of claim 8, for at least a partial coating of a wiper blade for a windshield wiper.

10. A wiper blade for a windshield wiper, wherein the wiper blade is at least partially coated with the composition according to any one of claims 1 to 7, or the composition obtained by use according to claim 9.

11. The wiper blade for a windshield wiper according to the preceding paragraph, wherein the wiper blade is at least partially coated with a composition having the form of a dry film, the composition comprising 0.4% to 4% silica and 0.5% to 3% cellulose fibers by weight percentage relative to the weight of the dry film.

12. A coating composition having the form of a dry film as defined in the preceding paragraph, characterized in that it contains 0.4% to 4% silica and 0.5% to 3% cellulose fibers by weight relative to the weight of the dry film.

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