JP2002088454A - Aging furnace for resin-coated aluminum alloy member - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an aging furnace with which heat treatment and resin remelting treatment can be applied to a resin-coated aluminum alloy member without blunting the aluminum alloy. SOLUTION: The aging furnace for resin-coated aluminum alloy members is used for applying heat treatment and successive resin remelting treatment to the resin-coated aluminum alloy members and has a hot-air injection mechanism or an infrared heating mechanism.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an aging furnace used for heat-treating and resin-remelting a resin-coated aluminum alloy member.

[0002]

2. Description of the Related Art Resin-coated aluminum alloy members obtained by coating an aluminum alloy with a resin film are widely used for frame parts of automotive window glass, aluminum sashes and the like.
As a method of manufacturing such a resin-coated aluminum alloy member, Japanese Patent Publication No. 58-22267 and the like first extrude an aluminum alloy for non-heat treatment by hot extrusion, and powder-coat the resin powder by using the heat of the extrusion molding. A method for forming a resin film is proposed. Normally, when left to cool to room temperature after extrusion, hydrates are formed on the surface of the aluminum alloy and the resin does not adhere at all. However, in this method, almost all hydrates are formed due to continuous powder coating after extrusion. Not done. Further, a method is also known in which an aluminum alloy is subjected to anodic treatment, chemical conversion treatment or the like, followed by baking. When a resin-coated aluminum alloy member is used in an automobile or the like, high strength is required, and therefore, it is usually necessary to heat-treat the aluminum alloy. However, in the above prior art, the aluminum alloy is limited to a non-heat-treated aluminum alloy. This is because in the conventional method, the adhesion between the resin film and the aluminum alloy is low, the control of the adhesion is difficult, and the heat treatment makes the resin brittle and the adhesion is impaired. Further, conventionally, the upper limit of the heat treatment temperature is 200 ° C. in order to maintain the properties such as the strength of the aluminum alloy, and it has been difficult to apply a resin having a melting point exceeding 200 ° C.

[0003] Under such circumstances, the present inventors have (A) a forming step of hot extrusion forming a heat-treated aluminum alloy at 350 to 530 ° C, and (B) a forming step of the formed aluminum alloy in the air within 900 seconds. (C) a resin coating step of applying a resin on the surface of the aluminum alloy and cooling to form a resin coating, and (D) heat treating the aluminum alloy with the resin coating formed thereon. According to a production method including a heat treatment step of performing a resin remelting step of performing a remelting treatment of the resin in the resin coating and cooling the resin coating, the resin-coated aluminum alloy having excellent adhesion of the resin coating even when the heat treatment is performed We have already found that parts can be manufactured (Japanese Patent Application 2000-2)
No. 76784). Specifically, in this production method, (i) by setting the cooling conditions strictly, to obtain an active aluminum alloy surface which is appropriately oxidized and does not form a hydrate, and (ii) heat treatment By performing a resin remelting process later, it is possible to improve the adhesion. However, this method has a problem that the aluminum alloy becomes dull due to the heating temperature when performing the resin remelting treatment. Accordingly, there is a need for a technique capable of performing a resin remelting process without dulling an aluminum alloy.

[0004]

SUMMARY OF THE INVENTION An object of the present invention is to provide an aging treatment furnace capable of performing heat treatment and resin remelting treatment on a resin-coated aluminum alloy member without dulling the aluminum alloy.

[0005]

Means for Solving the Problems In view of the above problems, as a result of intensive studies, the present inventors have found that when performing resin remelting treatment on a resin-coated aluminum alloy member, the temperature of the aluminum alloy is set within a range that does not slow down. The present inventors have found that the use of a specific heating mechanism capable of heating the resin to the melting temperature while holding the same can suppress dulling of the aluminum alloy during the resin remelting treatment, and reached the present invention.

That is, the aging furnace for resin-coated aluminum alloy members of the present invention is used when heat-treating and continuously remelting the resin to the resin-coated aluminum alloy members, and includes a hot air blowing mechanism or an infrared heating mechanism. It is characterized by having.

