JP3168595U - Wheel coating composition for vehicle and wheel - Google Patents

Abstract

An object of the present invention is to provide a vehicle wheel in which a super-water-repellent surface having a water droplet contact angle of 150 degrees or more is formed on the surface of the vehicle wheel to prevent adhesion of fine brake pad powder generated during braking of the vehicle. SOLUTION: After 97.9% by mass of isopropyl alcohol, 2% by mass of hydrophobic silica and 0.1% by mass of fluoroalkylsilane are mixed, the mixture is dispersed for 1 hour at a frequency of 44 KHz using an ultrasonic disperser, and the mixture is mixed. A silica dispersion is prepared. For vehicles with a super-water-repellent surface with a water droplet contact angle of 160 degrees by applying the above hydrophobic silica dispersion to the surface of an aluminum wheel whose surface has been subjected to clear coating with a paint brush and leaving it to dry as it is Get the wheel. [Selection diagram] Fig. 1

Description

The present invention relates to a vehicle wheel coating composition and a wheel for preventing adhesion of fine brake pad powder generated during braking of the vehicle to a vehicle wheel such as an automobile or a motorcycle.

As a conventional technique, in Japanese Patent Laid-Open No. 10-46054, a hydrophilic portion exposed so that the photocatalytic oxide particles are in contact with the outside air and a water repellency exposed so that the water repellent fluororesin is in contact with the outside air are disclosed in By forming a surface layer having a structure in which both presenting portions are microscopically dispersed on the surface, the hydrophilic surface and the water-repellent surface are adjacent to each other. In contrast, hydrophobic deposits that are easily adapted to the water-repellent surface do not conform to the adjacent hydrophilic portion. For this reason, neither hydrophilic deposits nor hydrophobic deposits are fixed to the surface of the member, and the surface is maintained in a clean state. Furthermore, the presence of the photocatalyst enables the photocatalyst according to the photoexcitation of the photocatalyst. Since the hydrophilic part exposed so that the conductive oxide particles are in contact with the outside air remains permanently hydrophilic, both the hydrophilic part and the water-repellent part are microscopically dispersed on the surface. A wheel having a structured structure has been proposed.

Further, as disclosed in WO2002-88269, an antifouling coating liquid characterized by containing inorganic polysilazane, a diluting solvent and a catalyst is applied to the wheel surface, the wheel surface is modified to vitreous, and dirt is removed. A way to prevent it has been proposed.

However, the main component of the dirt on the wheel of the vehicle is brake pad powder (brake dust) generated by rubbing the brake pad and disc when the brake is applied. Although there was a difference in adhesion and easy removal of dirt, it was necessary to wash the wheel in order to keep the appearance clean. Further, even after washing, dirt was immediately attached by running.
Japanese Patent Laid-Open No. 10-46054 WO2002-88269

The present invention has been made in view of the above-described problems of the prior art, and can prevent adhesion of fine brake pad powder generated during braking of a vehicle to a vehicle wheel such as an automobile or a two-wheeled vehicle. An object of the present invention is to provide a vehicle wheel and a composition for wheel coating, wherein the wheel surface has super water repellency with a water droplet contact angle of 150 ° or more. Further, in a vehicle wheel where the appearance is particularly important, it is preferable that the formation of the wheel surface is transparent so as not to impair the gloss and color tone of the surface.

