JPS60169569A - Surface treatment of aluminum plate for heat exchanger - Google Patents

Abstract

PURPOSE:To provide a hydrophilic surface to an Al material for assembling a heat exchanger, to improve the corrosion resistance and to maintan the pressability and the property of preventing the wear of dies by subjecting the Al material to chemical conversion treatment with a Zr salt soln. to form a Zr salt film. CONSTITUTION:An Al material for assembling a heat exchanger or a finned Al material is subjected to chemical conversion treatment with a Zr salt soln. in degreasing, washing, film forming, washing and drying stages. A Zr salt film formed by this method has a satisfactory initial hydrophilic property and undergoes little change with the lapse of time. The hydrophilic property is not deteriorated by heating in a brazing stage. The film provides high corrosion resistance to the Al material. The pressability of the Al material is not deteriorated, and the wear of dies is extremely reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION Technical Field The present invention relates to a method for treating aluminum 4Δ for heat exchangers with a chemical conversion coating.

Conventional technology Conventionally, in order to make the surface of aluminum materials for heat exchangers hydrophilic for the purpose of improving heat exchange performance, reducing noise, and preventing dew splatter, efforts were made to prevent the generation of white powder due to corrosion of raw aluminum. il) to improve color fastness for the purpose of
, Painting, (2), Chemical coating treatment, (3), Boehmai 1~
etc.: 1 Ilf A-me or after fin molding.

However, although 4T has the above-mentioned conventional h.gamma.fil, there are drawbacks as described below.

(1) In order to make the coating film hydrophilic, silica,
It is necessary to add a surfactant, and if the paint contains silica, the mold will wear out when pressing the aluminum material.
Also, the added surfactant flows out into the drain water.
As a result, the hydrophilicity 14 of the coating film decreases.

2) Regarding the brake + -t-+A of the coil frame A-, it is possible to form the draw press Efin, but the l-
'I] - With twin presses, a part of the coating film adheres to the mold (+1) during one press, which prevents continuous press.

3) In continuous coating after fin formation, bridges of the coating film occur between the fins, and a uniform coating thickness cannot be obtained.

(2) Chemical conversion coating treatment 1), chromic acid treatment does not provide a hydrophilic surface to the treated surface (A).

2) In the water glass treatment, the mold wears out during pressing of the treated material, and the corrosion resistance of the treated material is poor.

(3) Although the hydrophilicity and corrosion resistance of the boehmite treated material are good, the treatment time is long and the press 14 of the treated material 4j is stiff, so
~Re-1-1 In the case of one-way system, this process cannot be performed.

Purpose The present invention solves the drawbacks of the conventional surface treatment method for aluminum lx'M for heat exchangers, provides a hydrophilic surface to the aluminum side, and improves corrosion resistance. An object of the present invention is to provide a surface treatment method for an aluminum plate for a heat exchanger that does not impair pressability and mold wear resistance.

Structure The gist of the present invention is as described below.

It's a chemical coating that is applied to the aluminum material used for assembling the heat exchanger or the aluminum material subjected to foam processing in a zirconium salt solution! Surface treatment of aluminum for heat exchanger 4-10,000 tons without treatment for 1 hour.

The present invention will now be described in detail.

As mentioned above, the conventional chemical conversion coatings 1 and 11 used on aluminum are chromium-based coatings, and have a good electrodynamic effect for surface corrosion resistance of +41 and -1 for improving paint film adhesion. The surface is 4 water 1 (1).

In addition to this, the present inventors have applied Jζ1 to the sil-1 nium salt treatment that has recently been used in the chemical conversion coating treatment of IJi materials.
The resulting film has good hydrophilicity and corrosion resistance. Also, the fin press molding (!l)a 1flJ does not occur.
The mold wear was also found to be approximately the same as that of Qζ-treated 7/luminium material.

These characteristics are extremely good for the performance of aluminum heat exchangers, and in actual heat exchanger tests, equipment treated with a chemical conversion coating using a zirconyl salt solution showed excellent results. l ability was obtained.