The aging furnace of the present invention comprises: (A) a forming step of hot-extrusion forming a heat-treated aluminum alloy at 350 to 530 ° C .; and (B) a forming step of the formed aluminum alloy in air at a surface temperature of less than 900 seconds. (C) a resin coating step of applying a resin on the surface of the aluminum alloy and cooling to form a resin coating, (D) a heat treatment step of heat treating the aluminum alloy having the resin coating formed thereon, And (E) a particularly preferable method in a production method including a resin remelting step of subjecting the resin in the resin film to a remelting treatment and cooling.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The aging furnace for resin-coated aluminum alloy members of the present invention has a hot air blowing mechanism or an infrared heating mechanism. According to the aging treatment furnace of the present invention, the resin-coated aluminum alloy member can be subjected to the heat treatment and the resin remelting treatment continuous with the aluminum-coated aluminum alloy member without dulling the aluminum alloy. This is because if the aging treatment furnace of the present invention is used when performing the resin remelting treatment, the resin can be melted without increasing the temperature of the aluminum alloy. That is, according to the aging treatment furnace of the present invention, it is possible to heat the resin film to the melting temperature while maintaining the temperature of the aluminum alloy at a temperature that does not slow down.

FIG. 1 is a schematic view showing an example of the aging furnace of the present invention having a hot air blowing mechanism. The aging treatment furnace shown in FIG. 1 includes a furnace part 1, a hot air circulation device 2 for heat treatment, and a hot air blowing mechanism 31 for resin remelting treatment. The resin-coated aluminum alloy member 5 is supplied from the loading / unloading port 6 by the carrier 4.

FIG. 2 is a schematic view showing an example of the aging furnace of the present invention having an infrared heating mechanism. The aging furnace shown in FIG. 2 includes a furnace section 1, a hot air circulation device 2 for heat treatment, and an infrared heating mechanism 32 for remelting the resin. The resin-coated aluminum alloy member 5 is supplied from the loading / unloading port 6 by the carrier 4.

In the present invention, the resin-coated aluminum alloy member is not particularly limited as long as it is manufactured by forming a resin coating on the surface of the aluminum alloy and can be heat-treated. The aluminum alloy may be JIS standards A6063, 2024, 7075, etc., and the resin forming the resin film may be an olefin resin, a styrene resin, an acrylic resin, a polyester resin, a polyamide resin, a modified resin thereof, or the like. Further, a polymer alloy containing any of those resins can also be used, and polyvinylidene fluoride, an ethylene-tetrafluoroethylene copolymer, an ionomer, or the like, or a mixture thereof may be used.

The size of the resin-coated aluminum alloy member and the thickness of the resin coating are not particularly limited. For example, in an automobile, an aluminum alloy extruded material having a width of 3 to 100 mm and a thickness of about 0.5 to 5 mm coated with a resin coating having a thickness of about 2 to 150 μm is usually used. Can also be used for manufacturing such a resin-coated aluminum alloy member.

The aging furnace of the present invention comprises: (A) a forming step of hot-extrusion forming a heat-treated aluminum alloy at 350 to 530 ° C .; and (B) a forming step of the formed aluminum alloy in air at a surface temperature of less than 900 seconds. (C) a resin coating step of applying a resin on the surface of the aluminum alloy and cooling to form a resin coating, (D) a heat treatment step of heat treating the aluminum alloy having the resin coating formed thereon, And (E) a production method including a resin remelting step of remelting the resin in the resin film and cooling the resin film. As described above, according to this manufacturing method, it is possible to manufacture a resin-coated aluminum alloy member having excellent adhesion of the resin film even when heat treatment is performed. The aluminum alloy surface of the resin-coated aluminum alloy member obtained by this manufacturing method is oxidized and does not form a hydrate. Hereinafter, this manufacturing method will be described in detail.

(A) Forming Step First, a heat-treated aluminum alloy is formed by hot extrusion. The aluminum alloy used is as described above. The temperature at the time of extrusion may be 350 to 530 ° C, preferably 450 to 500 ° C. If the extrusion temperature is lower than 350 ° C., it is difficult to extrude, and if it exceeds 530 ° C., the surface of the extruded material undesirably undergoes partial melting due to heat generation during processing.

