JPH0690858A - Electric water heater - Google Patents

Abstract

PURPOSE:To provide an electric water heater which has a transparent coating film at the inner wall thereof absorbing noises on boiling of water and preventing fur on the wall. CONSTITUTION:After the surface of base material at the inner face of a liquid container 2 is activated by the corona discharge, a transparent coating film 3 is formed on the surface, which is chiefly made of at least one of polyimide, polysulfone, polyallylsulfone, or polyethersulfone, and at least one of fluorocarbon polymers of tetrafluoroethylene resin, tetrafluoroethylene perfluoroalkylvinyl ether copolymer resin, tetrafluoroethylene hexafluoropropylene copolymer, tetrafluoroethylene ethylene copolymer, and vinylidene fluoride resin.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electric water heater for boiling hot water, and more particularly to an electric water heater excellent in antifouling against water stains and making noise during boiling water.

[0002]

2. Description of the Related Art Conventionally, ferritic stainless steel having excellent corrosion resistance has been mainly used for a liquid container of an electric water heater.

When hot water is boiled with an electric water heater having such a structure, there is a high boiling noise, and there is a problem particularly when it is used at night or in a quiet room.

Further, there is a problem that the calcia and silica components contained in tap water become scale and stick to the liquid container.

For this reason, it has been desired to deal with noise reduction and antifouling. On the other hand, the portion of the liquid container facing the heat source may already be coated with a substance such as fluororesin or silicone resin having a smaller adhesive energy than the substance forming the liquid container (Japanese Patent Publication No. 52-14665). It has been proposed that a coating layer containing a tetrafluoroethylene resin (hereinafter abbreviated as PTFE) colored in gray or metallic tone as a main component is treated on the inner surface of the liquid container and put into practical use.

In general, such a coating layer is formed by blasting the surface of a liquid container, applying a paint containing a fluororesin as a main component prepared in various colors, and baking the surface.

For this reason, although the conventional coating layer is effective in reducing the noise and the antifouling property, the original metallic material feeling of the liquid container is impaired and the commercial value is remarkably reduced.

[0008] Therefore, there has been a demand for an electric water heater having a metallic material feeling and having a coating layer formed thereon which is effective against noise and stain resistance.

[0009]

DISCLOSURE OF THE INVENTION The present invention is to solve the above-mentioned problems of the prior art, and is an electric hot water having a coating layer which is transparent and exhibits a noise and a stain resistance at the time of boiling water. It is intended to provide a heater.

[0010]

In order to solve the above-mentioned problems, after activating the substrate surface of the inner surface of the liquid container by corona discharge treatment, polyimide (hereinafter abbreviated as PI), polysulfone (hereinafter abbreviated as PSF), Polyallyl sulfone (hereinafter abbreviated as PAS) or polyether sulfone (hereinafter PE)
At least one of S) and tetrafluoroethylene resin (hereinafter abbreviated as PTFE), tetrafluoroethylene perfluoroalkyl vinyl ether copolymer resin (hereinafter abbreviated as PFA), tetrafluoroethylene-6 fluoropropylene copolymer resin (Hereinafter abbreviated as FEP) By forming a transparent coating layer containing at least one fluororesin of tetrafluoroethylene-ethylene copolymer resin and vinylidene fluoride resin as a main component, and also on the inner surface of the liquid container. After activating the substrate surface by corona discharge treatment, PI, PS
A first coating containing at least either F or PAS as a main component, and PI, PSF, PAS, or PE on the first coating.
At least one of S and PTFE, PFA, FEP,
What is made by forming a transparent coating layer having a two-layer structure of a second coating containing, as a main component, at least one fluororesin of tetrafluoroethylene-ethylene copolymer resin and vinylidene fluoride resin Is.

[0011]

[Function] PI, PSF, PAS used in the present invention
And PES, and fluororesins such as PTFE PFA, FEP, tetrafluoroethylene ethylene copolymer resin and vinylidene fluoride resin are excellent in transparency, and an electric water heater in which a coating layer using these is treated on the inner surface of a liquid container is a liquid. It is possible to provide an unprecedented highly commercial liquid container that retains the metallic feel of the stainless steel base material that forms the container.

However, in order to ensure the transparency of these coating layers, only a degreasing treatment can be performed as a base treatment on the surface of the base material, and there is a problem in the adhesion of the coating layers.

On the other hand, the corona discharge treatment shown in the present invention can activate the surface while leaving the surface state of the base material as it is, so that the stainless base material has a metallic feeling and is excellent in adhesion. A coating layer can be formed.

