KR101315533B1 - Surface treated aluminium alloy material and bonded body using thereof - Google Patents

Abstract

An object of the present invention is an aluminum alloy material provided for bonding with an adhesive, and even if the adhesive layer deteriorates over time, the interface peeling hardly occurs on the surface of the adhesive layer and the aluminum alloy material. It is to provide an excellent surface treatment aluminum alloy material.
The surface treatment aluminum alloy material of this invention has a titania phosphate type | system | group film containing a titania phosphate compound or its condensate on at least one surface of an aluminum alloy base material.

Description

SURFACE TREATED ALUMINIUM ALLOY MATERIAL AND BONDED BODY USING THEREOF}

The present invention relates to a surface-treated aluminum alloy material having excellent adhesion durability and a bonded body to which the alloy material is bonded through an adhesive.

DESCRIPTION OF RELATED ART Conventionally, various aluminum alloy materials are used as a member of transporters, such as an automobile, a ship, and an aircraft, according to each characteristic for every alloy. In particular, in consideration of recent global environmental problems such as CO ₂ emissions, it is required to improve fuel efficiency by lightening the member, and the specific gravity is about one third of iron, and the use of an aluminum alloy material having excellent energy absorption is It is increasing.

For example, Mg containing aluminum alloys, such as an Al-Mg type alloy of JIS5000 type | system | group and the Al-Mg-Si type | system | group alloy of JIS 6000 type | system | group, are mentioned as an aluminum alloy material used as an automotive member. As the joining method of these aluminum alloy materials, there is an adhesion by welding or an adhesive, and as compared with the welding joined by a point or a line, the adhesive to join the whole surface becomes higher in bonding strength, which is advantageous in terms of collision safety. Cases joined using an adhesive are increasing.

On the other hand, in an aluminum alloy automotive member bonded with an adhesive, moisture, oxygen, or salt enters the joint portion during use, so that the interface between the adhesive and the aluminum alloy material deteriorates over time, resulting in interfacial peeling, resulting in a decrease in adhesive strength. There was problem to be.

As a method for improving the adhesion durability of an aluminum alloy automotive member having an adhesive layer, an oxide film which is present near the surface of an aluminum alloy material and causes adhesion failure is removed beforehand by pickling or the like before applying the adhesive. The method, the method of making the surface of an aluminum alloy material anodize, and the surface form which brings about an anchor effect, etc. are generally known among those skilled in the art (for example, patent document 1).

However, only the method of removing the oxide film beforehand improves the initial adhesive strength, but the deterioration of the adhesive layer progresses during use, and moisture or the like may penetrate into the base of the aluminum alloy material. Interfacial peeling may occur and adhesive strength may fall. In addition, in the method of controlling the surface form by the anodic oxidation method, it is necessary to form a thick film having a controlled surface form in order to sufficiently improve the durability, thus requiring a long time for the formation of the film, resulting in poor production efficiency. there was.

Japanese Patent Application Laid-open No. Hei 5-070741

The present invention has been made in view of the above circumstances, and the present inventors are an aluminum alloy material provided for bonding by an adhesive, and even if the adhesive layer deteriorates over time, the interface peeling on the surface of the adhesive layer and the aluminum alloy material hardly occurs. Therefore, the subject was providing the surface-treated aluminum alloy material excellent in adhesive durability which adhesive strength does not fall easily.

The surface-treated aluminum alloy material of this invention which could solve the said subject is characterized by having the titania phosphate type | system | group film containing a titania phosphate compound or its condensate on at least one surface of an aluminum alloy base material.

In the present invention, the titania phosphate compound is Ti (OH) _x (PO ₄ ) _y (HPO ₄ ) _z (H ₂ PO ₄ ) _l (OR) _m (R is an alkyl group having 1 to 4 carbon atoms, x = 1 , 2, 3, y = 0, 1, 2, 3, 4, z = 0, 1, 2, 3, 4, l = 0, 1, 2, 3, 4 and m = 0, 1, 2, 3 Satisfies x + 3y + 2z + l + m = 4, except that y + z + 1 is necessarily 1 or more).