In order to achieve the above object, the present invention is characterized in that a superhydrophobic surface having a water droplet contact angle of 150 ° or more is provided on the surface of the wheel. In order to exert super water repellency with a contact angle of 150 ° or more on the wheel surface, it is necessary to have a fractal structure with a hydrophobic surface, and the method is not particularly limited. A method of applying a water coating solution, a method of applying and drying a coating solution capable of forming fine irregularities, and a method of hydrophobizing after drying, a method of forming fine irregularities on the wheel surface by direct plasma treatment, etc., and then hydrophobizing the surface Etc. The simplest treatment method includes a method of applying a super-water-repellent coating liquid on the wheel surface, but the super-water-repellent coating liquid mainly includes a composition containing hydrophobic fine particles, a binder, a solvent, and the like. Conceivable. The material of the wheel may be aluminum or iron, and is not particularly limited. Further, the surface treatment of the wheel is not particularly limited, such as painting, plating, or untreated. The hydrophobic fine particles are at least one selected from the group consisting of oxides such as silicon, titanium, aluminum, zirconium, antimony, tin, tungsten, zinc, iron, cerium, manganese, copper, magnesium, holmium, and nickel.
The main component can be one made hydrophobic. Moreover, it is preferable that the particle diameter of hydrophobic fine particles is 5 nm or more and 100 nm or less.
As the binder, components that form a transparent body when dissolved in a solvent and dried are raised, methyl, methylphenyl, methyl hydrogen, amino modification, epoxy modification, epoxy polyether modification, carboxyl modification, carboxyl polyether modification, Alcohol-modified, alkyl-modified, alkyl-aralkyl-modified, alkyl-aralkyl polyether-modified, polyether-modified, silicon such as fluorine-modified silicon, phenylmethyl-based resin, methyl-based resin, resins such as modified resin, polyolefin-based resin, Resins such as vinyl resins, polyester resins, acrylic resins, epoxy resins, urethane resins, anionic surfactants, cationic surfactants, nonionic surfactants, amphoteric surfactants, etc. Surfactants, polyvinylpyrrolidone, Synthetic polymers such as livinyl alcohol, polyether copolymer, polyacrylamide, polyacrylic acid, higher alcohols, higher fatty acids, silica-based inorganic coating agents, silazane-based inorganic coating agents, rubbers such as silicone rubber, Examples thereof include polysaccharides such as starch, glycogen, and cellulose, and minerals such as smectite. As anionic surfactants, alkylbenzene sulfonic acid, α
-Olefin sulfonic acid, alkane sulfonic acid, alkyl sulfate, alkyl sulfate polyoxyethylene, alkyl phosphate, long chain fatty acid, α-sulfo fatty acid ester and their salts, etc. Ammonium salts, dialkyldimethylammonium salts, alkyldimethylbenzylammonium salts and the like can be mentioned. Examples of nonionic surfactants include alkylpolyoxyethylene ether, fatty acid diethanolamide, alkylpolyglucoside, and the like. Is dimethylalkylamine oxide, N
-Alkylbetaines, imidazoline derivatives and the like. As the solvent, alcohols such as methyl alcohol, ethyl alcohol, isopropyl alcohol, allyl alcohol, ethylene glycol, propylene glycol, 3-methoxy-3-methyl-1-butanol, 1-methoxy-2-propanol, acetone, ethylmethyl Polar solvents such as ketones such as ketones, ethers such as dimethyl ether, ethyl methyl ether, diethyl ether and dibutyl ether, esters such as ethyl acetate, and nonpolar solvents such as hexane, n-hexane, heptane and isooctane Can be mentioned

The super water-repellent surface has oil repellency. It is preferable that the wheel surface has oil repellency. In order to exhibit oil repellency, introduction of fluorine is preferable, and several methods are conceivable for this purpose. Examples thereof include a method of hydrophobizing fine particles with a fluoroalkylsilane compound and a method of coating the surface uneven structure with a fluorine-based resin. Examples of the fluoroalkylsilane compound include CF3 CH2 CH2 Si (OCH3) 3, CF3 CH2 CH2 SiCl3, CF3 (CF2) 3 CH2 CH2 Si (OCH3).
) 3, CF3 (CF2) 3 CH2 CH2 SiCl3, CF3 (CF2) 5 CH2 CH2 Si (OCH3) 3, CF3 (CF2) 5 CH2 CH2
SiCl3, CF3 (CF2) 7 CH2 CH2Si (OCH3) 3, CF3 (CF2) 7 CH2 CH2 SiCl3, CF3 (CF2) 7 CH2
CH2 Si (OCH3) Cl2 and the like.

Furthermore, the uneven Ra of the super water-repellent surface is 200 nm or less.

The present invention can prevent fine brake pad powder (brake dust) from adhering to the vehicle when braking, so the vehicle wheel can always be kept clean and maintain super water repellency. During this period, there is an advantage that the wheel cleaning work is unnecessary. Further, when the uneven Ra on the super water-repellent surface is 200 nm or less, irregular reflection of light is prevented and transparency is not impaired.