Further, since PI, PSF and PAS which are used as the main components of the coating layer of the present invention have excellent adhesiveness with metals, the adhesiveness can be further enhanced by using them together with the above corona discharge treatment.

On the other hand, the coating layer has a two-layer structure, and the first
As a film (metal side) of PI with excellent adhesion to metal,
Either PSF or PAS is used, and PI, PSF, PAS or PES is used as the second coating, and PTFE, PFA, FEP, Fluorinated ethylene ethylene copolymer resin and / or vinylidene fluoride resin is used. By using a resin, the PI, PSF and PAS of the first coating and the PI contained in the second coating formed thereon, as well as the PSF and PAS
Since alloying with PES and PES progresses during firing, the adhesion with each coating increases and a stronger coating can be formed.

Further, with the structure of the present invention as described above, a layer rich in fluororesin is formed on the surface of the coating layer, and therefore, as in the conventional case, the excellent effect of making noise and antifouling can be obtained. can get.

The fluororesin used is especially F
If EP, PTFE or PFA is preferable and the content of fluororesin is 50% by weight or less based on the whole coating layer, it is 2 if desired.
About 0% by weight is preferable.

[0018]

Embodiments of the present invention will be described below with reference to the accompanying drawings.

(Embodiment 1) FIG. 1 is a sectional view of an electric water heater.

An outer case 1 has a bottomed cylindrical liquid container 2 accommodated in the outer case 1.

The liquid container 2 comprises a bottom container 2-a and a side container 2-b, which are integrated by welding.

A coating layer 3 having a thickness of 8 μm is formed inside the bottom container 2-a as shown in FIG.

The coating layer 3 is formed by using a corona discharge device (manufactured by Tantech Co., Ltd.) at the frequency 2 inside the bottom container 2-a.
Corona discharge treatment was performed under the conditions of 0 KHz, voltage of 40 KV, and distance of 20 mm, and then the glass transition temperature was 260 ° C to 2 ° C.
Thermoplastic PI (LARC-TP1, manufactured by Mitsui Toatsu Chemicals, Inc.) at 70 ° C., PES and FEP in a weight ratio of 2
Apply the paint mixed in the mixing ratio of 0:60:20,
It was formed by baking at 350 ° C. for 20 minutes.

On the other hand, a heating element 4 using a mica heater is integrally welded to the bottom of the bottom container 2-a.

A lid 5 covers the opening of the liquid container 2 and is pivotally mounted so as to be openable and closable and has a vapor passage 6 therein.

Reference numeral 7 denotes a motor. A pump 8 is linked to the motor 7 so that the motor 7 is driven to suck the liquid from the suction port 9 and discharge the liquid from the discharge port 10.

Reference numeral 11 denotes an operating section composed of a variable section, a knob (neither of which is shown), etc., and controls the discharge amount of the liquid.

Reference numeral 12 denotes a spout, and the liquid discharged from the discharge port 10 passes through the communication pipe 13 and is discharged from the spout 12 to a container such as a cup.

In the electric water heater of the present invention having such a basic constitution, the liquid container has a high commercial property with the metallic base material feeling of the stainless steel base material.

On the other hand, the electric water heater of the present invention as described above was evaluated as shown in Table 1.

[0031]

[Table 1]

The results are shown in Table 2.

[0033]

[Table 2]

Incidentally, the current product 1 in which the inner surface of the liquid container 2 is not particularly treated, and the comparative product 1 in which the conventional degreasing treatment is performed and thereafter the coating layer having the above-mentioned composition is formed,
Further, the comparative product 2 in which the coating layer was formed in the same manner by further blasting was also evaluated in the same manner, and the results are also shown in Table 2.

In the column of coating change in the boiling water durability test in Table 2, ◯ means that there is no significant change in the coating, and x means that changes such as peeling of the coating components occur.

Further, in the column of the scale adhesion in the boiling water durability test of Table 2, ◯ means almost no adhesion and x means that the stain is large and cannot be easily wiped off.

As is clear from the above table, the electric water heater of the present invention, which has been subjected to the corona discharge treatment, can provide a coating layer having excellent transparency, and the peeling of the coating layer or the like can be prevented even in the boiling water durability test. No adhesion was observed at all, and the adhesion characteristics similar to those of the comparative product 2 subjected to the blast treatment were exhibited.

On the other hand, peeling of the coating layer was observed in Comparative Example 1 which was only degreased.