Further, on the titania phosphate-based film, an adhesive layer is further provided, or titanium tetrachloride is mixed with water and / or an alcohol having 1 to 4 carbon atoms, and then mixed with phosphoric acid to prepare a titania phosphate having a pH of 5.0 or less. It is preferable embodiment that the said titania phosphate film is formed using a compound aqueous solution.

In the present invention, the surface-treated aluminum alloy materials are joined to each other such that the titania phosphate coating films are opposed to each other via an adhesive layer, and the automobile member includes the joined body. do.

Since the surface-treated aluminum alloy material of the present invention has a titania phosphate coating on at least one surface of the aluminum alloy base material, the amount of surface hydration can be reduced. As a result, even if this surface-treated aluminum alloy material is bonded by an adhesive agent, the interface peeling becomes unlikely to occur between the adhesive layer and the titania phosphate coating film, and thus an aluminum alloy automobile member excellent in adhesive strength can be obtained.

BRIEF DESCRIPTION OF THE DRAWINGS The figure which shows the correlation of cohesion failure rate and surface hydration amount.

The surface-treated aluminum alloy material of the present invention has a titania phosphate-based film containing a titania phosphate compound or a condensate thereof (hereinafter sometimes referred to as "titania phosphate compounds") on at least one surface of an aluminum alloy base material. It features. EMBODIMENT OF THE INVENTION Hereinafter, the surface treatment aluminum alloy material of this invention is demonstrated in detail.

(Aluminum alloy base material)

The kind of aluminum alloy base material used by this invention is not specifically limited, For example, pure aluminum of JIS 1000 type | system | group, Al-Mn type alloy of JIS 3000 type, Al-Mg type alloy of JIS 5000 type , Al-Mg-Si alloy of JIS 6000 system, etc. are mentioned. In particular, when using the surface-treated aluminum alloy material of the present invention as an automobile member, Mg-containing aluminum alloy base materials such as Al-Mg alloys of JIS 5000 series and Al-Mg-Si alloys of JIS 6000 series are used. It is preferable to use. Although the thickness of an aluminum alloy base material is not specifically limited, When using for the said use, 0.1 mm or more (more preferably, 0.2 mm or more) is preferable, 3.0 mm or less (more preferably, 2.0 mm or less, Furthermore, Preferably it is 1.5 mm or less).

(Titania phosphate coating)

The surface-treated aluminum alloy material of the present invention is characterized in that a titania phosphate coating is formed on the surface of an aluminum alloy base material. Although it is not clear about the detail of the mechanism which improves the adhesion durability of the surface treatment aluminum alloy material obtained by having a titania phosphate coating film on the aluminum alloy base material surface, it guesses as follows. That is, according to the test mentioned later, as the surface-treated aluminum alloy material became less hydrated, it was found that the cohesive failure rate (non-interfacial peeling rate) of the joined body to which the surface-treated aluminum alloy material was bonded through an adhesive agent increased. (FIG. 1). From this, it is inferred that the titania phosphate coating suppressed the hydration of the surface of the aluminum alloy base material and prevented the hydrolysis of the adhesive agent at the interface.

The titania phosphate-based coating may be formed of any titania phosphate compounds as long as it can suppress hydration of the surface-treated aluminum alloy material, but from the viewpoint of availability and handleability, Ti (OH) _x (PO ₄ ) _y (HPO ₄ ) _z (H ₂ PO ₄ ) _l (OR) _m (R is an alkyl group having 1 to 4 carbon atoms, x = 1, 2, 3, y = 0, 1, 2, 3, 4, z = 0, 1, 2, 3, 4, l = 0, 1, 2, 3, 4 and m = 0, 1, 2, 3, satisfying x + 3 y + 2 z + 1 + m = 4. However, y + z + l is necessarily at least 1) It is preferable to form using.