Example 1
As shown in Table 1, 98% by mass of isopropyl alcohol (described as “IPA” in the table) and 2% by mass of hydrophobic silica (Reolosil HM30S: solid content 100%, manufactured by Tokuyama Corporation, average primary particle size: 7 nm) % Was mixed with an ultrasonic disperser for 1 hour at a frequency of 44 KHz to create a hydrophobic silica dispersion, and this hydrophobic surface was applied to the surface of the aluminum wheel that had been painted with a paint brush. The porous silica dispersion was applied, left to stand and dried to obtain a super water-repellent surface having a water droplet contact angle of 160 °.

After the vehicle equipped with the wheel obtained by the above operation is normally driven on a dry road for 500 km and 1000 km normally, the inner surface of the wheel is further thinly coated with brake oil. The state was observed, and the state of dirt on the surface of the wheel was visually evaluated based on the following evaluation criteria. The results are shown in Table 1.

Evaluation standard of dirt adhesion state ○: No dirt is attached.
Δ: Mottled dirt.
X: The whole is dirty.

Example 2
As shown in Table 1, 97.8% by mass of isopropyl alcohol (described as “IPA” in the table) and hydrophobic silica (Reorosil HM30S: solid content 100%, manufactured by Tokuyama Corporation, average primary particle diameter: 7 nm) After mixing 2% by mass and amino-modified silicon (TSF4700, solid content 100%, manufactured by Momentive) 0.2% by mass, the mixture was dispersed for 1 hour at a frequency of 44 KHz using an ultrasonic disperser, and a hydrophobic silica dispersion was obtained. Applying this hydrophobic silica dispersion to the surface of the aluminum wheel that has been prepared and painted with a paint brush, and leaving it to dry, a super water-repellent surface with a water droplet contact angle of 158 ° is obtained. Obtained.

After the vehicle equipped with the wheel obtained by the above operation is normally driven on a dry road for 500 km and 1000 km normally, the inner surface of the wheel is further thinly coated with brake oil. The state was observed and the wheel was visually evaluated based on the evaluation criteria for the state of dirt on the surface. The results are shown in Table 1.

Example 3
As shown in Table 1, 97.9% by mass of isopropyl alcohol (described as “IPA” in the table) and hydrophobic silica (Reorosil HM30S: solid content 100%, manufactured by Tokuyama Corporation, average primary particle size: 7 nm) After mixing 2% by mass and 0.1% by mass of fluoroalkylsilane (TSL8233, manufactured by Momentive), using an ultrasonic disperser, the mixture is dispersed for 1 hour at a frequency of 44 KHz to create a hydrophobic silica dispersion for coatings. The hydrophobic silica dispersion was applied to the surface of an aluminum wheel having a clear coating surface with a brush, and left to dry as it was to obtain a super water-repellent surface having a water droplet contact angle of 160 °.

After the vehicle equipped with the wheel obtained by the above operation is normally driven on a dry road for 500 km and after a normal drive of 1000 km, the inner surface of the wheel is further thinly coated with brake oil. The state was observed and the wheel was visually evaluated based on the evaluation criteria for the state of adhesion of dirt on the surface. The results are shown in Table 1.

Example 4
As shown in Table 1, 97.7% by mass of isopropyl alcohol (described as “IPA” in the table) and hydrophobic silica (Reorosil HM30S: solid content 100%, manufactured by Tokuyama Corporation, average primary particle diameter: 7 nm) After mixing 2% by mass, 0.2% by mass of amino-modified silicon (TSF4700, solid content 100%, manufactured by Momentive) and 0.1% by mass of fluoroalkylsilane (TSL8233, manufactured by Momentive), an ultrasonic disperser was used. Disperse at a frequency of 44 KHz for 1 hour to create a hydrophobic silica dispersion, apply this hydrophobic silica dispersion to the surface of the aluminum wheel that has been painted with a paint brush, and leave it as it is. By drying, a super water-repellent surface having a water droplet contact angle of 158 ° was obtained.

After the vehicle equipped with the wheel obtained by the above operation is normally driven on a dry road for 500 km and 1000 km normally, the inner surface of the wheel is further thinly coated with brake oil. The state was observed and the wheel was visually evaluated based on the evaluation criteria for the state of dirt on the surface. The results are shown in Table 1.

