WO1991001106A1

WO1991001106A1 - Fluororesin-coated article

Info

Publication number: WO1991001106A1
Application number: PCT/JP1990/000923
Authority: WO
Inventors: Hideki Kashihara; Nobutaka Matsushita; Fumio Matsuyama
Original assignee: Sumitomo Electric Industries, Ltd.
Priority date: 1989-07-19
Filing date: 1990-07-18
Publication date: 1991-02-07

Abstract

A fluororesin-coated article comprising a plate cladded with stainless steel and aluminum or its alloy, wherein the surface of the aluminum or its alloy is etched, and a coating formed on the etched surface comprising a fluororesin and 0.5 to 10 % by weight of at least one heat-resistant polymer selected from the group consisting of polyamide imide, polyimide, polyphenylene sulfide and polyether sulfone as a filler.

Description

Specification

Fluororesin coating

Technical field

The present invention relates to a fluororesin coating for an inner pot such as a jar rice cooker, an insulated jar, a rice cooker, and a rice cake cooker (hereinafter, simply referred to as an “inner pot”). The present invention relates to a fluororesin coating suitable for an inner pot of an electromagnetic induction heating type cooking device using an alloy and a stainless steel cladding material.

Background art

The prior art in the field of this type of inner pot includes the following techniques: After etching the surface of aluminum or aluminum alloy of aluminum or aluminum alloy and stainless steel cladding material, it is added to pure iron. A technology to apply a fluorinated titanium resin dispersion, dry, bake, and press mold to obtain an inner pot.

Aluminum or aluminum alloy and stainless steel cladding Press-forming so that the aluminum or aluminum alloy is on the inside, blasting the aluminum surface, applying a primer, and spray-coating a tetrafluoroethylene resin containing a filler such as a pigment and My power, A technique for obtaining an inner pot by baking.

Further, a metal resin is coated with a polyarylene sulfide resin, a polyamide imide resin and / or a polyimide resin, and a fluororesin coating composition in which at least three components of a fluororesin are dispersed in a liquid medium. There is known a technique for obtaining an adhesive coating film by fabric-cloning, drying and baking at a temperature of 330 to 400 (see Japanese Patent Publication No. 60-212193).

However, the conventional techniques as described above have the following problems.

-S o

In the case of an aluminum material having poor etching properties, the adhesion of the applied resin is extremely reduced. Therefore, it is necessary to obtain a uniform etching surface by controlling the degree of tempering of aluminum, adjusting the elements added to the alloy, etc., and it is necessary to control the surface state to a high degree. In addition, there was a problem that only limited ingredients can be used. In particular, for an electromagnetically heated rice cooker, a cladding material of aluminum and magnetic stainless steel is used.In this case, the etching properties of the aluminum surface are particularly deteriorated by the degree of the cladding, and if this is etched by conventional technology as it is. Adhesion with the coating resin is insufficient, and as a result, there is a practical problem such as deterioration of corrosion resistance.

Polytetrafluoroethylene (FTFE) or ethylene-tetrafluoroethylene copolymer (ETFE) is a soft resin that is transparent or translucent. Discoloration of aluminum is conspicuous _c

When spray coating a pressed product, coating unevenness is apt to occur, and pinholes are generated in that portion, causing serious defects in corrosion resistance.

The invention of Japanese Patent Publication No. 60-212193 is intended to obtain a strong adhesive coating film, but has a problem in elongation of the coating film.

In view of the above, the present invention solves such problems / "Secondly developed 7" Things.

Disclosure of the invention

That is, the present invention provides a plate in which aluminum or an aluminum alloy is etched on a surface of aluminum or an aluminum alloy and stainless steel, and a fluororesin and a polyamide imide formed on the etched surface. PAI), polyimide (PI), polyphenylene sulfide (PPS) and polyethersulfone (PES) at least one heat-resistant polymer to fluorine resin. It is intended to provide a fluororesin covering comprising a coating comprising 0.5 to 10% by weight.

BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 is a cross-sectional view of an aluminum / stainless clad material used in an embodiment of the present invention, and FIG. 2 is a diagram for explaining a method for evaluating film elongation in the embodiment of the present invention. =

Invention O Detailed description A feature of the present invention is that a fluorine resin layer containing a heat-resistant organic polymer is provided as a filler on the surface of aluminum or an aluminum alloy.

As a result, the abrasion resistance of the resin is improved, the appearance problem of discoloration of aluminum is solved, and the adhesion to an aluminum substrate having poor etching properties can be improved.

In the present invention, as the filler, at least one selected from the group consisting of polyamide (PAI), polyamide (PI), polyphenylene sulfide (PPS) and polyester tersulfone (PES). Both use one type of heat-resistant polymer.

By mixing this filler with the fluororesin, the adhesion of the coating to materials having poor etching properties is improved.