As such titania phosphate compounds, for example, Ti (OH) (H ₂ PO ₄ ) ₂ (OR), Ti (OH) (PO ₄ ), Ti (OH) ₂ (H ₂ PO ₄ ) (OR), Ti (OH) (HPO ₄ ) (OR), Ti (OH) (HPO ₄ ) (H ₂ PO ₄ ), Ti (OH) ₂ (H ₂ PO ₄ ) ₂ , Ti (OH) ₃ (H ₂ PO ₄ ) Etc. can be mentioned.

Titanium phosphate compounds can be prepared, for example, by the production method described in Japanese Patent No. 3829640. Specifically, titanium tetrachloride is first mixed with water and / or alcohol. Examples of the alcohol include methanol, ethanol, propanol, butanol and the like. When using the mixed solution of water and alcohol, it is preferable that 30% or more (more preferably, 40% or more) of water is contained by volume ratio, and 70% or less (more preferably, 60% or less) It is preferable that it is included. The amount of titanium tetrachloride added is preferably 0.01 parts or more (more preferably, 5 parts or more), and 30 parts or less (more preferably 20 parts or less) with respect to 100 parts of water and / or alcohol by volume ratio. It is preferable. The mixing temperature of titanium tetrachloride, water, and / or alcohol is not particularly limited, and may be 5 to 35 ° C. It is preferable to perform the said mixing until the pH of the liquid mixture obtained becomes about 1.

Next, phosphoric acid is mixed with the obtained liquid mixture to obtain titania phosphate compounds. Moreover, it is preferable to dilute the said mixed liquid in 10 times-500 times the range with solvents, such as water and alcohol, before mixing phosphoric acid. If the dilution ratio is less than 10 times, even if only a small amount of phosphoric acid is added, the resulting titania phosphate compounds may become cloudy and the film hardness of the titania phosphate-based coating film formed using this may be lowered, resulting in peeling or dropping out. For this reason, it is necessary to filter or precipitate the mixed liquid after phosphoric acid addition, and to use a supernatant liquid, and a manufacturing process increases. The dilution ratio is preferably 20 times or more, and more preferably 200 times or less (more preferably 100 times or less). As for the addition amount of phosphoric acid, 3 parts or more are preferable with respect to 100 parts of said mixed liquid (before dilution) by volume ratio, and 500 parts or less (more preferably, 450 parts or less) are preferable. It is preferable to mix phosphoric acid until the pH of the liquid mixture obtained becomes 4 or less (more preferably, 3 or less). When pH of a liquid mixture exceeds 4, unreacted phosphoric acid may remain.

The content rate of the titania phosphate compounds in the titania phosphate coating of the present invention is not particularly limited as long as the hydration of the surface of the aluminum alloy substrate can be suppressed, but is preferably 90 mass% or more (more preferably, 95 mass% or more). It is most preferable to consist only of titania phosphate compounds.

The formation method of the titania phosphate coating on the aluminum alloy substrate is not particularly limited, and the method of spraying or applying the mixture or dilution thereof obtained by mixing phosphoric acid to the surface of the aluminum alloy substrate or the aluminum alloy in the mixture The method of immersing a base material is mentioned.

Moreover, when using the dilution liquid of the said liquid mixture obtained by mixing phosphoric acid, it is preferable that pH of the said dilution liquid is 5.0 or less (more preferably, 4.5 or less). When pH of a dilution liquid exceeds 5.0, the hydration of the surface of an aluminum alloy base material may not be fully suppressed.

(Adhesive layer)

The surface-treated aluminum alloy material of the present invention may further have an adhesive layer on the titania phosphate coating.

It does not specifically limit as an adhesive agent which comprises this adhesive bond layer, The adhesive agent conventionally used when joining an aluminum alloy material can be used. For example, a thermosetting epoxy resin, an acrylic resin, a urethane resin, etc. are mentioned. 10 micrometers or more (more preferably, 50 micrometers or more) are preferable, and, as for the film thickness of an adhesive bond layer, 500 micrometers or less (more preferably, 200 micrometers or less) are preferable. When the film thickness of an adhesive bond layer is less than 10 micrometers, a surface-treated aluminum alloy material may not be joined by another surface-treated aluminum alloy material with high adhesive durability through an adhesive bond layer. When the film thickness of an adhesive bond layer exceeds 500 micrometers, cohesion failure strength may become small.

