JPS6251672B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for surface treatment of walls such as the ceiling wall of a washing tank of a dishwasher, the ceiling wall of a bathroom, and the wall consisting of a dehydrating lid on the dehydrating machine side of a dehydrating washing machine. Specifically, it is a hydrophilic coating layer that prevents water droplets from forming into beads due to their surface tension and from dripping onto tableware after drying, the human body during bathing, objects to be dehydrated after dehydration, etc. Regarding the forming method.

For example, in conventional dishwashers, after washing and drying dishes in the washing tank, water droplets adhering to the ceiling of the washing tank drip onto the dried dishes due to vibrations, etc. Despite completing the drying process, there was a drawback that a sufficient drying effect could not be obtained.

Dishwashers with such drawbacks will be explained in more detail. In Figure 1, 1 is an outer tank, inside which is a cleaning tank 2, the front opening of which is a lid 3.
It can be opened and closed at will.

Washing water is supplied into the washing tank 2 via a water supply valve 4 . The water accumulated in the lower part of the cleaning tank 2 passes through the drainage filter 5, is pressurized by the pump 6, is jetted out from the first nozzle 7 and the second nozzle 8, and is pumped into the cages 9, 1.
Wash the tableware (not shown) set to 0.

When the washing and rinsing steps are completed in the manner described above, the washing water is discharged to the outside through the drain hose 12 by the operation of the drain pump 11, and then the drying step begins. It is preferable that this drying step be carried out in a short time so that it can be carried out economically, but if this time is too short, water adhering to the inner surface of the cleaning tank, especially the ceiling wall surface, is likely to remain without being completely dried. In particular, when the cleaning tank is molded from a hydrophobic resin or coated with a hydrophobic resin, water droplets adhering to the ceiling surface tend to remain after the drying process is completed. For example, if the cleaning tank is made of resin such as polypropylene or polyethylene, or is coated with these resins, water droplets are likely to remain. This is because the contact angle between polypropylene and water is approximately 90°, and the contact angle between polyethylene and water is approximately 94°, resulting in the water droplets forming an extremely nearly spherical shape. .

To prevent such water droplets from remaining,
Inevitably, a longer drying time is required, and if the drying time is not sufficient, the water droplets may drip due to vibrations when taking out the dishes and adhere to the dried dishes. As a result, the painstaking drying process was rendered meaningless.

As shown in FIG. 2 and described above, the water droplet has an extremely rounded shape. A is a water drop.

Therefore, as shown in FIG. 3, it has been proposed to impart hydrophilicity to the surface of the cleaning tank in order to make the water droplets B as flat as possible. An example is as follows.

(1) A surfactant is added to the final rinse water to reduce the surface tension of the water and the contact angle with the cleaning tank surface.

(2) Chemically etching the cleaning tank surface,
It causes deterioration of the surface layer and imparts hydrophilicity. As the chemical at this time, for example, sulfuric acid is used.

(3) Perform a process such as sandblasting on the surface of the cleaning tank to create a rough surface with an unevenness of 50 to 100 microns to make the surface hydrophilic.

However, all of the above methods require a large amount of investment in terms of productivity and require complicated management in terms of pollution prevention.Especially in (1) above, surfactant As a result of the need for complex machinery for the input, an increase in operating costs is unavoidable.

The above explanation was about dishwashers, but there are many other devices that can cause similar problems, such as the ceiling wall of a bathroom, the back of the dehydrating lid of a dehydrator, etc. In particular, the former causes cold water droplets to splash onto the body while bathing. In addition, the latter method has problems such as water droplets adhering to the object to be dehydrated after dehydration, reducing the dehydration effect.

The present invention has been made in view of the various conventional problems mentioned above, and embodiments thereof will be described below. In FIG. 3, reference numeral 13 denotes a wall substrate made of, for example, a washing tank of a dishwasher, and has a synthetic resin layer 14 of polypropylene or the like on at least its surface. Then, the surface is physically treated to become microscopically uneven, forming a thin hydrophilic coating layer 15 of about 0.1 to 10μ that can be easily held by the static electricity of the wall substrate 13. do.