The amount of the filler resin is preferably from 0.5 to 0% by weight based on the fluororesin. If the amount is less than 0.5% by weight, the adhesion is not sufficiently improved, so that the corrosion resistance is not improved. Filler resin exceeds 10% by weight based on fluororesin In this case, although the adhesion is further improved, the elongation of the coating film becomes insufficient, and the coating film is locally broken by press molding, and the corrosion resistance and the like are reduced.

When the fluororesin coating of the present invention is an inner pot such as a plateware, the fluororesin paint is usually coated on the surface of the plate in a flat state, and then the rice cooker is obtained by press molding. For this reason, the elongation of the coating film after coating on a flat plate is preferably at least 200%. Also, by mixing the filler resin with the fluorine resin, the discoloration of aluminum generated during cooking rice or the like becomes less noticeable. However, the concealment of the coating film may not be perfect, and materials with poor etching properties are more likely to produce streaks in appearance and colors and vapors due to steam more easily than materials with good etching properties. It cannot be concealed sufficiently with a coated film. Therefore, it is more preferable to provide a fluororesin layer containing an inorganic inorganic material such as 0, my, carbon, titanium oxide, and oxidized oxide as the second layer so that the discoloration of aluminum can be completely hidden. This In addition, corrosion resistance is improved.

Among these heat-resistant polymers, PAI is the most preferred in terms of adhesion and corrosion resistance.

Examples · Hereinafter, the present invention will be described with reference to examples.

Example 1

As the material, a 2.0-mm thick clad material made of aluminum and stainless steel was used. This is made by Kobe Steel, Ltd., made of aluminum alloy (ASB material) (1), aluminum (2), and stainless steel (3), which are clad into three layers as shown in Fig. 1. (. = 0.75 mm,

First, using this aluminum surface as an anode, electrochemical etching was performed with 25 clones of Z cm ^{2 in} an aqueous solution of ammonium chloride to form fine irregularities on the surface.

On this etched surface, the resin coating shown in Table 1 The coating composition was coated by spin coating, and after drying the water, it was baked for 10 minutes at 400. The coating composition was coated so that the film thickness became 20.

The coating obtained in this manner was processed by press molding to obtain a rice cooker inner pot.

On the other hand, as a comparative example, a resin coating composition (including only PTFE disposable ion) having the composition shown in (1) of the comparative example in Table 1 was applied to an etching plate similar to the above method so as to have a film thickness of 20%. They were coated and baked and pressed by the same method.

The resulting rice cooker was evaluated for the following items.

①Adhesion

Insert a checkerboard (100 mm at 1 mm intervals) reaching the base with a knife on the coating surface, press a cellophane loop on this surface. 0 0 Resin S

Count &; ②Discoloration in practical use

Repeat cooking rice 300 times using a commercially available rice cooking jar, and investigate the occurrence of discoloration.

③ Corrosion resistance

Make a raw oden solution by dissolving house oden element 2 δ 2 in water 1, pour the scrap into a kettle to about 80% of the volume, boil for 8 hours while refilling the liquid as needed, and then Insulate for hours. Repeat this cycle and measure the time until blisters of 1 mm or more in diameter occur on the coating surface.

④Film elongation

Put the specimen on the side of the kettle into 8% hydrochloric acid solution, dissolve the aluminum and stainless steel parts, and collect only the coating film. Cut this to a width of 1 O mm, and insert both ends into a 30 mm gap check as shown in Fig. 2. One end of this check is fixed, and the other end is pulled with a tension of 100 μm to measure the elongation of the film when the film breaks.

In Fig. 2, (5) is a movable chuck (moving upward, arrow), and (6) is a fixed chuck. Fixed chuck (fixed), (7) is the coating film, L = 30 dragons.

⑤Pinhole test

Soak the aluminum solution in the filter paper, attach it to the coating surface of the kettle, and press down with aluminum foil from above. Apply a voltage of 15 V with the aluminum foil as the negative electrode and the shuttle as the positive electrode. There pinholes in the coating film, the energized portion, red point remains in the filter paper _c

As can be seen from the results shown in Table 1, in the examples, both the adhesion and the film elongation were superior to those of the comparative examples, and as a result, there were no pinholes, and the corrosion resistance was excellent.

Example 2

Cladding was etched in the same manner as in Example 1, and a resin coating composition having the composition shown in the column of Examples in Table 2 was coated on the surface by spin coating as the first layer to remove water. dry. The coating composition was coated so as to have a film thickness of 20 / /. Then, as the second layer, the resin composition shown in Table 2 was coated. Bake for 10 minutes. The second layer was coated so that the total resin thickness of the first and second layers was about 40z. These were evaluated as in Example 1.