The method for forming the adhesive layer is not particularly limited. For example, when the adhesive component is a solid, it is dissolved in a solvent to form a solution, and in the case of a liquid, sprayed onto the titania-phosphate coating in this state. Or a coating method.

(Bonded body)

This invention also includes the bonded body obtained using the said surface treatment aluminum alloy material. For example, the bonded body which bonded another aluminum alloy material (it does not have a titania phosphate film on the surface) to the surface-treated aluminum alloy material which has an adhesive bond layer on a titania phosphate film, and the said surface treatment The joined body which joined together aluminum alloy materials so that mutual titania phosphate coating films may face each other via an adhesive bond layer is mentioned. Moreover, in order to prevent the interface peeling by age-deterioration, the latter joined body is preferable.

Since the hydration of the surface of an aluminum alloy base material is suppressed by the titania phosphate film | membrane in the joined body of this invention, interface peeling hardly arises even by age-degradation of an adhesive bond layer. For this reason, the joined body of this invention can be used suitably as a member of the conveyer of automobiles, ships, aircraft, etc. which the conventional joined body of aluminum alloy material was used.

[Example]

Hereinafter, the present invention will be described in detail based on examples. However, the following Examples do not limit the present invention, and all modifications are made within the technical scope of the present invention without departing from the spirit of the above and later.

First, the test method used by the experiment example is demonstrated below.

(Measurement Method of Surface Hydration)

The surface hydration amount of the produced surface-treated aluminum alloy material was measured on condition of the following. In addition, the measurement of the amount of hydration is stored after the surface-treated aluminum alloy material is produced without being exposed to the wet state, and within 2 hours after the production, and the surface-treated aluminum alloy material produced is wetted at 50 ° C. and 95 RH%. It carried out about the thing after leaving for seven days in atmosphere.

Device: Nikore Magna-750 FT-IR Spectrometer

Attachment: External Reflective Attachment

Measurement conditions: nitrogen purge, parallel deflection, angle of incidence 75 degrees, resolution 8 kaiser, integration count 1000 times

Analysis: Use the analysis software that comes with the device. After baseline correction, the absorption peak area of the hydroxyl group having a peak near 3400 Kaiser was determined.

(Coagulation rate)

The edge length of two surface-treated aluminum alloy materials (test piece; width 25mm) having the same configuration is 13 mm of lap length (adhesion) through a thermosetting epoxy resin-based adhesive (manufactured by Sunstar Corp., Penguin Cement # 1086). Area: 25 mm x 13 mm = 325 mm <2>) so that it might overlap. In addition, a small amount of glass beads (particle size: 150 µm) was added to the adhesive so as to have a thickness of the adhesive layer of 150 µm, and adjusted. After overlapping, it was dried at room temperature for 30 minutes, and then heated at 170 ° C. for 20 minutes to cure the adhesive. Then, it left still at room temperature for 24 hours and produced the adhesion test body.

After holding the obtained adhesive test body for 10 days in 50 degreeC and 95% RH wet atmosphere, it pulls by the tensile tester at the speed | rate of 50 mm / min, and based on the following formula, the cohesive failure of the adhesive bond layer of an adhesive part is carried out. The rate (non-interface peel rate) was calculated | required. In addition, in each test condition, three adhesion test bodies were produced, and the aggregation failure rate was made into three average values.

Cohesive Fracture Rate (%) = 100-{(Adhesion Area of Test Piece A / Adhesion Area of Test Piece A) × 100} + {(Adhesion Area of Test Piece B / Adhesion Area of Test Piece B) × 100}

(One side of the adhesive test body is called specimen A and the other side is specimen B)

(First to Fourth Experimental Examples)

<Production of aluminum alloy base material>

The alloy piece of length 100mm x width 25mm was cut out from the aluminum alloy cold-rolled sheet of 6022 standard of JIS 6000 type of plate thickness 1.0mm. Subsequently, the alloy piece was immersed in hexane, the oil content which remained on the surface of the alloy piece was removed, and the aluminum alloy base material was produced.