The reason for the good hydrophilicity of the chemical conversion coating that is soaked in the zirconium salt solution is the chemical conversion coating I+! ,! It is presumed that this is because many hydroxyl groups are oriented on the surface, and the reason why the pressability of the treated material is good and there is little mold wear is due to the 71% concentration in the film.
・The diameter is 30 m g7') 2 (The amount of film is c150
This is thought to be due to the fact that it is only about m (1/m2) and the adhesion of the skin to the surface of the material to be treated is extremely good.

The processing steps in the present invention are as follows. Aluminum plate: Coil 5, V output (), degreasing (
1) → Water washing (2) → Film formation (3) → Water washing (/1) -→
After the drying step (5), it is rolled up.

This processing step can be performed even in the case of pre-1 to re-1-men 1 one-way system.
The same applies to the treatment after fin forming, and only the surface treatment conditions differ due to constraints on the treatment time.

Below is the surface J! I! Article A9 will be explained.

[111112 A film is formed even with no fat or hot water washing, and the corrosion resistance is improved, but the hydrophilicity of the film is poor. Commercially available 1it
) Grease agents, e.g. Japan Pay] i h Gastric lidrin 53.2
%,! i 0 'C;, washing η- for 5 seconds results in hydrophilicity (!
l gets better.

[3] Chemically formed zirconium in film treatment JJ Dojitte IJ, and commercially available products include JZ Robukun 404.41; 3 manufactured by Nippon Paint. The treatment method may be dipping, spraying, or coating.
desirable. Treatment line ('l LJ, desired Zr□□□
The depth 1α, temperature, and time are determined so that the temperature is 1!7. .

(/I) Water washing When chemical conversion treatment is performed by dipping or spraying, water washing is performed, but if chemical conversion treatment is by coating method, water washing may be omitted.

This step is carried out in the case of a pre-treatment method using a coil form, but this step is not required when the product is processed after being assembled.

Examples of the present invention are listed below.

Example 1 JIS I-14000A 1050P-l-l
0.12x1 of 22 (100x coil as sample,
This was treated under the conditions shown below. Regarding the zirconium salt film formed on each sample, its contact angle, water wettability, 7l-f3. was measured. These results are shown in Table 1.

■, No treatment conditions 11LllL dry cleaning 0°C x 10sec, Spray Rd53: Ridrin 2%, manufactured by Nippon Bain, 50'Q
10, 20.30sec > W crush → water washing 5300
, Spray Shiheki' - Ahead Δd 413: Manufactured by Nippon Bain 1 711' Jin 5%,
50℃ x 10, 20, 30sec, water washing for 5sec, spray drying at 110℃, 53OC (2) About the results 1) No degreasing, no hot water washing, no peeling! is formed, its water wettability is high, and its contact angle is high.

2) R53F IIt2 greasy, water wettability (, L
Good and low contact angle.

3) Therefore, it can be seen that degreasing is necessary.

Fruit #11@+2 Using the same sample sample as in Example 1, it was treated with − under the following conditions. Regarding the film formed on the table wipe 1 - UZ
The contact angle was measured using rftl. Furthermore, the time required for 5% of the 1-bath meals to occur in salt water r@TA test (,) I 5Z2371> e row 'ate, test '1 was investigated.

The results are shown in Table 2.

■, Processing conditions +11211Ej Rd 53: Same film formation as in Example 1 △(+413: 5%, !i0℃x [i,!i-
・2 (!C water wash 5SOC, spray fall 110℃, 5sec (2) About the results 1), Zrff) increases, the contact angle decreases, and if the contact angle is 20° or less (,1,71゛Hanging is 18 m
(1/Il+'2) is required.

2), To reach a contact angle of 30° or more, 7. r
(i ['1lnl/11' or later]').

3) Corrosion resistance 1/1- is one of the best in terms of 7R cliffs.