Next, a method for forming this coating layer 15 will be described. First, an alcohol-soluble substance having water absorbing properties is dissolved in alcohol, and a solvent such as toluene in which a resin material is dissolved is mixed with this to create a solution. In this solution, the water-absorbing alcohol-soluble substance is decomposed, and the same conditions as when fine powder of this substance is mixed can be easily obtained.

When this solution is applied to the wall substrate 13, it is possible to obtain a coating layer 15 with good water wettability, in which the water-absorbing alcohol-soluble substance 16 compensates for the hydrophilicity of the coated resin. To give a concrete example,
It is as follows.

Material of the wall substrate: Polypropylene alcohol-soluble nylon 1g Alcohol (ETOH) 50c.c. Epoxy resin 4g Toluene 50c.c. The surface of the base 13 coated with a solution having the above composition by brush or spray is as shown in Figure 4. , alcohol-soluble nylon dotted in epoxy resin,
It is in a state of excellent quality and good water wettability. Fourth
In the figure, 16 is the above-mentioned particulate alcohol-soluble substance, and 17 is water attached across the plurality of alcohol-soluble substances 16.

According to the method for forming the coating layer 15 as described above, it is possible to form a coating layer having a thickness of about 0.1 to 5 μm, and if the wall substrate 13 side has fine irregularities, the degree of adhesion of the layer 15 can be improved. is extremely good.

In the above example, an epoxy resin with a contact angle with water of 60° to 70° was used, so the water-absorbing nylon scattered on the epoxy resin surface reduces the apparent contact angle of the epoxy resin with water. When the resin surface is the ceiling wall of a dishwasher tank, water droplets with a diameter of 7 to 10 mm will adhere, compared to when no surface treatment is applied.
Almost no water droplets are observed, and it is extremely effective in shortening drying time and preventing tableware from getting wet due to dripping water droplets. In addition, the epoxy resin absorbs a small amount of water on the surface and adhesion of impurities in the water to the surface, making it possible to obtain a surface with good water wettability with an apparent water contact angle of 0°.

The above-mentioned alcohol-soluble substance having water-absorbing property is a substance that can be dissolved in alcohol, and includes, for example, alcohol-soluble nylon such as CM4000 and CM8000 manufactured by Toray Industries, Inc., and polyvinyl alcohol.

Moreover, the alcohol in the present invention refers to lower aliphatic alcohols such as methanol and ethanol in a normal state.

The resin material in the present invention is a resin having a polarity close to that of water, such as an epoxy resin or a urethane resin.

Since alcohol-soluble substances dissolve in alcohol, the alcohol-soluble substances are first dissolved in alcohol. A solution is prepared by mixing a solvent in which the resin is dissolved and the above-mentioned alcohol-soluble substance dissolved in alcohol. In this solution, an alcohol-soluble substance with water absorption is dispersed, and when this solution is applied to the wall substrate, the alcohol-soluble substance with water absorption is scattered on the wall substrate using the resin material as a binder, and the applied resin is dispersed. It is possible to obtain a wall with good water wettability, whose hydrophilicity is compensated for by the water-absorbing alcohol-soluble substance.

As described above, according to the present invention, water-absorbing alcohol-soluble nylon or polyvinyl alcohol can be reliably dotted on a wall substrate using a resin material as a binder. This has the effect of reliably preventing water droplets from dripping from the ceiling wall, the back surface of the dehydration lid of the dehydration tank, etc.

[Brief explanation of the drawing]

Figure 1 is a vertical cross-sectional view of a typical dishwasher, Figure 2
3 is a sectional view of a wall in an embodiment of the present invention, and FIG. 4 is a sectional view showing details of the wall. 13... Wall substrate, 16... Alcohol soluble substance.

Claims (1)

[Claims] 1 Dissolve water-absorbing alcohol-soluble nylon or polyvinyl alcohol in alcohol, mix this with a solvent in which a resin material is dissolved to create a solution, and apply this solution to a wall having a synthetic resin layer on at least the surface. A method for treating the surface of a wall by coating the surface of a body substrate.