(B) Cooling Step Next, the aluminum alloy is cooled in the air to a surface temperature of 240 to 340 ° C. within 900 seconds. More preferably, it is cooled to a surface temperature of 260 to 340 ° C within 300 seconds. By cooling under these conditions, an aluminum alloy having the above-mentioned preferred active surface can be obtained.

The cooling may be carried out simply by leaving it alone, or may be carried out using a cooling gas or a refrigerant. In order to prevent the formation of hydrates and control the adhesion, it is preferable to use dry air as a cooling gas. The temperature of the dry air may be usually from room temperature to 50 ° C.

(C) Resin Coating Step Subsequently, a resin is applied on the surface of the cooled aluminum alloy, and cooled to form a resin coating. The application of the resin may be performed in the air, and is preferably performed in dry air. If the humidity of the air is high, hydrates are easily formed on the surface of the aluminum alloy, and in addition, hydrolysis of the resin may occur, which is not preferable.

As a method for applying the resin, a general dipping method, a curtain coating method by extruding a resin by a T-die, or the like can be used. The resin may be applied in a molten state or powder-coated, but is preferably applied in a molten state by heating. When a powdery resin is used, it is necessary to raise the temperature of the aluminum alloy (about 400 ° C.), so that the resin is likely to be deteriorated and sufficient adhesion may not be obtained. Further, by applying a resin in a molten state, cost can be reduced as compared with the case of performing powder coating.

When the resin is applied in a molten state by heating, the temperature of the resin is preferably 230 to 330 ° C.
The temperature is more preferably 0 to 300 ° C, and particularly preferably 260 to 280 ° C. If the resin temperature is lower than 230 ° C., the viscosity of the resin is so high that application is difficult, while if it exceeds 330 ° C., the deterioration of the resin is remarkable.

The resin film is preferably made of a thermoplastic resin having a melting point of 200 ° C. or higher. The thermoplastic resin is preferably a polyester resin or a polyamide resin or a modified resin thereof, or a polymer alloy containing the same, and more preferably polybutylene terephthalate. When such a thermoplastic resin is used, after the thermoplastic resin is applied on the surface of the aluminum alloy, the resin is kept in a molten state for at least 1.5 seconds and then cooled to form a resin film. , It is preferable to partially thermally decompose the thermoplastic resin in the resin film. This thermal decomposition improves the adhesion between the aluminum alloy and the resin film. The molten state holding time is more preferably 1.8 seconds or more.

For example, when polybutylene terephthalate is used as the resin, by holding the molten state for at least 1.5 seconds after coating, the polybutylene terephthalate partially thermally decomposes as in the following formula (I) to form a carboxyl group. I do. The carboxyl group coordinates or forms a bond with an active site on the surface of the aluminum alloy, thereby improving the adhesion between the resin and the aluminum alloy. Although the molecular weight of the resin is reduced by the thermal decomposition, no adverse effect is usually observed due to the reduced molecular weight.

[0022]

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Cooling after application of the resin can be performed by air cooling or water cooling, or simply by leaving it in the air, and the cooling rate is not particularly limited, but rapid cooling by water cooling is preferable. The quenching makes the crystals amorphous and improves the adhesion.

(D) Heat treatment step Next, the aluminum alloy having the resin film formed thereon is subjected to a heat treatment. In this manufacturing method, a resin-coated member having high adhesion of the resin film can be obtained by the above steps (A) to (C), so that heat treatment can be performed.

The heat treatment may be performed at 150 to 250 ° C. for 1 to 24 hours. If the heat treatment temperature is lower than 150 ° C., it takes too much time, and if it exceeds 250 ° C., it becomes difficult to control aging. The heat treatment temperature is preferably from 160 to 240 ° C. The time of the heat treatment may be appropriately selected according to the temperature, but is usually 1 to 10
Preferably, it is time. If it is less than 1 hour, the effect of the heat treatment cannot be obtained, and if it exceeds 10 hours, the productivity is reduced.

The heat treatment can be performed using the aging furnace of the present invention. In the case of the aging furnace shown in FIGS. 1 and 2, the heat treatment is performed by the hot air circulation device 2 for heat treatment. The heating means for heat treatment is not limited to this, and may be a direct heating electric furnace or the like.

(E) Resin Remelting Step Finally, the resin of the resin coating material formed on the surface of the aluminum alloy is remelted, and then cooled to obtain a resin-coated aluminum alloy member.