Example 3 sro, io%, r”co, 1596, M n 0.1
0%, Ct, +, Mg, C1., Zn, l-i each 0.05% or less, the balance A1. J, Tsumuru aluminum (Δ) 0.11X 500x coil was treated with the same strip 1'1 as in Example 2 using a sample dowel. The formation time and Zr@ of the film for each sample are shown in Table 33. 1.Next, in Example 2 and Example J3, a silicone cum salt skin B was prepared. ) hoberu.

Press property test (1) Draw fin (overhanging fin) A sample treated in Example 2 and an untreated sample of 4A, which is the same as the sample of Example 2, were subjected to draw press processing to form fins.

As a result, both N011 to No.6 and the non-processed side
J-pressing] No abnormalities were observed at the second time, and a good fin of 27 was obtained.

(2) Drawless fins (shigoki fins) Fins were formed by drawless press processing on trial 1 treated in Example 3 and the same material as the sample of Example J3 on untreated fins.

As a result, good fins were produced in No. 7 to No. 12 and on the untreated side, Drawless Press + JII-r, II''J without any liability.

Sample subjected to J1v in heat resistance test example 2 and pressability test (1)
, (test the lζ sample pressed with a knife with a gas burner)
IJH heat was applied until just before 1'3+ dissolved. After heating, the sample was subjected to the -C test for water wettability.

For this test, use ion-exchanged water for all samples! 1sQc immersion i
After washing, I pulled it up and observed the water temperature after 30 scc.

As a result, water wetness was observed on the entire surface of each sample. After Σ1, 1, and 1, no changes such as yellowing or yellowing were observed in the external appearance.

Hydrophilicity lasting 111W, (After receiving the test, the test material was planted with hydrophilicity, and a test was conducted to make 111 λ station.) Method and its results, 14
has the sentence as shown below.

(1) Test (1st) Sample oil treated in Example 2 No. 30.1
2x50xi00nln1 2) Comparative material J I S l-+ 4000 △1 (150P-11
0.12X of 22! iox 100nlllll water-soluble acrylic/melamine resin with 1'l surfactant in the coating film.
Paint with 5% J, sea urchin added to a thickness of 1μ11, and bake this at 240° x 3 (IsOc).
(2) Test method The test piece was immersed in ion-exchanged water for 2 minutes, pulled out and dried with cold air Try A7- for 6 minutes, and this process was repeated several times.

After that, the contact angle of the test piece was measured and the water temperature test was conducted.

(3) Test results The test results are shown in Table 4 and were J5.

Attempt l N O, 31, 'U' treated in Example 2
1000 times - (-b The contact angle and water resistance were good, but the comparative material was wet 11 after 3 times and became submerged.

There are 43 summaries of electrodynamics from the Song and Ming dynasties, listed below.

(11. The zirconium film obtained by the method of Mizu Raki has good initial hydrophilicity.
, Even if J3 is heated in '1, it is still hydrophilic! '＋I can't be heard.

(2) The Jill:1 Ni film (Jl, J!I) provides good corrosion resistance to the Jill 7 Fluminium.

(3) Two aluminum plates treated according to the present invention (Yo,
It does not impair pressability (41), but it also extremely reduces mold wear.

(4) The method of the present invention allows treatment by dipping, spraying, and coating, and treatment 11.1 and 9.1. ii The method of the present invention can also be carried out using the post-processing method. No discoloration occurs during processing.

(6) The chemical conversion coating treatment described in this defense is generally cheaper than the painting method: 1) The cost per coating is lower than that of the chemical conversion coating treatment solution.

2) From the baking time of repainting 1, the process can be completed in 1 hour.

3) Chemical coating treatment is possible due to the drying temperature of the coated fish (the drying temperature is low, so chemical conversion coating treatment on this fish can save energy and be carried out at low cost.

Claims (1)

[Claims] 1. A method for treating aluminum materials for heat exchangers, which comprises applying a chemical conversion coating treatment using a zirconium salt solution to aluminum materials or fin-processed aluminum materials used for assembling heat exchangers.