Example 5
As shown in Table 1, 10% by mass of isopropyl alcohol (described as “IPA” in the table), 88% by mass of n-hexane, hydrophobic silica (Reolosil HM30S: solid content 100%, manufactured by Tokuyama Corporation, average After mixing 2% by mass (primary particle size 7 nm), an ultrasonic disperser was used to disperse for 1 hour at a frequency of 44 KHz to create a hydrophobic silica dispersion, and the surface was painted with a paint brush. The hydrophobic silica dispersion was applied to the surface of the aluminum wheel and left to dry as it was to obtain a super water-repellent surface having a water droplet contact angle of 160 °.

After the vehicle equipped with the wheel obtained by the above operation is normally driven on a dry road for 500 km and 1000 km normally, the inner surface of the wheel is further thinly coated with brake oil. The state was observed and the wheel was visually evaluated based on the evaluation criteria for the state of dirt on the surface. The results are shown in Table 1.

Comparative Example 1
As shown in Table 1, the surface of the aluminum wheel with a clear coating on the surface was maintained in an untreated state, and a surface with a water droplet contact angle of 80 ° was obtained.

After the vehicle equipped with the wheel obtained by the above operation is normally driven on a dry road for 500 km and 1000 km normally, the inner surface of the wheel is further thinly coated with brake oil. The state was observed and the wheel was visually evaluated based on the evaluation criteria for the state of dirt on the surface. The results are shown in Table 1.

Comparative Example 2
As shown in Table 1, a commercially available wheel coating agent (manufactured by Company C) was coated on the surface of an aluminum wheel having a clear coating on the surface according to the method of use to obtain a surface with a water droplet contact angle of 95 °.

After the vehicle equipped with the wheel obtained by the above operation is normally driven on a dry road for 500 km and 1000 km normally, the inner surface of the wheel is further thinly coated with brake oil. The state was observed and the wheel was visually evaluated based on the evaluation criteria for the state of dirt on the surface. The results are shown in Table 1.

Comparative Example 3
As shown in Table 1, after mixing 99.8% by mass of n-hexane and 0.2% by mass of amino-modified silicon (TSF4700, solid content 100%, manufactured by Momentive), using an ultrasonic disperser, a frequency of 44 kHz Then, this dispersion was applied to the surface of an aluminum wheel that had been subjected to clear coating with a paint brush, and left to dry to obtain a surface with a water droplet contact angle of 100 °.

After the vehicle equipped with the wheel obtained by the above operation is normally driven on a dry road for 500 km and 1000 km normally, the inner surface of the wheel is further thinly coated with brake oil. The state was observed and the wheel was visually evaluated based on the evaluation criteria for the state of dirt on the surface. The results are shown in Table 1.

Comparative Example 4
As shown in Table 1, after 99.9% by mass of isopropyl alcohol (described as “IPA” in the table) and 0.1% by mass of fluoroalkylsilane (TSL8233, manufactured by Momentive) were mixed, an ultrasonic disperser was used. The surface with a water droplet contact angle of 90 ° was applied by dispersing this dispersion on the surface of an aluminum wheel that had been dispersed for 1 hour at a frequency of 44 KHz, and with a paint brush applied to the surface. Got.

After the vehicle equipped with the wheel obtained by the above operation is normally driven on a dry road for 500 km and 1000 km normally, the inner surface of the wheel is further thinly coated with brake oil. The state was observed and the wheel was visually evaluated based on the evaluation criteria for the state of dirt on the surface. The results are shown in Table 1.