The re-melting treatment may be performed at 230 to 300 ° C. for about 0.1 to 300 seconds so that the temperature of the resin film surface exceeds the melting point for a moment. The heating temperature during remelting is particularly preferably 230 to 240 ° C. If the heating temperature is lower than 230 ° C., re-melting is difficult, and if it exceeds 240 ° C., aging tends to proceed. The time may be appropriately selected according to the heating temperature, but is preferably as short as possible from the viewpoint of maintaining the heat treatment characteristics of the aluminum alloy, and is usually preferably 0.1 to 10 seconds.

The resin remelting treatment is performed continuously with the heat treatment by using a hot air blowing mechanism or an infrared heating mechanism of the aging furnace of the present invention. With the aging treatment furnace of the present invention, the remelting treatment can be performed by heating only the resin temperature to the melting point or more while keeping the temperature of the aluminum alloy below the overaging condition.

Heat treatment at 180 ° C.
When the re-melting treatment is carried out at a temperature of 0 ° C., it is preferable to raise the temperature of the resin to a desired re-melting treatment temperature in about 0.1 to 10 seconds after the heat treatment and to re-melt the resin.

When a hot air blowing mechanism is used, the temperature of the hot air to be blown may be appropriately selected according to the size of the resin-coated aluminum alloy member. As mentioned above, 0.1-10
To raise the temperature from 180 ° C to 230-240 ° C in about seconds,
Usually, the temperature of the hot air is preferably set to 260 to 450 ° C. On the other hand, when an infrared heating mechanism is used, its wavelength range and output may be appropriately selected according to the size of the resin-coated aluminum alloy member and the material of the resin coating.

The cooling after the remelting treatment can be performed by air cooling or water cooling, or simply by leaving it in the air, and the cooling rate is not particularly limited, but rapid cooling by water cooling is preferable. By quenching, the resin becomes amorphous and elongation and toughness can be imparted.

[0033]

As described in detail above, by using the aging furnace of the present invention, it becomes possible to perform heat treatment and resin remelting treatment on the resin-coated aluminum alloy member without dulling the aluminum alloy.

[Brief description of the drawings]

FIG. 1 is a schematic view showing an example of an aging furnace of the present invention having a hot air blowing mechanism.

FIG. 2 is a schematic view showing an example of an aging furnace of the present invention having an infrared heating mechanism.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Furnace part 2 ... Hot air circulating apparatus for heat treatment 31 ... Hot air blowing mechanism 32 ... Infrared heating mechanism 4 ... Carrier 5 ... Resin-coated aluminum alloy member 6 ... Carry in exit

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) C21D 1/34 C21D 1/34 JS // C22F 1/00 612 C22F 1/00 612 613 613 613 624 624 683 683 692 692A 692B 694 694B F27D 7/04 F27D 7/04 (72) Inventor Masataka Kumada 1-4-1, Chuo, Wako-shi, Saitama F-term in Honda R & D Co., Ltd. BB95Z CA03 CA13 DA13 DB07 DC01 DC13 EB13 EB14 EB17 EB18 EB22 EB35 EB39 4F042 AA02 DA09 DB03 DB09 DB10 DB18 DB25 DC01 4K063 AA05 BA03 CA03 DA13

Claims (2)

[Claims] 1. Aging for a resin-coated aluminum alloy member, which is used when a heat-treating process and a resin re-melting process are continuously performed on the resin-coated aluminum alloy member, and which is provided with a hot air blowing mechanism or an infrared heating mechanism. Processing furnace. 2. The aging treatment furnace according to claim 1, wherein
(A) a forming step of hot-extrusion forming a heat-treated aluminum alloy at 350 to 530 ° C, (B) a cooling step of cooling the formed aluminum alloy to a surface temperature of 240 to 340 ° C within 900 seconds in the atmosphere, C) a resin coating step of applying a resin on the surface of the aluminum alloy and cooling to form a resin film;
(D) a heat treatment step of heat-treating the aluminum alloy having a resin film formed thereon, and (E) a resin re-melting treatment of the resin in the resin film, and a resin re-melting step of cooling, which is used in a manufacturing method including: Aging furnace for resin-coated aluminum alloy members.