<Preparation of aqueous solution of phosphate titania compound>

To a mixture of 25 ml of isopropyl alcohol and 25 ml of purified water, 5 ml of titanium tetrachloride was mixed with stirring, and then diluted 100 times with purified water. 5 ml of 85 mass% phosphoric acid aqueous solution was added to this, and the aqueous phosphoric acid titania compound solution was prepared. The obtained titania phosphate compound is estimated to be Ti (OH) _x (PO ₄ ) _y (HPO ₄ ) _z (H ₂ PO ₄ ) ₁ (OCH (CH ₃ ) ₂ ) _m or a condensed composition.

Since the prepared aqueous phosphoric acid titania compound solution was cloudy, the supernatant liquid which had become standing and transparent was taken out by decantation, and it was set as the aqueous phosphoric acid titania compound solution. Then, ion-exchange water was added to the obtained aqueous solution, and the aqueous solution diluted 10 times, 100 times, and 1000 times was prepared.

<Production of surface treated aluminum alloy material>

The aluminum alloy base material was immersed for 20 second in each said aqueous solution hold | maintained at 60 degreeC. After immersion, it was washed with ion-exchanged water and dried at room temperature to obtain a surface-treated aluminum alloy material whose surface of the aluminum alloy substrate was coated with a titania phosphate coating.

Table 1 shows the results of the surface hydration amount and the cohesive failure rate of the obtained surface-treated aluminum alloy material.

(5th to 6th experimental example)

Instead of the surface-treated aluminum alloy material used in the first to fourth experimental examples, the aluminum alloy base material was used (the fifth experimental example), or nitrate pickling was applied to the aluminum alloy base material to remove the oxide film on the surface. Except having used the film removal aluminum alloy base material (6th experiment example), it carried out similarly to the 1st experiment example, and measured the surface hydration amount and the cohesion failure rate. The results are shown in Table 1.

From the comparison of the first to fourth experimental examples and the fifth experimental example, the surface-treated aluminum alloy material (first to fourth experimental examples) having a titania phosphate coating on its surface is an aluminum alloy material (fifth) that does not have the coating. As a result of the higher cohesive failure rate compared to Experimental Example, it was found that the adhesion durability was excellent. In addition, from the comparison of the first to fourth experimental examples and the sixth experimental example, the surface-treated aluminum composite material of the present application does not pickle its surface before forming the adhesive layer (first to fourth experimental examples), but the pickled aluminum alloy It turned out that it is equivalent to the ash (6th experiment example), or has the outstanding adhesive durability.

Claims (6)

On at least one side of the aluminum alloy base material,
A titania phosphate coating comprising a titania phosphate compound or a condensate thereof, wherein the titania phosphate coating is formed on a surface of the aluminum alloy substrate,
The surface treatment aluminum alloy material characterized by further having an adhesive bond layer on the said titania phosphate type film. The titania phosphate compound of claim 1, wherein Ti (OH) _x (PO ₄ ) _y (HPO ₄ ) _z (H ₂ PO ₄ ) _l (OR) _m (R is an alkyl group having 1 to 4 carbon atoms, x = 1, 2, 3, y = 0, 1, 2, 3, 4, z = 0, 1, 2, 3, 4, l = 0, 1, 2, 3, 4 and m = 0, 1, 2, 3. It satisfy | fills x + 3y + 2z + l + m = 4, but y + z + l is necessarily 1 or more), The surface-treated aluminum alloy material. delete 3. The titania phosphate coating film according to claim 1 or 2, wherein the titania phosphate coating is prepared by mixing titanium tetrachloride with one or more of water and an alcohol having 1 to 4 carbon atoms, followed by mixing with phosphoric acid again, and having a pH of 5.0 or less. The surface-treated aluminum alloy material formed using the compound aqueous solution. The surface-treated aluminum alloy materials according to claim 1 or 2 are bonded to each other so that the titania phosphate coating films face each other via an adhesive layer. The joint body of Claim 5 is provided, The automobile member characterized by the above-mentioned.

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