By thus performing corona discharge treatment and forming a coating layer made of PI, PES and FEP on the corona discharge treatment, the material has a metallic feel, stability as a coating layer, and a murmur during boiling. It also showed an excellent effect in antifouling.

Although the coating layer 3 is formed only on the bottom of the liquid container 2 in the present invention, the present invention is not limited to this and may be formed on the entire liquid container 2.

(Example 2) After the corona discharge treatment was applied to the inside of the bottom container 2-a in the same manner as in Example 1, Example 1 was performed.
The same paint as 100% by weight of PI was dissolved in a solvent to apply the prepared coating material, which was pre-dried at 150 ° C and then FEP.
A coating prepared by dissolving 20% by weight and 80% by weight of PES in a solvent was applied, followed by baking at 350 ° C. to form a first coating of PI and PES and F on top of this.
A coating layer 3 having a two-layer structure of a second coating made of EP was formed.

When an electric water heater was prepared in this manner and evaluated in the same manner as in Example 1, it had transparency and was excellent in stability as a coating layer and also in producing noise and stain resistance during boiling. The effect was obtained.

In the present invention, PI and PES are used as base resins, and FE is used as a fluororesin.
Each of P is shown, but the present invention is not particularly limited to these, and other base resins such as PSF or PA can be used.
S, and as the fluororesin, PTFE, PFA, tetrafluoroethylene-ethylene copolymer resin and vinylidene fluoride resin may be used.

[0044]

As is clear from the above examples, according to the electric water heater of the present invention, the surface of the base material inside the liquid container is activated by corona discharge treatment, and then polyimide, polysulfone, polyallylsulfone is used. Alternatively, at least one of polyether sulfone and tetrafluoroethylene resin, tetrafluoroethylene perfluoroalkyl vinyl ether copolymer resin, tetrafluoroethylene-6-fluoropropylene copolymer resin, 4-fluoroethylene ethylene copolymer resin and fluorine. By forming a transparent coating layer containing at least one fluororesin of vinylidene chloride resin as a main component, and after activating the substrate surface of the inner surface of the liquid container by corona discharge treatment, polyimide, polysulfone, Alternatively, a first coating containing at least one of polyallylsulfone as a main component Polyimide, polysulfone, polyallylsulfone, and / or polyethersulfone and fluoroethylene resin, tetrafluoroethylene perfluoroalkyl vinyl ether copolymer resin, 4-fluoroethylene-6-fluoropropylene copolymer resin, 4 By forming a transparent coating layer having a two-layer structure of a second coating containing, as a main component, at least one fluororesin of a fluoroethylene-ethylene copolymer resin and a vinylidene fluoride resin, a metallic material feeling can be obtained. It is possible to provide an electric water heater having a coating layer that has the effect of reducing noise and preventing stains.

[Brief description of drawings]

FIG. 1 is a sectional view of an electric water heater according to an embodiment.

FIG. 2 is a partial cross-sectional view of a liquid container according to an embodiment.

[Explanation of symbols]

 2 Liquid container 3 Coating layer

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Tsuneo Shibata 1006 Kadoma, Kadoma City, Osaka Prefecture Matsushita Electric Industrial Co., Ltd.

Claims (2)

[Claims] 1. A substrate surface inside a liquid container is activated by corona discharge treatment, and then at least one of polyimide, polysulfone, polyallylsulfone or polyethersulfone, and tetrafluoroethylene resin, tetrafluoroethylene perfluoride. Fluoroalkyl vinyl ether copolymer resin, tetrafluoroethylene-6 fluoropropylene copolymer resin, tetrafluoroethylene ethylene copolymer resin and / or vinylidene fluoride resin, which is a fluororesin as a main component and has transparency. An electric water heater with a coating layer. 2. A first coating film containing at least one of polyimide, polysulfone, and polyallylsulfone as a main component after activating the inner surface of the substrate of the liquid container by corona discharge treatment and polyimide on the first coating film. Polysulfone,
At least one of polyallyl sulfone or polyether sulfone and fluorinated ethylene resin, 4 fluorinated ethylene perfluoroalkyl vinyl ether copolymer resin, 4
Transparency consisting of a two-layer structure of a second coating film containing, as a main component, at least one fluororesin of a fluoroethylene-6 fluoropropylene copolymer resin, a tetrafluoroethylene ethylene copolymer resin and a vinylidene fluoride resin. Electric water heater having a coating layer formed thereon.