As can be seen from the results in Table 2, the base layer can be sufficiently concealed as the second layer.By coating a pigment and a fluorine resin containing my power, the adhesion and film elongation characteristics are not deteriorated. Color unevenness due to steam during actual cooking and streaks after etching can be completely inconspicuous. In addition, the corrosion resistance is dramatically improved.

Example 3

The first layer and the second layer were coated in the same manner as in Example 2 using a heat-resistant polymer other than PAI. The results are shown in Tables 3-5.

Table 1 ο

ο

o

: 100 1.0 100 1 0 0 96Η; 192H Example 100/100: 270; 〇 96Η. 192H

100 I 10.0! 100/100: 230! 〇 80Η 160H

100 50/100; 400 X 32H ί 64 Η 〇 100! 0.3; 70/100 400! 〇! 48H I 96H 铰 100! 20.0 100/100 120 32H 64H Example 100! 50.0 \ 100/100 70 ■ Ο 24Η-48Η X

100; 100! 100/100 30: 〇; 16H 32Η X

^ Table 2

l m ίΐ 2mn Membrane intermediate rice cooked After press corrosion resistance After press

PTFE · Ί · PTFE pigment My strength Dense% discoloration Oden boil Insulation pinhole

100 0.5 100 10 2 100/100 350 224 H 448 H 〇 Application 100 1.0 100/100 300 (Q) 256H 512H 〇 Example 100 5.0 100/100 230 (0 264 H 528 II 〇

100 10.0 100/100 200 (0) 248 II 496H 〇

100 0 50/100 350 (6) 56 H 112 II 〇

Jb 100 0.3 70/100 350 (<: 120 II 2Ί0Μ 〇 f.¾ 100 20.0 100/100 120 (0) 7211 144 H 〇

100 50.0 100/100 100 () 6 II 128H Δ

100 100 100/100 90 (0! 56 M 112II Δ

1 No grain 30/100 150 16H 32H X

No. 3

2 m 11 Membrane ¾ Cooking rice Corrosion resistance after pressing After pressing

PTFK PPS PTFE マイ力力力力力力力%%

% 100 0.5 100 10 2 100/100 340 (C) 216H 32 II 〇 lii! I 100 1.0 〃 100/100 300 () 232 H 464 Π 例 Example 100 5.0 〃 100/100 220 (O) 224 II 448H 〇

100 10.0 100/100 200 (0) 232H 46 H 〇

1 no 0.3 〃 70/100 350 (0) 11211 224 H 〇

100 20.0 100/100 120 () 56 II Π2Η 〇

()

Example 100 50.0 〃 100/100 100 \ 96H Δ

100 100 〃 100/100 80 () Lake 80 H Δ

Table 4

1st grain 2nd grain Film elongation Real cooked rice Corrosion resistance after pressing After pressing

ΠΊ'Ί ': PES PTFE Pigment My strength Appetizer% Discoloration Oden boil Insulation Pinhole

% 100 0.5 100 10 2 100/100 340 (§) 224 H 448H cell 100 1.0 100/100 300 (O) 240 Π 480 II 例 Example 100 5.0 100/100 240 (O) 248H 496H 〇

100 10.0 100/100 210 (O) 224 H 448H 比 Ratio 100 0.3 60/100 350 @ 120H 240 II 〇 School 100 20.0 100/100 120 (q) 64 H 128H 例 Example 100 50.0 100/100 110 () 56 II 112II Δ

100 100 100/100 100 (0) 48H 96H Δ

1 11 2 FH 1 ΐΓΚ PI PTFE pigment

100 0.5 100 10 Application 100 1.0

Example 100 5.0

100 10.0

it 100 0.3

100 20.0

100 50.0

100 100

Claims

The scope of the claims

1. A plate in which aluminum or aluminum alloy is etched on the surface of aluminum or aluminum alloy and stainless steel, and a polyimide resin formed on the etched surface as a fluororesin and a filler. At least one heat-resistant polymer selected from the group consisting of polyimide, polyphenylene sulfide and polyether sulfone in an amount of 0.5 to 10% by weight based on the fluororesin. A fluororesin coating comprising a coating comprising:

2. The fluororesin-coated product according to claim 1, wherein the second fluorocarbon resin is coated with a C-fluorine resin containing a filler capable of sufficiently concealing an underlayer as a second coating layer.

3. The fluororesin coating according to claim 1 or 2, wherein the elongation of the coated film is at least 200%.

Abstract

A plate in which aluminum or an aluminum alloy is etched with aluminum or aluminum alloy and stainless steel clad, and a polyimide resin and a polyimide formed as a filler formed on the etched surface. A fluorine-containing coating comprising at least one heat-resistant polymer selected from the group consisting of mid, polyphenylene sulfide and polyether sulfone in an amount of 0.5 to 10% by weight based on the fluororesin. Resin coating.