As is apparent from Table 1, the isopropyl alcohol of Examples 1 to 5 (described as “IPA” in the table) and hydrophobic silica (Reolosil HM30S: solid content 100%, manufactured by Tokuyama Corporation, average primary particle size) The wheel coated with each hydrophobic silica dispersion mixed with 7 nm) has a super water repellency with a water droplet contact angle of 150 ° or more. The brake oil was thinly applied to the inner surface of the tire, and even with a visual evaluation after a normal running of 500 km, the adhesion of dirt remained in a part, and good results were obtained.
Furthermore, the hydrophobic silica dispersion obtained by mixing at least one of amino-modified silicon (TSF4700, solid content: 100%, manufactured by Momentive) or fluoroalkylsilane (TSF8233, manufactured by Momentive) with the hydrophobic silica dispersion of Examples 2 to 4. The wheel on which the liquid was applied remained partly contaminated even after a normal travel of 1000 km on a dry road. Among them, a mixture of fluoroalkylsilane (TSF8233, manufactured by Momentive) was used. The brake oil is thinly applied to the surface, and even when visually evaluated after normal running at 500 km, no dirt can be confirmed. Further, amino-modified silicon (TSF4700, solid content 100%, manufactured by Momentive) or fluoroalkylsilane (TSL8233) is added to the hydrophobic silica dispersion. Momentive ) In Example 4 in which both were mixed in, in all tests, not confirmed all contamination became best evaluation result.

On the other hand, in Comparative Examples 1 to 4, all the wheels had a water droplet contact angle of less than 150 °, did not have super water repellency, and were inferior to the examples in all test items.

As described above, the reason why good results were obtained in Examples 1 to 5 is not necessarily all clarified, but in the state of the superhydrophobic surface where the wheel surface has a water droplet contact angle of 150 ° or more. Because the surface is composed of irregularities finer than the particle size of particles such as mud dirt and brake dust, mud dirt and brake dust come into contact with the super water-repellent surface at points, It is considered that mud dirt and brake dust do not slide down and adhere due to the synergistic effect of low frictional force and centrifugal force in a wheel that has extremely low frictional resistance and always has centrifugal force during traveling. Traditionally, the surface of the lotus leaf is super water-repellent, and this non-wetting leaf surface not only prevents the water droplets and the surface from coalescing, but also prevents the soil and the surface from coalescing, It is known to take up dirt and spill it. In this phenomenon, dust that naturally accumulated on the lotus leaf was cleaned at the same time as water such as rain fell. Thus, although the super water-repellent surface does not merge with dirt, dust and the like are deposited. In order to remove this dirt, it can be removed by an external force such as wind or vibration in addition to washing away with water droplets. Wheels for automobiles and motorcycles rotate about 5 revolutions per second even when traveling at 40 km / h, and strong centrifugal force acts on the wheel surface to remove dust accumulated on the super water-repellent surface. Is convenient. In addition, the wheel dirt is mainly dirt from the brake dust. This dirt does not occur during normal operation (when the vehicle is stopped), but is always generated when the vehicle is running. Since it can be removed by centrifugal force, making the surface of the wheel super water-repellent is an optimal method for maintaining the aesthetic appearance of the wheel surface.

In addition, the vehicle wheel may have oily dirt due to oil from the brake part, etc. The surface is not only water-repellent, but by adding fluorine repellency by introducing fluorine, etc., it is more suitable for wheel use A composition for wheel coating can be obtained.
In addition, since it has a super-water-repellent surface, it is a natural well-known effect that it prevents dirt-containing rainwater from adhering. And brake dust have the effect of washing away the dirt and automatically removing the dirt on the wheel, so that it is not necessary to wash the wheel while maintaining super water repellency. Examples of the method for maintaining super water repellency on the wheel surface include the following. Any method such as composite plating, coating, painting, etc. may be used, but a method of forming a hydrophobic fine uneven structure on the wheel surface, or after forming a hydrophilic fine uneven structure, the surface is subjected to a hydrophobic treatment. May be. From the viewpoint of the aesthetics of the wheel, the super water-repellent film is preferably transparent, and the surface roughness Ra of the fine uneven structure is preferably 200 nm or less.

INDUSTRIAL APPLICABILITY The present invention can be industrially used as a vehicle wheel coating composition and a wheel that can easily prevent and remove dirt from a vehicle wheel.

Reference diagram showing an AFM photograph of the super water-repellent film produced in Example 1 of the present invention

Claims (3)

A vehicle wheel coating composition and a wheel having a super water-repellent surface having a water droplet contact angle of 150 ° or more on the surface of the wheel. 2. The vehicle wheel coating composition and wheel according to claim 1, wherein the super water-repellent surface has oil repellency. 3. The vehicle wheel coating composition and wheel according to claim 1, wherein Ra of the unevenness of the super water-repellent surface is 200 nm or less.

Images